Gallery: Add the offset feature in the slide mode.

ui/file_manager/gallery/js/image_editor/viewport.js

 // Copyright 2014 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';
 
 /**
  * Viewport class controls the way the image is displayed (scale, offset etc).
  * @constructor
  */
@@ skipping 68 matching lines @@
   this.offsetY_ = 0;
 
   /**
    * Generation of the screen size image cache.
    * This is incremented every time when the size of image cache is changed.
    * @type {number}
    * @private
    */
   this.generation_ = 0;
 
-  this.update();
+  this.update_();
   Object.seal(this);
 }
 
 /**
  * Zoom ratios.
  *
  * @type {Object.<string, number>}
  * @const
  */
 Viewport.ZOOM_RATIOS = Object.freeze({
   '3': 3,
   '2': 2,
   '1': 1.5,
   '0': 1,
   '-1': 0.75,
   '-2': 0.5,
   '-3': 0.25
 });
 
 /**
  * @param {number} width Image width.
  * @param {number} height Image height.
  */
 Viewport.prototype.setImageSize = function(width, height) {
   this.imageBounds_ = new Rect(width, height);
-  this.update();
-  this.invalidateCaches();
+  this.update_();
 };
 
 /**
  * @param {number} width Screen width.
  * @param {number} height Screen height.
  */
 Viewport.prototype.setScreenSize = function(width, height) {
   this.screenBounds_ = new Rect(width, height);
-  this.update();
-  this.invalidateCaches();
+  this.update_();
 };
 
 /**
  * Sets the new zoom ratio.
  * @param {number} zoomIndex New zoom index.
  */
 Viewport.prototype.setZoomIndex = function(zoomIndex) {
   // Ignore the invalid zoomIndex.
   if (!Viewport.ZOOM_RATIOS[zoomIndex.toString()])
     return;
   this.zoomIndex_ = zoomIndex;
   this.zoom_ = Viewport.ZOOM_RATIOS[zoomIndex];
-  this.update();
+  this.update_();
 };
 
 /**
  * Returns the current zoom index.
  * @return {number} Zoon index.
  */
 Viewport.prototype.getZoomIndex = function() {
   return this.zoomIndex_;
 };
 
 /**
- * @return {number} Scale.
+ * Returns the value of zoom.
+ * @return {number} Zoom value.
  */
-Viewport.prototype.getScale = function() { return this.scale_; };
-
-/**
- * @param {number} scale The new scale.
- */
-Viewport.prototype.setScale = function(scale) {
-  if (this.scale_ == scale)
-    return;
-  this.scale_ = scale;
-  this.update();
-  this.invalidateCaches();
+Viewport.prototype.getZoom = function() {
+  return this.zoomIndex_;
 };
 
 /**
- * @return {number} Best scale to fit the current image into the current screen.
- */
-Viewport.prototype.getFittingScale = function() {
-  return this.getFittingScaleForImageSize_(
-      this.imageBounds_.width, this.imageBounds_.height);
-};
-
-/**
  * Obtains the scale for the specified image size.
  *
  * @param {number} width Width of the full resolution image.
  * @param {number} height Height of the full resolution image.
  * @return {number} The ratio of the fullresotion image size and the calculated
  * displayed image size.
  */
 Viewport.prototype.getFittingScaleForImageSize_ = function(width, height) {
   var scaleX = this.screenBounds_.width / width;
   var scaleY = this.screenBounds_.height / height;
   // Scales > (1 / devicePixelRatio) do not look good. Also they are
   // not really useful as we do not have any pixel-level operations.
   return Math.min(1 / window.devicePixelRatio, scaleX, scaleY);
 };
 
 /**
- * Set the scale to fit the image into the screen.
- */
-Viewport.prototype.fitImage = function() {
-  this.setScale(this.getFittingScale());
-};
-
-/**
  * @return {number} X-offset of the viewport.
  */
 Viewport.prototype.getOffsetX = function() { return this.offsetX_; };
 
 /**
  * @return {number} Y-offset of the viewport.
  */
 Viewport.prototype.getOffsetY = function() { return this.offsetY_; };
 
 /**
  * Set the image offset in the viewport.
  * @param {number} x X-offset.
  * @param {number} y Y-offset.
- * @param {boolean} ignoreClipping True if no clipping should be applied.
  */
-Viewport.prototype.setOffset = function(x, y, ignoreClipping) {
-  if (!ignoreClipping) {
-    x = this.clampOffsetX_(x);
-    y = this.clampOffsetY_(y);
-  }
-  if (this.offsetX_ == x && this.offsetY_ == y) return;
+Viewport.prototype.setOffset = function(x, y) {
+  if (this.offsetX_ == x && this.offsetY_ == y)
+    return;
   this.offsetX_ = x;
   this.offsetY_ = y;
-  this.invalidateCaches();
+  this.update_();
 };
 
 /**
  * @return {Rect} The image bounds in image coordinates.
  */
 Viewport.prototype.getImageBounds = function() { return this.imageBounds_; };
 
 /**
 * @return {Rect} The screen bounds in screen coordinates.
 */
@@ skipping 11 matching lines @@
 
