[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: GNUstep cookbook: screen grab with X11. Misc.
From: |
Alexander Malmberg |
Subject: |
Re: GNUstep cookbook: screen grab with X11. Misc. |
Date: |
Tue, 23 Sep 2003 18:43:41 +0200 |
Marko Riedel wrote:
[snip]
> 1. I looked at the code in XGServer where improvements are
> solicited. As far as I can see this code tries to guess the bitmap
> structure of TrueColor pixels by trying different combinations,
> sending them as a pixel value to the server, reading the component
> values that the server returned and checking whether the guess was
> correct. Shouldn't we be able to do without guessing? It seems to
> me that we need only look at the fields "red_mask", "green_mask"
> and "blue_mask" of the visual, the way I do in my recipe.
It should. back-art uses the masks.
> That way
> we could handle all pixel structures and not just the few that are
> hardcoded into XGServer.
Not all, only the ones that can be described using these three masks.
You still need to query the server for pseudo-color visuals, and I don't
think it'd help with grayscale visuals (although I guess those are rare
today).
[snip]
> 3. Stefan Urbanek asked whether we could use the code from my recipe
> in a color picker. I don't quite understand what he means.
[snip]
I think what he means is that the color picker should have a function
that lets you click on a location on the screen and have the color
picker grab the color of a nearby pixel.
The answer is that the color picker couldn't use this code directly
(it's X-specific), but similar code could be added in the implementation
in back-x11 of a GSReadPixelFromScreen operator (or something) and the
color picker could use that.
- Alexander Malmberg