Yury Delendik
10 years ago
9 changed files with 268 additions and 144 deletions
@ -0,0 +1,237 @@
@@ -0,0 +1,237 @@
|
||||
/* Copyright 2015 Mozilla Foundation |
||||
* |
||||
* Licensed under the Apache License, Version 2.0 (the "License"); |
||||
* you may not use this file except in compliance with the License. |
||||
* You may obtain a copy of the License at |
||||
* |
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
* |
||||
* Unless required by applicable law or agreed to in writing, software |
||||
* distributed under the License is distributed on an "AS IS" BASIS, |
||||
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
||||
* See the License for the specific language governing permissions and |
||||
* limitations under the License. |
||||
*/ |
||||
/* globals PDFJS, createPromiseCapability */ |
||||
|
||||
'use strict'; |
||||
|
||||
/** |
||||
* Text layer render parameters. |
||||
* |
||||
* @typedef {Object} TextLayerRenderParameters |
||||
* @property {TextContent} textContent - Text content to render (the object is |
||||
* returned by the page's getTextContent() method). |
||||
* @property {HTMLElement} container - HTML element that will contain text runs. |
||||
* @property {PDFJS.PageViewport} viewport - The target viewport to properly |
||||
* layout the text runs. |
||||
* @property {Array} textDivs - (optional) HTML elements that are correspond |
||||
* the text items of the textContent input. This is output and shall be |
||||
* initially be set to empty array. |
||||
* @property {number} timeout - (optional) Delay in milliseconds before |
||||
* rendering of the text runs occurs. |
||||
*/ |
||||
var renderTextLayer = (function renderTextLayerClosure() { |
||||
var MAX_TEXT_DIVS_TO_RENDER = 100000; |
||||
|
||||
var NonWhitespaceRegexp = /\S/; |
||||
|
||||
function isAllWhitespace(str) { |
||||
return !NonWhitespaceRegexp.test(str); |
||||
} |
||||
|
||||
function appendText(textDivs, viewport, geom, styles) { |
||||
var style = styles[geom.fontName]; |
||||
var textDiv = document.createElement('div'); |
||||
textDivs.push(textDiv); |
||||
if (isAllWhitespace(geom.str)) { |
||||
textDiv.dataset.isWhitespace = true; |
||||
return; |
||||
} |
||||
var tx = PDFJS.Util.transform(viewport.transform, geom.transform); |
||||
var angle = Math.atan2(tx[1], tx[0]); |
||||
if (style.vertical) { |
||||
angle += Math.PI / 2; |
||||
} |
||||
var fontHeight = Math.sqrt((tx[2] * tx[2]) + (tx[3] * tx[3])); |
||||
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.left = left + 'px'; |
||||
textDiv.style.top = top + 'px'; |
||||
textDiv.style.fontSize = fontHeight + 'px'; |
||||
textDiv.style.fontFamily = style.fontFamily; |
||||
|
||||
textDiv.textContent = geom.str; |
||||
// |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
|
||||
// not worth the effort to do a more accurate test.
|
||||
if (PDFJS.pdfBug) { |
||||
textDiv.dataset.fontName = geom.fontName; |
||||
} |
||||
// Storing into dataset will convert number into string.
|
||||
if (angle !== 0) { |
||||
textDiv.dataset.angle = angle * (180 / Math.PI); |
||||
} |
||||
// We don't bother scaling single-char text divs, because it has very
|
||||
// little effect on text highlighting. This makes scrolling on docs with
|
||||
// lots of such divs a lot faster.
|
||||
if (geom.str.length > 1) { |
||||
if (style.vertical) { |
||||
textDiv.dataset.canvasWidth = geom.height * viewport.scale; |
||||
} else { |
||||
textDiv.dataset.canvasWidth = geom.width * viewport.scale; |
||||
} |
||||
} |
||||
} |
||||
|
||||
function render(task) { |
||||
if (task._canceled) { |
||||
return; |
||||
} |
||||
var textLayerFrag = task._container; |
||||
var textDivs = task._textDivs; |
||||
var capability = task._capability; |
||||
var textDivsLength = textDivs.length; |
||||
|
||||
// No point in rendering many divs as it would make the browser
|
||||
// unusable even after the divs are rendered.
