comunic/3rdparty/pdf.js/web/pdf_thumbnail_view.js
2016-11-19 12:08:12 +01:00

322 lines
11 KiB
JavaScript
Executable File

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/* Copyright 2012 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 mozL10n, RenderingStates, Promise, getOutputScale */
'use strict';
var THUMBNAIL_WIDTH = 98; // px
var THUMBNAIL_CANVAS_BORDER_WIDTH = 1; // px
/**
* @typedef {Object} PDFThumbnailViewOptions
* @property {HTMLDivElement} container - The viewer element.
* @property {number} id - The thumbnail's unique ID (normally its number).
* @property {PageViewport} defaultViewport - The page viewport.
* @property {IPDFLinkService} linkService - The navigation/linking service.
* @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
*/
/**
* @class
* @implements {IRenderableView}
*/
var PDFThumbnailView = (function PDFThumbnailViewClosure() {
function getTempCanvas(width, height) {
var tempCanvas = PDFThumbnailView.tempImageCache;
if (!tempCanvas) {
tempCanvas = document.createElement('canvas');
PDFThumbnailView.tempImageCache = tempCanvas;
}
tempCanvas.width = width;
tempCanvas.height = height;
// Since this is a temporary canvas, we need to fill the canvas with a white
// background ourselves. |_getPageDrawContext| uses CSS rules for this.
var ctx = tempCanvas.getContext('2d');
ctx.save();
ctx.fillStyle = 'rgb(255, 255, 255)';
ctx.fillRect(0, 0, width, height);
ctx.restore();
return tempCanvas;
}
/**
* @constructs PDFThumbnailView
* @param {PDFThumbnailViewOptions} options
*/
function PDFThumbnailView(options) {
var container = options.container;
var id = options.id;
var defaultViewport = options.defaultViewport;
var linkService = options.linkService;
var renderingQueue = options.renderingQueue;
this.id = id;
this.renderingId = 'thumbnail' + id;
this.pdfPage = null;
this.rotation = 0;
this.viewport = defaultViewport;
this.pdfPageRotate = defaultViewport.rotation;
this.linkService = linkService;
this.renderingQueue = renderingQueue;
this.hasImage = false;
this.resume = null;
this.renderingState = RenderingStates.INITIAL;
this.pageWidth = this.viewport.width;
this.pageHeight = this.viewport.height;
this.pageRatio = this.pageWidth / this.pageHeight;
this.canvasWidth = THUMBNAIL_WIDTH;
this.canvasHeight = (this.canvasWidth / this.pageRatio) | 0;
this.scale = this.canvasWidth / this.pageWidth;
var anchor = document.createElement('a');
anchor.href = linkService.getAnchorUrl('#page=' + id);
anchor.title = mozL10n.get('thumb_page_title', {page: id}, 'Page {{page}}');
anchor.onclick = function stopNavigation() {
linkService.page = id;
return false;
};
var div = document.createElement('div');
div.id = 'thumbnailContainer' + id;
div.className = 'thumbnail';
this.div = div;
if (id === 1) {
// Highlight the thumbnail of the first page when no page number is
// specified (or exists in cache) when the document is loaded.
div.classList.add('selected');
}
var ring = document.createElement('div');
ring.className = 'thumbnailSelectionRing';
var borderAdjustment = 2 * THUMBNAIL_CANVAS_BORDER_WIDTH;
ring.style.width = this.canvasWidth + borderAdjustment + 'px';
ring.style.height = this.canvasHeight + borderAdjustment + 'px';
this.ring = ring;
div.appendChild(ring);
anchor.appendChild(div);
container.appendChild(anchor);
}
PDFThumbnailView.prototype = {
setPdfPage: function PDFThumbnailView_setPdfPage(pdfPage) {
this.pdfPage = pdfPage;
this.pdfPageRotate = pdfPage.rotate;
var totalRotation = (this.rotation + this.pdfPageRotate) % 360;
this.viewport = pdfPage.getViewport(1, totalRotation);
this.reset();
},
reset: function PDFThumbnailView_reset() {
if (this.renderTask) {
this.renderTask.cancel();
}
this.hasImage = false;
this.resume = null;
this.renderingState = RenderingStates.INITIAL;
this.pageWidth = this.viewport.width;
this.pageHeight = this.viewport.height;
this.pageRatio = this.pageWidth / this.pageHeight;
this.canvasHeight = (this.canvasWidth / this.pageRatio) | 0;
this.scale = (this.canvasWidth / this.pageWidth);
this.div.removeAttribute('data-loaded');
var ring = this.ring;
var childNodes = ring.childNodes;
for (var i = childNodes.length - 1; i >= 0; i--) {
ring.removeChild(childNodes[i]);
}
var borderAdjustment = 2 * THUMBNAIL_CANVAS_BORDER_WIDTH;
ring.style.width = this.canvasWidth + borderAdjustment + 'px';
ring.style.height = this.canvasHeight + borderAdjustment + 'px';
