AltME groups: search

This is a bit funny:

>> y: 'x
== x
>> type? y
== word!
>> type? :y
== word!
>> y: to-lit-word 'x
== 'x
>> type? y
== word!
>> type? :y
== lit-word!


So variables can hold lit-words. When we use the variable normally, 
it's content is seen as a word. But if we use the get-word notation 
(:y) we get the 'real' value.

It's worth notice, there is a difference in how words are evaluated 
and how numbers are. At first they seem to behave the same:

>> 1 = 1.0
== true
>> 1 == 1.0
== false
>> (to-word 'x) = (to-lit-word 'x)
== true
>> (to-word 'x) == (to-lit-word 'x)
== false

But using variables, you have to be a bit careful:

>> a: 1
== 1
>> b: 1.0
== 1.0
>> a == b
== false
>> x: 'x
== x
>> y: to-lit-word 'x
== 'x
>> x == y
== true
>> :x == :y
== false

The thing is, both integers and decimals are sub-types of the number! 
datatype, and you can't have a variable of type number!. A word! 
datatype is sort of more general than a lit-word, so my compare above 
is mis-leading (can be seen as mis-leading). If you compare lit-words 
with set-words, they behave more like integers and decimals:

>> x: to-lit-word 'x
== 'x
>> y: to-set-word 'x
== x:
>> x = y
== true
>> x == y
== false

i don't think lit-words are word-active anymore, since a long time 
:)

mmm, weird, they still are. i'm tempted to call this a bug but i 
guess Carl has a good reason for this.

Fork, i will explain this to you, if you can explain me why you need 
to have a lit-word inside the switch block.

A couple of these solutions seem pretty close, e.g. assignments to 
the variable with first ['x] or with to-lit-word "x" will make it 
hold the proper value so that it matches

The only missing piece is how do I get from a variable that has already 
been assigned with 'x to the above possibilities

How I came about this is that I was writing a REBOL script that would 
dump out a file of function definitions for all the builtins.  I 
made some symbol browsing rules for a code editor that would pick 
up on function and variable definitions and let me jump around the 
code easily.  So I was using a lot of function names very literally, 
and in fact, as conditions of switch statements.  e.g. switch commandname 
[usage [print "Usage"]]

I knew I could go commandname: 'usage and then later switch commandname 
[usage [print "Usage"]]. But  I was looking for a symmetry and was 
working on quoteswitch commandname ['usage [print "Usage"]] .  I 
could not figure out how to write quoteswitch without the above ability.

Note: f(y) that I sought seems to work as " to-lit-word to-string 
y", hence z is superfluous.  I'm still wondering if there's a better 
f(y)...

e.g. if z is a lit-word of value 'x  ... then ? z says just x ... 
but :z says 'x

When evaluate a z that is assigned a lit-word! value, it will return 
the lit-word! value. If you evaluate 'z, which is a lit-word! literal 
value, it would return z, the word value.

Er, I meant just a reference to z and not ? z, sorry.

(Quick question, I'm new to altme... how do I type in a multiple 
lines without submitting the message?)

I wonder if  this is a bug or a feature?  e.g. is there a fundamental 
part of REBOL depending on this behavior in order to make certain 
evaluations work...

I already did a review for other word-active values in a lot of the 
mezzanines. I just have to check for lit-word! values too. Fortunately 
lit-word! values assigned to variables are _really_ rare. Most people 
use word! values, just using lit-words literally.

That feature you mention is the word-active feature. It's also what 
causes functions to be evaluated. It's sort of like putting a function 
reference in the first position of the list in Scheme rather than 
the other positions.

about "word-active" values: i'm not sure lit-word! being word-active 
is useful, but i'm sure Carl has a good reason for that. it's a good 
thing to always use :x instead of x when you want to get the value 
as opposed to evaluate the word (they are the same in most cases 
except a few types, especially any-function! types and, as you have 
seen, lit-word!)

One of the first errors I encountered while trying to run an installer 
that was built in REBOL was that a state machine driven by a variable 
was failing to match a case and falling through to a default, due 
to a spurious linefeed on one of the cases that was read in.  It 
was attempting to match foo, but had foo^/ ... and so it fell through 
to the wrong case.  So I have been tinkering with a checked enum 
for REBOL.

Oops, deleted some spurious code and that made a typo, will make 
a better version that prints section headers for the tests...

A small tip:
	for index 1 (length? cases) 1 [
is usually better as:
	repeat index length? cases [

Fork, perhaps you can show us the original (approximate) example 
from your installer state machine, with a few example inputs and 
expected results. Then we can see what started all this :)

Here is a better documented version:

Ok, that explains the enum object well. However, it looks like a 
waste of time to me ! (sorry) but I haven't felt I needed this in 
rebol for many years !

This specific case came up when I tried to install a large, professional 
grade REBOL system written by people who are as I understand it very 
good at REBOL

So it was getting a CGI variable in an HTTP post

A bug in the cgi system left a trailing newline on the nextstep variable

It validates on all sides, it protects against programmer error in 
the usage as well as things like this where the data source or function 
has a problem.

I do like REBOL from what I've seen so far!  But I saw somewhere 
that it was being compared to modeling clay... it's a paradigm shift 
for people who are used to systems that do a lot of global analysis 
of your program before it runs the first line of code to catch basic 
errors.

I get the feeling that I'm going to want to have an analysis tool 
which will read through the functions, find any variable: assignments, 
and ensure they're in the local list unless there's some sort of 
indication they should be global.  Because it seems relatively uncommon 
that I would, inside a function, set things in the global space. 
 I'd be happy to use something wordier (set?) for that

I recommend FUNC over FUNCTION because having "/local" written makes 
it clearer and explicit what the locals are, and is shorter when 
there are no locals. Compare:

When there are no locals, func wins, because less characters to type.
	func []
	function [][]

When there are locals, same number of characters written, but func 
more clearly specifies the locals.
	func [/local]
	function [][]

Additionally, when you are modifying your func spec back and forth 
so that there is a need, or no longer a need, for locals, then func 
wins by less typing needed.

Hm, well, it's not a tremendous deal but I feel like always being 
forced to remember typing in that second group would remind me that 
I need to think about what goes in it

Is there a way to set things locally in a do block?

Or do you have to do a nameless function to get a local context?

I go without such a tool for analysing function local variable consistency, 
which, I think, turns out to be a difficult problem to solve. Some 
people have written alternative function creators which somehow make 
set-words into locals by default (Ladislav ? with his lfunc ?) or 
something like that. I just maintain a strict habit of checking for 
accidental globals. It's good to review your use of variables regularly 
anyway, and be aware of what context they're bound to.

I see... context looks like a good thing, great!

When I do something like a for loop and I specify a name for the 
loop variable, is that defined globally by default or locally?

so no need for a local at all.

Loop functions set words local, in a temporary context. You can test 
whether loop functions set words global or not quite easily:

Is there a way to get the native-switch that is better than how I've 
done it?

A-ha... nice.  Now here's something... can I make it so that my test-block 
runs the code in its body in a local context?

Because, by not specifying any use locals, you are making a context 
without any local words in it.

Now that one I got from a sample on the web.  :)  http://www.rebol.org/cgi-bin/cgiwrap/rebol/view-script.r?script=timeblk.r

do context[do :block] ... that would give it a new context and run 
it there.  What kind of thing would that break?

Hmmm.  Ok, so if I want to have local variables in a test-block the 
context declaration would need to live there?  That is different?

Well, I have one test block after another in a line

So I was wondering if I could let the concept of each test-block 
being a scope come from test-block itself

It appears that REBOL is just more free about this by default.  You 
make a context for a whole bunch of code, the words bind freely, 
and then you blow it all away on the context level.

I'm an EE, so my biases are going to be a certain way.  In fact, 
I try to bring that need for structure and formalism to things that 
are typically thought of as unimportant for having them, e.g. GUI 
code.

I worry, for instance, about the semantics of if your app starts 
drawing on MOUSE_DOWN and then keeps processing MOUSE_MOVE as if 
you are drawing until you get a MOUSE_UP... but then your app loses 
focus while the mouse is down (for instance, due to a window popping 
up or maybe the user hit alt-tab).  So the app gets lost, or information 
gets lost, or whatever

If you mean the mouse thing, I have a blog article / screencast about 
it

I like this quote: "Some facets of usability (
such as cancellation, 
undo, progress bars, and others) 
require software architecture support 
 .
Because they reach so deeply into the architecture of a system,
these 
facets must be built into the system from its inception 
rather than 
added after an initial system design
and user interface has been 
achieved."

Glad you like it... I just think it would be nice to see more things 
like that.  I don't know that I think this particular issue is super 
high priority, it just represents a more rigorous way of thinking 
about such problems.  My article on undo/redo tied to single user 
events is actually probably something I care more about, but it's 
another thing that people don't take as seriously as I... http://hostilefork.com/2007/11/25/undo-single-user-event/

Thanks again.  Well, I decided the best thing I could do was to show 
the ideas as I haven't really been writing software for a few years

Well, back to REBOL/Core :) I do feel that it's nice to find ways 
in which it can be applied more formally.  Maybe you can't validate 
the *process* by which a REBOL program achieves a result, but you 
can validate the *product* of its processes and check them for validity. 
 I think I would consider it that way, in that I would write tools 
to do all kinds of massive things in REBOL but then very carefully 
write an output-checker in another language.

Parenthesis are good for readability, but you should know, that they're 
not necessary in many cases.
repeat index (length? cases) [
can be written:
repeat index length? cases [

Again it's a tiny issue, but it's good to know, if you wanna become 
a shark in REBOL coding.

It's good work, you've pulled! And a fine idea with an enum! type 
implemented as an object. A good way to get a feeling about context 
and functions in REBOL.

You talked about locals. If you have a function with locals and no 
parameters, you can also use HAS:
f: has [v] [v: 1 + 2]

As one who has been pushing for better PitL tools for REBOL, I hear 
you Fork. When I found REBOL, a lot of the initial things I did were 
to replace stuff from lanugages I was used to, that were "missing" 
in REBOL. There are still holes, and each of us will have different 
ones, but I eventually found that REBOL's way is not bad or wrong, 
just different. It takes a very different mindset to work effectively 
in REBOL. And use can use its power and flexibility to create a mess 
as easily (or more) as to create a beautiful and elegant solution.

For me, a breakthrough came not when I realized code was data and 
data was code, but (in my mind) that *everything* is data, and sometimes 
it gets evaluated. This can give rise to a view that things like 
mistyping "banana" aren't syntax errors, as you would view them in 
other langs, but "unexpected data". And if you think that way, in 
the enum case, how would you write code to deal with that. Not just 
at the local level of a /default handler for switch, but for propagating 
that information all the way up to the caller and user.

Another question I still struggle with is how forgiving and flexible 
to be. On the one hand, it's nice when you can accept a variety of 
input forms. On the other hand, where do you draw the line, and how 
to you write "soft" specs. At some point you still need to be able 
to make sense of the input and do the right thing with it.

Thanks Geomol!   I like these variations for function definitions 
(does, has, func) but the thing about the way I work is that I'm 
not particularly fond of having to change the structure of the program 
just because I've added a local or a parameter, or taken a local 
or parameter away.  To me the conceptual act of removing a parameter 
should be as simple as going to where the parameter is defined and 
deleting it, without having to worry about converting the container.

I did note a philosophical difference in REBOL where reducing the 
# of characters affects the performance characteristics... so using 
a shorter name for a variable or not using parens is going to be 
faster code by some measure... given my other biases, of course, 
I'd prefer anything that can help stop errors.

Hi Gregg... yes it is a somewhat fundamental truism that code and 
data are one in the computer's own mind.  But separating this out 
and re-designing the computer to put them separate has shown benefit, 
even if it makes the model less simple.  For instance, chips where 
they actually have separate memory stores for code and data, which 
helps protect against things like buffer overflow exploits...!

Is it considered good practice to treat "none" as a false in a conditional 
expression?  I find that a little confusing, e.g. either find list 
value [truecondition] [falsecondition] ... what if "false" is an 
element in the list?

Ah, I see find returns a series, not a word.  Got it.

A ha

Is there a version of probe that prints the type also?

