[REBOL] Re: Capturing transparent faces.
From: volker:nitsch:g:mail at: 26-Jun-2005 1:30
On 6/26/05, Carl Read <[carl--cybercraft--co--nz]> wrote:
> On Saturday, 25-June-2005 at 23:47:09 Volker Nitsch wrote,
>
> >On 6/25/05, Petr Krenzelok <[petr--krenzelok--trz--cz]> wrote:
>
> >> >If you have a transparent face in View, it can be used to grab an image
> >> >of the faces under it. However, I can only get this to work on a layout in
> >> >an open window - when I attempt it on layout, all I get is a black image.
> >> >
> >> >Here's an example of this: Just run it, click on the "Grab Area" button
> > and you'll see what I mean...
> >> >
> >> >
> >> >rebol []
> >> >lo: layout [
> >> > title "Grab area test."
> >> > at 30x20
> >> > b: box 80x30 with [color: none] ; Transparent box.
> >> > button "Grab Area" [
> >> > window-grab: to-image b
> >> > unview/all
> >> > ]
> >> >]
> >> >lo-grab: to-image b
> >> >
> >> >
> >>
> >> Look, I am no guru at View, but imo following happens. Feel free to
> >> correct me eventually:
> >>
> >> you create snapshot of 'b (lo-grab), even before it is being shown for
> >> the first time. Imo layout just defines structures, but does not apply
> >> effect, until the face is actually shown.
> >
> >Pekr, if you continue at that pace, you will be guru shortly ;)
> >And the solution is:
> >You can show things without viewing them.
> >That forces /view to paint into the internal buffers.
> >A to-image just dumps these buffers, without a 'show there is just black..
> >So
> >
> >!>> lo: layout [
> >[ title "Grab area test."
> >[ at 30x20
> >[ b: box 80x30 with [color: none] ; Transparent box.
> >[ button "Grab Area" [
> >[ window-grab: to-image b
> >[ unview/all
> >[ ]
> >[ ]
> >!>> show lo
> >; ^^^^^^^^!!!!!!!!!
> >!>> lo-grab: to-image lo
> >== make image! [220x102 #{
> >C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8
> >C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C...
> >!>> view layout[image lo-grab]
>
> Thanks Volker (and Petr), but that still doesn't do what I want, which is to capture
'b, not 'lo.
>
Tried a bit, quite confusing. found two ways:
1) One was with 'view, grabbing the face itself does not work without it.
2) But what you can do is:
lo-grab: copy/part at to-image lo 30x20 80x30
(note you have to get it from the whole layout, not just the box)
Easier than those numbers to exact face-content:
lo-grab: copy/part at to-image lo b/offset b/size
> And incidentally, you don't need to SHOW a layout before capturing it - this works
just fine...
>
> pic: to-image layout [text "Some text." button "A button"]
> view layout [image pic]
>
Ooops. hmm. Once long before something did not work! Must have been
something different. Ok, thanks for the tip :)
> -- Carl Read.
>
> --
> To unsubscribe from the list, just send an email to
> lists at rebol.com with unsubscribe as the subject.
>
--
-Volker
Any problem in computer science can be solved with another layer of
indirection. But that usually will create another problem.
David
Wheeler
