lib: fb: add igt_paint_color_gradient_range

This is a helper to draw a gradient between 2 colors.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
2 files changed