Oh my.  Well, I think I'd rather define a "safe" if that only accepts 
true/false if there isn't such a thing

Btw, " favorite_fruit/set-value 'banana " doesn't look very rebolish 
to me...IMHO, REBOL way would be more like : " set-enum favorite_fruit 
'banana ". When you MAKE an object! in REBOL, all its functions are 
duplicated, so keeping the functions inside an object! and using 
it as in a class/instances model ends up eating a lot of memory. 
That's why the more "rebolish" way, where the code is out of the 
objects, is the way to go if you deal with a lot of instances (which 
might be the case for a "class" like enum!).  Remember that REBOL 
objects are prototype-based, meaning that they are created by cloning, 
not by instantiating a class. R3 will maybe bring us true class! 
datatype or at least a clean way to implement it by ourselves.

It was a quick ping-pong up there, so I'm not sure, if you know the 
answer, but to find false in a series:

>> if find [false true] 'false [print "false is in the list"]
false is in the list

And you know, this isn't the value FALSE, it's just words.

because FALSE there is a word!, not  logic!.

Yes, it's still a word! and not a logic!, even if you reduce it.

So what turns it into a logic, if not reduce?

I'm confused as to why reduce, which seems to perform other evaluations, 
would not (in R2) turn false into a logic!... Henrik, you are saying 
it does?

It's often works, if you turn stuff into a string and then load that. 
Other ways to turn stuff into strings:

>> load mold 'false
== false
>> load form 'false
== false

Not quite;    reduce 'false  is a word,  reduces as a word!     reduce 
[false]   reduces the block, evaluating false to the logic! false. 
  It's fun stuff.   ;)    mold/all  can be your friend exploring 
the ins and outs of evaluated values.

It seems like reduce is a core notion, and it would be nice to see 
a list mapping what conversions it performs.  Changing that between 
R2 and R3 seems rather... fundamental?

I'd suggest coming up with a new keyword, e.g. reduce3, if something 
like that were to change.

Fork, R3 is not meant to be compatible with R2, so that would not 
be likely to happen. If a function doesn't behave consistently, it 
will change. Just for the record. :-)

Ok, I appreciate the help... but I do wonder if there is a certain 
answer that Rebol 3 reduces words to logic

Nope;  words reduce as words.

Here is a good article by one of heroes;   http://en.wikibooks.org/wiki/REBOL_Programming/Advanced/Interpreter

In regards to what I said: "Im confused as to why reduce, which seems 
to perform other evaluations, would not (in R2) turn false into a 
logic!... Henrik, you are saying it does?"

Give Ladislav's article a read...it cleared up a lot for me, but 
I still can't explain it  :)

Fork, you also have a problem with your check, if 'false isn't in 
the series:

>> first find [true something-else] 'false

** Script Error: first expected series argument of type: series pair 
event money date object port time tuple any-function library struct 
...

Thanks for your help everyone, I will clean up enum a bit... read 
Ladislav's article, and look into the implementation of lfunc and 
a few other "critical" missing pieces from my point of view...

Yep.  Ladislav has a bunch of technical articles.  Good reading, 
but not for newbies; although maybe they should be.  :)

Well, an article that shows me how to "print 1 + 2" as a first example 
is the wrong angle of attack for teaching me (in particular) a new 
language.  I'm not at all troubled by C++ class libraries for sending 
email, drawing graphics, etc... so "syntax sugar" doesn't matter, 
my approaches are usually generative anyway.

I will write a blog article about REBOL and put enum in it and do 
a screencast

The weird part Henrik;  most rebols are talent.  Or they'd be C coders 
and rely on mickey soft visual studio products.  But I'll agree. 
 Superstar rebols can drag the rest us along quite nicely.  :)   
(Note I said rely on ... not dissing anyone that uses studio ... 
just dissing those that use it a crutch to pretend to program.)

The funny thing is that I find those IDEs to be a hindrance to do 
any real work. I wouldn't even know how to use them as a crutch. 
:-)

Well; you're not a pretend programmer then  :)   Henrik; to be honest, 
count yourself in the top ten, I do.

Fork,


does has func : "converting the container". This must be a first 
impression only, since each of those creates a function!

(See  ?? has  ?? does  ?? func)    This is a nice gradation of function 
specifications which saves keystrokes (and thus overall script size 
and complexity), by gradually increasing the options. So you only 
ever specify what you need to specify.


Using shorter words will not speed up rebol much, because they are 
converted at load time to symbols (which is just an integer, internally). 
However, the general aim is to shrink the program in order to make 
it more easily understandable. In mathematics, concepts have been 
reduced to single-letter symbols, and can thus be more easily manipulated 
in a single page. (Of course, I don't recommend using single-letter 
symbols in rebol, most of the time.)


You can share functions in an object by putting them in a "sub-object", 
eg.
	enum!: context [
		v: none    ; current value	
		access: context [
			get-enum: func [enum] ...
			set-enum: func [enum new-value] ...
		]
	]

Then:
	my-enum/access/set-enum my-enum 'new-value


The "sub-object" (access) will be shared amongst all enum! instances 
(unless you explicitly clone it when you make your enum! instances). 
(Cloning is done just using MAKE.)

if find [false true] 'false ...   

You will almost never have to do this (using true and false, that 
is). It usually boils down much simpler, you will happily discover.

Wow Anton, that sub-object thing definitely is a bit of a surprise. 
 I should probably get straight to reading Ladislav's article!

Each face has a "feel" object in it. These are the functions which 
define how events are processed by the face. When cloning a face, 
the feel is shared by default, so the feel functions code is shared.

Thanks for the example... I've not gotten into REBOL/View yet... 
I'm looking at REBOL used to power a website

Brian; Look to Cheyenne...  It's a showcase REBOL product.  Using 
its embed technology, in theory, a website with server can be a single 
REBOL script.  It's a Go Doc Go! example of where skilled REBOL really 
shines. 

http://softinnov.org/cheyenne.shtmlbut look to the !Cheyenne group 
here for  updates http://softinnov.org/tmp/cheyenne-r0918.zip


Just so ya know, I'm a real Go Doc Go! fan of Cheyenne.  Running 
on GNU/Linux ... webhosting from anywhere ... just nice.   Go Doc 
Go!   :)

Diss'ing IDE's might alienate some Smalltalk folk.  I cannot imagine 
maintaining an application suite such as I deal with everyday without 
an IDE.  I just wish it was not eclipse ...  Of course only wimps 
used a Disk Operating System and real men code in machine codes only 
... and real pro's dictated their SNOBOL punch cards to lovely assistants 
...  and ANT scripts are for sissies.  Some must have ridiculed Tcl, 
Expect and TK in their day ... but if my IDE can facilitate my efforts 
to systematically (key word there) shrirnk company''s codebase as 
it becomes more reliable with better test coverage then maybe a refactoring 
browser would be a good tool after all.  Even better if it is an 
integrated part of the IDE, as in Dolphin Smalltalk or Squeak Smalltalk 
or Smalltalk/X or Cincom Visual Smalltalk.  Not that I couldn't survive 
on grep and diff's.  But once the codebase is too large for any one 
person to author or maintain on their lonesome, a tool that remebers 
what you did last and where can be a god-send.  If you want to know 
hell without an IDE join an actuarial department working in APL. 
 There you don't even know if they have talent: you just hope most 
of it works as each quarter rolls around and try to survive year-end. 
 But you know they're smart, cuz after all, they're actuaries - and 
look at all that APL code in all those files ... of course a few 
of them look back wistfully at their student days in C with Borland's 
decent IDE.  REBOL [
    File: %vid-usage.r
    Date: 09-Jan-2004   
    Title: "VID Usage"
    Purpose: "VID Usage Tutorial with Runnable Examples"
    Version: 1.2.1
    Author: "Cybarite"
    Edits: RobertS
    Source: {
        Based on %easy-vid.r by Carl Sassenrath.

        Clips from various sites including email that are attributed in the 
        section
        }
    library: [
        level: 'intermediate
        platform: 'all
        type: [tutorial]
        domain: [gui]
        tested-under: [view 1.2.8.3.1 on W2K]
        support: none
        license: none
        see-also: none
    ]
]
 
flash "Fetching image..."
read-thru/to http://www.rebol.com/view/demos/palms.jpg%palms.jpg

read-thru/to http://www.rebol.com/graphics/reb-logo.gif%rebo-logo.gif
read-thru/to http://www.rebol.com/view/bay.jpg%bay.jpg
pic: %palms.jpg
unview

customer: make object! [  ; this sets a default customer object in 
case the user does not push the samples in order
        name: "Rosetta Stone"
        date-of-birth: 14-March-1959        
]

stylize/master [text-note: txt maroon bold]         ; this sets a 
default for users who run the samples out of order
; polished is an image that is embedded in this script file
; so that no outside files need to be loaded.
; This technique is used in many of the REBOL samples

polished: load #{      
89504E470D0A1A0A0000000D49484452000000670000003808020000006FFB71
8C0000001374455874536F667477617265005245424F4C2F566965778FD91678
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C44B92E17454A309F14F348DDD4D5B98195BB2AF6B7E4E545B57FEBAE0415DA0
43EFE62C70B196362285D74C35F0782ECF26A0FC8492E20EAAED6CC35ACE13FC
61646467C69D5715EA4F9D3725B1703BF45AB2768A9D5F59CA6E716E5A747CBF
23D6A7E418C2C53C6EB440FCE803B106E6D94C8AAF4B42694871B9FB237035C8
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03D4796E80532E986D273B71CEA8D81672739E0F1B329F8E999D0D9D04080769
CABC1D21260C2BB8E43D2A9D70BE3A2207D66EA09E5BCAFFB742F9F0A0C37677
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B782F5E9FDE4918360C9F666A6F61647F2EDB342A2FA3F6E9B0C8AC2699B9B3F
53847BB992B5707FDE5B6D721EA3EB55E3D8190D8BD998923A68917BE3FEDD32
EE1BDCA216275C1CCFBD0A07F35A40A6CC05A1357E6BF512D26DC470BAC927A3
B0078A42DD22E10000000049454E44AE426082
}
content: {VID Usage - REBOL Visual Interfaces


===Updates

--01-Apr-2008


* Fixed oddity with last item on stylesheets which was locking up 
some versions of VIEW

---09-Jan-2004

* Fixed slider initialize. 

* Focus section was not parsed out. --- fixed

* Fixed some text errors for the parsing of ===


---07-Jan-2004

* Revived vid-usage.r 

* added more examples from the script library

* manage source as vid-usage.leo an outliner file

---12-August-2001

Added supply examples. See:

!List/Supply

!List With Supplied Data

!Supply List With Scroll

---13-August-2001

!Add Subpanel example ported by Anton

===Caveats

---Work In Progress


This is a work in progress. Whether the progress will continue depends 
on the feedback.

---All Rights Reserved


The work is based on the documentation of REBOL View provided by 
REBOL Technology and its mailing list.

All rights to this documentation remain the property of REBOL Technology.

---Plagiarized Examples


Things are shamelessly plagiarized.  There are many experts on the 
mailing list whose work is included here; most notably the examples 
from the REBOL documentation.

---Approach


The approach that this document uses is to use REBOL/View/VID to 
demonstrate its abilities and give a visual tutorial. To enable this 
some changes have been made to the core %easyvid.r program from Carl 
Sassenrath. A scoll bar was added to the right pane because it was 
just too difficult to constrain the examples to the screen real estate 
that was available.

---Order Order


The order of the items needs some work. The easyvid presentation 
approach today does not allow for the drilling down and expansion 
of an outline tree which is needed for a large amount of documentation.


The preferred approach is to put a multi-level tree for navigation 
purposes and then allow navigation up and down the tree. 


===To Do

* make this a true outline tree

* re-organize it better


* update as requested and as possible by suggestions on AltME's REBOL 
world under group EasyVID

* correct numerous flaws


* better scrolling implementation using the updates that have been 
used in other examples such as Didier's %delete-email.r


* allow clipping to clipboard like AltME does on a row for the source 
examples




===Introduction to VID

With REBOL/View it's easy and quick to create your own user
interfaces. The purpose of this tutorial is to teach you the
basic concepts or REBOL/View interfaces in about 20 minutes.

VID is REBOL's Visual Interface Dialect.  A dialect is an
extension of the REBOL language that makes it easier to express
or describe information, actions, or interfaces.  VID is a
dialect that provides a powerful method of describing user
interfaces.

VID is simple to learn and provides a smooth learning curve from
basic user interfaces to sophisticated distributed computing
applications.


---Creating VID Interfaces

VID interfaces are written in plain text. You can use any text
editor to create and edit your VID script. Save your script
as a text file, and run it with REBOL/View.

!Note: Using a word processor like Word or Wordpad is not
recommended because files are not normally saved as text.
If you use a word processor, be sure to save the output
file as text, not as a document (.doc) file.


