Provide cross-browser Rects for box model dimensions for Elements.

tools/dom/src/CssRectangle.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of html;
+
+class _ContentCssRect extends CssRect {

[Jennifer Messerly, 2013/07/16 22:03:16]

might be worth adding a short class comment here and on the others. Even though
it's internal, would still be useful to help orient a new reader

[Emily Fortuna, 2013/07/18 22:45:02]

Done.

+
+  _ContentCssRect(element) : super(element);
+  num get height => _element.offsetHeight +
+      _addOrSubtractToBoxModel(CssRect._HEIGHT, 'content');
+
+  num get width => _element.offsetWidth +
+      _addOrSubtractToBoxModel(CssRect._WIDTH, 'content');
+
+  /**
+   * Set the height to `newHeight`.
+   *
+   * Values of newHeight that are less than zero are converted to effectively
+   * setting the height to 0. This is equivalent to the `height`
+   * function in jQuery and the calculated `height` css value, converted to a

[Jennifer Messerly, 2013/07/16 22:03:16]

uppercase CSS?

[Emily Fortuna, 2013/07/18 22:45:02]

Done.

+   * num in pixels.
+   */
+  void set height(Dimension newHeight) {

[Jennifer Messerly, 2013/07/16 22:03:16]

hmmm. I'm not sure about having the setter take a different type than the
getter. Maybe if this is untyped and you could take the union of Dimension and
num?

[Emily Fortuna, 2013/07/18 22:45:02]

Done.

+    if (newHeight.value < 0) newHeight = new Dimension.px(0);
+    _element.style.height = newHeight.toString();
+  }
+
+  /**
+   * Set the current computed width in pixels of this element.
+   *
+   * This is equivalent to the `width` function in jQuery and the calculated
+   * `width` css value, converted to a dimensionless num in pixels.
+   */
+  void set width(Dimension newWidth) {
+    if (newWidth.value < 0) newWidth = new Dimension.px(0);
+    _element.style.width = newWidth.toString();
+  }
+
+  num get left() => _element.getBoundingClientRect().left -

[Jennifer Messerly, 2013/07/16 22:03:16]

not sure about the parens here. that looks like old-style Dart getters...
surprised it still works :)

[Emily Fortuna, 2013/07/18 22:45:02]

Oh man. Old habits die hard. Fixed.

+      _addOrSubtractToBoxModel(['left'], 'content');
+  num get top() => _element.getBoundingClientRect().top -
+      _addOrSubtractToBoxModel(['top'], 'content');
+}
+
+class _ContentCssListRect extends _ContentCssRect {
+  List<Element> _elementList;

[Jennifer Messerly, 2013/07/16 22:03:16]

this could be final?

