| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| 'use strict'; |
| |
| /** |
| * Command queue is the only way to modify images. |
| * Supports undo/redo. |
| * Command execution is asynchronous (callback-based). |
| * |
| * @param {Document} document Document to create canvases in. |
| * @param {HTMLCanvasElement} canvas The canvas with the original image. |
| * @param {function(callback)} saveFunction Function to save the image. |
| * @constructor |
| */ |
| function CommandQueue(document, canvas, saveFunction) { |
| this.document_ = document; |
| this.undo_ = []; |
| this.redo_ = []; |
| this.subscribers_ = []; |
| this.currentImage_ = canvas; |
| |
| // Current image may be null or not-null but with width = height = 0. |
| // Copying an image with zero dimensions causes js errors. |
| if (this.currentImage_) { |
| this.baselineImage_ = document.createElement('canvas'); |
| this.baselineImage_.width = this.currentImage_.width; |
| this.baselineImage_.height = this.currentImage_.height; |
| if (this.currentImage_.width > 0 && this.currentImage_.height > 0) { |
| var context = this.baselineImage_.getContext('2d'); |
| context.drawImage(this.currentImage_, 0, 0); |
| } |
| } else { |
| this.baselineImage_ = null; |
| } |
| |
| this.previousImage_ = document.createElement('canvas'); |
| this.previousImageAvailable_ = false; |
| |
| this.saveFunction_ = saveFunction; |
| this.busy_ = false; |
| this.UIContext_ = {}; |
| } |
| |
| /** |
| * Attach the UI elements to the command queue. |
| * Once the UI is attached the results of image manipulations are displayed. |
| * |
| * @param {ImageView} imageView The ImageView object to display the results. |
| * @param {ImageEditor.Prompt} prompt Prompt to use with this CommandQueue. |
| * @param {function(boolean)} lock Function to enable/disable buttons etc. |
| */ |
| CommandQueue.prototype.attachUI = function(imageView, prompt, lock) { |
| this.UIContext_ = { |
| imageView: imageView, |
| prompt: prompt, |
| lock: lock |
| }; |
| }; |
| |
| /** |
| * Execute the action when the queue is not busy. |
| * @param {function} callback Callback. |
| */ |
| CommandQueue.prototype.executeWhenReady = function(callback) { |
| if (this.isBusy()) |
| this.subscribers_.push(callback); |
| else |
| setTimeout(callback, 0); |
| }; |
| |
| /** |
| * @return {boolean} True if the command queue is busy. |
| */ |
| CommandQueue.prototype.isBusy = function() { return this.busy_ }; |
| |
| /** |
| * Set the queue state to busy. Lock the UI. |
| * @private |
| */ |
| CommandQueue.prototype.setBusy_ = function() { |
| if (this.busy_) |
| throw new Error('CommandQueue already busy'); |
| |
| this.busy_ = true; |
| |
| if (this.UIContext_.lock) |
| this.UIContext_.lock(true); |
| |
| ImageUtil.trace.resetTimer('command-busy'); |
| }; |
| |
| /** |
| * Set the queue state to not busy. Unlock the UI and execute pending actions. |
| * @private |
| */ |
| CommandQueue.prototype.clearBusy_ = function() { |
| if (!this.busy_) |
| throw new Error('Inconsistent CommandQueue already not busy'); |
| |
| this.busy_ = false; |
| |
| // Execute the actions requested while the queue was busy. |
| while (this.subscribers_.length) |
| this.subscribers_.shift()(); |
| |
| if (this.UIContext_.lock) |
| this.UIContext_.lock(false); |
| |
| ImageUtil.trace.reportTimer('command-busy'); |
| }; |
| |
| /** |
| * Commit the image change: save and unlock the UI. |
| * @param {number=} opt_delay Delay in ms (to avoid disrupting the animation). |
| * @private |
| */ |
| CommandQueue.prototype.commit_ = function(opt_delay) { |
| setTimeout(this.saveFunction_.bind(null, this.clearBusy_.bind(this)), |
| opt_delay || 0); |
| }; |
| |
| /** |
| * Internal function to execute the command in a given context. |
| * |
| * @param {Command} command The command to execute. |
| * @param {Object} uiContext The UI context. |
| * @param {function} callback Completion callback. |
| * @private |
| */ |
| CommandQueue.prototype.doExecute_ = function(command, uiContext, callback) { |
| if (!this.currentImage_) |
| throw new Error('Cannot operate on null image'); |
| |
| // Remember one previous image so that the first undo is as fast as possible. |
| this.previousImage_.width = this.currentImage_.width; |
| this.previousImage_.height = this.currentImage_.height; |
| this.previousImageAvailable_ = true; |
| var context = this.previousImage_.getContext('2d'); |
| context.drawImage(this.currentImage_, 0, 0); |
| |
| command.execute( |
| this.document_, |
| this.currentImage_, |
| function(result, opt_delay) { |
