Gallery: Random fixes for the Viewport class.

ui/file_manager/gallery/js/image_editor/image_util.js

Index: ui/file_manager/gallery/js/image_editor/image_util.js
diff --git a/ui/file_manager/gallery/js/image_editor/image_util.js b/ui/file_manager/gallery/js/image_editor/image_util.js
index 7a7a2bfb85a36563af2c992124dc25a5a4ffff8c..2b1e2d6c3dd95daa611001a961b1f9bd071590ed 100644
--- a/ui/file_manager/gallery/js/image_editor/image_util.js
+++ b/ui/file_manager/gallery/js/image_editor/image_util.js
@@ -139,6 +139,24 @@ function Rect() {
        Array.apply(null, arguments));
 }
 
+Rect.prototype = {
+  /**
+   * Obtains the x coordinate number of right edge.

[mtomasz, 2014/07/17 06:08:56]

nit: Please add a comment, that the edge is one pixel after the last pixel, or
sth like that.

[hirono, 2014/07/17 06:26:54]

Done.

+   * @return {number}
+   */
+  get right() {
+    return this.left + this.width;

[mtomasz, 2014/07/17 05:43:20]

I think it should be:
this.left + this.width - 1.

Eg. For rect: left = 0, top = 0, width = 1, height = 1.
The right most pixel is at 0 position, not 1.

[hirono, 2014/07/17 05:56:47]

Exactly. but the right edge of the pixel is a line (x = 1).
The number is not a position of pixel, it is the coordinate value of the right
edge. The definition is sometimes convenient to calculate geometry. e.g. var
center = (rect.left + rect.right) / 2; WDYT?

[mtomasz, 2014/07/17 06:08:56]

This is quite confusing. The left edge is within the image, but the right
outside. However, seems that SkRect in Chromium uses the same logic, so I'm fine
with it.

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/skia/i...

[hirono, 2014/07/17 06:26:54]

Maybe this is common when implementing rectangle class. I also saw the logic in
.NET.
http://msdn.microsoft.com/en-us//library/system.windows.rect.right(v=vs.110)....

+  },
+
+  /**
+   * Obtains the y coordinate number of bottom edge.

[mtomasz, 2014/07/17 06:08:56]

nit: coordinate number -> coordinate

[hirono, 2014/07/17 06:26:54]

Done.

+   * @return {number}
+   */
+  get bottom() {
+    return this.top + this.height;
+  }
+};
+
 /**
  * @param {number} factor Factor to scale.
  * @return {Rect} A rectangle with every dimension scaled.