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overleaf/services/web/public/js/libs/pdfListView/TextLayerBuilder.js

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2014-02-12 05:23:40 -05:00
(function (name, context, definition) {
if (typeof module != 'undefined' && module.exports) module.exports = definition()
else if (typeof define == 'function' && define.amd) define(definition)
else context[name] = definition()
})('TextLayerBuilder', this, function (name, context) {
// optimised CSS custom property getter/setter
var CustomStyle = (function CustomStyleClosure() {
// As noted on: http://www.zachstronaut.com/posts/2009/02/17/
// animate-css-transforms-firefox-webkit.html
// in some versions of IE9 it is critical that ms appear in this list
// before Moz
var prefixes = ['ms', 'Moz', 'Webkit', 'O'];
var _cache = { };
function CustomStyle() {
}
CustomStyle.getProp = function get(propName, element) {
// check cache only when no element is given
if (arguments.length == 1 && typeof _cache[propName] == 'string') {
return _cache[propName];
}
element = element || document.documentElement;
var style = element.style, prefixed, uPropName;
// test standard property first
if (typeof style[propName] == 'string') {
return (_cache[propName] = propName);
}
// capitalize
uPropName = propName.charAt(0).toUpperCase() + propName.slice(1);
// test vendor specific properties
for (var i = 0, l = prefixes.length; i < l; i++) {
prefixed = prefixes[i] + uPropName;
if (typeof style[prefixed] == 'string') {
return (_cache[propName] = prefixed);
}
}
//if all fails then set to undefined
return (_cache[propName] = 'undefined');
};
CustomStyle.setProp = function set(propName, element, str) {
var prop = this.getProp(propName);
if (prop != 'undefined')
element.style[prop] = str;
};
return CustomStyle;
})();
function TextLayerBuilder(textLayerDiv) {
this.textLayerDiv = textLayerDiv;
};
TextLayerBuilder.prototype = {
beginLayout: function() {
this.textDivs = [];
this.textLayerQueue = [];
this.renderingDone = false;
},
endLayout: function() {
this.layoutDone = true;
this.insertDivContent();
},
appendText: function(geom) {
var textDiv = document.createElement('div');
// vScale and hScale already contain the scaling to pixel units
var fontHeight = geom.fontSize * Math.abs(geom.vScale);
textDiv.dataset.canvasWidth = geom.canvasWidth * geom.hScale;
textDiv.dataset.fontName = geom.fontName;
textDiv.style.fontSize = fontHeight + 'px';
textDiv.style.fontFamily = geom.fontFamily;
textDiv.style.left = geom.x + 'px';
textDiv.style.top = (geom.y - fontHeight) + 'px';
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textDiv.ondblclick = function(e) {
if (window.getSelection)
window.getSelection().removeAllRanges();
else if (document.selection)
document.selection.empty();
}
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// The content of the div is set in the `setTextContent` function.
this.textDivs.push(textDiv);
},
setTextContent: function(textContent) {
this.textContent = textContent;
this.insertDivContent();
},
insertDivContent: function() {
// Only set the content of the divs once layout has finished, the content
// for the divs is available and content is not yet set on the divs.
if (!this.layoutDone || this.divContentDone || !this.textContent)
return;
this.divContentDone = true;
var textDivs = this.textDivs;
var bidiTexts = this.textContent.bidiTexts;
for (var i = 0; i < bidiTexts.length; i++) {
var bidiText = bidiTexts[i];
var textDiv = textDivs[i];
if (!/\S/.test(bidiText.str)) {
textDiv.dataset.isWhitespace = true;
continue;
}
textDiv.textContent = bidiText.str;
// bidiText.dir may be 'ttb' for vertical texts.
textDiv.dir = bidiText.dir === 'rtl' ? 'rtl' : 'ltr';
}
this.renderLayer();
},
renderLayer: function() {
var self = this;
var textDivs = this.textDivs;
var bidiTexts = this.textContent.bidiTexts;
var textLayerDiv = this.textLayerDiv;
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
var textLayerFrag = document.createDocumentFragment();
// No point in rendering so many divs as it'd make the browser unusable
// even after the divs are rendered
var MAX_TEXT_DIVS_TO_RENDER = 100000;
if (textDivs.length > MAX_TEXT_DIVS_TO_RENDER)
return;
for (var i = 0, ii = textDivs.length; i < ii; i++) {
var textDiv = textDivs[i];
if ('isWhitespace' in textDiv.dataset) {
continue;
}
textLayerFrag.appendChild(textDiv);
ctx.font = textDiv.style.fontSize + ' ' + textDiv.style.fontFamily;
var width = ctx.measureText(textDiv.textContent).width;
if (width > 0) {
var textScale = textDiv.dataset.canvasWidth / width;
var transform = 'scale(' + textScale + ', 1)';
if (bidiTexts[i].dir === 'ttb') {
transform = 'rotate(90deg) ' + transform;
}
CustomStyle.setProp('transform' , textDiv, transform);
CustomStyle.setProp('transformOrigin' , textDiv, '0% 0%');
textLayerDiv.appendChild(textDiv);
}
}
this.renderingDone = true;
//this.updateMatches();
textLayerDiv.appendChild(textLayerFrag);
},
/*setupRenderLayoutTimer: function() {
// Schedule renderLayout() if user has been scrolling, otherwise
// run it right away
var RENDER_DELAY = 200; // in ms
var self = this;
if (Date.now() - PDFView.lastScroll > RENDER_DELAY) {
// Render right away
this.renderLayer();
} else {
// Schedule
if (this.renderTimer)
clearTimeout(this.renderTimer);
this.renderTimer = setTimeout(function() {
self.setupRenderLayoutTimer();
}, RENDER_DELAY);
}
}*/
};
return TextLayerBuilder;
});