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Merge pull request #3034 from matrix-org/bwindels/colr-check-race 

fix COLR font check being racy
pull/21833/head
Bruno Windels 2019-05-29 10:25:47 +00:00 committed by GitHub
parent 84dc2f8429 3014180762
commit f61e771f7a
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 38 additions and 17 deletions
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55
src/utils/FontManager.js
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@ -21,21 +21,43 @@ limitations under the License.
* MIT license
*/
let colrFontSupported = undefined;
function safariVersionCheck(ua) {
try {
const safariVersionMatch = ua.match(/Mac OS X ([\d|_]+).*Version\/([\d|.]+).*Safari/);
if (safariVersionMatch) {
const macOSVersionStr = safariVersionMatch[1];
const safariVersionStr = safariVersionMatch[2];
const macOSVersion = macOSVersionStr.split("_").map(n => parseInt(n, 10));
const safariVersion = safariVersionStr.split(".").map(n => parseInt(n, 10));
const colrFontSupported = macOSVersion[0] >= 10 && macOSVersion[1] >= 14 && safariVersion[0] >= 12;
// https://www.colorfonts.wtf/ states safari supports COLR fonts from this version on
console.log(`Browser is Safari - requiring macOS 10.14 and Safari 12, ` +
`detected Safari ${safariVersionStr} on macOS ${macOSVersionStr}, ` +
`COLR supported: ${colrFontSupported}`);
return colrFontSupported;
}
} catch (err) {
console.error("Couldn't determine Safari version to check COLR font support, assuming no.", err);
}
return false;
}
async function isColrFontSupported() {
if (colrFontSupported !== undefined) {
return colrFontSupported;
}
console.log("Checking for COLR support");
// Firefox has supported COLR fonts since version 26
// but doesn't support the check below with content blocking enabled.
// but doesn't support the check below without
// "Extract canvas data" permissions
// when content blocking is enabled.
if (navigator.userAgent.includes("Firefox")) {
colrFontSupported = true;
console.log("Browser is Firefox - assuming COLR is supported");
return colrFontSupported;
return true;
}
// Safari doesn't wait for the font to load (if it doesn't have it in cache)
// to emit the load event on the image, so there is no way to not make the check
// reliable. Instead sniff the version.
if (navigator.userAgent.includes("Safari")) {
return safariVersionCheck(navigator.userAgent);
}
try {
@ -61,26 +83,25 @@ async function isColrFontSupported() {
img.src = 'data:image/svg+xml;charset=utf-8,' + encodeURIComponent(svg);
// FIXME wait for safari load our colr font
const wait = ms => new Promise((r, j)=>setTimeout(r, ms));
await wait(500);
console.log("Waiting for COLR SVG to load");
await new Promise(resolve => img.onload = resolve);
console.log("Drawing canvas to detect COLR support");
context.drawImage(img, 0, 0);
colrFontSupported = (context.getImageData(10, 10, 1, 1).data[0] === 200);
const colrFontSupported = (context.getImageData(10, 10, 1, 1).data[0] === 200);
console.log("Canvas check revealed COLR is supported? " + colrFontSupported);
return colrFontSupported;
} catch (e) {
console.error("Couldn't load COLR font", e);
colrFontSupported = false;
return false;
}
return colrFontSupported;
}
let colrFontCheckStarted = false;
export async function fixupColorFonts() {
if (colrFontSupported !== undefined) {
if (colrFontCheckStarted) {
return;
}
colrFontCheckStarted = true;
if (await isColrFontSupported()) {
const path = `url('${require("../../res/fonts/Twemoji_Mozilla/TwemojiMozilla-colr.woff2")}')`;