Recommendation: Look at TextPad from http://www.textpad.com




===Minimal VID Example

Here is a minimal VID example.  It creates a window that
displays a short text message.  Only one line of code
is required:

    view layout [text "Hello REBOL World!"]

You can type this line at the REBOL console prompt, or save
it in a text file and run it with REBOL.  If you save it
as a file, the script will also need a REBOL header. The
header tells REBOL that the file contains a script. Here
is an example of the script file with a header:

    REBOL [Title: "Example VID Script"]

    view layout [text "VID Example!"]

You can also add buttons and other gadgets to the script. The
example below displays a text, list of files, and a button:

    view layout [
        h2 "File List:"
        text-list data read %.
        button "Great!"
    ]

!Click on the examples above to see how they will appear on your
screen.  Click on their close box to remove them.  All of the
examples that follow can be viewed this way.


===Window Management


The code that displays the examples also shows how to manage the 
number of windows that are open.


Look at the show-example block in the code near the end of this script.


The location of the example window is also managed here by keeping 
track of the co-ordinates for the sample. After the sample window 
is moved, the next use will open at the same location.



===Pre-loaded Images


For this script, the image which represented a Portable Network Graphic
definition of an image is held in the script and loaded.


For a small number of graphics, this can achieve some packaging and
performance benefits.


The image "polished" is used through the script to achieve the polished 
steel
look that is one the outer frame.

    backtile polished orange
    button 200x50 "Polished Steel Look" polished 


===Two Basic Functions

Two functions are used to create graphical user interfaces
in REBOL: VIEW and LAYOUT.

The LAYOUT function creates a set of graphical objects.  These
objects are called faces.  You describe faces with words and

values that are put into a block and passed to the LAYOUT function.

The VIEW function displays faces that were previously created by
LAYOUT. The example below shows how the result of
the LAYOUT function is passed to the VIEW function, and the
interface is displayed.

    view layout [
        text "Layout passes its result to View for display."
        button "Ok"
    ]

Click on the above example to view it.

!Note: the block provided to a layout is not normal REBOL code,
it is a dialect of REBOL.  Using a dialect makes it much easier
to express user interfaces.



===Styles

Styles describe faces.  The examples above use the text and
button styles to specify a text line and a button. REBOL has
40 predefined face styles. You can also create your own custom
styles.  Here are a few example styles:

    view layout [
        h1 "Style Examples"
        box brick 240x2
        vtext bold "There are 40 styles built into REBOL."
        button "Great"
        toggle "Press" "Down"
        rotary "Click" "Several" "Times"
        choice "Choose" "Multiple" "Items"
        text-list 120x80 "this is" "a list" "of text"
        across
        check
        radio radio
        led
        arrow
        below
        field "Text Entry"
    ]


The words like backdrop, banner, box, text, and button are styles.

===Facets

Facets let you modify a style.  For instance, you can change the
color, size, text, font, image, edge, background, special
effects, and many other facets of a style.

Facets follow the style name.  Here is an example that shows
how you modify the text style to be bold and navy blue:

    view layout [txt bold navy "Facets are easy to use."]

The words bold and navy are not styles.  They are facets that
modify a style. Facets can appear in any order so you don't
have to remember which goes first.  For example, the line
above could be written as:

    view layout [txt "Facets are easy to use." navy bold]

Many facets that can be specified.  Here is an example that
creates bold red text centered in a black box.

    view layout [txt 300 bold red black center "Red Text"]

You can create facets that produce special effects, such
as a gradient colored backdrop behind the text:

    view layout [
        vtext bold "Wild Thing" effect [gradient 200.0.0 0.0.200]
    ]

===Custom Styles

Custom styles are shortcuts that save time.  When you define a
custom style, the facets you need go into the new style.  This
reduces what you need to specify each time you use the style,
and it allows you to modify the look of your interface by
changing the style definitions.

For example, here is a layout that defines a style for red
buttons.  The style word defines the new style, followed by
the old style name and its facets.

    view layout [
        style red-btn button red
        text "Testing red button style:"
        red-btn "Test"
        red-btn "Red"
    ]

So, if you wanted to create a text style for big, bold,
underlined, yellow, typewriter text:

    view layout [
        style yell tt 220 bold underline yellow font-size 16
        yell "Hello"
        yell "This is big old text."
        yell "Goodbye"
    ]


===Master Stylesheet 

REBOL holds its styles in a master stylesheet. When you are
sure that you want to share them without having to add the
style sheet line then do it as follows:

First add the style to the master sheet:

    button 200x50 "Define text-note as maroon bold text" [stylize/master 
    [
        text-note: txt maroon bold      
    ]]

    button 200x50 "Define text-note as white italic text" [stylize/master 
    [
        text-note: txt white italic     
    ]]

Then invoke it:

    view layout [
        across
        size 200x200

        return text-note "This shows a master stylesheet style in use." 

        return text-note "This shows another usage of the same style."

        return text-note "If you want to see the other style displayed, click 
        the Add Style section again and then use the other button"
    ]
    
    
===Note About Examples

!From this point forward, all examples will assume that
the view and layout functions are provided.  Only the layout
block contents will be shown.  To use these examples in your
scripts, you will need to put them in a layout block, as was
shown earlier.

For example, code that is written as:

    view layout [button red "Test it"]

will now appear as:

    button red "Test it"


===Face Sizes

The size of a face depends on its style.  Most styles, such as
buttons, toggles, boxes, checks, text-lists, and fields, have a
convenient default size.  Here are some examples.

    button "Button"
    toggle "Toggle"
    box blue
    field
    text-list

If no size is given, text will automatically compute its size,
and images will use whatever their source size is:

    text "Short text line"
    text "This is a much longer line of text than that above."
    image %palms.jpg

You can change the size of any face by providing a size facet.
The size can be an integer or a pair.  An integer specifies
the width of the face.  A pair specifies both width and height.
Images will be stretched to fit the size.

    button 200 "Big Button"
    button 200x100 "Huge Button"
    image %palms.jpg 50x50
    image %palms.jpg 150x50

===Color Facets

Most styles have a default color.  For example the body of
buttons will default to a teal color.  To modify the color of
a face, provide a color facet:

    button blue "Blue Button"
    h2 red "Red Heading"
    image %palms.jpg orange

Colors can also be specifed as tuples. Each tuple contains three
numbers: the red, green, and blue components of the color. Each
component can range from 0 to 255. For example:

    button 200.0.200 "Red + Blue = Magenta" 200
    image %palms.jpg 0.200.200 "Green + Blue"

Some face styles also allow more than one color.  The effect of
the color depends on the style.  For text styles the first color
will be used for the text and the second color for the background
of the text:

    txt "Yellow on red background" yellow red
    banner "White on Navy Blue" white navy

For other styles, the body of the face is the first color, and
the second color will be used as its alternate.

    button "Multicolor" olive red
    toggle "Multicolor" blue orange
===Layout Commands


To drop user interface elements on the canvas according to VIDs 
directional layout controls 

---Across

You are placing elements in a row orientation
    
    across 
    return button "A" button "B" button "C"
    return button "D" button "E" button "F"
    

---Below

You are placing elements in a column orientation

    below 
    return button "A" button "B" button "C"
    return button "D" button "E" button "F"

---Mix

You can mix the directional controls 

    across 
    return button "A" button "B" 
    below button "C" 
    across button "D" button "E" button "F"


---Padding


The pad keyword creates extra padding between styles. It uses a pair 
or integer value. When it is an integer, spacing is created either 
horizontally (across) or vertically (below). When it is a pair, the 
spacing will be created both horizontal and vertically. The following 
example illustrates both uses. First, the buttons "one" and "two" 
are padded with an integer representing 40 pixels in one direction. 
Then the buttons "three" and "four" are padded with a pair representing 
40x40 pixels. 

    across 
    button "one" pad 40 button "two" return 
    button "three" pad 40x40 button "four" 


Padding can be negative.
    
        backtile polished orange
        pad 200x200 button "A"
        pad -100x-100 button "B"
        
---Guide

A guide is a virtual alignment control

      title "Buttons Without A Guide" 
    button "one"   button "two"  return 
    button "three" button "four" return 
    button" five" button "six" 

With an implicit guide location

    title "Buttons With An Implicit Guide Location" 
    guide 
    button "one"   button "two"  return 
    button "three" button "four" return 
    button" five" button "six" 

With an explicit guide location

    across title "Buttons With An Explicit Guide Location"
    guide 55x100 
    button "one"   button "two"  return 
    button "three" button "four" return 
    button" five" button "six" 
    
===Tabstops

Tabs can be used for alignment.

---Across

    tabs 200 ; sets tabs every 200 pixels   
    across button 20 "A" tab button 20 "B" tab button 20 "C" 
    tabs 100 ; sets tabs every 100 pixels   
    return button 20 "D" tab button 20 "E" tab button 20 "F"
    
---Below

    tabs 200 ; sets tabs every 200 pixels   
    below button 20 "A" tab button 20 "B" tab button 20 "C" 
    tabs 100 ; sets tabs every 100 pixels   
    return button 20 "D" tab button 20 "E" tab button 20 "F"

---Explicit Settings

Tabstops can be set at explicit values 

    tabs [100 124  166 212 300]

    across tab button 20 "A" tab button 20 "B" tab button 20 "C" tab 
    button 20 "D"
    
===Color Facets

Most styles have a default color.  For example the body of
buttons will default to a teal color.  To modify the color of
a face, provide a color facet:

    button 200 blue "Blue Button"
    h2 red "Red Heading"
    image polished orange

Colors can also be specifed as tuples. Each tuple contains three
numbers: the red, green, and blue components of the color. Each
component can range from 0 to 255. For example:

    button 200.0.200 "Red + Blue = Magenta" 200
    image polished 0.200.200 "Green + Blue"


Some face styles also allow more than one color.  The effect of the 
color depends on the style.  For text styles the first color will 
be used for the text and the second color for the background of the 
text:

    txt "Yellow on red background" yellow red
    title "White on Navy Blue" white navy


For other styles, the body of the face is the first color, and the 
second color will be used as its alternate.

    button 200 "Multicolor" olive red
    toggle 200 "Multicolor" blue orange


From the mailing list, there was a problem reported in changing button 
color:

    view layout [
        b: button "New color" [
            b/color: random 255.255.255 
            show b
        ]
    ]
    

And the answer was that the gradient of the color was preventing 
this change from working:


    style color-changing-button button 0.0.0        ; new style overwrites 
    gradient effect
    b: color-changing-button "New color" [
        b/color: random 255.255.255 
        show b
    ]

===Text Facets


Most faces will accept text to be displayed.  Even graphical faces 
can display text.  For example, the box and image faces will display 
text if it is provided:

    box blue "Box Face"
    image polished "Image Face"


Most button faces will accept more than one text string. The strings 
will be shown as alternates as the face is selected.

    button 200 "Up" "Down"
    toggle 200 "Off" "On"
    rotary 200 "Red" "Green" "Blue" "Yellow"
    choice 200 "Monday" "Tuesday" "Wednesday" "Thursday" "Friday"

    text-list 200 "Monday" "Tuesday" "Wednesday" "Thursday" "Friday"


When other datatypes need to be displayed as text, use the form function 
to convert them first:

    button 250 form now
    field form first read %.
    
===Normal Text Style


Normal text is light on dark and can include a number of facets to 
set the font, style, color, shadow, spacing, tabbing, and other attributes.

    text "Normal"
    text "Bold" bold
    text "Italic" italic
    text "Underline" underline
    text "Bold italic underline" bold italic underline
    text "Big" font-size 32
    text "Serif style text" font-name font-serif
    text "Spaced text" font [space: 5x0]

Text also includes these predefined styles:

    title "Title" 200
    vh1 "vh1"
    vh2 "vh2"
    vh3 "vh3"
    vh4 "vh4"
    label "Label"
    
    
===Document Text Style


Document text is dark on light and can also include a number of facets 
to set the font, style, color, shadow, spacing, tabbing, and other 
attributes.

    txt "Normal"
    txt "Bold" bold
    txt "Italic" italic
    txt "Underline" underline
    txt "Bold italic underline" bold italic underline
    txt "Big" font-size 32
    txt "Serif style text" font-name font-serif
    txt "Spaced text" font [space: 5x0]

Document text also includes these predefined styles:

    title "Centered title" 200
    h1 "Heading 1"
    h2 "Heading 2"
    h3 "Heading 3"
    h4 "Heading 4"
    tt "Typewriter text"
===Text Entry Fields


Text input fields accept text until the enter or tab key is pressed. 
 A text input field can be created with:

    field

To make the field larger or smaller, provide a width:

    field 30
    field 300

Fields will scroll when necessary.