| this.currentImage_ = result; |
| callback(opt_delay); |
| }.bind(this), |
| uiContext); |
| }; |
| |
| /** |
| * Executes the command. |
| * |
| * @param {Command} command Command to execute. |
| * @param {boolean=} opt_keep_redo True if redo stack should not be cleared. |
| */ |
| CommandQueue.prototype.execute = function(command, opt_keep_redo) { |
| this.setBusy_(); |
| |
| if (!opt_keep_redo) |
| this.redo_ = []; |
| |
| this.undo_.push(command); |
| |
| this.doExecute_(command, this.UIContext_, this.commit_.bind(this)); |
| }; |
| |
| /** |
| * @return {boolean} True if Undo is applicable. |
| */ |
| CommandQueue.prototype.canUndo = function() { |
| return this.undo_.length != 0; |
| }; |
| |
| /** |
| * Undo the most recent command. |
| */ |
| CommandQueue.prototype.undo = function() { |
| if (!this.canUndo()) |
| throw new Error('Cannot undo'); |
| |
| this.setBusy_(); |
| |
| var command = this.undo_.pop(); |
| this.redo_.push(command); |
| |
| var self = this; |
| |
| function complete() { |
| var delay = command.revertView( |
| self.currentImage_, self.UIContext_.imageView); |
| self.commit_(delay); |
| } |
| |
| if (this.previousImageAvailable_) { |
| // First undo after an execute call. |
| this.currentImage_.width = this.previousImage_.width; |
| this.currentImage_.height = this.previousImage_.height; |
| var context = this.currentImage_.getContext('2d'); |
| context.drawImage(this.previousImage_, 0, 0); |
| |
| // Free memory. |
| this.previousImage_.width = 0; |
| this.previousImage_.height = 0; |
| this.previousImageAvailable_ = false; |
| |
| complete(); |
| // TODO(kaznacheev) Consider recalculating previousImage_ right here |
| // by replaying the commands in the background. |
| } else { |
| this.currentImage_.width = this.baselineImage_.width; |
| this.currentImage_.height = this.baselineImage_.height; |
| var context = this.currentImage_.getContext('2d'); |
| context.drawImage(this.baselineImage_, 0, 0); |
| |
| var replay = function(index) { |
| if (index < self.undo_.length) |
| self.doExecute_(self.undo_[index], {}, replay.bind(null, index + 1)); |
| else { |
| complete(); |
| } |
| }; |
| |
| replay(0); |
| } |
| }; |
| |
| /** |
| * @return {boolean} True if Redo is applicable. |
| */ |
| CommandQueue.prototype.canRedo = function() { |
| return this.redo_.length != 0; |
| }; |
| |
| /** |
| * Repeat the command that was recently un-done. |
| */ |
| CommandQueue.prototype.redo = function() { |
| if (!this.canRedo()) |
| throw new Error('Cannot redo'); |
| |
| this.execute(this.redo_.pop(), true); |
| }; |
| |
| /** |
| * Closes internal buffers. Call to ensure, that internal buffers are freed |
| * as soon as possible. |
| */ |
| CommandQueue.prototype.close = function() { |
| // Free memory used by the undo buffer. |
| this.previousImage_.width = 0; |
| this.previousImage_.height = 0; |
| this.previousImageAvailable_ = false; |
| |
| if (this.baselineImage_) { |
| this.baselineImage_.width = 0; |
| this.baselineImage_.height = 0; |
| } |
| }; |
| |
| /** |
| * Command object encapsulates an operation on an image and a way to visualize |
| * its result. |
| * |
| * @param {string} name Command name. |
| * @constructor |
| */ |
| function Command(name) { |
| this.name_ = name; |
| } |
| |
| /** |
| * @return {string} String representation of the command. |
| */ |
| Command.prototype.toString = function() { |
| return 'Command ' + this.name_; |
| }; |
| |
| /** |
| * Execute the command and visualize its results. |
| * |
| * The two actions are combined into one method because sometimes it is nice |
| * to be able to show partial results for slower operations. |
| * |
| * @param {Document} document Document on which to execute command. |
| * @param {HTMLCanvasElement} srcCanvas Canvas to execute on. |
| * @param {function(HTMLCanvasElement, number)} callback Callback to call on |
| * completion. |
| * @param {Object} uiContext Context to work in. |
| */ |
| Command.prototype.execute = function(document, srcCanvas, callback, uiContext) { |
| console.error('Command.prototype.execute not implemented'); |
| }; |
| |
| /** |
| * Visualize reversion of the operation. |
| * |
| * @param {HTMLCanvasElement} canvas Image data to use. |
| * @param {ImageView} imageView ImageView to revert. |
| * @return {number} Animation duration in ms. |
| */ |
| Command.prototype.revertView = function(canvas, imageView) { |
| imageView.replace(canvas); |
| return 0; |
| }; |
| |
| /** |
| * Creates canvas to render on. |
| * |
| * @param {Document} document Document to create canvas in. |
