49 lines
2.2 KiB
HTML
49 lines
2.2 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Compositing and Blending Level 1: getComputedStyle().backgroundBlendMode</title>
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<link rel="help" href="https://drafts.fxtf.org/compositing-1/#propdef-background-blend-mode">
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<meta name="assert" content="background-blend-mode computed value is as specified even when the number of images vary.">
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<script src="/css/support/computed-testcommon.js"></script>
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<style>
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#target {
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background-image: linear-gradient(green, green), linear-gradient(green, green), linear-gradient(green, green);
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}
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</style>
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</head>
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<body>
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<div id="target"></div>
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<script>
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// This is testing the case with multiple background images
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//
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// see https://drafts.fxtf.org/compositing-1/#background-blend-mode
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// and https://drafts.csswg.org/css-backgrounds-3/#layering
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// > The lists are matched up from the first value: excess values at the end are not used.
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// and
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// > If a property doesn’t have enough comma-separated values
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// > to match the number of layers, the UA must calculate its used value
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// > by repeating the list of values until there are enough.
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// but in https://drafts.csswg.org/css-values-4/#linked-properties
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// it was decided that
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// > The computed values of the coordinating list properties are not affected by such truncation or repetition.
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//
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// There is a distinction between specified values, used values, and computed values.
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// if three images and one value, just send back the specified list.
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test_computed_value("background-blend-mode", "normal");
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test_computed_value("background-blend-mode", "multiply");
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// if three images and two values, just send back the specified list.
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test_computed_value("background-blend-mode", "normal, luminosity");
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test_computed_value("background-blend-mode", "screen, overlay");
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test_computed_value("background-blend-mode", "color, saturation");
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// if three images and three values, just send back the specified list.
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test_computed_value("background-blend-mode", "normal, luminosity, color");
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test_computed_value("background-blend-mode", "screen, overlay, screen");
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</script>
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</body>
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</html>
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