pub fn alpha_mode_is_translucent(mode: CompositeAlphaMode) -> boolExpand description
Whether a resolved wgpu::CompositeAlphaMode actually composites the
surface’s alpha against what is behind it — i.e. whether the surface really
came up translucent, as opposed to what the caller requested.
This is the truth behind ConfiguredSurface::resolved_translucent:
resolve_alpha_mode can silently degrade a
SurfaceAlphaRequest::TranslucentPreferred to Auto when the platform
advertises no translucent mode, and a shell that kept keying its paint
contract off the request would then clear to transparent and punch its
native-view slots against an OPAQUE swapchain — presenting black rectangles.
The three translucent modes are exactly resolve_alpha_mode’s preference
list — Inherit (Android), PostMultiplied (iOS), PreMultiplied;
Opaque/Auto ignore the surface’s alpha entirely and are therefore not
translucent (Auto is what every opaque caller and every fallback resolves
to).