Add support for exporting virtual test images

Add support for operating on a virtual buffer in RAM instead of on a
real frame buffer device, and exporting the result as a PPM image.
The size of the virtual buffer is configurable, but for now the format
is fixed to Truecolor 8:8:8:0.

This is useful for e.g. testing drawing algorithms on screen sizes not
supported by your hardware.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
7 files changed