Larger amounts of text can be entered in an area.  Areas also accept 
an enter key and will break lines.

    area

You can also specify the area size:

    area 160x200


To force the text in an area to wrap rather than scroll horizontally, 
provide the wrap option:

    area wrap
===Text Setting


To set the value of a text field under program control, use /text: 
e.g.

    across backtile polished
    return t1: txt      200 "This is some original text"
    return f1: field    200 "Some field text"   
    return a1: area  {Some original area text.} wrap 200x80
    return button 200 "Change Text" [
        t1/text: "Some different text" 
        f1/text: "Some new field text"

        a1/text: {Some wrapping text in the^/ area field to^/ show that this^/ 
        is supported}
        show [t1 f1 a1]
    ]
    
===Text Lists

Text lists are easy to create.  Here is an example.

    text-list "Eureka" "Ukiah" "Mendocino"

You can also provide it as a block:

    text-list data ["Eureka" "Ukiah" "Mendocino"]


Almost any type of block can be provided. Here is a list of all the 
files in your current directory:

    text-list data read %.

Here is a list of all the words REBOL has scanned:

    text-list data first system/words
===Scrolling Text List


A style to allow maintenance of lists from Brett Handley on the REBOL 
list:

        style updatable-text-list text-list
        with [
            update-slider: does [
                sld/redrag lc / max 1 length? head lines
            ]
        ]

        tl: updatable-text-list 300x100 data copy system/locale/months
        button  300x20 "Delete first entry on the list" [
            remove tl/data tl/update-slider show tl
        ]
        button 300x20 "Append the 'now' timestamp to list" [
            append tl/data mold now tl/update-slider show tl
        ]
===Text List Picked Values

    list-of-letters: text-list "a" "b" "c" "d" "e" 
    button 200  "Pick Item 3" [
        clear list-of-letters/picked 

        append list-of-letters/picked pick list-of-letters/data 3 
        show list-of-letters
    ]
===Images

By default an image will be scaled to fit within a face.

    image 60x60 polished
    image polished red

Images can be framed in a number of ways:

    image 100x100 polished frame blue 5x5
    image 100x100 polished bevel
    image 100x100 polished ibevel 6x6

Most other faces can accept an image as well as text:

    box 100x100 polished
    button "Button" polished purple
    toggle "Toggle" polished blue red
    field bold  "This is a field." polished effect [emboss tile]

    field bold "This is another field." polished effect [brighten 100]

The image can be provided as a filename, URL, or image data.



===Backdrops

A backdrop can be a color, an effect, an image, or a combination
of the three.  For example a backdrop color would be written as:

    backdrop navy
    title "Color Backdrop" gold

To create a backdrop effect provide it on the line:

    backdrop effect [gradient 1x1 0.0.100 100.0.0]
    title "Gradient Backdrop" gold

A backdrop image can be a file, URL, or image data:

    backdrop polished
    title "Image Backdrop" red

The backdrop image can be colorized:

    size 400x500 
    backdrop polished blue
    title "Blue Image Backdrop"

The image can include an effect:

    backdrop polished effect [fit gradcol 1x1 100.0.0 0.0.250]
    title "Gradient Image Backdrop"
    
===Backtile

To make a backdrop use a tile effect there are two options:

    backdrop polished effect [tile]
    banner "This shows a backdrop with a tile effect"
    
or

    backtile polished
    banner "This demonstrates backtile"


Note the difference between:

    size 400x500 
    backdrop polished
    banner "Here one image is stretched to cover the canvas"

and

    size 400x500 
    backtile polished
    banner "Here one image is repeated to cover the canvas"
    
===Effect Facets


A range of effects are supported for faces.  All of these effects 
are performed directly on the face when it is rendered. Here are 
examples of a few possible effects in top to bottom then left to 
right order:

    style polished-steel image 80x60 polished 
    polished-steel effect [flip 1x1]
    polished-steel effect [rotate 90]
    polished-steel effect [reflect 1x1]
    polished-steel effect [crop 0x50 120x60 fit]
    polished-steel effect [grayscale]
    polished-steel effect [invert]
    polished-steel effect [difference 200.0.0]
    polished-steel effect [tint 80]
    return
    polished-steel effect [contrast 50]
    polished-steel effect [brighten 50]
    polished-steel effect [sharpen]
    polished-steel effect [blur]
    polished-steel effect [colorize 204.0.0]
    polished-steel effect [gradcol 1x1 150.0.0 0.0.150]
    polished-steel effect [gradmul 0x1 0.100.0]
    polished-steel effect [grayscale emboss]


Effects can be used in combination to create other interesting results. 
 However, keep in mind that the computations are performed in real 
time.  If complex combinations are required, a temporary image should 
be created with the to-image function.


===Actions


An action can be associated with almost any face. To do so, follow 
the face style with a block:

    button "Test" [alert "test"]


The block is used as the body of a function that is passed the face 
and the current value (if the face has one).  For example:

    toggle "Toggle" [alert form value] 
    rotary "A" "B" "C" [alert form value]
    text "Click Here" [alert  face/text]

If a second block is provide, it is used for the alternate
actions (right key):


    button "Click Here" [view/new layout [txt "action"]] [view/new layout 
    [txt "alt-action"]]


Use variables to modify the contents or state of other faces. For 
example, the slider will update the progress bar:

    slider 200x16 [p1/data: value show p1]
    p1: progress

!More action on actions needed...

===Show


After the state is changed for a user interface element, it must 
be re-drawn to be reflected on the user interface canvas.

Accomplish this with the show message.

    backtile polished
    across 
    toggle "Toggle State"  
            [   cybernetics?/data: not cybernetics?/data
                show cybernetics?]  

    return  label "Are you interested in cybernetics?" cybernetics?: 
    check 

One show command can be used for multiple user interface elements

        backtile polished orange
        across
        b1: check label "Red" return
        b2: check label "Green" return

        button 200 "Change State But No Refresh" [b1/data: not b1/data b2/data: 
        not b2/data] return
        button "Show" [show [b1 b2]]
===Hide

A user interface element can also be hidden.

        backtile polished orange
        across
        c1: check 
        hide-button: button "Hide" [hide c1] return
        show-button: button "Show" [show [c1 d2]]


The show-button action tries to show a user interface element 'd2' 
that does not exist.
REBOL/View ignores these.
===Invisible Faces


To make a button invisible when the view is opened, you can define 
an invisible button style

This approach sets the show? value to false when the user interface 
element is initialized.

    across

    style invisible-button button with [append init [show?: false]]
    late-shower: invisible-button "I'm Here" return
    return button 200 "Show Invisible Button" [show late-shower]
    
This works for the other visible user interface element.

===Focus

A user interface element can programmatically be given the focus.

    across backtile polished 
    button 200 "Set focus to Phone Field" [focus f2] 
    return label "Name: "   f1: field 100 
    return label "Phone: " f2: field 100 

    return button 200 "Remove focus from Phone Field" [unfocus f2] 
    return button 200 "Hide the Phone Field" [hide f2] return

---Focus Defect


!Note that the tab function shows a hidden field. I have assumed 
that this is a defect. If a field is hidden, the tab button should 
not make it visible. This has been previously sent to feedback.

===Radio Buttons


A radio button is used to make a choice between mutually exclusive 
values. Your preferred programming language is REBOL or C++ or PL/1 
or APL but it is only one of those.

            across backtile polished

            radio of 'programming-language pad 0x-4 label "REBOL" return

            radio of 'programming-language pad 0x-4 label "C++" return

            radio of 'programming-language pad 0x-4 label "PL/1" return

            radio of 'programming-language pad 0x-4 label "APL" return


To mix two groups of radio buttons on one screen, associate them 
with their groups using the "of 'word". In the above, the grouping 
is 'programming-language.

            across backtile polished

            radio of 'programming-language pad 0x-4 label "Language: REBOL" return

            radio of 'programming-language pad 0x-4 label "Language: C++" return

            radio of 'editor pad 0x-4 label "Editor: TextPad" return

            radio of 'editor pad 0x-4 label "Editor: Notepad" return


The padding in the above is needed to keep the label aligned with 
the radio button.

            across backtile polished orange

            radio of 'programming-language pad 0x-4 label "REBOL" return

            radio of 'programming-language          label "APL" return
            
            
            
            

===Radio Button Settings


A radio button is not very useful unless you can find out what its 
setting is and change that setting under program control.


            across backtile polished orange

            rebol-radio:    radio of 'programming-language  [programming-language: 
            'rebol] pad 0x-4 label "REBOL" return

            apl-radio:      radio of 'programming-language  [programming-language: 
            'apl]         label "APL" return
            button 200 "Toggle radio button" [

                    apl-radio/data: not rebol-radio/data: not rebol-radio/data
                    show [rebol-radio apl-radio]
            ]
            
===Check Box

---Purpose


A check box is used to allow user interface choices where the choices 
are not mutually exclusive.

        across backtile polished orange
        c1: check label "Likes animals" return
        c2: check label "Like Monkees" return
        c3: check label "Like The Animals"
        
---State


A check box is not much good if you can't get and set its state (on 
or off).

        across backtile polished orange
        c1: check label "Likes animals" return
        c2: check label "Like Monkees" return
        
    button "Set State" [
        c1/data: true 
        show c1
        c2/data: false
        show c2
    ]
 
 
===Sensor

---Purpose


A sensor is an invisible user interface element. Using a sensor only 
makes sense in a few instances. 


If you want a keycode action where there is no visible user interface 
element to link the action to then a sensor can be used.


This sensor code adds an Escape or Back or Enter action that will 
close the window. 

    sensor 1x1 keycode [#"^M" #" " #"^(back)" #"^(ESC)"] [unview]


Or if you want to make portions of an image 'hot' instead of putting 
buttons on top of the image, then a sensor will achieve this.

        across backtile polished orange

        txt "Click on the upper left section of the gray image to invoke 
        the sensor action"

        return animage: image 100x100 polished      ; here the image is just 
        the polished area

        at animage/offset sensor 50x50 [alert "You pushed over the sensor"]
        
===Displaying Script Values


If the script has a standard format headings, including custom ones, 
these can be used in the application by picking them from the system/script/header.

        backtile polished
        across banner "About"

        return text font-size 16    rejoin ["Title: "           form system/script/header/title]

        return text font-size 16  rejoin ["Originator: "    form system/script/header/author] 
              

        return text font-size 16  rejoin ["Modifier: "      form system/script/header/modifier]

        return text font-size 16  rejoin ["Version: "       form system/script/header/version]

        return text font-size 16  rejoin ["Updated: "       form system/script/header/date]
        return button "OK" [unview] 

===Toggle


A toggle button represents boolean state - either on or off. The 
button stays down until toggled again.
Colors and text can be paired for "on" and "off" state.

    toggle "Up" "Down" red blue

To set the state via program control, use:

        across backtile polished
        return t1: toggle "Up" "Down" red blue
        return button polished 204.0.0 100 "Toggle State" [
            t1/state: not t1/state
            show t1
        ]


===Rotary Buttons


Rotary buttons are a different sort of user interface device. They 
can cause some challenges because the state is what's showing so 
you have to blindly "toggle" to get to a state that you want.  But 
for quick and easy uses where the user is familiar with the options, 
they can be handy.  If you plan to use them for a long list of items 
such as shown  below, they might give you some usability concerns.


---Example

        across backtile polished
        rotary data ["First" "Second" "Third"]

---Setting State

        across backtile polished

        return r1: rotary data (my-options: ["First" "Second" "Third"])
        return button 200 "Change Rotary State" [
            r1/data: next r1/data
            if tail? r1/data [r1/data: head r1/data]
            show r1
        ]

---Example - Usability For Unfamiliar List Contents


The rotary button demonstrated here contains some information unfamiliar 
to most (Saturn's satellites). Use it to to set the state so that 
"Calypso" is set. Doable but without knowing the order each re-paint 
has to be checked to ensure that it is not "Calypso" before clicking 
again.  If you do click past the choice that you want, there is no 
back function so you have to cycle through again.

        return rotary data [

            "Pan" "Atlas" "Prometheus" "Pandora" "Epimetheus" "Janus" "Mimas" 
            "Enceladus" "Tethys" "Telesto" "Calypso" "Dione" "Helene" "Rhea" 
            "Titan" "Hyperion" "Iapetus" "Phoebe"        
        ]


===Arrows


REBOL/View supports arrows as simple user interface elements. Actions 
can be associated with them.



