[racket] Graphical Toolkit change question

From: Christophe Vandenberghe (chvndb at gmail.com)
Date: Fri Feb 25 10:52:25 EST 2011

Indeed, transparency only makes sense if the order of the panels can be guaranteed. So unless this can be manipulated somehow or the order is always fixed, it is not always certain that the background panel will be "behind" all others. So my original problem still exists.

-----Original Message-----
From: robby.findler at gmail.com [mailto:robby.findler at gmail.com] On Behalf Of Robby Findler
Sent: vrijdag 25 februari 2011 16:27
To: Christophe Vandenberghe
Cc: users at racket-lang.org
Subject: Re: [racket] Graphical Toolkit change question

Sorry to but in, but I think I missed a step: if you cannot guarantee
the order of the panels, how does this kind of thing work?


On Fri, Feb 25, 2011 at 9:17 AM, Christophe Vandenberghe
<chvndb at gmail.com> wrote:
> Well, if panels can be transparent then I could use one main panel and add a canvas to draw the background and overlay it with the transparent panels (or use a message% with a bitmap label instead of the canvas if it is a fixed image). Then there is no need for the 'on-paint' for panels.
> -----Original Message-----
> From: Matthew Flatt [mailto:mflatt at cs.utah.edu]
> Sent: vrijdag 25 februari 2011 13:55
> To: Christophe Vandenberghe
> Cc: users at racket-lang.org
> Subject: RE: [racket] Graphical Toolkit change question
> Ok, but to be clear, you need both `on-paint' and transparency for
> panels, right? Transparent panels can group and hide controls, but you
> need `on-paint' to draw a background in the first place.
> It turns out that transparency more or less falls out of supporting
> `on-paint' for panels, so I'll work on both.
> At Fri, 25 Feb 2011 08:30:44 +0100, "Christophe Vandenberghe" wrote:
>> That is indeed my problem. I am using Win32 and panels take the same color as
>> their parent. That is why I could never make something like a background panel
>> with another panel on top that is the same size as the background and only
>> contains for example one button centered in the middle (a.k.a a menu). This
>> would make it easy to be able to hide that "menu" and show another one when the
>> button is clicked. But since the panels take the same color as their parent (in
>> this case the frame), the overlaying panel hides the background panel.
>> The only workaround I have found is to use a container panel for each of these
>> "menus" that on their own contain the background and then a pane (as panes do
>> show transparent, but cannot be removed unless it's parent is removed)
>> containing the menu. That way I can always show and hide the container panel
>> and create a navigation between menus. The huge problem with this approach is
>> that the background has to be loaded and inserted for each of the menus
>> separately instead of just once in the main frame.
>> -----Original Message-----
>> From: Matthew Flatt [mailto:mflatt at cs.utah.edu]
>> Sent: donderdag 24 februari 2011 15:11
>> To: Christophe Vandenberghe
>> Cc: users at racket-lang.org
>> Subject: RE: [racket] Graphical Toolkit change question
>> At Thu, 24 Feb 2011 09:30:26 +0100, "Christophe Vandenberghe" wrote:
>> > But then again like I said before. It would be easier to have
>> > transparency for panels, as it would resolve the need for panes
>> > inserted in panels to be able to hide or delete them when needed.
>> > That would also solve the background problem. Would that be easy to
>> > achieve with the new implementation?
>> I'm not clear on the sense in which panels are currently opaque.
>> Since siblings are not supposed to overlap, the only kind of window
>> that can be behind a panel is another panel or eventually a frame.
>> I'm relatively clear on what happens with Win32 and Cocoa:
>>  * Under Win32 (the way `racket/gui' currently uses it), all panels and
>>    frames are the same color, so you can't really tell whether panels
>>    are transparent (i.e., transparent and solid is all the same).
>>  * Under Cocoa, all panels are transparent, allowing a frame's texture
>>    (if any) to show through.
>> Is there a Gtk theme where frame content and/or panels can be textured
>> (as opposed to being all the same color), so that you can tell the
>> difference between an opaque panel and a transparent one? Or are you
>> talking about something else completely?
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