|
||||
if (textDivsLength > MAX_TEXT_DIVS_TO_RENDER) { |
||||
capability.resolve(); |
||||
return; |
||||
} |
||||
|
||||
var canvas = document.createElement('canvas'); |
||||
//#if MOZCENTRAL || FIREFOX || GENERIC
|
||||
canvas.mozOpaque = true; |
||||
//#endif
|
||||
var ctx = canvas.getContext('2d', {alpha: false}); |
||||
|
||||
var lastFontSize; |
||||
var lastFontFamily; |
||||
for (var i = 0; i < textDivsLength; i++) { |
||||
var textDiv = textDivs[i]; |
||||
if (textDiv.dataset.isWhitespace !== undefined) { |
||||
continue; |
||||
} |
||||
|
||||
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); |
||||
var transform; |
||||
if (textDiv.dataset.canvasWidth !== undefined) { |
||||
// Dataset values come of type string.
|
||||
var textScale = textDiv.dataset.canvasWidth / width; |
||||
transform = 'scaleX(' + textScale + ')'; |
||||
} else { |
||||
transform = ''; |
||||
} |
||||
var rotation = textDiv.dataset.angle; |
||||
if (rotation) { |
||||
transform = 'rotate(' + rotation + 'deg) ' + transform; |
||||
} |
||||
if (transform) { |
||||
PDFJS.CustomStyle.setProp('transform' , textDiv, transform); |
||||
} |
||||
} |
||||
} |
||||
capability.resolve(); |
||||
} |
||||
|
||||
/** |
||||
* Text layer rendering task. |
||||
* |
||||
* @param {TextContent} textContent |
||||
* @param {HTMLElement} container |
||||
* @param {PDFJS.PageViewport} viewport |
||||
* @param {Array} textDivs |
||||
* @private |
||||
*/ |
||||
function TextLayerRenderTask(textContent, container, viewport, textDivs) { |
||||
this._textContent = textContent; |
||||
this._container = container; |
||||
this._viewport = viewport; |
||||
textDivs = textDivs || []; |
||||
this._textDivs = textDivs; |
||||
this._canceled = false; |
||||
this._capability = createPromiseCapability(); |
||||
this._renderTimer = null; |
||||
} |
||||
TextLayerRenderTask.prototype = { |
||||
get promise() { |
||||
return this._capability.promise; |
||||
}, |
||||
|
||||
cancel: function TextLayer_cancel() { |
||||
this._canceled = true; |
||||
if (this._renderTimer !== null) { |
||||
clearTimeout(this._renderTimer); |
||||
this._renderTimer = null; |
||||
} |
||||
this._capability.reject('canceled'); |
||||
}, |
||||
|
||||
_render: function TextLayer_render(timeout) { |
||||
var textItems = this._textContent.items; |
||||
var styles = this._textContent.styles; |
||||
var textDivs = this._textDivs; |
||||
var viewport = this._viewport; |
||||
for (var i = 0, len = textItems.length; i < len; i++) { |
||||
appendText(textDivs, viewport, textItems[i], styles); |
||||
} |
||||
|
||||
if (!timeout) { // Render right away
|
||||
render(this); |
||||
} else { // Schedule
|
||||
var self = this; |
||||
this._renderTimer = setTimeout(function() { |
||||
render(self); |
||||
self._renderTimer = null; |
||||
}, timeout); |
||||
} |
||||
} |
||||
}; |
||||
|
||||
|
||||
/** |
||||
* Starts rendering of the text layer. |
||||
* |
||||
* @param {TextLayerRenderParameters} renderParameters |
||||
* @returns {TextLayerRenderTask} |
||||
*/ |
||||
function renderTextLayer(renderParameters) { |
||||
var task = new TextLayerRenderTask(renderParameters.textContent, |
||||
renderParameters.container, |
||||
renderParameters.viewport, |
||||
renderParameters.textDivs); |
||||
task._render(renderParameters.timeout); |
||||
return task; |
||||
} |
||||
|
||||
return renderTextLayer; |
||||
})(); |
||||
|
||||
PDFJS.renderTextLayer = renderTextLayer; |
||||
Loading…
Reference in new issue