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Merge pull request #15507 from Snuffleupagus/FontLoader-cleanup

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Improve the `FontLoader` code
This commit is contained in:
Tim van der Meij 2022-09-25 13:31:33 +02:00 committed by GitHub
commit dab81f5981
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 179 additions and 209 deletions
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86
src/display/font_loader.js
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@ -19,22 +19,17 @@ import {
FeatureTest,
shadow,
string32,
unreachable,
UNSUPPORTED_FEATURES,
warn,
} from "../shared/util.js";
class BaseFontLoader {
class FontLoader {
constructor({
docId,
onUnsupportedFeature,
ownerDocument = globalThis.document,
// For testing only.
styleElement = null,
styleElement = null, // For testing only.
}) {
if (this.constructor === BaseFontLoader) {
unreachable("Cannot initialize BaseFontLoader.");
}
this.docId = docId;
this._onUnsupportedFeature = onUnsupportedFeature;
this._document = ownerDocument;
@ -44,6 +39,11 @@ class BaseFontLoader {
typeof PDFJSDev === "undefined" || PDFJSDev.test("!PRODUCTION || TESTING")
? styleElement
: null;
if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
this.loadingRequests = [];
this.loadTestFontId = 0;
}
}
addNativeFontFace(nativeFontFace) {
@ -120,10 +120,6 @@ class BaseFontLoader {
}
}
_queueLoadingCallback(callback) {
unreachable("Abstract method `_queueLoadingCallback`.");
}
get isFontLoadingAPISupported() {
const hasFonts = !!this._document?.fonts;
if (
@ -139,42 +135,11 @@ class BaseFontLoader {
return shadow(this, "isFontLoadingAPISupported", hasFonts);
}
// eslint-disable-next-line getter-return
get isSyncFontLoadingSupported() {
unreachable("Abstract method `isSyncFontLoadingSupported`.");
}
// eslint-disable-next-line getter-return
get _loadTestFont() {
unreachable("Abstract method `_loadTestFont`.");
}
_prepareFontLoadEvent(rules, fontsToLoad, request) {
unreachable("Abstract method `_prepareFontLoadEvent`.");
}
}
let FontLoader;
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
FontLoader = class MozcentralFontLoader extends BaseFontLoader {
get isSyncFontLoadingSupported() {
return shadow(this, "isSyncFontLoadingSupported", true);
}
};
} else {
// PDFJSDev.test('CHROME || GENERIC')
FontLoader = class GenericFontLoader extends BaseFontLoader {
constructor(params) {
super(params);
this.loadingContext = {
requests: [],
nextRequestId: 0,
};
this.loadTestFontId = 0;
}
get isSyncFontLoadingSupported() {
let supported = false;
if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("CHROME")) {
if (typeof navigator === "undefined") {
@ -183,9 +148,7 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
} else {
// User agent string sniffing is bad, but there is no reliable way to
// tell if the font is fully loaded and ready to be used with canvas.
const m = /Mozilla\/5.0.*?rv:(\d+).*? Gecko/.exec(
navigator.userAgent
);
const m = /Mozilla\/5.0.*?rv:(\d+).*? Gecko/.exec(navigator.userAgent);
if (m?.[1] >= 14) {
supported = true;
}
@ -196,33 +159,39 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
}
_queueLoadingCallback(callback) {
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
throw new Error("Not implemented: _queueLoadingCallback");
}
function completeRequest() {
assert(!request.done, "completeRequest() cannot be called twice.");
request.done = true;
// Sending all completed requests in order of how they were queued.
while (context.requests.length > 0 && context.requests[0].done) {
const otherRequest = context.requests.shift();
while (loadingRequests.length > 0 && loadingRequests[0].done) {
const otherRequest = loadingRequests.shift();
setTimeout(otherRequest.callback, 0);
}
}
const context = this.loadingContext;
const { loadingRequests } = this;
const request = {
id: `pdfjs-font-loading-${context.nextRequestId++}`,
done: false,
complete: completeRequest,
callback,
};
context.requests.push(request);
loadingRequests.push(request);
return request;
}
get _loadTestFont() {
const getLoadTestFont = function () {
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
throw new Error("Not implemented: _loadTestFont");
}
// This is a CFF font with 1 glyph for '.' that fills its entire width
// and height.
return atob(
const testFont = atob(
"T1RUTwALAIAAAwAwQ0ZGIDHtZg4AAAOYAAAAgUZGVE1lkzZwAAAEHAAAABxHREVGABQA" +
"FQAABDgAAAAeT1MvMlYNYwkAAAEgAAAAYGNtYXABDQLUAAACNAAAAUJoZWFk/xVFDQAA" +
"ALwAAAA2aGhlYQdkA+oAAAD0AAAAJGhtdHgD6AAAAAAEWAAAAAZtYXhwAAJQAAAAARgA" +
@ -246,11 +215,14 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
"Dov6fAH6fAT+fPp8+nwHDosMCvm1Cvm1DAz6fBQAAAAAAAABAAAAAMmJbzEAAAAAzgTj" +
"FQAAAADOBOQpAAEAAAAAAAAADAAUAAQAAAABAAAAAgABAAAAAAAAAAAD6AAAAAAAAA=="
);
};
return shadow(this, "_loadTestFont", getLoadTestFont());
return shadow(this, "_loadTestFont", testFont);
}
_prepareFontLoadEvent(rules, fonts, request) {
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
throw new Error("Not implemented: _prepareFontLoadEvent");
}
/** Hack begin */
// There's currently no event when a font has finished downloading so the
// following code is a dirty hack to 'guess' when a font is ready.
@ -320,8 +292,7 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
}
if (i < loadTestFontId.length) {
// align to 4 bytes boundary
checksum =
(checksum - XXXX_VALUE + int32(loadTestFontId + "XXX", i)) | 0;
checksum = (checksum - XXXX_VALUE + int32(loadTestFontId + "XXX", i)) | 0;
}
data = spliceString(data, CFF_CHECKSUM_OFFSET, 4, string32(checksum));
@ -355,8 +326,7 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
});
/** Hack end */
}
};
} // End of PDFJSDev.test('CHROME || GENERIC')
}
class FontFaceObject {
constructor(