registered-var-to-registered-animating.html (1968B)
1 <!DOCTYPE html> 2 <link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api-1"> 3 <script src="/resources/testharness.js"></script> 4 <script src="/resources/testharnessreport.js"></script> 5 <style> 6 #target { 7 --static: 100; 8 } 9 </style> 10 <div id="target"></div> 11 <script> 12 setup(() => { 13 for (let name of ['--test', '--static', '--animated']) { 14 CSS.registerProperty({ 15 name, 16 syntax: '<number>', 17 initialValue: '0', 18 inherits: false, 19 }); 20 } 21 }); 22 23 test(() => { 24 // --test is animating from a static value to an animated value resulting in it changing quadratically. 25 let animation = target.animate({'--test': ['var(--static)', 'var(--animated)']}, 100); 26 let referencedAnimation = target.animate({'--animated': ['200', '300']}, 100); 27 28 referencedAnimation.currentTime = 25; 29 { 30 animation.currentTime = 25; 31 // lerp(100, lerp(200, 300, 25%), 25%) == 0.75*100 + 0.25*(0.75*200 + 0.25*300) == 131.25 32 assert_equals(getComputedStyle(target).getPropertyValue('--test'), '131.25', 'target at 25%, to at 25%'); 33 34 animation.currentTime = 75; 35 // lerp(100, lerp(200, 300, 25%), 75%) == 0.25*100 + 0.75*(0.75*200 + 0.25*300) == 193.75 36 assert_equals(getComputedStyle(target).getPropertyValue('--test'), '193.75', 'target at 75%, to at 25%'); 37 } 38 39 referencedAnimation.currentTime = 75; 40 { 41 animation.currentTime = 25; 42 // lerp(100, lerp(200, 300, 75%), 25%) == 0.75*100 + 0.25*(0.25*200 + 0.75*300) == 143.75 43 assert_equals(getComputedStyle(target).getPropertyValue('--test'), '143.75', 'target at 25%, to at 25%'); 44 45 animation.currentTime = 75; 46 // lerp(100, lerp(200, 300, 75%), 75%) == 0.25*100 + 0.75*(0.25*200 + 0.75*300) == 231.25 47 assert_equals(getComputedStyle(target).getPropertyValue('--test'), '231.25', 'target at 75%, to at 25%'); 48 } 49 }, 'Animated registered custom properties can var() reference other animated registered custom properties across separate Animations.'); 50 </script>