World: r3wp

Try this:

view layout [
    box 640x480 effect [

        draw [line-width 48 pen 0.132.28.0 0.0.0.0 arc 0x0 90x90 358.163265306122 
        90]
    ]
]

Thanks Kru! Put it into the Rambo. I'll fix that for next release.

I've probably got more of deadly bugs, but this one was the only 
I was able to reproduce. Probably later.

Good to know. There is so much combinations in the dialect so I appreciate 
any other reports ;)

Is is possible to deform an image into a triangular shape ?


I tried the following .... but specifying the 3rd & 4th co-ordinates 
as the same produces no image at all ....
view layout [

    box 100x100 effect [draw [image logo.gif 10x10 90x10 90x90 10x90]]

    box 100x100 effect [draw [image logo.gif 10x10 90x10 60x90 40x90]]

    box 100x100 effect [draw [image logo.gif 10x10 90x10 51x90 49x90]]

    box 100x100 effect [draw [image logo.gif 10x10 90x10 50x90 50x90]]
]

It looks like the algorithm always takes four points, so specifying 
two coincident points means a point at infinity, which means the 
image is infinitely stretched out. Mmmm....

try them a pixel apart

The reason for the question is I want to stretch the image into a 
triangle .... just wondered if this were a bug or a feature of the 
algorithm.
Is there another way of doing it using draw ?

a pixel apart still has the same problem - it is tending towards 
infinity.

(so you lose most of the image).

We want a "non-perspective" deform, I suppose.

Could do it with rebcode, I suppose.

Yes, the 'perspective' transforamtion cannot be used for triangles.

We can provide 'bilinear' transformer. But the bilinear algorithm 
in AGG is behave somehow strange. If anoyne know about correct one 
we might try to implement it or fix the current one in AGG.

In draw ref manual, I noticed an error about image: the third coordinate 
is not lower-left but lower-right

Does anyone knows what is the actual algo when resizing an image 
as a face attribute using 'aspect or 'fit ?

Now, using AGG style, I don't see any difference using bilinear or 
nearest neighboor... maybe I'm wrong in my code...

Actually, there is a diffrence when upscaling but not when downscaling

I think bilinear only works when scaling up. for scaling down, you 
need a different smoothling algorithm. I noticed this in Canvas as 
well

Reviewer: typo submited to the author.

ReViewver: the FIT and ASPECT effect block command are using the 
old(non Agg based) scaling algorithm. You can use the bilinear filter 
mode only in the DRAW block.

Also there is quality difference(nearest vs. bilinear)  when downscaling 
pictures.
See: http://www.rebol.cz/~cyphre/tests/filters.png

(But it is true there exists better quality algorithms for downscaling 
than simple bilinear one. Maybe we will add one of them in next version? 
Would be handy for high quality thumbnails etc.)

or spanned window to lower resolution?

If you don't need it in realtime the why not ;) Those HQ filters 
are much more time consuming.

Sorry Cyphre, but if you want to make thumbnails, you need possibility 
to save them as JPG. PNG is too big for thumbnail and there are still 
problems with this format. Forexample today I had problem when I 
wanted to use PNG as a background texture with IE.

It's not problem with PNG but with IE. Result is the same, I know.

Oldes. The discussion was about image quality when rescaling. Not 
about distirbution formats. But anyway, you can convert the PNG output 
from Rebol using some third party tool or library on-the-fly to JPG. 
This is no problem. AFAIK jpg saver is not included in rebol because 
of its binary size. But maybe in Rebol 3.0 we could porvide it as 
an module? ;)

a workaround is to blur the image a few times before scaling it down. 
A little time consuming, but if you need HQ thumbnails right now... 
:-)

cyphres did you looked at my  SVG rendere and the matrix problem 
in it ?

not yet, but I have it on my 'todo' ;) ...will let you know in a 
few days.

AGG and flash rendering... Cyphre, what's your view on this news?

I'll be reviewing the new official version of AGG (2.4) very soon. 
Maybe we could put the Flash rasterizer into DRAW dialect (it depends 
how much usable it is in real world, also how much code increase 
ould cost etc.

Ok.

But this type of rendering is usable only for relatively easy reproducing 
Flash shapes. I don't think it could be usful for some other things.

Cartoons? :)

ie. you have to have parsed the .fla or .swf file to get the shapes. 
Beacause the compound shapes are generated by Flash IDE (this is 
not an easy process) to achieve validity of the rendering.

hmm, I thought we could use Flash IDE tools, "export" curves and 
let it be "played" by rebol/agg :-)

yes, that is the only purpose..but by 'exporting' you have to parse 
the fla/swf to get the compound shapes. All other formats works in 
SVG-like rendering way (ie shapes are z-ordered and rendered one 
over another)

Would make it easier for flash-knowing artist.

Usually Flash-atrist don't event know how Flash interpret and render 
his gaphics :)

But I agree this feature could be handy for Olde's Rebol/Flash dialect 
tool.

But they know the drawing-tools?

The usage would be FlashIDE->Rebol/flash convertor->DRAW

So someone would have to make the Rebol/flash convertor for them 
to be able render it in Rebol. Maybe a good enhancement for Oldes? 
;)

WHich means save flash and click rebol-viewer (with integrated extractor?

I thought that Flash tools are able to export to text file thier 
curves and commands :-)

Then we need an action-script-<rebol converter. Which is javascript 
at the same time. And thanks to google we can then run java in rebol. 
hehe :)

yes, afaik you can export to many formats for m the IDE. But the 
trick is in the way how the cureves are described ;)