 /**
  * A counter that is incremented with each viewport state change.
  * Clients that cache anything that depends on the viewport state should keep
  * track of this counter.
  * @return {number} counter.
  */
 Viewport.prototype.getCacheGeneration = function() { return this.generation_; };
 
 /**
- * Called on event view port state change.
- */
-Viewport.prototype.invalidateCaches = function() { this.generation_++; };
-
-/**
  * @return {Rect} The image bounds in screen coordinates.
  */
 Viewport.prototype.getImageBoundsOnScreen = function() {
   return this.imageBoundsOnScreen_;
 };
 
 /**
  * The image bounds in screen coordinates.
  * This returns the bounds of element before applying zoom and offset.
  * @return {Rect}
  */
 Viewport.prototype.getImageElementBoundsOnScreen = function() {
   return this.imageElementBoundsOnScreen_;
 };
 
 /**
  * The image bounds on screen, which is clipped with the screen size.
  * @return {Rect}
  */
 Viewport.prototype.getImageBoundsOnScreenClipped = function() {
   return this.imageBoundsOnScreenClipped_;
 };
 
 /**
  * @param {number} size Size in screen coordinates.
  * @return {number} Size in image coordinates.
  */
 Viewport.prototype.screenToImageSize = function(size) {
-  return size / this.getScale();
+  return size / this.scale_;
 };
 
 /**
  * @param {number} x X in screen coordinates.
  * @return {number} X in image coordinates.
  */
 Viewport.prototype.screenToImageX = function(x) {
-  return Math.round((x - this.imageBoundsOnScreen_.left) / this.getScale());
+  return Math.round((x - this.imageBoundsOnScreen_.left) / this.scale_);
 };
 
 /**
  * @param {number} y Y in screen coordinates.
  * @return {number} Y in image coordinates.
  */
 Viewport.prototype.screenToImageY = function(y) {
-  return Math.round((y - this.imageBoundsOnScreen_.top) / this.getScale());
+  return Math.round((y - this.imageBoundsOnScreen_.top) / this.scale_);
 };
 
 /**
  * @param {Rect} rect Rectangle in screen coordinates.
  * @return {Rect} Rectangle in image coordinates.
  */
 Viewport.prototype.screenToImageRect = function(rect) {
   return new Rect(
       this.screenToImageX(rect.left),
       this.screenToImageY(rect.top),
       this.screenToImageSize(rect.width),
       this.screenToImageSize(rect.height));
 };
 
 /**
  * @param {number} size Size in image coordinates.
  * @return {number} Size in screen coordinates.
  */
 Viewport.prototype.imageToScreenSize = function(size) {
-  return size * this.getScale();
+  return size * this.scale_;
 };
 
 /**
  * @param {number} x X in image coordinates.
  * @return {number} X in screen coordinates.
  */
 Viewport.prototype.imageToScreenX = function(x) {
-  return Math.round(this.imageBoundsOnScreen_.left + x * this.getScale());
+  return Math.round(this.imageBoundsOnScreen_.left + x * this.scale_);
 };
 
 /**
  * @param {number} y Y in image coordinates.
  * @return {number} Y in screen coordinates.
  */
 Viewport.prototype.imageToScreenY = function(y) {
-  return Math.round(this.imageBoundsOnScreen_.top + y * this.getScale());
+  return Math.round(this.imageBoundsOnScreen_.top + y * this.scale_);
 };
 
 /**
  * @param {Rect} rect Rectangle in image coordinates.
  * @return {Rect} Rectangle in screen coordinates.
  */
 Viewport.prototype.imageToScreenRect = function(rect) {
   return new Rect(
       this.imageToScreenX(rect.left),
       this.imageToScreenY(rect.top),
@@ skipping 27 matching lines @@
   return Math.round(
     (this.screenBounds_.height - this.imageBounds_.height * this.scale_) / 2);
 };
 
 /**
  * @param {number} x X-offset.
  * @return {number} X-offset clamped to the valid range.
  * @private
  */
 Viewport.prototype.clampOffsetX_ = function(x) {
-  var limit = Math.round(Math.max(0, -this.getMarginX_() / this.getScale()));
+  var limit = Math.round(Math.max(0, -this.getMarginX_() / this.scale_));
   return ImageUtil.clamp(-limit, x, limit);
 };
 
 /**
  * @param {number} y Y-offset.
  * @return {number} Y-offset clamped to the valid range.
  * @private
  */
 Viewport.prototype.clampOffsetY_ = function(y) {
-  var limit = Math.round(Math.max(0, -this.getMarginY_() / this.getScale()));
+  var limit = Math.round(Math.max(0, -this.getMarginY_() / this.scale_));
   return ImageUtil.clamp(-limit, y, limit);
 };
 
 /**
  * @private
  */
 Viewport.prototype.getCenteredRect_ = function(
     width, height, offsetX, offsetY) {
   return new Rect(
       ~~((this.screenBounds_.width - width) / 2) + offsetX,
       ~~((this.screenBounds_.height - height) / 2) + offsetY,
       width,
       height);
 };
 
