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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /gfx/wr/wrench/reftests/blend/difference-transparent-ref.yaml
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gfx/wr/wrench/reftests/blend/difference-transparent-ref.yaml')
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diff --git a/gfx/wr/wrench/reftests/blend/difference-transparent-ref.yaml b/gfx/wr/wrench/reftests/blend/difference-transparent-ref.yaml
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+---
+root:
+ items:
+ - type: rect
+ bounds: [0, 0, 100, 100]
+
+ # First blend black rect with green in place
+ # Cs = (1 - αb) x Cs + αb x B(Cb, Cs)
+ # B(Cb, Cs) = | Cb - Cs | = (0, 0, 0)
+ # 0.5 * (0, 255, 0) + 0.5 * (0, 0, 0) = (0, 127.5, 0)
+ #
+ # Now, composite the resulting color with src-over; the alpha is the original alpha for the top layer
+ # while the color is the blending result
+ # co = αs x Fa x Cs + αb x Fb x Cb - this is premultiplied
+ # αo = αs + αb x (1 – αs)
+ # Source over: Fa = 1; Fb = 1 – αs
+ # co = 0.5 * 1 * (0, 127.5, 0) + 0.5 * 0.5 * (0, 255, 0) = (0, 63.5, 0) + 0.25 * (0, 255, 0) = (0, 127.5, 0)
+ # ao = 0.5 + 0.5 * 0.5 = 0.75
+ # Co = co/ao = (0, 127.5, 0) / 0.75
+ #
+ # Now alpha composite on white background
+ # co = 0.75 * 1 * (0, 127.5, 0) / 0.75 + 1 * 0.25 * (255, 255, 255) = (0, 127.5, 0) + (63.75, 63.75, 63.75) = (63.75, 159, 63.75) = (64, 191, 64)
+ color: [64, 191, 64]