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Merge pull request #5137 from CodingFabian/optimize-textbuilder-renderLayer

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Optimize TextLayerBuilder_renderLayer() for text heavy documents.
This commit is contained in:
Yury Delendik 2014-08-06 09:09:32 -05:00
commit 666cf02f91
1 changed files with 38 additions and 9 deletions
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45
web/text_layer_builder.js
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@ -56,20 +56,34 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
return;
}
var lastFontSize;
var lastFontFamily;
for (var i = 0; i < textDivsLength; i++) {
var textDiv = textDivs[i];
if (textDiv.dataset.isWhitespace !== undefined) {
continue;
}
ctx.font = textDiv.style.fontSize + ' ' + textDiv.style.fontFamily;
var fontSize = textDiv.style.fontSize;
var fontFamily = textDiv.style.fontFamily;
// Only build font string and set to context if different from last.
if (fontSize !== lastFontSize || fontFamily !== lastFontFamily) {
ctx.font = fontSize + ' ' + fontFamily;
lastFontSize = fontSize;
lastFontFamily = fontFamily;
}
var width = ctx.measureText(textDiv.textContent).width;
if (width > 0) {
textLayerFrag.appendChild(textDiv);
// Dataset values come of type string.
var textScale = textDiv.dataset.canvasWidth / width;
var rotation = textDiv.dataset.angle;
var transform = 'scale(' + textScale + ', 1)';
transform = 'rotate(' + rotation + 'deg) ' + transform;
if (rotation) {
transform = 'rotate(' + rotation + 'deg) ' + transform;
}
CustomStyle.setProp('transform' , textDiv, transform);
CustomStyle.setProp('transformOrigin' , textDiv, '0% 0%');
}
@ -114,18 +128,34 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
angle += Math.PI / 2;
}
var fontHeight = Math.sqrt((tx[2] * tx[2]) + (tx[3] * tx[3]));
var fontAscent = (style.ascent ? style.ascent * fontHeight :
(style.descent ? (1 + style.descent) * fontHeight : fontHeight));
var fontAscent = fontHeight;
if (style.ascent) {
fontAscent = style.ascent * fontAscent;
} else if (style.descent) {
fontAscent = (1 + style.descent) * fontAscent;
}
var left;
var top;
if (angle === 0) {
left = tx[4];
top = tx[5] - fontAscent;
} else {
left = tx[4] + (fontAscent * Math.sin(angle));
top = tx[5] - (fontAscent * Math.cos(angle));
}
textDiv.style.position = 'absolute';
textDiv.style.left = (tx[4] + (fontAscent * Math.sin(angle))) + 'px';
textDiv.style.top = (tx[5] - (fontAscent * Math.cos(angle))) + 'px';
textDiv.style.left = left + 'px';
textDiv.style.top = top + 'px';
textDiv.style.fontSize = fontHeight + 'px';
textDiv.style.fontFamily = style.fontFamily;
textDiv.textContent = geom.str;
textDiv.dataset.fontName = geom.fontName;
textDiv.dataset.angle = angle * (180 / Math.PI);
// Storing into dataset will convert number into string.
if (angle !== 0) {
textDiv.dataset.angle = angle * (180 / Math.PI);
}
if (style.vertical) {
textDiv.dataset.canvasWidth = geom.height * this.viewport.scale;
} else {
@ -324,4 +354,3 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
};
return TextLayerBuilder;
})();