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Fixes font loading concurency

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This commit is contained in:
Yury Delendik 2012-08-17 11:05:51 -05:00
parent d38781d72e
commit c414c76461
1 changed files with 88 additions and 55 deletions
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143
src/fonts.js
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@ -404,28 +404,16 @@ function mapPrivateUseChars(code) {
}
var FontLoader = {
listeningForFontLoad: false,
loadingContext: {
pending: 0,
requests: [],
nextRequestId: 0
},
bind: function fontLoaderBind(fonts, callback) {
function checkFontsLoaded() {
for (var i = 0, ii = fonts.length; i < ii; i++) {
var fontObj = fonts[i];
if (fontObj.loading) {
return false;
}
}
document.documentElement.removeEventListener(
'pdfjsFontLoad', checkFontsLoaded, false);
// Use timeout to fix chrome intermittent failures on font loading.
setTimeout(callback, 0);
return true;
}
var rules = [], names = [], fontsToLoad = [];
var fontCreateTimer = 0;
assert(!isWorker, 'bind() shall be called from main thread');
var rules = [], fontsToLoad = [];
for (var i = 0, ii = fonts.length; i < ii; i++) {
var font = fonts[i];
@ -436,8 +424,6 @@ var FontLoader = {
}
font.attached = true;
fontsToLoad.push(font);
var str = '';
var data = font.data;
if (data) {
@ -448,28 +434,79 @@ var FontLoader = {
var rule = font.bindDOM(str);
if (rule) {
rules.push(rule);
names.push(font.loadedName);
fontsToLoad.push(font);
}
}
}
this.listeningForFontLoad = false;
if (!isWorker && rules.length) {
FontLoader.prepareFontLoadEvent(rules, names, fontsToLoad);
}
if (!checkFontsLoaded()) {
document.documentElement.addEventListener(
'pdfjsFontLoad', checkFontsLoaded, false);
var request = FontLoader.queueLoadingCallback(callback);
if (rules.length > 0) {
FontLoader.prepareFontLoadEvent(rules, fontsToLoad, request);
} else {
request.complete();
}
},
queueLoadingCallback: function FontLoader_queueLoadingCallback(callback) {
function LoadLoader_completeRequest() {
assert(!request.end, 'completeRequest() cannot be called twice');
request.end = Date.now();
if (context.pending <= 1) {
// it's simple completion for one request
context.pending = 0;
context.requests.pop();
callback();
return;
}
// calculating the load delay for all fonts and checking if all loaded
var totalTime = 0;
for (var i = 0, ii = context.requests.length; i < ii; i++) {
var otherRequest = context.requests[i];
if (!otherRequest.end)
return; // one more font to load, cancel the completion
totalTime += otherRequest.end - otherRequest.start;
}
var now = Date.now();
var startTime = context.requests[0].start;
var leftToWait = Math.max(totalTime - (now - startTime), 0);
context.timeout = setTimeout(function completeAllRequests() {
for (var i = 0, ii = context.requests.length; i < ii; i++) {
context.requests[i].callback();
}
context.pending = 0;
context.requests = [];
delete context.timeout;
}, leftToWait);
}
var context = FontLoader.loadingContext;
var requestId = 'pdfjs-font-loading-' + (context.nextRequestId++);
context.pending++;
var request = {
id: requestId,
complete: LoadLoader_completeRequest,
callback: callback,
started: Date.now()
};
context.requests.push(request);
if (context.timeout) {
// timeout for callbacks was set, removing that
clearTimeout(context.timeout);
delete context.timeout;
}
return request;
},
// Set things up so that at least one pdfjsFontLoad event is
// dispatched when all the @font-face |rules| for |names| have been
// dispatched when all the @font-face |rules| for |fonts| have been
// loaded in a subdocument. It's expected that the load of |rules|
// has already started in this (outer) document, so that they should
// be ordered before the load in the subdocument.
prepareFontLoadEvent: function fontLoaderPrepareFontLoadEvent(rules, names,
fonts) {
prepareFontLoadEvent: function fontLoaderPrepareFontLoadEvent(rules,
fonts,
request) {
/** Hack begin */
// There's no event when a font has finished downloading so the
// following code is a dirty hack to 'guess' when a font is
@ -493,6 +530,10 @@ var FontLoader = {
// The postMessage() hackery was added to work around chrome bug
// 82402.
var names = [];
for (var i = 0, ii = fonts.length; i < ii; i++)
names.push(fonts[i].loadedName);
// Validate the names parameter -- the values can used to construct HTML.
if (!/^\w+$/.test(names.join(''))) {
error('Invalid font name(s): ' + names.join());
@ -514,22 +555,19 @@ var FontLoader = {
div.innerHTML = html;
document.body.appendChild(div);
if (!this.listeningForFontLoad) {
window.addEventListener(
'message',
function fontLoaderMessage(e) {
var fontNames = JSON.parse(e.data);
for (var i = 0, ii = fonts.length; i < ii; ++i) {
var font = fonts[i];
font.loading = false;
}
var evt = document.createEvent('Events');
evt.initEvent('pdfjsFontLoad', true, false);
document.documentElement.dispatchEvent(evt);
},
false);
this.listeningForFontLoad = true;
}
var requestId = request.id;
window.addEventListener(
'message',
function fontLoaderMessage(e) {
if (e.data !== requestId)
return;
for (var i = 0, ii = fonts.length; i < ii; ++i) {
var font = fonts[i];
font.loading = false;
}
request.complete();
},
false);
// XXX we should have a time-out here too, and maybe fire
// pdfjsFontLoadFailed?
@ -540,13 +578,8 @@ var FontLoader = {
}
src += '</style>';
src += '<script type="application/javascript">';
var fontNamesArray = '';
for (var i = 0, ii = names.length; i < ii; ++i) {
fontNamesArray += '"' + names[i] + '", ';
}
src += ' var fontNames=[' + fontNamesArray + '];\n';
src += ' window.onload = function fontLoaderOnload() {\n';
src += ' parent.postMessage(JSON.stringify(fontNames), "*");\n';
src += ' parent.postMessage("' + requestId + '", "*");\n';
src += ' }';
// Hack so the end script tag isn't counted if this is inline JS.
src += '</scr' + 'ipt></head><body>';