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Test Info: Warnings
- This test has a WPT meta file that expects 1 subtest issues.
- This WPT test may be referenced by the following Test IDs:
- /html/canvas/element/manual/draw-element-image/onpaint-post-tree-order-shadow-dom.tentative.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<title>Canvas paint events should fire in reverse shadow-including tree order across Shadow DOM</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/html/canvas/resources/wait-for-canvas-paint.js"></script>
<style>
canvas {
width: 100px;
height: 100px;
}
</style>
<!-- Host component with Declarative Shadow DOM -->
<my-element>
<!-- 1. Light DOM that is unslotted (no slot="unslotted" exists in shadow root) -->
<canvas id="unslotted" content="drawable"></canvas>
<!-- 2. Light DOM assigned to slot "slotted" -->
<canvas id="slotted" slot="slotted" content="drawable"></canvas>
<!-- 3. Light DOM assigned to slot "canvasslot" -->
<canvas id="slottedintocanvas" slot="canvasslot" content="drawable"></canvas>
<!-- Shadow Root -->
<template shadowrootmode="open">
<!-- 4. Slot with fallback canvas, and NO light DOM assigned to it -->
<slot name="empty">
<canvas id="activefallback" content="drawable"></canvas>
</slot>
<!-- 5. Slot with fallback canvas, but light DOM IS assigned to it -->
<slot name="slotted">
<canvas id="inactivefallback" content="drawable"></canvas>
</slot>
<!-- 6. Canvas slot host -->
<canvas id="canvasslothost" content="drawable">
<slot name="canvasslot"></slot>
</canvas>
</template>
</my-element>
<script>
'use strict';
function waitForOneFrame() {
return new Promise(resolve => {
requestAnimationFrame(() => {
setTimeout(resolve, 0);
});
});
}
promise_test(async t => {
await waitForOneFrame();
let paint_order = [];
const shadow = document.querySelector('my-element').shadowRoot;
const inactiveFallback = shadow.getElementById('inactivefallback');
const activeFallback = shadow.getElementById('activefallback');
const canvasSlotHost = shadow.getElementById('canvasslothost');
unslotted.addEventListener('paint', () => paint_order.push('unslotted'), {once: true});
slottedintocanvas.addEventListener('paint', () => paint_order.push('slottedintocanvas'), {once: true});
slotted.addEventListener('paint', () => paint_order.push('slotted'), {once: true});
inactiveFallback.addEventListener('paint', () => paint_order.push('inactiveFallback'), {once: true});
activeFallback.addEventListener('paint', () => paint_order.push('activeFallback'), {once: true});
canvasSlotHost.addEventListener('paint', () => paint_order.push('canvasslothost'), {once: true});
await Promise.all([
waitForCanvasPaint(unslotted),
waitForCanvasPaint(slottedintocanvas),
waitForCanvasPaint(slotted),
waitForCanvasPaint(inactiveFallback),
waitForCanvasPaint(activeFallback),
waitForCanvasPaint(canvasSlotHost),
]);
assert_array_equals(
paint_order,
[
'slottedintocanvas',
'slotted',
'unslotted',
'canvasslothost',
'inactiveFallback',
'activeFallback',
],
'Paint events should fire in reverse shadow-including tree order');
}, 'Canvas paint events fire in reverse shadow-including tree order across shadow DOM, slots, and fallback content');
</script>