 /**
+ * Resets zoom and offset.
+ */
+Viewport.prototype.resetView = function() {
+  this.zoomIndex_ = 0;
+  this.zoom_ = 1;
+  this.offsetX_ = 0;
+  this.offsetY_ = 0;
+  this.update_();
+};
+
+/**
  * Recalculate the viewport parameters.
+ * @private
  */
-Viewport.prototype.update = function() {
-  var scale = this.getScale();
+Viewport.prototype.update_ = function() {
+  // Update scale.
+  this.scale_ = this.getFittingScaleForImageSize_(
+      this.imageBounds_.width, this.imageBounds_.height);
+
+  // Limit offset values.
+  var zoomedWidht = ~~(this.imageBounds_.width * this.scale_ * this.zoom_);
+  var zoomedHeight = ~~(this.imageBounds_.height * this.scale_ * this.zoom_);
+  var dx = Math.max(zoomedWidht - this.screenBounds_.width, 0) / 2;
+  var dy = Math.max(zoomedHeight - this.screenBounds_.height, 0) /2;
+  this.offsetX_ = ImageUtil.clamp(-dx, this.offsetX_, dx);
+  this.offsetY_ = ImageUtil.clamp(-dy, this.offsetY_, dy);
 
   // Image bounds on screen.
   this.imageBoundsOnScreen_ = this.getCenteredRect_(
-      ~~(this.imageBounds_.width * scale * this.zoom_),
-      ~~(this.imageBounds_.height * scale * this.zoom_),
-      this.offsetX_,
-      this.offsetY_);
+      zoomedWidht, zoomedHeight, this.offsetX_, this.offsetY_);
 
   // Image bounds of element (that is not applied zoom and offset) on screen.
+  var oldBounds = this.imageElementBoundsOnScreen_;
   this.imageElementBoundsOnScreen_ = this.getCenteredRect_(
-      ~~(this.imageBounds_.width * scale),
-      ~~(this.imageBounds_.height * scale),
+      ~~(this.imageBounds_.width * this.scale_),
+      ~~(this.imageBounds_.height * this.scale_),
       0,
       0);
+  if (!oldBounds ||
+      this.imageElementBoundsOnScreen_.width != oldBounds.width ||
+      this.imageElementBoundsOnScreen_.height != oldBounds.height) {
+    this.generation_++;
+  }
 
   // Image bounds on screen cliped with the screen bounds.
   var left = Math.max(this.imageBoundsOnScreen_.left, 0);
   var top = Math.max(this.imageBoundsOnScreen_.top, 0);
   var right = Math.min(
       this.imageBoundsOnScreen_.right, this.screenBounds_.width);
   var bottom = Math.min(
       this.imageBoundsOnScreen_.bottom, this.screenBounds_.height);
   this.imageBoundsOnScreenClipped_ = new Rect(
       left, top, right - left, bottom - top);
 };
 
 /**
  * Obtains CSS transformation for the screen image.
  * @return {string} Transformation description.
  */
 Viewport.prototype.getTransformation = function() {
-  return 'scale(' + (1 / window.devicePixelRatio * this.zoom_) + ')';
+  return 'translate(' + this.offsetX_ + 'px, ' + this.offsetY_ + 'px) ' +
+      'scale(' + (1 / window.devicePixelRatio * this.zoom_) + ')';
 };
 
 /**
  * Obtains shift CSS transformation for the screen image.
  * @param {number} dx Amount of shift.
  * @return {string} Transformation description.
  */
 Viewport.prototype.getShiftTransformation = function(dx) {
   return 'translateX(' + dx + 'px) ' + this.getTransformation();
 };
 
 /**
  * Obtains CSS transformation that makes the rotated image fit the original
  * image. The new rotated image that the transformation is applied to looks the
  * same with original image.
  *
  * @param {boolean} orientation Orientation of the rotation from the original
  *     image to the rotated image. True is for clockwise and false is for
  *     counterclockwise.
  * @return {string} Transformation description.
  */
 Viewport.prototype.getInverseTransformForRotatedImage = function(orientation) {
   var previousImageWidth = this.imageBounds_.height;
   var previousImageHeight = this.imageBounds_.width;
   var oldScale = this.getFittingScaleForImageSize_(
       previousImageWidth, previousImageHeight);
-  var scaleRatio = oldScale / this.getScale();
+  var scaleRatio = oldScale / this.scale_;
   var degree = orientation ? '-90deg' : '90deg';
   return [
     'scale(' + scaleRatio + ')',
     'rotate(' + degree + ')',
     this.getTransformation()
   ].join(' ');
 };
 
 /**
  * Obtains CSS transformation that makes the cropped image fit the original
@@ skipping 37 matching lines @@
   var screenWidth = this.screenBounds_.width;
   var screenHeight = this.screenBounds_.height;
   var dx = screenRect.left + screenRect.width / 2 - screenWidth / 2;
   var dy = screenRect.top + screenRect.height / 2 - screenHeight / 2;
   return [
     'translate(' + dx + 'px,' + dy + 'px)',
     'scale(' + scaleX + ',' + scaleY + ')',
     this.getTransformation()
   ].join(' ');
 };