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Replace div.dataset with a WeakMap in text_layer.js

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This patch improves performance by avoiding unnecessary type
conversions, which also help the JIT for optimizations.

Moreover, this patch fixes issues with the div expansion code where
`textScale` would be undefined in a division. Because of the `dataset`
usage, other comparisons evaluated to `true` while `false` would have
been correct. This makes the expansion mode now work correctly for cases
with, for example, each glyph in one div.

The polyfill for `WeakMap` has been provided by @yurydelendik.
This commit is contained in:
Tim van der Meij 2016-09-02 18:10:37 +02:00
parent b10add14f3
commit b3818d5c36
2 changed files with 117 additions and 65 deletions
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149
src/display/text_layer.js
View File

@ -12,6 +12,7 @@
* See the License for the specific language governing permissions and * See the License for the specific language governing permissions and
* limitations under the License. * limitations under the License.
*/ */
/* globals WeakMap */
'use strict'; 'use strict';
@ -58,16 +59,31 @@ var renderTextLayer = (function renderTextLayerClosure() {
return !NonWhitespaceRegexp.test(str); return !NonWhitespaceRegexp.test(str);
} }
function appendText(task, geom) { function appendText(task, geom, styles) {
var style = task._textContent.styles[geom.fontName]; // Initialize all used properties to keep the caches monomorphic.
var textDiv = document.createElement('div'); var textDiv = document.createElement('div');
var textDivProperties = {
angle: 0,
canvasWidth: 0,
isWhitespace: false,
originalTransform: '',
originalWidth: 0,
paddingBottom: 0,
paddingLeft: 0,
paddingRight: 0,
paddingTop: 0,
};
task._textDivs.push(textDiv); task._textDivs.push(textDiv);
if (isAllWhitespace(geom.str)) { if (isAllWhitespace(geom.str)) {
textDiv.dataset.isWhitespace = true; textDivProperties.isWhitespace = true;
task._textDivProperties.set(textDiv, textDivProperties);
return; return;
} }
var tx = Util.transform(task._viewport.transform, geom.transform); var tx = Util.transform(task._viewport.transform, geom.transform);
var angle = Math.atan2(tx[1], tx[0]); var angle = Math.atan2(tx[1], tx[0]);
var style = styles[geom.fontName];
if (style.vertical) { if (style.vertical) {
angle += Math.PI / 2; angle += Math.PI / 2;
} }
@ -96,24 +112,26 @@ var renderTextLayer = (function renderTextLayerClosure() {
textDiv.textContent = geom.str; textDiv.textContent = geom.str;
// |fontName| is only used by the Font Inspector. This test will succeed // |fontName| is only used by the Font Inspector. This test will succeed
// when e.g. the Font Inspector is off but the Stepper is on, but it's // when e.g. the Font Inspector is off but the Stepper is on, but it's
// not worth the effort to do a more accurate test. // not worth the effort to do a more accurate test. We only use `dataset`
// here to make the font name available for the debugger.
if (getDefaultSetting('pdfBug')) { if (getDefaultSetting('pdfBug')) {
textDiv.dataset.fontName = geom.fontName; textDiv.dataset.fontName = geom.fontName;
} }
// Storing into dataset will convert number into string.
if (angle !== 0) { if (angle !== 0) {
textDiv.dataset.angle = angle * (180 / Math.PI); textDivProperties.angle = angle * (180 / Math.PI);
} }
// We don't bother scaling single-char text divs, because it has very // We don't bother scaling single-char text divs, because it has very
// little effect on text highlighting. This makes scrolling on docs with // little effect on text highlighting. This makes scrolling on docs with
// lots of such divs a lot faster. // lots of such divs a lot faster.
if (geom.str.length > 1) { if (geom.str.length > 1) {
if (style.vertical) { if (style.vertical) {
textDiv.dataset.canvasWidth = geom.height * task._viewport.scale; textDivProperties.canvasWidth = geom.height * task._viewport.scale;
} else { } else {
textDiv.dataset.canvasWidth = geom.width * task._viewport.scale; textDivProperties.canvasWidth = geom.width * task._viewport.scale;
} }
} }
task._textDivProperties.set(textDiv, textDivProperties);
if (task._enhanceTextSelection) { if (task._enhanceTextSelection) {
var angleCos = 1, angleSin = 0; var angleCos = 1, angleSin = 0;
if (angle !== 0) { if (angle !== 0) {