---Arrowheads And Actions

By default, the arrow is 20x20

    across size 200x100 
    backtile polished
    at 50x50 arrow left 
        [alert "You pressed the left arrow"] 

        [alert "You pushed the alternate button on the left arrow"] 
    at 70x30 arrow up
    at 90x50 arrow right [alert "You pressed the right arrow"]
    at 70x70 arrow down
    
---Very Sharp Arrows


And with a little work the arrows and boxes can be merged to look 
sharper. Here is a "sharp at both ends" arrow from the block diagram 
script by Carl:

    origin 0
    backcolor white
    at 0x0 box 40x40 white effect [arrow rotate 270]
    at 110x0 box 40x40 white effect [arrow rotate 90]
    at 24x10 box black 100x20
    
---Arrow Blend

So that shows you how to make an arrow blend into your background

    size 100x100
    across backdrop gray
    at 50x50 box 40x40 gray effect [arrow rotate 90]
    at 40x67 box 25x5 black
    
===LED

LEDs would be used to display state (on or off).  

Clicking the LED toggles its state and changes its color.

LEDs do not support alternate mouse button actions.

    across banner "Light Emitting Diode"
    return 

    l1: led 10x10 [alert "LED left mouse action"] label "Alert status"

    l2: led 10x10 [alert "LED left mouse action"] label "Network status"
    return button "Change state" [
        l1/data: not l1/data
        l2/data: not l2/data 
        show [l1 l2]        
    ]
    
===Box


---Boxing

Draw boxes of any heigth and width with the box style

    box "Large Box" 200x400 polished orange
    
---Boxes As Lines


If you make the box narrow enough or short enough it is a line (or 
a dot).

    across size 300x300 backtile polished
    at 50x0 box 3x100 gold
    at 0x50 b1: box 100x3 gold
    at 10x10 box 5x5 red
    
---Boxes Can Grow

    across size 300x300 backtile polished
    at 150x0 b1: box 100x3 gold
    return pad 0x100 button "Grow Down" [
        for i 3 300 1 [
            b1/size/y: 1 + b1/size/y
            wait 00:00:00.01
            show b1
        ]
    ]

    return pad 0x100 button "Back Up" [
        for i 300 3 -1 [
            b1/size/y: b1/size/y - 1
            wait 00:00:00.01
            show b1
        ]
    ]

You might even find a use for it.


---Grid Effect

Not sure of the use for this yet but here is what you can do:


 return box "Grid Lock" with [effect: [grid 20x20 8x8 4x3]] white 
 300x200
 

 return box "Grid Lock" with [effect: [grid 20x20 5x5 3x3]] white 
 - 80 300x200
 
===Frame

Earlier versions of REBOL VID supported frames in layouts such as
view layout [frame "This is the Bay" %bay.jpg]

These are no longer valid.

But frames can be put around some user interface devices:

    image 100x100 polished frame red
    
===List


A list is an iterated sub layout and takes a layout block that uses 
the Visual Interface Dialect. The styles in the layout will be repeated 
until there is no more room to fit them within the list dimensions.


---Why


A face can be iterated to create a number of virtual faces. For instance, 
when displaying a list of ten buttons, each of the buttons does not 
need to be created as a separate object. If the buttons only differ 
by a few facets (such as position, text, and action taken on selection), 
a model face can be created and iterated for its other position. 
This is useful when creating scrolling lists of files and other data 
sets that share the same appearance. 

---Supply


Supply provides the data to the list for an iterated face.

    do [cnt: 0
        list-collection: [aqua sky water]    
    ]
    backtile polished orange
    across
    list-displayed: list 100x72 [
        origin 0 space 0x0 across
        color-field: txt bold 80x24
    ] supply [
            if none? one-color: pick list-collection count [exit]
            face/text: do pick [one-color] index

    ]

    return txt gold 180 "OK ... but not too useful"


---Supply Columns

Maybe adding some more columns would be better.

Here I'll add a column of buttons that display the color name
and a column of text strings in italic.

    do [
        cnt: 0
        list-collection: [aqua sky water gold silver coffee]    
    ]
    backtile polished orange
        across
        list-displayed: list 300x200 [
            origin 0 space 0x0 across
            color-field: txt bold 80x24
            color-button: button 80x24
            pad 5x1
            txt 100 italic
        ] supply [

                if none? one-color: pick list-collection count [exit]
                face/text: do pick [
                    [one-color]
                    [to-string one-color]
                    [rejoin ["  " to-string one-color]]
                    ] index 
    ]
    

    return txt gold 300 {A bit more interesting but the last row repeats 
    to fill the list size. Some of the other VID components will automatically 
    stretch to fit the size needed (such as this txt field) but the list 
    does not behave that way.  You have to make the list size fit its 
    data or make it smaller and add a vertical scroll capability. That 
    is shown a little later on.}

===List With Supplied Data

This example is to show adding action to the list
and adds a horizontal line between the rows.


    do [
        cnt: 0
        list-collection: [aqua sky water gold silver coffee]    
    ]
    backtile polished orange
        across

        list-displayed: list water edge [size: 6x6 color: silver]  350x96 
        [  
            origin 0 space 0x0 across

            color-field: txt 60 [alert rejoin ["You pressed the " face/text " 
            text field"]]
            pad 45x0            

            color-button: button 80 [alert rejoin ["You pressed the " face/text 
            " button"]]
            pad 5x0
            txt 120 italic

            return box 350x1 white      ; this causes a horizontal line to appear 
            between each row

        ] supply [

                if none? one-color: pick list-collection count [exit]
                face/text: do pick [
                    [one-color]
                    [to-string one-color]
                    [rejoin ["  " to-string one-color]]
                    ] index 
    ]


===Supply List With Scroll

This example shows a supplied list with a scroll capability.
More colors are added to demonstrate scrolling.

Note that this is a verbose list of code where I added comments
for my understanding of how the scroll was linked to the list.
The same effect can be accomplished with fewer lines of code.
    

    do [    ; first this do block creates the data definitions needed.
        slider-position-clicked:  0
        count: 0    
        x: 450
        y: 300

        row-y: 16           ; the row height includes the data plus any separator 
        lines 

        list-size: to-pair reduce [x y]     ; this is the size of the display 
        list  
        separator-size: to-pair reduce [x 1]
        slider-size: to-pair reduce [24 y ]
        list-collection: [

            aqua           bar-color   base-color     beige         black    
                  blue           brick          brown      

        button-color   coal        coffee         crimson       cyan     
              forest         gold           gray       

        green          ivory       khaki          leaf          linen    
              magenta        main-color     maroon     

        mint           navy        oldrab         olive         orange   
              over-color     papaya         pewter         

            pink           purple      rebolor        red           sienna   
                  silver         sky            snow

        tan            teal        violet         water         wheat    
              white          yellow        
        ]    
        
        supply-style: stylize [

                button-fixed: button left coal to-pair reduce [80 row-y]        ; 
                these keep the row elements the same height

                text-fixed: txt to-pair reduce [160 row-y]          
        ]
        
        data-size: length? list-collection  
    ]
    

    backtile polished orange                        ; this section layouts 
    out the list
        
        across

        list-position: at                                   ; the position 
        is captured here in order to later put the slider beside it
        list-displayed: list linen 
            edge [size: 6x6 color: tan]  list-size [  
            origin 0 space 0x0 across
            styles supply-style

            text-fixed [alert rejoin ["You pressed the " face/text " text field"]]

            button-fixed [alert rejoin ["You pressed the " face/text " button"]]
            pad 5x0 

            text-fixed 80 italic [alert rejoin ["You pressed the italic " face/text 
            " text field"]]

            return box separator-size gray      ; this causes a horizontal line 
            to appear between each row

        ] supply [
                count: count + slider-position-clicked  

                if none? one-color: pick list-collection count [exit]
        face/text: 
            either count > (1 + data-size) 
            [""]
            [
                             do pick [

                                    [one-color]                                                      
                                           ; this is supplied to the first txt field (text-fixed)

                                    [to-string one-color]                                           ; 
                                    this is supplied to the button (button-fixed)

                                    [rejoin ["  " to-string one-color " "]]     ; this value is supplied 
                                    to the last text-fixed field
                            ] index 
                    ]
        ]


        ; now add a slider to the side of the list



        at list-position + (list-size * 1x0)                             
           ; this finds the top right border of the list widget
        vertical-slider: slider slider-size to-integer y / row-y
        [

                    slider-position-clicked: vertical-slider/data   ; the slider has 
                    to be bound to the size of the list                

                        * ((1 + data-size) - ((y / (1 + row-y))))       ; including the row 
                        height
                    if slider-position-clicked <> count [
                        count: slider-position-clicked 
                        show list-displayed
                    ]
                ]


===Slider


A slider is interactive user interface element. The data of a slider 
varies from 0 to 1.

    backtile polished   orange across
    slider-1: slider 200x40 
    return button 200 "Move first slider to 50%" [
        slider-1/data: .5 
        show slider-1
    ]

    return txt 200 "The second slider in this example is initialized 
    to the 80% mark."  
    return slider 200x40 with [append init [data: .8]]
    
===Progress Indicator


The progress-1 face in this example is a progress indicator. Because 
it is only displaying information, it is non-interactive i.e. you 
can not change its value by dragging its edges.  The alternate button 
is not supported on a progress indicator.

    backtile polished   orange across
    slider 200x40 [
        progress-1/data: value 
        field-1/text: join (to-integer (100 * value)) " %"
        show [progress-1 field-1]
    ] 
    return progress-1: progress
    return field-1: field
===Panels 


Panels are used to create sub-panes that can be more easily managed 
by grouping

the user interface devices on a panel. The first example below shows 
how to use panels for layout alignment. By creating a panel definition, 
all of the components defined within it are aligned relative to its 
origin.

    across backtile polished brick
    tabs 50
    return panel-1: panel 250x120 [
        backtile polished
        across
        return button water 200 "Button A"
        return button aqua  200 "Button B"
        return button sky   200 "Button C" 
    ]


    at panel-1/offset + panel-1/size panel 60x90 [  ; start at the bottom 
    right corner of panel-1
        backtile polished
        across
        return button tan       20 "1"
        return button coffee    20 "2"
    ]
    
---Multiple SubPanels example


This example from the REBOL html documentation shows how to easily 
hide and show sections of a user interface by displaying them on 
the face area of a box.  


        do [                                ; define two panels
            panel1: layout [
                    origin 8x8
                    h2 "Panel 1"
                    field "Field 1"
                    field "Field 2"
                    button "The Answer" [alert "I know nothing."]
            ]


            panel2: layout [
                origin 8x8
                    h2 "Panel 2"
                    across
                    txt "X:"
                    slider 150x16
                    return
                    txt "Y:"
                    slider 150x16
                    return
                    check [panel2/color: maroon  show panel2]
                    txt "Don't click this"
                    return 
                    check [panel2/color: silver  show panel2]
                    txt "Click this" 
                    return
                ]

                panel1/offset: 0x0
                panel2/offset: 0x0
        ]


        vh2 "Subpanel Examples"     ; now demonstrate panel use
        guide
        pad 20
        button "Panel 1" [panels/pane: panel1  show panels]
        button "Panel 2" [panels/pane: panel2  show panels]
        button "Quit" [unview]
        return
        box 2x140 maroon
        return
        panels: box 220x140
        do [panels/pane: panel1]
        
===Simple Default Style Override


The style's default look can be overriden easily with one line of 
code. 


For example, to make the default button size 200x200 with a water 
color, use

    style button button 200x200 water
    button "Big Blue Button" [unview]

To make the toggle some different default colors:

    style toggle toggle crimson sky
    toggle "Up" "Down"


Note that these stay in effect until they are overridden so if you 
use the default values, exercise some care unless you meant to do 
that. 



===Image Maker


An option used by Carl in some of his programs is to let View create 
specific icons so that you have portability and more control of look 
of the image then if you referenced an external file such as gif 
that was a bullet display. Here's how to do that:

    do [    
        make-image: func [xy wh eff] [
            eff: layout [
                size 20x20 at xy
                box wh effect eff
            ]
        eff/color: rebolor
        to-image eff
        ]


        dot: make-image 6x5 9x9 [gradient 1x1 255.0.0 0.0.0 oval key 0.0.0]

        dot-big: make-image 8x7 12x12 [gradient 1x1 255.0.0 0.0.0 oval key 
        0.0.0]
        arr: make-image 3x3 14x14 [arrow 0.0.127 rotate 90]
        ard: make-image 3x3 14x14 [arrow 0.0.127 rotate 180]    

    ]   ; end of "do" - it is needed here because easyvid approach is 
    expecting vid dialect commands

    banner "Presentation Points"
    size 400x300 across

    style label label gold     ; make a label's text be a different color 
    than the default
    return image dot label "This is bullet point number 1" 
    return image dot label "This is bullet point number 2"
    return image arr label "This is arrow point number 1"

    return image ard label "This is an arrow making a different point"

    return image dot-big pad 0x4 area 300x80 wrap "And because these 
    arrows and dots are images, action can be added to them to make them 
    'hot' with mouse actions including 'over'."
    
