| <!DOCTYPE html> |
| <!-- |
| | This test checks that the intersection is correctly computed when an element |
| | in the containing block chain undergoes a transform. One side of the border |
| | box of the containing block is disproportionately large to check that the |
| | rotations are being calculated relative to the border box and not any other |
| | others (i.e. padding). |
| | The containing block element turns yellow only if the intersection between |
| | the target and the viewport is correctly computed to be 0.5. |
| | https://www.w3.org/TR/intersection-observer/ |
| --> |
| <html> |
| <head> |
| <style> |
| #moving { |
| border-left-width: 100px; |
| border-style: solid; |
| background-color: red; |
| width: 100px; |
| height: 100px; |
| left: 0px; |
| top: 0px; |
| position: absolute; |
| } |
| #target { |
| background-color: green; |
| width: 100px; |
| height: 100px; |
| left: -100px; |
| top: 0px; |
| position: relative; |
| } |
| </style> |
| </head> |
| <body> |
| <div id="moving"> |
| <div id="target"> |
| </div> |
| </div> |
| |
| <script> |
| if (window.testRunner) { |
| window.testRunner.waitUntilDone(); |
| } |
| |
| window.addEventListener("load", function() { |
| var movingElement = document.querySelector('#moving'); |
| var targetElement = document.querySelector('#target'); |
| var expectedRatio = 0.5; |
| // leave room for some rounding differences due to rotation calculations |
| var epsilon = 0.02; |
| |
| function buildThresholdsList() { |
| var thresholds = [] |
| var numSteps = 100; |
| for (var i = 0; i < numSteps; i++) { |
| thresholds.push(i / numSteps); |
| } |
| return thresholds; |
| } |
| |
| function handleIntersect(entries, observer) { |
| entries.forEach(function(entry) { |
| console.log(entry.intersectionRatio); |
| if (Math.abs(entry.intersectionRatio - expectedRatio) < epsilon) { |
| movingElement.style.backgroundColor = "yellow"; |
| } |
| }); |
| } |
| |
| function createObserver() { |
| var options = { |
| root: null, |
| rootMargin: "0px", |
| threshold: buildThresholdsList() |
| }; |
| |
| var observer = new IntersectionObserver(handleIntersect, options); |
| observer.observe(targetElement); |
| } |
| |
| createObserver(); |
| |
| movingElement.style.transform = "rotate(90deg)"; |
| |
| if (window.testRunner) { |
| window.testRunner.DoNonMeasuredLayout(); |
| window.setTimeout(function() { window.testRunner.notifyDone(); }, 0); |
| } |
| }); |
| </script> |
| |
| </body> |
| </html> |