@ -171,7 +189,8 @@ var renderTextLayer = (function renderTextLayerClosure() {
var lastFontFamily; var lastFontFamily;
for (var i = 0; i < textDivsLength; i++) { for (var i = 0; i < textDivsLength; i++) {
var textDiv = textDivs[i]; var textDiv = textDivs[i];
if (textDiv.dataset.isWhitespace !== undefined) { var textDivProperties = task._textDivProperties.get(textDiv);
if (textDivProperties.isWhitespace) {
continue; continue;
} }
@ -186,25 +205,23 @@ var renderTextLayer = (function renderTextLayerClosure() {
} }
var width = ctx.measureText(textDiv.textContent).width; var width = ctx.measureText(textDiv.textContent).width;
textDiv.dataset.originalWidth = width; textDivProperties.originalWidth = width;
textLayerFrag.appendChild(textDiv); textLayerFrag.appendChild(textDiv);
var transform; var transform = '';
if (textDiv.dataset.canvasWidth !== undefined && width > 0) { if (textDivProperties.canvasWidth !== 0 && width > 0) {
// Dataset values are of type string. var scale = textDivProperties.canvasWidth / width;
var textScale = textDiv.dataset.canvasWidth / width; transform = 'scaleX(' + scale + ')';
transform = 'scaleX(' + textScale + ')';
} else {
transform = '';
} }
var rotation = textDiv.dataset.angle; var rotation = textDivProperties.angle;
if (rotation) { if (rotation !== 0) {
transform = 'rotate(' + rotation + 'deg) ' + transform; transform = 'rotate(' + rotation + 'deg) ' + transform;
} }
if (transform) { if (transform !== '') {
textDiv.dataset.originalTransform = transform; textDivProperties.originalTransform = transform;
CustomStyle.setProp('transform' , textDiv, transform); CustomStyle.setProp('transform', textDiv, transform);
} }
task._textDivProperties.set(textDiv, textDivProperties);
} }
task._renderingDone = true; task._renderingDone = true;
capability.resolve(); capability.resolve();
@ -217,11 +234,13 @@ var renderTextLayer = (function renderTextLayerClosure() {
var expanded = expandBounds(viewport.width, viewport.height, bounds); var expanded = expandBounds(viewport.width, viewport.height, bounds);
for (var i = 0; i < expanded.length; i++) { for (var i = 0; i < expanded.length; i++) {
var div = bounds[i].div; var div = bounds[i].div;
if (!div.dataset.angle) { var divProperties = task._textDivProperties.get(div);
div.dataset.paddingLeft = bounds[i].left - expanded[i].left; if (divProperties.angle === 0) {
div.dataset.paddingTop = bounds[i].top - expanded[i].top; divProperties.paddingLeft = bounds[i].left - expanded[i].left;
div.dataset.paddingRight = expanded[i].right - bounds[i].right; divProperties.paddingTop = bounds[i].top - expanded[i].top;
div.dataset.paddingBottom = expanded[i].bottom - bounds[i].bottom; divProperties.paddingRight = expanded[i].right - bounds[i].right;
divProperties.paddingBottom = expanded[i].bottom - bounds[i].bottom;
task._textDivProperties.set(div, divProperties);
continue; continue;
} }
// Box is rotated -- trying to find padding so rotated div will not // Box is rotated -- trying to find padding so rotated div will not
@ -266,10 +285,11 @@ var renderTextLayer = (function renderTextLayerClosure() {
// Not based on math, but to simplify calculations, using cos and sin // Not based on math, but to simplify calculations, using cos and sin
// absolute values to not exceed the box (it can but insignificantly). // absolute values to not exceed the box (it can but insignificantly).
var boxScale = 1 + Math.min(Math.abs(c), Math.abs(s)); var boxScale = 1 + Math.min(Math.abs(c), Math.abs(s));
div.dataset.paddingLeft = findPositiveMin(ts, 32, 16) / boxScale; divProperties.paddingLeft = findPositiveMin(ts, 32, 16) / boxScale;
div.dataset.paddingTop = findPositiveMin(ts, 48, 16) / boxScale; divProperties.paddingTop = findPositiveMin(ts, 48, 16) / boxScale;
div.dataset.paddingRight = findPositiveMin(ts, 0, 16) / boxScale; divProperties.paddingRight = findPositiveMin(ts, 0, 16) / boxScale;
div.dataset.paddingBottom = findPositiveMin(ts, 16, 16) / boxScale; divProperties.paddingBottom = findPositiveMin(ts, 16, 16) / boxScale;
task._textDivProperties.set(div, divProperties);
} }
} }
@ -492,6 +512,7 @@ var renderTextLayer = (function renderTextLayerClosure() {
this._container = container; this._container = container;
this._viewport = viewport; this._viewport = viewport;
this._textDivs = textDivs || []; this._textDivs = textDivs || [];
this._textDivProperties = new WeakMap();
this._renderingDone = false; this._renderingDone = false;