===Needs Some Work

!More to come.  These still need to be covered in this
tutorial:

    text-list data [
        icon
    ]
    
===Digital Clock

    origin 0
    banner "00:00:00" rate 1 effect [gradient 0x1 0.0.150 0.0.50]

        feel [engage: func [face act evt] [face/text: now/time  show face]]


 


===REBOL Logo

 image %rebo-logo.gif [unview]

===Paint Drops

REBOL one liner by Vincent Ecuyer


 b: box rate 9 effect[draw[pen(random snow)circle(random 99x99)2]blur]box 
 1x1 rate 9 effect[draw[(b/image: to-image b)]]
 
===eMailer

One line emailer by Doc Kimbel

Assumes you have set up your email in set-user



 e: field "Email" s: field "Subject" m: area "Body" btn "Send"[send/subject 
 to-email e/text m/text s/text alert "ok"]
 
===Hello World

 text "Hello World!" button "Close" [unview]
===Three Buttons

 button "Yes" button "Maybe" button "No"

===View Web Text

 text 800x600 read http://www.rebol.com
 
===View Image

 image %palms.jpg
 
===View Image and File Name


Here a do block is used to initialize the file variable within the 
layout code.

 do [file: %palms.jpg]
 image file  text form file
 
 
===View Image behind File Name


Here a do block is used to initialize the file variable within the 
layout code.

 do [file: %palms.jpg]

 image file form file
 
 
===Buttons From Images

    backdrop 40.70.140
    stat: text bold "Click a Button" 100x20 240.140.40 center
    button "Bay Test"  %bay.jpg 100x100 [
        stat/text: "Upper" 
        show stat
    ]
    button "Blue Test" %bay.jpg 100x100 10.30.180 [
        stat/text: "Lower" 
        show stat
    ]
===View List


 list blue 320x200 [across text white 200 text white 100] data [
    ["John" 100] 
    ["Joe" 200] 
    ["Martin" 300]
 ]
===Movie Credits



    backdrop %bay.jpg effect [fit]

    text center bold 240x30 "REBOL, The Movie" yellow font [size: 16]
    credits: text {

 Edit This File 

 To Add Your Own Credits 
 

 It is very simple to do. 

 Only takes a minute. 

 Only REBOL Makes It Possible...

 } white bold center 240x180 rate 30 para [origin: 0x+100]
        feel [engage: func [f a e] [

            if a = 'time [f/para/origin: f/para/origin - 0x1 show f]
        ]
    ]



===Fire Demo

    box 150x150 with [
        edge: none
        img: image: make image! 150x150
        rate: 20
        text: "FIREBOLEK"
        font: make font [size: 24 color: 255.125.0]

        basic: [draw [image make pair! reduce [(random 3)  - 2 -1] img]]
        effects: reduce [
            append copy basic [blur luma -10]
            append copy basic [sharpen luma -10 blur]
            append copy basic [contrast 10 blur luma -5]        
        ]
        effect: first effects
        feel: make feel [
            engage: func [f a e][
                switch a [

                    down [f/effects: next f/effects if tail? f/effects [f/effects: head 
                    f/effects] f/effect: first f/effects show f]

                    time [show f repeat i f/size/x - 4 [poke f/image (f/size/x * f/size/y) 
                    - i - 2 (random 255.0.0 + random 0.127.0) * 3] f/img: to-image f] 
                           
                ]       
            ]
        ]
    ]
    text 150 {classical fire demo for REBOL^/
 press on fire to see other effects.^/   
 Written by ReBolek, 2001 in 15 mins.^/
 We need new category on Assembly:^/
 less-than-kb-demo ;-)} with [font: make font  [size: 9]]
===Bezier 

Oldes Bezier Line Demo

See script library for %bezier-curve.r

Uses functions and data initialized at script startup

The end points are draggable to change the curve!!!!


Here a do block is used to allow executable lines for initialization 
purposes.

 do [

    draw-beziere-curve: has [result pp x0 x1 x2 x3 y0 y1 y2 y3 cx bx 
    ax cy by ay t tx ty s] [
    result: make block! 120
    pp: p0/size/x / 2
    x0: p0/offset/x + pp
    y0: p0/offset/y + pp
    x1: p1/offset/x + pp
    y1: p1/offset/y + pp
    x2: p2/offset/x + pp
    y2: p2/offset/y + pp 
    x3: p3/offset/x + pp
    y3: p3/offset/y + pp

    insert result compose [
        pen 155.0.0
        line (p0/offset + pp) (p1/offset + pp)
        line (p2/offset + pp) (p3/offset + pp)
        pen 255.255.255 line (p0/offset + pp)
    ]    
    cx: 3 * (x1 - x0)
    bx: 3 * (x2 - x1) - cx
    ax: x3 - x0 - cx - bx
    cy: 3 * (y1 - y0)
    by: 3 * (y2 - y1) - cy
    ay: y3 - y0 - cy - by
    
    t: s: 0.01 ;this value sets quality of the curve
    
    while [t <= 1][
        tx: to integer! (

                (ax * (t * t * t)) + (bx * (t * t)) + (cx * t) + .5
            ) + x0
        ty: to integer! (

                (ay * (t * t * t)) + (by * (t * t)) + (cy * t) + .5
            ) + y0

        t: t + s
        insert tail result to pair! reduce [tx ty]
    ]
    return result
 ]


 click?: false
 mouse-pos: 0x0


 ]

    origin 0

    bkg: box black 400x400 with [effect: reduce ['draw make block! 120]]
    style point box 10x10 with [

        effect: [draw [pen 0.255.0 fill-pen 0.200.0 circle 4x4 4]]
        changes: [offset]
        feel: make feel [
            engage: func [f a e][
                if a = 'down [click?: on mouse-pos: e/offset]
                if a = 'up   [click?: off]
                if find [over away] a [
                    if click? [
                        f/offset: f/offset + e/offset - mouse-pos
                        bkg/effect/2: draw-beziere-curve
                        show [bkg f]
                    ]
                ]
            ]
        ]
    ]
    at 300x200 p0: point
    at 200x100 p1: point
    at 200x300 p2: point
    at 100x200 p3: point
    do [bkg/effect/2: draw-beziere-curve]
                   
===Buttons Galore

Buttons galore from the library script %buttons.r


Here a do block is used to execute the initialization needed within 
the layout block.



    do [
        group: ["rotary" "test" "button"]
    ]

    origin 20x10
    backdrop effect [gradient 0x1 100.20.0]

    vh1 "52 Button Click-up - Each with a different click effect..."

    vtext bold "Here is a small sampling of the thousands of button effects 
    you can create. (This is 78 lines of code.)"
    at 20x80 guide
    button "simple"
    button form now/date
    button "colored" 100.0.0
    button "text colored" font [colors: [255.80.80 80.200.80]]
    button with [texts: ["up text" "down text"]]
    button "bi-colored" colors [0.150.100 150.20.20]

    button with [texts: ["up color" "down color"] colors: [0.150.100 
    150.20.20]]
    button "image" pic
    button "color image" pic 200.100.50

    button "flip color" pic with [effects: [[fit colorize 50.50.200][fit 
    colorize 200.50.50]]]
    button "blink" with [rate: 2 colors: [160.40.40 40.160.40]]
    return

    button "multiply" pic with [effects: [[fit][fit multiply 128.80.60]]]
    button "brighten" pic with [effects: [[fit][fit luma 80]]]

    button "contrast" pic with [effects: [[fit][fit contrast 80]]]
    button "horiz flip" pic with [effects: [[fit][fit flip 1x0]]]

    button "vert reflect" pic with [effects: [[fit][fit reflect 0x1]]]
    button "invert" pic with [effects: [[fit][fit invert]]]

    button "vert grad" with [effects: [[gradient 0x1 0.0.0 0.200.0] [gradient 
    0x1 0.200.0 0.0.0]]]

    button "horiz grad" with [effects: [[gradient 1x0 200.0.0 200.200.200][gradient 
    1x0 200.200.200 200.0.0]]]

    button "both grad" with [effects: [[gradient 1x0 140.0.0 40.40.200] 
    [gradient 0x1 40.40.200 140.0.0]]]

    button "blink grad" with [rate: 4 effects: [[gradient 1x0 0.0.0 0.0.200] 
    [gradient 1x0 0.0.200 0.0.0]]]

    button "blink flip" pic with [rate: 8 effects: [[fit][fit flip 0x1]]]
    return
    button "big dull button with several lines" 100x80 0.0.100

    button "dual color" pic 50.50.100 100.50.50 100x80 with [edge: [color: 
    80.80.80]]

    button "big edge" pic 100x80 with [edge: [size: 5x5 color: 80.80.80] 
    effects: [[fit colorize 50.100.50][fit]]]

    button "oval reflect" pic 50.100.50 100x80 with [effect: [fit reflect 
    1x0 oval]]
    return

    button "text on top" pic 100x80 with [font: [valign: 'top] effects: 
    [[fit gradcol 1x1 200.0.0 0.0.200] [fit gradcol -1x-1 200.0.0 0.0.200]]]

    button "text on bottom" pic 100x80 50.50.100 with [font: [valign: 
    'bottom] effects: [[fit][fit invert]]]

    button "big text font" pic 100x80 with [font: [size: 24] effects: 
    [[fit multiply 50.100.200][fit]]]

    button "cross flip" pic 50.100.50 100x80 with [effect: [fit flip 
    0x1 reflect 0x1 cross]]
    return
    toggle "toggle"
    toggle "toggle red" 100.0.0 
    toggle "toggle up" "toggle down"
    toggle "toggle colored" 0.150.100 150.20.20
    toggle "up color" "down color" 0.150.100 150.20.20

    toggle "toggle multiply" pic with [effects: [[fit][fit multiply 128.80.60]]]

    toggle "toggle contrast" pic with [effects: [[fit][fit contrast 80]]]
    toggle "toggle cross" pic with [effects: [[fit][fit cross]]]

    toggle "toggle v-grad" with [effects: [[gradient 0x1 0.0.0 0.200.0] 
    [gradient 0x1 0.200.0 0.0.0]]]

    toggle "toggle h-grad" with [effects: [[gradient 1x0 200.0.0 200.200.200][gradient 
    1x0 200.200.200 200.0.0]]]

    toggle "toggle both" with [effects: [[gradient 1x0 140.0.0 40.40.200] 
    [gradient 0x1 40.40.200 140.0.0]]]
    return
    rotary data group
    rotary data reduce [now/date now/time]
    rotary data group 100.0.0 0.100.0 0.0.100

    rotary data group with [font: [colors: [255.80.80 80.200.80]]]
    rotary data group with [colors: [0.150.100 150.20.20]]
    rotary data group pic
    rotary data group pic 200.100.50

    rotary data group pic with [effects: [[fit colorize 50.50.200][fit 
    colorize 200.50.50]]]

    rotary data group with [effects: [[gradient 0x1 0.0.0 0.200.0] [gradient 
    0x1 0.200.0 0.0.0]]]

    rotary data group with [effects: [[gradient 1x0 200.0.0 200.200.200][gradient 
    1x0 200.200.200 200.0.0]]]

    rotary data group with [effects: [[gradient 1x0 140.0.0 40.40.200] 
    [gradient 0x1 40.40.200 140.0.0]]]
===Paint Program


This section is a clip of the layout portion of Frank Sievertsen's 
remarkable paint program. Open this example to enable a quick link 
to the real source:


 button "Browse Source" [browse http://www.reboltech.com/library/html/paint.html]
 button "Close" [unview]


In the example below, a DO block is used to execute initialize code.