if (this.canvas) {
// Zeroing the width and height causes Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
this.canvas.width = 0;
this.canvas.height = 0;
delete this.canvas;
}
},
update: function PDFThumbnailView_update(rotation) {
if (typeof rotation !== 'undefined') {
this.rotation = rotation;
}
var totalRotation = (this.rotation + this.pdfPageRotate) % 360;
this.viewport = this.viewport.clone({
scale: 1,
rotation: totalRotation
});
this.reset();
},
/**
* @private
*/
_getPageDrawContext:
function PDFThumbnailView_getPageDrawContext(noCtxScale) {
var canvas = document.createElement('canvas');
canvas.id = this.renderingId;
canvas.className = 'thumbnailImage';
canvas.setAttribute('aria-label', mozL10n.get('thumb_page_canvas',
{page: this.id}, 'Thumbnail of Page {{page}}'));
this.canvas = canvas;
this.div.setAttribute('data-loaded', true);
this.ring.appendChild(canvas);
var ctx = canvas.getContext('2d');
var outputScale = getOutputScale(ctx);
canvas.width = (this.canvasWidth * outputScale.sx) | 0;
canvas.height = (this.canvasHeight * outputScale.sy) | 0;
canvas.style.width = this.canvasWidth + 'px';
canvas.style.height = this.canvasHeight + 'px';
if (!noCtxScale && outputScale.scaled) {
ctx.scale(outputScale.sx, outputScale.sy);
}
return ctx;
},
draw: function PDFThumbnailView_draw() {
if (this.renderingState !== RenderingStates.INITIAL) {
console.error('Must be in new state before drawing');
}
if (this.hasImage) {
return Promise.resolve(undefined);
}
this.hasImage = true;
this.renderingState = RenderingStates.RUNNING;
var resolveRenderPromise, rejectRenderPromise;
var promise = new Promise(function (resolve, reject) {
resolveRenderPromise = resolve;
rejectRenderPromise = reject;
});
var self = this;
function thumbnailDrawCallback(error) {
// The renderTask may have been replaced by a new one, so only remove
// the reference to the renderTask if it matches the one that is
// triggering this callback.
if (renderTask === self.renderTask) {
self.renderTask = null;
}
if (error === 'cancelled') {
rejectRenderPromise(error);
return;
}
self.renderingState = RenderingStates.FINISHED;
if (!error) {
resolveRenderPromise(undefined);
} else {
rejectRenderPromise(error);
}
}
var ctx = this._getPageDrawContext();
var drawViewport = this.viewport.clone({ scale: this.scale });
var renderContinueCallback = function renderContinueCallback(cont) {
if (!self.renderingQueue.isHighestPriority(self)) {
self.renderingState = RenderingStates.PAUSED;
self.resume = function resumeCallback() {
self.renderingState = RenderingStates.RUNNING;
cont();
};
return;
}
cont();
};
var renderContext = {
canvasContext: ctx,
viewport: drawViewport,
continueCallback: renderContinueCallback
};
var renderTask = this.renderTask = this.pdfPage.render(renderContext);
renderTask.promise.then(
function pdfPageRenderCallback() {
thumbnailDrawCallback(null);
},
function pdfPageRenderError(error) {
thumbnailDrawCallback(error);
}
);
return promise;
},
setImage: function PDFThumbnailView_setImage(pageView) {
var img = pageView.canvas;
if (this.hasImage || !img) {
return;
}
if (!this.pdfPage) {
this.setPdfPage(pageView.pdfPage);
}
this.hasImage = true;
this.renderingState = RenderingStates.FINISHED;
var ctx = this._getPageDrawContext(true);
var canvas = ctx.canvas;
if (img.width <= 2 * canvas.width) {
ctx.drawImage(img, 0, 0, img.width, img.height,
0, 0, canvas.width, canvas.height);
return;
}
// drawImage does an awful job of rescaling the image, doing it gradually.
var MAX_NUM_SCALING_STEPS = 3;
var reducedWidth = canvas.width << MAX_NUM_SCALING_STEPS;
var reducedHeight = canvas.height << MAX_NUM_SCALING_STEPS;
var reducedImage = getTempCanvas(reducedWidth, reducedHeight);
var reducedImageCtx = reducedImage.getContext('2d');
while (reducedWidth > img.width || reducedHeight > img.height) {
reducedWidth >>= 1;
reducedHeight >>= 1;
}
reducedImageCtx.drawImage(img, 0, 0, img.width, img.height,
0, 0, reducedWidth, reducedHeight);
while (reducedWidth > 2 * canvas.width) {
reducedImageCtx.drawImage(reducedImage,
0, 0, reducedWidth, reducedHeight,
0, 0, reducedWidth >> 1, reducedHeight >> 1);
reducedWidth >>= 1;
reducedHeight >>= 1;
}
ctx.drawImage(reducedImage, 0, 0, reducedWidth, reducedHeight,
0, 0, canvas.width, canvas.height);
}
};
return PDFThumbnailView;
})();
PDFThumbnailView.tempImageCache = null;