Testing Xft and screen scraping
Glynn Clements
glynn at gclements.plus.com
Sat Sep 16 05:48:30 PDT 2006
Fujinaka, Todd wrote:
> I am a total newbie and I need to do some X programming to test for the
> operational presence of Xft. This is for the Linux Standard Base
> project.
>
> So I was told by Keith that I should "paint 'em and scrape 'em." So does
> that mean that I just render some text into a pixmap and then compare
> the memory contents to something I've stored?
Yes.
> How does the actual screen
> setting affect that as far as bit depth and resolution are concerned?
The depth and visual will affect the format of the raster data. The
resolution shouldn't have any impact; Xft works in pixels.
> Do I need to start up a virtual server to set the bit depth and resolution?
Yes.
> Would I need to have different comparisons for different processor
> architectures?
No.
> Also, I don't know the standard workflow for this. Would I need to have
> an event handler if I'm just writing into a pixmap (if that's even
> correct in the first place)?
No.
A minimal test program would open the display, create a Pixmap, do
whatever setup Xft requires, draw onto the pixmap with Xft, then grab
its contents with XGetImage().
--
Glynn Clements <glynn at gclements.plus.com>
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