 do [

    color: fill-color: start: draw-image: draw-pos: tmp: none
    type: 'box
    undos: [] redos: []
    draw: func [offset /local tmp] [
        compose [
            pen (color/color) fill-pen (fill-color/color)
            (type) (start) (either type = 'circle [
                tmp: offset - start
                to-integer square-root add tmp/x ** 2 tmp/y ** 2
            ] [offset])
        ]
    ]
 ]
 
        backdrop effect compose [gradient 1x1 (sky) (water)]
        across
        draw-image: image white 300x300 effect [draw []]
        feel [engage: func [face action event] [
            if all [type start] [
                if find [over away] action [
                    append clear draw-pos draw event/offset
                    show face
                ]
                if action = 'up [
                    append/only undos draw-pos
                    draw-pos: tail draw-pos
                    start: none
                ]
            ]
            if all [type action = 'down] [
                start: event/offset
            ]
        ]]
        do [draw-pos: draw-image/effect/draw]
        guide
        style text text [
            tmp: first back find face/parent-face/pane face
            tmp/feel/engage tmp 'down none
            tmp/feel/engage tmp 'up none
        ]
        label "Tool:" return
        radio [type: 'line] text "Line"
        return
        radio [type: 'box] on text "Box"
        return
        radio [type: 'circle] text "Circle"
        return
        style color-box box 15x15 [

            face/color: either face/color [request-color/color face/color] [request-color]
        ] ibevel
        color: color-box 0.0.0 text "Pen"
        return
        fill-color: color-box text "Fill-pen"
        return
        button "Undo" [if not empty? undos [
            append/only redos copy last undos
            draw-pos: clear last undos
            remove back tail undos
            show draw-image
        ]]
        return
        button "Redo" [if not empty? redos [
            append/only undos draw-pos
            draw-pos: insert draw-pos last redos
            remove back tail redos
            show draw-image
        ]]
===Font Lab

Carl's Font lab



Here a do block is used to initialize some values needed in the layout

 do [

    change-styles: func [style start facet subfacet value /local v][
    start: find style/pane start
    foreach f start [
        f: in f facet
        if subfacet <> 'none [f: in get f subfacet]
        either block? value [

            if not block? get f [set f either none? get f [copy []][reduce [get 
            f]]]

            either v: find get f value [remove v][head insert get f value]
        ][set f value]
    ]
    show style
 ]

 chg: func ['facet 'subfacet value] [
    change-styles external-view norm-start facet subfacet value
 ]
 shad: does [chg font shadow sdir * to-integer sl2/data * 16]
 sdir: 1x1
 sz: 180x40
 sx2: sz/x / 2 
 ]



    style tgl toggle 60
    style lab vtext bold
    backcolor rebolor
    space 0x5
    across 

    p: choice 180 "Sans-Serif Style" "Serif Style" "Fixed Width Style" 

        [chg font name pick reduce [font-sans-serif font-serif font-fixed] 
        index? p/data]
        return
    tgl "Bold" [chg font style [bold]]
    tgl "Italic" italic [chg font style [italic]]
    tgl "Lined" underline [chg font style [underline]]
    return
    tgl "Left" of 'tg1 [chg font align 'left]
    tgl "Center" of 'tg1 [chg font align 'center]
    tgl "Right" of 'tg1 [chg font align 'right]
    return
    tgl "Top" of 'tg2 [chg font valign 'top]
    tgl "Middle" of 'tg2 [chg font valign 'middle]
    tgl "Bottom" of 'tg2 [chg font valign 'bottom]
    return
    lab "Size:" 60x20 font []

    sl: slider 120x20 [chg font size max 8 to-integer sl/data * 40] 
     with [append init [data: .5]]
    
    return
    lab "Space:" 60x20 font []

    sl1: slider 120x20 [chg font space (1x0 * to-integer sl1/data * 20) 
    - 5x0]
    return
    lab "Shadow:" 60x20 font []
    sl2: slider 120x20 [shad]  with [append init [data: .5]]
    return
    lab "Shad Dir:" 60x20
    arrow left  [sdir: sdir * 0x1 + -1x0 shad] pad 6
    arrow right [sdir: sdir * 0x1 + 1x0 shad]  pad 6
    arrow up    [sdir: sdir * 1x0 + 0x-1 shad] pad 6
    arrow down  [sdir: sdir * 1x0 + 0x1 shad]  pad 6
    return
    button sx2 "Text Color" [chg font color request-color]
    button sx2 "Area Color" [chg color none request-color]
    return

    button sx2 "Help" [alert "Click the controls on the left to change 
    text on the right."]
    button sx2 "Close" #"^Q" [unview]
    below
    at p/offset + (p/size * 1x0) + 10x0
    norm-start:
    Title "Title" sz
    h1 "Heading 1" sz
    h2 "Heading 2" sz
    h3 "Heading 3" sz
    h4 "Heading 4" sz
    h5 "Heading 5" sz
    at norm-start/offset + (norm-start/size * 1x0) + 10x0
    banner "Banner" sz
    vh1 "Video Heading 1" sz
    vh2 "Video Heading 2" sz
    vh3 "Video Heading 3" sz
    vtext "Video Text" sz
    text "Document Text" sz
    

===Windows Clipboard


---Cut or Copy to Clipboard


Normal Windows cut and copy commands are supported e.g. on a field, 
contents can be copied to the clipboard. Programmatic access is also 
supported for text contents.

    across 
    label "Entry field: "
    return input-field: field 200 "Enter your text here"

    return button 200 "Copy Entry field data to clipboard" [write clipboard:// 
    input-field/text]

    return button 200 "Show Clipboard Contents" [alert read clipboard://] 


---Clearing The Clipboard


    across 
    button 200 "Clear The Clipboard" [write clipboard:// ""]

    return button 200 "Show Clipboard Contents" [alert read clipboard://] 



---Paste from Clipboard


Normal Windows paste commands are supported e.g. on a field, contents 
can be pasted. Programmatic access is also supported for text contents.

    across 

    button 200 "Show Clipboard Contents" [alert read clipboard://] 
===Requesters


REBOL View supports an assortment of requesters. 


The results of the request-* code are returned as its value e.g. 
chosen-date: request-date


---Request Yes | No | Cancel


Provides the user the capability to pick from choices "Yes" | "No" 
| "Cancel"

The result is "True" | "False" | none

    do [user-response: none]

    button "Simple Request" 200 [user-response: request "Do you want 
    to abandon your input so far?"]
    button "View User Response" 200 [alert form user-response]
    

---Pick A Color

    do [chosen-color: gold] 
    button "Pick Color" 200 [chosen-color: request-color]
    button "View Chosen Color" 200 [alert form chosen-color]



---Pick An Answer

The request allows a descriptive value then 1, 2, or 3 options.


    button "Format" 100 [request ["Your message goes here. It will wrap 
    if it is very very long." "Choice 1" "Choice 2" "Choice 3"]]
    

    button "Example 1" 100 [request ["Pick The Color of Your New Model 
    T" "Black"]]
    

    button "Example 2" 100 [request ["Pick one country" "England" "France"]]


    button "Example 3" 100 [request ["Run Extract Script?" "Yes" "No" 
    "Cancel"]]


---Pick A Date

    do [chosen-date: 01-Jun-1990]
    button "Pick Date" 200 [chosen-date: request-date]
    button "See Chosen Date" 200 [alert form chosen-date]

---Get A LogonID and Password

    do [credentials: none]
    button "Get Credentials" 200 [credentials: request-pass]
    button "View Credentials" 200 [
        view/new layout [
            size 200x200 backtile polished orange 
            across banner "Credentials" 
            return label "LogonID:  " txt pick credentials 1
            return label "Password: " txt pick credentials 2
        ]
    ]


---Pick A File


Format: REQUEST-FILE /title title-line button-text /file name /filter 
filt /keep    

        do [filter-block: ["*.gif" "*.jpg" "*.png" "*.bmp"]]

        button "Pick Any File" 300 [request-file "Select"]      

        button "Pick With A Title" 300 [request-file/title "Pick The Data 
        File to Process" "OK"]

        button "Change the Action Button Name" 300 [request-file/title "Pick 
        The Data File to Process" "OK"]        

        button "Keep Results" 300 [request-file/title/keep "Previous Select 
        On This Button Is Kept" "OK"]

        button "Filter Files" 300 [request-file/title/filter "Pick An Image 
        File" "OK" filter-block]    



---Request Text Input

Format: REQUEST-TEXT /offset xy /title title-text /default str
    

    button "Request Text Input - all default parameters" 300 [request-text]

    button "Request Text Input - with offset to window" 300 [request-text/offset 
    40x40]

    button "Request Text Input - with title" 300 [request-text/title 
    "Input your question"]

    button "Request Text Input - with default" 300 [request-text/default 
    "Key your question here"]

    button "Request Text Input - with all parameters" 300 [request-text/offset/title/default 
    100x100 "Input your question" "Key your question here"]



---Request Download from Net


Request a file download from the net. Show progress. Return none 
on error.

Format: REQUEST-DOWNLOAD url /to local-file

    backtile polished orange    

    button "Request File Download To local REBOL Cache" 300 [request-download 
    http://www.rebol.com/index.html]

    button "Request File Download To This Directory" 300 [request-download/to 
    http://www.rebol.com/index.htmlnone]

    button "Request File Download To Specific File" 300 [request-download/to 
    http://www.rebol.com/index.html%/c/temp.html]

===Message Box


    button "Format" 100 [request ["Your message goes here. It will wrap 
    if it is very very long and tedious." "Close"]] 
    button "Example" 100 [request ["You done good!" "OK"]]



---Confirmation

    button "Exit" 100 [
        request/confirm "Do you want to quit without saving?" []
    ]
    

===Calling the Editor

The REBOL editor is now callable with the editor function

    backtile polished
    button 300 "Create a test file and edit it" [
        write %temp.txt "This is a test file"
        editor %temp.txt
    ] frame 204.0.0 
    

===Calling Windows

With View/Pro the calling of executables is supported.

Here are two simple examples that will work if you have View/Pro 
on a platform where a notepad and calc are avaiable.

    across backtile size 200x200
    return button "Notepad" [call ["notepad.exe"]]
    return button "Calculator" [call ["calc.exe"]]


===Window Options


Note that these are options which are ignored by the easyvid.r code 
that displays them in this tutorial.
Copy the code out and run it standalone in REBOL/View.

---Block Options: No Border and No Title

    view/options layout [
        size 200x200 
        banner "Window Options" 
        button "Close" [unview]
        ] [
            no-border
            no-title
        ]


---Word Option: No Title


Note that the results of this are surprising if you run it from within 
a script that has a title option. It is displayed near location 0x0 
of the resulting window instead of in the window frame that has been 
suppressed. 

    view/options layout [
        size 200x200 
        banner "Window Options" 
        button "Close" [unview]
        ] 'no-title

===REBOL/View Notifiers


REBOL/View supports simple notifiers to send messages to a user interface


---Alert

    button 220 polished "Send alert message" [
        alert "This causes a dialogue box to popup"
    ]





---Flash

Flash is provided to provide a message and keep on processing.

    across size 200x200
    return button 150 "Create Flash Message" [flash "Testing"]
    return button 150 "Unview Flash" [unview]



---Inform

    inform layout  [
        backtile polished sky 

        across text font-size 16 bold underline red "Action complete!" 
        return button "OK"  [unview]]

---Popup

REBOL supports popups  (see note below before running!)

        across size 200x200 
        button "Show Popup" [
            show-popup popup-layout: layout [
                    across size 200x200 
                    backtile polished
                    banner "The Popup Worked" 
                    return button "Unview" [unview]
                ]
        ]
        return button "Hide Popup" [unview/only popup-layout]

I have had some difficulties (process lockup) when using

these popups so just use view layout [...] and skip the popup part.

===Diagram Example


Carl has created some diagrams in REBOL using styles to make an architecture 
diagram.

This is a slightly modified version.


Here again a DO block precedes the layout code for non-layout initiatiation 
... here the definition of a function.

Why make a diagram this way?


1. One reason is that it can be interactive ... the sections are 
all "hot" with a few lines of code.  Here they pop up REBOL Dialogs 
but they could do anything that can be coded even something as simple 
as launching a browser on a different URL for each diagram component. 
 The "Compositor" box demonstrates this by launching your browser 
on the REBOL.com site.


