Gallery.app: Move geometry calculation for the slide image to Viewport class.

This is a preparation for implementing the zoom feature in Gallery.app.

BUG=245926
TEST=manually

Review URL: https://codereview.chromium.org/384573002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282553 0039d316-1c4b-4281-b951-d872f2087c98

ui/file_manager/gallery/js/image_editor/image_view.js

@@ -626,9 +626,8 @@ ImageView.prototype.setTransform = function(element, opt_effect, opt_duration) {
  * @return {ImageView.Effect.Zoom} Zoom effect object.
  */
 ImageView.prototype.createZoomEffect = function(screenRect) {
-  return new ImageView.Effect.Zoom(
-      this.viewport_.screenToDeviceRect(screenRect),
-      null /* use viewport */,
+  return new ImageView.Effect.ZoomToScreen(
+      screenRect,
       ImageView.MODE_TRANSITION_DURATION);
 };
 
@@ -644,21 +643,17 @@ ImageView.prototype.createZoomEffect = function(screenRect) {
  */
 ImageView.prototype.replaceAndAnimate = function(
     canvas, imageCropRect, rotate90) {
-  var oldScale = this.viewport_.getScale();
-  var deviceCropRect = imageCropRect && this.viewport_.screenToDeviceRect(
-        this.viewport_.imageToScreenRect(imageCropRect));
-
+  var oldImageBounds = {
+    width: this.viewport_.getImageBounds().width,
+    height: this.viewport_.getImageBounds().height
+  };
   var oldScreenImage = this.screenImage_;
   this.replaceContent_(canvas);
   var newScreenImage = this.screenImage_;
-
-  // Display the new canvas, initially transformed.
-  var deviceFullRect = this.viewport_.getDeviceClipped();
-
   var effect = rotate90 ?
-      new ImageView.Effect.Rotate(
-          oldScale / this.viewport_.getScale(), -rotate90) :
-      new ImageView.Effect.Zoom(deviceCropRect, deviceFullRect);
+      new ImageView.Effect.Rotate(rotate90 > 0) :
+      new ImageView.Effect.Zoom(
+          oldImageBounds.width, oldImageBounds.height, imageCropRect);
 
   this.setTransform(newScreenImage, effect, 0 /* instant */);
 
@@ -683,26 +678,20 @@ ImageView.prototype.replaceAndAnimate = function(
  * @return {number} Animation duration.
  */
 ImageView.prototype.animateAndReplace = function(canvas, imageCropRect) {
-  var deviceFullRect = this.viewport_.getDeviceClipped();
-  var oldScale = this.viewport_.getScale();
-
   var oldScreenImage = this.screenImage_;
   this.replaceContent_(canvas);
   var newScreenImage = this.screenImage_;
-
-  var deviceCropRect = this.viewport_.screenToDeviceRect(
-        this.viewport_.imageToScreenRect(imageCropRect));
-
   var setFade = ImageUtil.setAttribute.bind(null, newScreenImage, 'fade');
   setFade(true);
   oldScreenImage.parentNode.insertBefore(newScreenImage, oldScreenImage);
+  var effect = new ImageView.Effect.Zoom(
+      this.viewport_.getImageBounds().width,
+      this.viewport_.getImageBounds().height,
+      imageCropRect);
 
-  var effect = new ImageView.Effect.Zoom(deviceCropRect, deviceFullRect);
   // Animate to the transformed state.
   this.setTransform(oldScreenImage, effect);
-
   setTimeout(setFade.bind(null, false), 0);
-
   setTimeout(function() {
     if (oldScreenImage.parentNode)
       oldScreenImage.parentNode.removeChild(oldScreenImage);
@@ -711,7 +700,6 @@ ImageView.prototype.animateAndReplace = function(canvas, imageCropRect) {
   return effect.getSafeInterval();
 };
 
-
 /**
  * Generic cache with a limited capacity and LRU eviction.
  * @param {number} capacity Maximum number of cached item.
@@ -852,15 +840,13 @@ ImageView.Effect.prototype.getSafeInterval = function() {
 ImageView.Effect.prototype.getTiming = function() { return this.timing_; };
 
