background-blend-mode-computed-multiple.html (2206B)
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title>Compositing and Blending Level 1: getComputedStyle().backgroundBlendMode</title> 6 <link rel="help" href="https://drafts.fxtf.org/compositing-1/#propdef-background-blend-mode"> 7 <meta name="assert" content="background-blend-mode computed value is as specified even when the number of images vary."> 8 <script src="/resources/testharness.js"></script> 9 <script src="/resources/testharnessreport.js"></script> 10 <script src="/css/support/computed-testcommon.js"></script> 11 <style> 12 #target { 13 background-image: linear-gradient(green, green), linear-gradient(green, green), linear-gradient(green, green); 14 } 15 </style> 16 </head> 17 <body> 18 <div id="target"></div> 19 <script> 20 // This is testing the case with multiple background images 21 // 22 // see https://drafts.fxtf.org/compositing-1/#background-blend-mode 23 // and https://drafts.csswg.org/css-backgrounds-3/#layering 24 // > The lists are matched up from the first value: excess values at the end are not used. 25 // and 26 // > If a property doesn’t have enough comma-separated values 27 // > to match the number of layers, the UA must calculate its used value 28 // > by repeating the list of values until there are enough. 29 // but in https://drafts.csswg.org/css-values-4/#linked-properties 30 // it was decided that 31 // > The computed values of the coordinating list properties are not affected by such truncation or repetition. 32 // 33 // There is a distinction between specified values, used values, and computed values. 34 35 // if three images and one value, just send back the specified list. 36 test_computed_value("background-blend-mode", "normal"); 37 test_computed_value("background-blend-mode", "multiply"); 38 39 // if three images and two values, just send back the specified list. 40 test_computed_value("background-blend-mode", "normal, luminosity"); 41 test_computed_value("background-blend-mode", "screen, overlay"); 42 test_computed_value("background-blend-mode", "color, saturation"); 43 44 // if three images and three values, just send back the specified list. 45 test_computed_value("background-blend-mode", "normal, luminosity, color"); 46 test_computed_value("background-blend-mode", "screen, overlay, screen"); 47 </script> 48 </body> 49 </html>