2. Very small footprint size compared to other presentation source 
formats.




 do [
        information: func [info [string!]][
        request/ok reform [ info]
    ]
 ]



    style bx box 255.255.255 0.0.0 font-size 11 font [color: 0.0.0 shadow: 
    0x0] edge [size: 5x2] 
        [request/ok reform ["No information on" face/text]] 

    style bb box bold left top para [origin: 6x10] edge [size: 2x2]
        [request/ok reform ["No information on" face/text]]
    backcolor silver + 30
    at 15x15 h1 486 left "Arch Structure" 
    at 15x50    bb "Client" 506x436 160.80.80 [

        information "Any client machine e.g. branch or Call Centre"]

    at 25x252   bb "Mid-Tier" 486x68 effect [gradient 1x1 169.91.155 
    80.45.75]

    at 25x152   bb "UI" 486x96    effect [gradient 1x1 38.156.82 19.78.41]

    at 25x324   bb "Servers" 486x151   effect [gradient 1x1 103.96.200 
    50.45.100] [

        information "Mid-tiers servers with XYZ relational database server" 
                                                                         
              
    ]

    at 130x216  bx "Compositor" 182x24 bold [browse http://www.rebol.com]

    at 130x60   bx "Browser" 120x24 [information "Branch standard browser"]

    at 130x188  bx "Sound" 182x24 bold [information "Sound services"]
    at 255x60   bx "Win32" 120x24 [information "Win32 App"]

===Column Images


Creates a layout looking (a little) like columns. It uses a gradient 
effect going from darker to lighter

 do [
     column: make image! layout [

            backdrop effect [gradient 1x0 20.20.20 250.240.230 luma 60]
        ]

    column-size: 50x420

    area-size: 400x420  ; height should be the same as column-size
 ]
 backtile polished tan
   across 
   image column-size  column 
   pad -10x0        ; this brings the default VID spacing back
   area wrap area-size  

   edge none        ; take the edge off of area so that it more closely 
   blends 
   shadow 2x2

   pad -10x0 image column-size column  ; if you want a right column

===Tree View of Directory

This is Didier's tree view %request-dir.r


In this sample, you must be online because the code is accessed on 
the Rebol script server

 do [do http://www.rebol.org/library/scripts/request-dir.r
     request-dir
 ]


Note that:

* the script is read from the script library but runs locally

* it is showing the files in your directories


===The emailer Function


The function for emailing has appeared in Jan-2004 on the rebol list.


It is a simple idea ... to create a standard emailer by invoking 
a function emailer. This window will show the source:

  text wrap 400x300 mold get 'emailer

And it is simple to run:

    across size 200x200
    return button 150 "Run emailer" [emailer]


But on my machine there is again a problem - the emailer locks up 
REBOL/View.

Recommendation:

* if it works use it if you like


* use Doc Kimbel's one liner (works for me). Assumes you have set 
up your email in set-user



 e: field "Email" s: field "Subject" m: area "Body" btn "Send"[send/subject 
 to-email e/text m/text s/text alert "ok"]



* better yet, make your own... if the code for the basic is 1 line, 
then a custom version is not far away. Here's an example that allows 
selection of your frequent contacts (entered in the names-addresses 
series) and keeps a journal of email that you have sent (using this 
code) in file email-journal.txt.  Assumes you have setup your user 
profile correctly to allow sending of email.


 do [

  names-addresses: [
    "Contact 1"         [contact1-:-no-such-address-:-com]
    "Contact 2"         [contact2-:-no-such-address-:-com]
    "Contact 3"         [contact3-:-no-such-address-:-com]
  ]

  names: copy []
  foreach [name address] names-addresses [append names name]


  journal?: false  ; set to true if want to journalize sent email
 ]

    e: rotary 200 data sort names
    s: field "Subject" 
    m: area 500x400 wrap "Body" 
    btn "Send"[

        send/subject who-to: select names-addresses e/text m/text s/text 
        alert join "Sent email to: " form who-to
        
        if journal? [
            write/append %email-journal.txt rejoin [
                "[ When-sent: " now/precise 
                " To: " who-to
                " Subject: {" s/text
                "} Message: {" m/text "} ] "
                newline
            ]
        ]
    ]
    btn "Quit" [unview]



It won't take much to change this from the rotary used to a text 
list allowing multiple selections.





===Some More email


Earlier there have been a few examples of sending email. Here are 
a few more that often appear in the mailing list

---Simple Send


This is not a runnable version because you don't need anything but 
REBOL/Core to run it. It has been wrapped in a DO block so it does 
not send errors to the console.

---Quick Send Short Message

 do [
    send [address-:-isp-:-com] "My Message"
 ]
 
---Send Longer Message  

Now a more complex message where there is a body to the message:

 do [
    send [address-:-isp-:-com] {Sample Message
               
    This is the body of the message
    } 
 ]

---Send with One Attachment


Here, so that the sample does not fail, test file(s) are created 
by the code before attempting the send. 

 do [
    test-file: %file-attachment.txt
    write test-file {Just some test data to create a file}
    send/attach [address-:-isp-:-com] {Sample Message
               
    This is the body of the message
    } test-file
 ]
 
---Send with Attachments

And a message with multiple attachments.


Here, so that the sample does not fail, test file(s) are created 
by the code before attempting the send. 

 do [
    files: [%file-attachment.txt %second-attachment.txt]

    foreach file files [write file {Just some test data to create a file}]
    send/attach [address-:-isp-:-com] {Sample Message
               
    This is the body of the message
    } files
 ]
 
---Send to Multiple Addresses


Here, so that the sample does not fail, test file(s) are created 
by the code before attempting the send. 

 do [
    files: [%file-attachment.txt %second-attachment.txt]

    foreach file files [write file {Just some test data to create a file}] 

    send/attach [[address-:-isp-:-com][asecondAddress-:-isp-:-com]] {Sample Message
               
    This is the body of the message
    } files
 ]
 
---Send/only

Same send only just provide the SMTP server with one copy:

Here, so that the sample does not fail, test file(s) are created 
by the code before attempting the send. 

  do [
    files: [%file-attachment.txt %second-attachment.txt]

    foreach file files [write file {Just some test data to create a file}] 

    send/only/attach [[address-:-isp-:-com][asecondAddress-:-isp-:-com]] {Sample 
    Message
               
    This is the body of the message
    } files
 ]
 
---Send With Header


This example uses a Do block to wrap the code. If you execute the 
email should be sent.
But it is unlikely to be delivered.


The addresses for me and you should be changed in your use as well 
as the

* Subject

* Organization

* Content 

 do [
   me: [myaddress-:-isp-:-com]
   you: [youraddress-:-isp-:-com]
   header-object: make system/standard/email [
            From: me
            Reply-To: me
            Subject: "Some Stuff"
            Organization: "Cyberia"
            MIME-Version: 1.0 
            Content-Type: "text/plain"
    ]
 send/header you {Test Message
    This is the message body.
    }                 
    header-object 
 ] 

---Send with CC

This adds a copy value in the header-object

 do [
   me: [myaddress-:-isp-:-com]
   you: [youraddress-:-isp-:-com]
   header-object: make system/standard/email [
            From: me
            Reply-To: me
            Subject: "Some Stuff"
            Organization: "Cyberia"
            MIME-Version: 1.0 
            Content-Type: "text/plain"
        cc: [another-address-:-isp-:-com]
    ]
 send/header you {Test Message
    This is the message body.
    }                 
    header-object 
 ] 


   
---Doctored Code

Again Doc Kimbel's one liner that does not waste a character


 e: field "Email" s: field "Subject" m: area "Body" btn "Send"[send/subject 
 to-email e/text m/text s/text alert "ok"]


===Sharp Styles


I really like the style that Didier has put around his email previewer

 do [
    ss-light: stylize [
        text: text feel none
        vtext: vtext feel none
        col-hdg: text black 255.255.204 bold middle effect []
        col-txt: text edge [size: 1x0 color: gray effect: 'bevel]
        ban: vh3 left to-pair reduce [
            50 logo.gif/size/y] edge [

                color: 0.0.0 size: 0x1] feel none with [color: black]
        lab: label para [origin: 2x3 margin: 0x2]
        labe: lab edge [size: 1x1 color: water effect: 'ibevel]
        inf: info 100 font-color yellow
        bkg: backdrop water - 10.10.10
        txt-big: vtext 300 font-size 18 font-color yellow center
        rti: vtext font-size 14 bold
        txt-ch: rti font-color white 170x22 para [
            origin: 2x3] with [font: make font [
                    color: white] colors: [55.95.155 235.170.55]]
        btnb: btn 70.70.70 font-color white

        men: rti 264 edge [size: 1x1 color: water effect: 'bevel] para [origin: 
        20x2 margin: 1x4]

             with [color: water - 40.40.40 effect: first effects: [

                [draw [pen white fill-pen white polygon 5x2 13x10 5x18]] [draw [pen 
                white fill-pen white polygon 2x5 10x13 18x5]]
             ] feel: none]  ;system/view/vid/vid-feel/hot]

        cbox: box 60x20 edge [size: 1x1 color: water effect: 'bevel] [

            if temp: request-color/color first face/data [face/color: temp change 
            face/data temp show face]
        ] with [append init [color: first data]]
    ]
    stylesheet: ss-heavy: stylize/styles [

        col-hdg: col-hdg effect [gradcol 0x1 200.200.160 155.155.104]

        ban: ban effect [merge gradcol 150.180.200 0.0.0] with [color: none]

        bkg: backdrop effect [gradient 1x1 65.125.175 45.75.115 grid 2000x4 
        1999x4 70.130.190 blur]
        txt-big: vtext 300 font-size 18 font-color yellow center
        rti: vtext font-size 14 bold

        txt-ch: txt-ch effect [gradcol -1x1 105.105.105 151.151.151]
        men: men effect [gradcol -1x0 black water]
    ] ss-light
 ]
    styles stylesheet
    space 4x4 origin 4x4 across
    bkg
    pad 15 ban 235 :title para [origin: 32x0]
    pad -254
    image 30x30 %palms.jpg effect [fit key 255.0.255]
}
code: text: layo: external-view: none
sections: []
layouts: []
space: charset " ^-"
chars: complement charset " ^-^/"

rules: [title some parts]

title: [text-line (title-line: text)]

parts: [
      newline
    | "===" section
    | "---" subsect
    | "!" note
    | example
    | paragraph
]

text-line: [copy text to newline newline]
indented:  [some space thru newline]
paragraph: [copy para some [chars thru newline] (emit txt para)]
note: [copy para some [chars thru newline] (emit-note para)]
example: [
    copy code some [indented | some newline indented]
    (emit-code code)
]

section: [
    text-line (
        append sections text
        append/only layouts layo: copy page-template
        emit h1 text
    ) newline
]
subsect: [text-line (emit h2 text)]
emit: func ['style data] [repend layo [style data]]
emit-code: func [code] [
    remove back tail code
    repend layo ['code 460x-1 trim/auto code 'show-example]
]
emit-note: func [code] [
    remove back tail code
    repend layo ['tnt 460x-1 code]
]

show-example: [

    if external-view [xy: external-view/offset  unview/only external-view]
    xcode: load/all face/text
    if not block? xcode [xcode: reduce [xcode]] ;!!! fix load/all
    if here: select xcode 'layout [xcode: here]
    external-view: view/new/offset layout xcode xy
]

page-template: [
    size 500x480 origin 8x8
    backdrop white - 80

    style code tt snow navy bold as-is para [origin: margin: 12x8]
    style tnt txt maroon bold
]

parse/all detab content rules
show-page: func [i /local blk last-face][
    i: max 1 min length? sections i
    append clear tl/picked pick sections i 
    if blk: pick layouts this-page: i [
        f-box/pane: layout/offset blk 0x0 
        last-face: last f-box/pane/pane    ; bh slider

    f-box/pane/pane/1/size: f-box/pane/size: max 500x480 add 20x20 add 
    last-face/offset last-face/size ; bh slider
    update-slider ; bh slider
        show f-box
    ]

    show tl    ; changed to after slider update ; was not refreshing 
    the index display
]


update-slider: does [
    sld/data: 0
    either object? f-box/pane [
        sld/redrag min 1.0 divide sld/size/2 f-box/pane/size/2
        sld/action: func[face event] compose [

            f-box/pane/offset/2: multiply face/data (subtract 480 f-box/pane/size/2)
            show f-box
        ]
    ][
        sld/redrag 1.0 show sld
        sld/action: none
    ]
    show sld
]

main: layout [
    backtile polished
    across
    vh2 title-line return
    tl: text-list 160x480 bold black white data sections [
        show-page index? find sections value
    ]
    h: at
    f-box: box 500x480

  at h + 500x0 sld: slider 24x480                 ; add brett's slider
    at h + 456x-24
    across space 4
    arrow left  keycode [up left] [show-page this-page - 1]
    arrow right keycode [down right] [show-page this-page + 1]
    pad -150

    txt white italic font-size 16 form system/script/header/date/date
]

show-page 1
xy: main/offset + either system/view/screen-face/size/x > 900 [
    main/size * 1x0 + 8x0][300x300]
view main

!
erm, you could have posted a link to that...