 /**
- * @param {HTMLCanvasElement} element Element.
- * @return {number} Preferred pixel ration to use with this element.
- * @private
+ * Obtains the CSS transformation string of the effect.
+ * @param {DOMCanvas} element Canvas element to be applied the transforamtion.
+ * @param {Viewport} viewport Current viewport.
+ * @return CSS transformation description.
  */
-ImageView.Effect.getPixelRatio_ = function(element) {
-  if (element.constructor.name === 'HTMLCanvasElement')
-    return Viewport.getDevicePixelRatio();
-  else
-    return 1;
+ImageView.Effect.prototype.transform = function(element, viewport) {
+  throw new Error('Not implemented.');
 };
 
 /**
@@ -868,6 +854,7 @@ ImageView.Effect.getPixelRatio_ = function(element) {
  * for devicePixelRatio.
  *
  * @constructor
+ * @extends {ImageView.Effect}
  */
 ImageView.Effect.None = function() {
   ImageView.Effect.call(this, 0);
@@ -880,11 +867,11 @@ ImageView.Effect.None.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
  * @param {HTMLCanvasElement} element Element.
+ * @param {Viewport} viewport Current viewport.
  * @return {string} Transform string.
  */
-ImageView.Effect.None.prototype.transform = function(element) {
-  var ratio = ImageView.Effect.getPixelRatio_(element);
-  return 'scale(' + (1 / ratio) + ')';
+ImageView.Effect.None.prototype.transform = function(element, viewport) {
+  return viewport.getTransformation();
 };
 
 /**
@@ -893,6 +880,7 @@ ImageView.Effect.None.prototype.transform = function(element) {
  * @param {number} direction -1 for left, 1 for right.
  * @param {boolean=} opt_slow True if slow (as in slideshow).
  * @constructor
+ * @extends {ImageView.Effect}
  */
 ImageView.Effect.Slide = function Slide(direction, opt_slow) {
   ImageView.Effect.call(this,
@@ -903,25 +891,21 @@ ImageView.Effect.Slide = function Slide(direction, opt_slow) {
   if (this.direction_ < 0) this.shift_ = -this.shift_;
 };
 
-/**
- * Inherits from ImageView.Effect.
- */
 ImageView.Effect.Slide.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
- * @return {ImageView.Effect.Slide} Reverse Slide effect.
+ * Reverses the slide effect.
+ * @return {ImageView.Effect.Slide} Reversed effect.
  */
 ImageView.Effect.Slide.prototype.getReverse = function() {
   return new ImageView.Effect.Slide(-this.direction_, this.slow_);
 };
 
 /**
- * @param {HTMLCanvasElement} element Element.
- * @return {string} Transform string.
+ * @override
  */
-ImageView.Effect.Slide.prototype.transform = function(element) {
-  var ratio = ImageView.Effect.getPixelRatio_(element);
-  return 'scale(' + (1 / ratio) + ') translate(' + this.shift_ + 'px, 0px)';
+ImageView.Effect.Slide.prototype.transform = function(element, viewport) {
+  return viewport.getShiftTransformation(this.shift_);
 };
 
 /**
@@ -930,72 +914,75 @@ ImageView.Effect.Slide.prototype.transform = function(element) {
  * Animates the original rectangle to the target rectangle. Both parameters
  * should be given in device coordinates (accounting for devicePixelRatio).
  *
- * @param {Rect} deviceTargetRect Target rectangle.
- * @param {Rect=} opt_deviceOriginalRect Original rectangle. If omitted,
- *     the full viewport will be used at the time of |transform| call.
- * @param {number=} opt_duration Duration in ms.
+ * @param {number} previousImageWidth Width of the full resolution image.
+ * @param {number} previousImageHeight Hieght of the full resolution image.
+ * @param {Rect} imageCropRect Crop rectangle in the full resolution image.
+ * @param {number=} opt_duration Duration of the effect.
  * @constructor
+ * @extends {ImageView.Effect}
  */
 ImageView.Effect.Zoom = function(
-    deviceTargetRect, opt_deviceOriginalRect, opt_duration) {
+    previousImageWidth, previousImageHeight, imageCropRect, opt_duration) {
   ImageView.Effect.call(this,
       opt_duration || ImageView.Effect.DEFAULT_DURATION);
-  this.target_ = deviceTargetRect;
-  this.original_ = opt_deviceOriginalRect;
+  this.previousImageWidth_ = previousImageWidth;
+  this.previousImageHeight_ = previousImageHeight;
+  this.imageCropRect_ = imageCropRect;
 };
 
