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Test Info:
- Manifest: layout/base/tests/browser.toml
/* Any copyright is dedicated to the Public Domain.
"use strict";
const PAGECONTENT =
"<!DOCTYPE html>" +
"<html>" +
"<style>" +
"html { height: 100vh; }" +
"</style>" +
"</html>";
const pageUrl = "data:text/html," + encodeURIComponent(PAGECONTENT);
add_task(async function test() {
SpecialPowers.DOMWindowUtils.setHiDPIMode(true);
registerCleanupFunction(() => {
SpecialPowers.DOMWindowUtils.restoreHiDPIMode();
});
const tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, pageUrl);
// Enter fullscreen.
let fullscreenChangePromise = BrowserTestUtils.waitForContentEvent(
tab.linkedBrowser,
"fullscreenchange"
);
await SpecialPowers.spawn(tab.linkedBrowser, [], () => {
content.document.documentElement.requestFullscreen();
});
await fullscreenChangePromise;
let [originalInnerWidth, originalInnerHeight] = await SpecialPowers.spawn(
tab.linkedBrowser,
[],
() => {
return [content.window.innerWidth, content.window.innerHeight];
}
);
// Then change the DPI.
let originalPixelRatio = await SpecialPowers.spawn(
tab.linkedBrowser,
[],
() => {
return content.window.devicePixelRatio;
}
);
let dpiChangedPromise = TestUtils.waitForCondition(async () => {
let pixelRatio = await SpecialPowers.spawn(tab.linkedBrowser, [], () => {
return content.window.devicePixelRatio;
});
return pixelRatio != originalPixelRatio;
}, "Make sure the DPI changed");
SpecialPowers.DOMWindowUtils.setHiDPIMode(false);
await dpiChangedPromise;
let [innerWidth, innerHeight] = await SpecialPowers.spawn(
tab.linkedBrowser,
[],
() => {
return [content.window.innerWidth, content.window.innerHeight];
}
);
Assert.less(
originalInnerWidth,
innerWidth,
"window.innerWidth on a lower DPI should be greater than the original"
);
Assert.less(
originalInnerHeight,
innerHeight,
"window.innerHeight on a lower DPI should be greater than the original"
);
fullscreenChangePromise = BrowserTestUtils.waitForContentEvent(
tab.linkedBrowser,
"fullscreenchange"
);
await SpecialPowers.spawn(tab.linkedBrowser, [], () => {
content.document.exitFullscreen();
});
await fullscreenChangePromise;
BrowserTestUtils.removeTab(tab);
});