This introduces a new .ini config option: output-straight-alpha. It's
currently only supported by the headless backend, and it forces
renderers to produce straight alpha framebuffers for headless backend
outputs.
For now, only the GL renderer supports creating straight alpha
framebuffers (the support was introduced in "backend-drm: add support
for KMS devices with only coverage blend mode").
This is useful mostly for testing, and the main motivation to add such
support in our DRM-backend and GL-renderer was to be able to support KMS
devices that only supports straight alpha framebuffers.
Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>
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