-/**
- * Inherits from ImageView.Effect.
- */
 ImageView.Effect.Zoom.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
- * @param {HTMLCanvasElement} element Element.
- * @param {Viewport} viewport Viewport.
- * @return {string} Transform string.
+ * @override
  */
 ImageView.Effect.Zoom.prototype.transform = function(element, viewport) {
-  if (!this.original_)
-    this.original_ = viewport.getDeviceClipped();
-
-  var ratio = ImageView.Effect.getPixelRatio_(element);
+  return viewport.getInverseTransformForCroppedImage(
+      this.previousImageWidth_, this.previousImageHeight_, this.imageCropRect_);
+};
 
-  var dx = (this.target_.left + this.target_.width / 2) -
-           (this.original_.left + this.original_.width / 2);
-  var dy = (this.target_.top + this.target_.height / 2) -
-           (this.original_.top + this.original_.height / 2);
+/**
+ * Effect to zoom to a screen rectangle.
+ *
+ * @param {Rect} screenRect Rectangle in the application window's coordinate.
+ * @param {number=} opt_duration Duration of effect.
+ * @constructor
+ * @extends {ImageView.Effect}
+ */
+ImageView.Effect.ZoomToScreen = function(screenRect, opt_duration) {
+  ImageView.Effect.call(this, opt_duration);
+  this.screenRect_ = screenRect;
+};
 
-  var scaleX = this.target_.width / this.original_.width;
-  var scaleY = this.target_.height / this.original_.height;
+ImageView.Effect.ZoomToScreen.prototype = {
+  __proto__: ImageView.Effect.prototype
+};
 
-  return 'translate(' + (dx / ratio) + 'px,' + (dy / ratio) + 'px) ' +
-    'scaleX(' + (scaleX / ratio) + ') scaleY(' + (scaleY / ratio) + ')';
+/**
+ * @override
+ */
+ImageView.Effect.ZoomToScreen.prototype.transform = function(
+    element, viewport) {
+  return viewport.getScreenRectTransformForImage(this.screenRect_);
 };
 
 /**
- * Rotate effect.
+ * Rotation effect.
  *
- * @param {number} scale Scale.
- * @param {number} rotate90 Rotation in 90 degrees increments.
+ * @param {boolean} orientation Orientation of rotation. True is for clockwise
+ *     and false is for counterclockwise.
  * @constructor
+ * @extends {ImageView.Effect}
  */
-ImageView.Effect.Rotate = function(scale, rotate90) {
+ImageView.Effect.Rotate = function(orientation) {
   ImageView.Effect.call(this, ImageView.Effect.DEFAULT_DURATION);
-  this.scale_ = scale;
-  this.rotate90_ = rotate90;
+  this.orientation_ = orientation;
 };
 
-/**
- * Inherits from ImageView.Effect.
- */
 ImageView.Effect.Rotate.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
- * @param {HTMLCanvasElement} element Element.
- * @return {string} Transform string.
+ * @override
  */
-ImageView.Effect.Rotate.prototype.transform = function(element) {
-  var ratio = ImageView.Effect.getPixelRatio_(element);
-  return 'rotate(' + (this.rotate90_ * 90) + 'deg) ' +
-         'scale(' + (this.scale_ / ratio) + ')';
+ImageView.Effect.Rotate.prototype.transform = function(element, viewport) {
+  return viewport.getInverseTransformForRotatedImage(this.orientation_);
 };

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

@@ -9,9 +9,26 @@
  * @constructor
  */
 function Viewport() {
+  /**
+   * Size of the full resolution image.
+   * @type {Rect}
+   * @private
+   */
   this.imageBounds_ = new Rect();
+
+  /**
+   * Size of the application window.
+   * @type {Rect}
+   * @private
+   */
   this.screenBounds_ = new Rect();
 
+  /**
+   * Scale from the full resolution image to the screen displayed image. This is
+   * not zoom operated by users.
+   * @type {number}
+   * @private
+   */
   this.scale_ = 1;
   this.offsetX_ = 0;
   this.offsetY_ = 0;
@@ -22,10 +39,6 @@ function Viewport() {
   this.update();
 }
 