| * @param {HTMLCanvasElement} srcCanvas to copy optional dimensions from. |
| * @param {number=} opt_width new canvas width. |
| * @param {number=} opt_height new canvas height. |
| * @return {HTMLCanvasElement} Newly created canvas. |
| * @private |
| */ |
| Command.prototype.createCanvas_ = function( |
| document, srcCanvas, opt_width, opt_height) { |
| var result = document.createElement('canvas'); |
| result.width = opt_width || srcCanvas.width; |
| result.height = opt_height || srcCanvas.height; |
| return result; |
| }; |
| |
| |
| /** |
| * Rotate command |
| * @param {number} rotate90 Rotation angle in 90 degree increments (signed). |
| * @constructor |
| * @extends {Command} |
| */ |
| Command.Rotate = function(rotate90) { |
| Command.call(this, 'rotate(' + rotate90 * 90 + 'deg)'); |
| this.rotate90_ = rotate90; |
| }; |
| |
| Command.Rotate.prototype = { __proto__: Command.prototype }; |
| |
| /** @override */ |
| Command.Rotate.prototype.execute = function( |
| document, srcCanvas, callback, uiContext) { |
| var result = this.createCanvas_( |
| document, |
| srcCanvas, |
| (this.rotate90_ & 1) ? srcCanvas.height : srcCanvas.width, |
| (this.rotate90_ & 1) ? srcCanvas.width : srcCanvas.height); |
| ImageUtil.drawImageTransformed( |
| result, srcCanvas, 1, 1, this.rotate90_ * Math.PI / 2); |
| var delay; |
| if (uiContext.imageView) { |
| delay = uiContext.imageView.replaceAndAnimate(result, null, this.rotate90_); |
| } |
| setTimeout(callback, 0, result, delay); |
| }; |
| |
| /** @override */ |
| Command.Rotate.prototype.revertView = function(canvas, imageView) { |
| return imageView.replaceAndAnimate(canvas, null, -this.rotate90_); |
| }; |
| |
| |
| /** |
| * Crop command. |
| * |
| * @param {Rect} imageRect Crop rectangle in image coordinates. |
| * @constructor |
| * @extends {Command} |
| */ |
| Command.Crop = function(imageRect) { |
| Command.call(this, 'crop' + imageRect.toString()); |
| this.imageRect_ = imageRect; |
| }; |
| |
| Command.Crop.prototype = { __proto__: Command.prototype }; |
| |
| /** @override */ |
| Command.Crop.prototype.execute = function( |
| document, srcCanvas, callback, uiContext) { |
| var result = this.createCanvas_( |
| document, srcCanvas, this.imageRect_.width, this.imageRect_.height); |
| Rect.drawImage(result.getContext('2d'), srcCanvas, null, this.imageRect_); |
| var delay; |
| if (uiContext.imageView) { |
| delay = uiContext.imageView.replaceAndAnimate(result, this.imageRect_, 0); |
| } |
| setTimeout(callback, 0, result, delay); |
| }; |
| |
| /** @override */ |
| Command.Crop.prototype.revertView = function(canvas, imageView) { |
| return imageView.animateAndReplace(canvas, this.imageRect_); |
| }; |
| |
| |
| /** |
| * Filter command. |
| * |
| * @param {string} name Command name. |
| * @param {function(ImageData,ImageData,number,number)} filter Filter function. |
| * @param {string} message Message to display when done. |
| * @constructor |
| * @extends {Command} |
| */ |
| Command.Filter = function(name, filter, message) { |
| Command.call(this, name); |
| this.filter_ = filter; |
| this.message_ = message; |
| }; |
| |
| Command.Filter.prototype = { __proto__: Command.prototype }; |
| |
| /** @override */ |
| Command.Filter.prototype.execute = function( |
| document, srcCanvas, callback, uiContext) { |
| var result = this.createCanvas_(document, srcCanvas); |
| |
| var self = this; |
| |
| var previousRow = 0; |
| |
| function onProgressVisible(updatedRow, rowCount) { |
| if (updatedRow == rowCount) { |
| uiContext.imageView.replace(result); |
| if (self.message_) |
| uiContext.prompt.show(self.message_, 2000); |
| callback(result); |
| } else { |
| var viewport = uiContext.imageView.viewport_; |
| |
| var imageStrip = new Rect(viewport.getImageBounds()); |
| imageStrip.top = previousRow; |
| imageStrip.height = updatedRow - previousRow; |
| |
| var screenStrip = new Rect(viewport.getImageBoundsOnScreen()); |
| screenStrip.top = Math.round(viewport.imageToScreenY(previousRow)); |
| screenStrip.height = |
| Math.round(viewport.imageToScreenY(updatedRow)) - screenStrip.top; |
| |
| uiContext.imageView.paintDeviceRect( |
| viewport.screenToDeviceRect(screenStrip), result, imageStrip); |
| previousRow = updatedRow; |
| } |
| } |
| |
| function onProgressInvisible(updatedRow, rowCount) { |
| if (updatedRow == rowCount) { |
| callback(result); |
| } |
| } |
| |
| filter.applyByStrips(result, srcCanvas, this.filter_, |
| uiContext.imageView ? onProgressVisible : onProgressInvisible); |
| }; |