this._canceled = false; this._canceled = false;
this._capability = createPromiseCapability(); this._capability = createPromiseCapability();
@ -516,8 +537,9 @@ var renderTextLayer = (function renderTextLayerClosure() {
_render: function TextLayer_render(timeout) { _render: function TextLayer_render(timeout) {
var textItems = this._textContent.items; var textItems = this._textContent.items;
var textStyles = this._textContent.styles;
for (var i = 0, len = textItems.length; i < len; i++) { for (var i = 0, len = textItems.length; i < len; i++) {
appendText(this, textItems[i]); appendText(this, textItems[i], textStyles);
} }
if (!timeout) { // Render right away if (!timeout) { // Render right away
@ -540,55 +562,52 @@ var renderTextLayer = (function renderTextLayerClosure() {
this._expanded = true; this._expanded = true;
this._bounds.length = 0; this._bounds.length = 0;
} }
if (expandDivs) {
for (var i = 0, ii = this._textDivs.length; i < ii; i++) { for (var i = 0, ii = this._textDivs.length; i < ii; i++) {
var div = this._textDivs[i]; var div = this._textDivs[i];
var transform; var divProperties = this._textDivProperties.get(div);
var width = div.dataset.originalWidth;
if (div.dataset.canvasWidth !== undefined && width > 0) { if (expandDivs) {
// Dataset values are of type string. var transform = '';
var textScale = div.dataset.canvasWidth / width; var scale = 1;
transform = 'scaleX(' + textScale + ')';
} else { if (divProperties.canvasWidth !== 0 &&
transform = ''; divProperties.originalWidth > 0) {
scale = divProperties.canvasWidth / divProperties.originalWidth;
transform = 'scaleX(' + scale + ')';
} }
var rotation = div.dataset.angle; if (divProperties.angle !== 0) {
if (rotation) { transform = 'rotate(' + divProperties.angle + 'deg) ' + transform;
transform = 'rotate(' + rotation + 'deg) ' + transform;
} }
if (div.dataset.paddingLeft) { if (divProperties.paddingLeft !== 0) {
div.style.paddingLeft = div.style.paddingLeft =
(div.dataset.paddingLeft / textScale) + 'px'; (divProperties.paddingLeft / scale) + 'px';
transform += ' translateX(' + transform += ' translateX(' +
(-div.dataset.paddingLeft / textScale) + 'px)'; (-divProperties.paddingLeft / scale) + 'px)';
} }
if (div.dataset.paddingTop) { if (divProperties.paddingTop !== 0) {
div.style.paddingTop = div.dataset.paddingTop + 'px'; div.style.paddingTop = divProperties.paddingTop + 'px';
transform += ' translateY(' + (-div.dataset.paddingTop) + 'px)'; transform += ' translateY(' + (-divProperties.paddingTop) + 'px)';
} }
if (div.dataset.paddingRight) { if (divProperties.paddingRight !== 0) {
div.style.paddingRight = div.style.paddingRight =
div.dataset.paddingRight / textScale + 'px'; divProperties.paddingRight / scale + 'px';
} }
if (div.dataset.paddingBottom) { if (divProperties.paddingBottom !== 0) {
div.style.paddingBottom = div.dataset.paddingBottom + 'px'; div.style.paddingBottom = divProperties.paddingBottom + 'px';
} }
if (transform) { if (transform !== '') {
CustomStyle.setProp('transform' , div, transform); CustomStyle.setProp('transform', div, transform);
} }
} } else {
} else {
for (i = 0, ii = this._textDivs.length; i < ii; i++) {
div = this._textDivs[i];
div.style.padding = 0; div.style.padding = 0;
transform = div.dataset.originalTransform || ''; CustomStyle.setProp('transform', div,
CustomStyle.setProp('transform', div, transform); divProperties.originalTransform);
} }
} }
}, },
}; };
/** /**
* Starts rendering of the text layer. * Starts rendering of the text layer.
* *

33
src/shared/util.js
View File

@ -1442,6 +1442,39 @@ function createPromiseCapability() {
//#endif //#endif
})(); })();
//#if !MOZCENTRAL
(function WeakMapClosure() {
if (globalScope.WeakMap) {
return;
}
var id = 0;
function WeakMap() {
this.id = '$weakmap' + (id++);
}
WeakMap.prototype = {
has: function(obj) {
return !!Object.getOwnPropertyDescriptor(obj, this.id);
},
get: function(obj, defaultValue) {
return this.has(obj) ? obj[this.id] : defaultValue;
},
set: function(obj, value) {
Object.defineProperty(obj, this.id, {
value: value,
enumerable: false,
configurable: true
});
},
delete: function(obj) {
delete obj[this.id];
}
};
globalScope.WeakMap = WeakMap;
})();
//#endif
var StatTimer = (function StatTimerClosure() { var StatTimer = (function StatTimerClosure() {
function rpad(str, pad, length) { function rpad(str, pad, length) {
while (str.length < length) { while (str.length < length) {