-/*
- * Viewport modification.
- */
-
 /**
  * @param {number} width Image width.
  * @param {number} height Image height.
@@ -86,11 +99,24 @@ Viewport.prototype.setScale = function(scale, notify) {
  * @return {number} Best scale to fit the current image into the current screen.
  */
 Viewport.prototype.getFittingScale = function() {
-  var scaleX = this.screenBounds_.width / this.imageBounds_.width;
-  var scaleY = this.screenBounds_.height / this.imageBounds_.height;
-  // Scales > (1 / this.getDevicePixelRatio()) do not look good. Also they are
+  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 / Viewport.getDevicePixelRatio(), scaleX, scaleY);
+  return Math.min(1 / window.devicePixelRatio, scaleX, scaleY);
 };
 
 /**
@@ -281,11 +307,6 @@ Viewport.prototype.imageToScreenRect = function(rect) {
       Math.round(this.imageToScreenSize(rect.height)));
 };
 
-/**
- * @return {number} The number of physical pixels in one CSS pixel.
- */
-Viewport.getDevicePixelRatio = function() { return window.devicePixelRatio; };
-
 /**
  * Convert a rectangle from screen coordinates to 'device' coordinates.
  *
@@ -296,7 +317,7 @@ Viewport.getDevicePixelRatio = function() { return window.devicePixelRatio; };
  * @return {Rect} Rectangle in device coordinates.
  */
 Viewport.prototype.screenToDeviceRect = function(rect) {
-  var ratio = Viewport.getDevicePixelRatio();
+  var ratio = window.devicePixelRatio;
   var screenCenterX = Math.round(
       this.screenBounds_.left + this.screenBounds_.width / 2);
   var screenCenterY = Math.round(
@@ -417,3 +438,95 @@ Viewport.prototype.repaint = function() {
   for (var i = 0; i != this.repaintCallbacks_.length; i++)
     this.repaintCallbacks_[i]();
 };
+
+/**
+ * Obtains CSS transformation for the screen image.
+ * @return {string} Transformation description.
+ */
+Viewport.prototype.getTransformation = function() {
+  return 'scale(' + (1 / window.devicePixelRatio) + ')';
+};
+
+/**
+ * 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 degree = orientation ? '-90deg' : '90deg';
+  return [
+    'scale(' + scaleRatio + ')',
+    'rotate(' + degree + ')',
+    this.getTransformation()
+  ].join(' ');
+};
+
+/**
+ * Obtains CSS transformation that makes the cropped image fit the original
+ * image. The new cropped image that the transformaton is applied to fits to the
+ * the cropped rectangle in the original image.
+ *
+ * @param {number} imageWidth Width of the original image.
+ * @param {number} imageHeight Height of the origianl image.
+ * @param {Rect} imageCropRect Crop rectangle in the image's coordinate system.
+ * @return {string} Transformation description.
+ */
+Viewport.prototype.getInverseTransformForCroppedImage =
+    function(imageWidth, imageHeight, imageCropRect) {
+  var wholeScale = this.getFittingScaleForImageSize_(
+      imageWidth, imageHeight);
+  var croppedScale = this.getFittingScaleForImageSize_(
+      imageCropRect.width, imageCropRect.height);
+  var dx =
+      (imageCropRect.left + imageCropRect.width / 2 - imageWidth / 2) *
+      wholeScale;
+  var dy =
+      (imageCropRect.top + imageCropRect.height / 2 - imageHeight / 2) *
+      wholeScale;
+  return [
+    'translate(' + dx + 'px,' + dy + 'px)',
+    'scale(' + wholeScale / croppedScale + ')',
+    this.getTransformation()
+  ].join(' ');
+};
+
+/**
+ * Obtains CSS transformaton that makes the image fit to the screen rectangle.
+ *
+ * @param {Rect} screenRect Screen rectangle.
+ * @return {string} Transformation description.
+ */
+Viewport.prototype.getScreenRectTransformForImage = function(screenRect) {
+  var screenImageWidth = this.imageBounds_.width * this.getScale();
+  var screenImageHeight = this.imageBounds_.height * this.getScale();
+  var scaleX = screenRect.width / screenImageWidth;
+  var scaleY = screenRect.height / screenImageHeight;
+  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(' ');
+};