+
+  _ContentCssListRect(elementList) : super(elementList.first) {
+    _elementList = elementList;
+  }
+
+  /**
+   * Set the height to `newHeight`.
+   *
+   * Values of newHeight that are less than zero are converted to effectively
+   * setting the height to 0. This is equivalent to the `height`
+   * function in jQuery and the calculated `height` css value, converted to a
+   * num in pixels.
+   */
+  void set height(Dimension newHeight) {
+    _elementList.forEach((e) => e.contentEdge.height = newHeight);
+  }
+
+  /**
+   * Set the current computed width in pixels of this element.
+   *
+   * This is equivalent to the `width` function in jQuery and the calculated
+   * `width` css value, converted to a dimensionless num in pixels.
+   */
+  void set width(Dimension newWidth) {
+    _elementList.forEach((e) => e.contentEdge.width = newWidth);
+  }
+}
+
+class _PaddingCssRect extends CssRect {
+  _PaddingCssRect(element) : super(element);
+  num get height => _element.offsetHeight +
+      _addOrSubtractToBoxModel(CssRect._HEIGHT, 'padding');
+  num get width => _element.offsetWidth +
+      _addOrSubtractToBoxModel(CssRect._WIDTH, 'padding');
+
+  num get left() => _element.getBoundingClientRect().left -
+      _addOrSubtractToBoxModel(['left'], 'padding');
+  num get top() => _element.getBoundingClientRect().top -
+      _addOrSubtractToBoxModel(['top'], 'padding');
+}
+
+class _BorderCssRect extends CssRect {
+  _BorderCssRect(element) : super(element);
+  num get height() => _element.offsetHeight;
+  num get width() => _element.offsetWidth;
+
+  num get left() => _element.getBoundingClientRect().left;
+  num get top() => _element.getBoundingClientRect().top;
+}
+
+class _MarginCssRect extends CssRect {
+  _MarginCssRect(element) : super(element);
+  num get height() => _element.offsetHeight +
+      _addOrSubtractToBoxModel(CssRect._HEIGHT, 'margin');
+  num get width() =>
+      _element.offsetWidth + _addOrSubtractToBoxModel(CssRect._WIDTH, 'margin');
+
+  num get left() => _element.getBoundingClientRect().left -
+      _addOrSubtractToBoxModel(['left'], 'margin');
+  num get top() => _element.getBoundingClientRect().top -
+      _addOrSubtractToBoxModel(['top'], 'margin');
+}
+
+/**
+ * A class for representing CSS dimensions.
+ *
+ * In contrast to the more general purpose [Rect] class, this class's values are
+ * mutable, so one can change the height of an element programmatically.
+ *
+ * SPECIAL NOTE: Do _not_ use these methods of setting or getting dimensions

[Jennifer Messerly, 2013/07/16 22:03:16]

trivial nit: I think this one is "SPECIAL NOTE" and the other was "Important
note"... maybe just reuse the verbiage. Also might be worth having "important
note" it be italics.

[Emily Fortuna, 2013/07/18 22:45:02]

Done.

+ * for animations, as they will trigger a redraw of the layout.
+ */
+abstract class CssRect extends RectBase implements Rect {
+  Element _element;
+
+  CssRect(this._element);
+
+  num get left();

[Jennifer Messerly, 2013/07/16 22:03:16]

same issue here with parens

[Emily Fortuna, 2013/07/18 22:45:02]

Done.

+
+  num get top();
+
+  /**
+   * The height of this rectangle.
+   *
+   * This is equivalent to the `height` function in jQuery and the calculated
+   * `height` css value, converted to a dimensionless num in pixels. Unlike
+   * [getBoundingClientRect], `height` will return the same numerical width if
+   * the element is hidden or not.
+   */
+  num get height();
+
+  /**
+   * The width of this rectangle.
+   *
+   * This is equivalent to the `width` function in jQuery and the calculated
+   * `width` css value, converted to a dimensionless num in pixels. Unlike
+   * [getBoundingClientRect], `width` will return the same numerical width if
+   * the element is hidden or not.
+   */
+  num get width();
+
+  /**
+   * Set the height to `newHeight`.
+   *
+   * Values of newHeight that are less than zero are converted to effectively
+   * setting the height to 0. Note that only the content height can be set via
+   * this method.
+   */
+  void set height(Dimension newHeight) {
+    throw new UnsupportedError("Can only set height for content rect.");
+  }
+
+  /**
+   * Set the current computed width in pixels of this element.
+   *
+   * Note that only the content width can be set via this method.
+   */
+  void set width(Dimension newWidth) {
+    throw new UnsupportedError("Can only set width for content rect.");
+  }
+
+  /**
+   * Return a value that is used to modify the initial height or width
+   * measurement of an element. Depending on the value (ideally an enum) passed
+   * to augmentingMeasurement, we may need to add or subtract margin, padding,
+   * or border values, depending on the measurement we're trying to obtain.
+   */
+  num _addOrSubtractToBoxModel(List<String> dimensions,
+      String augmentingMeasurement) {
+    // getComputedStyle always returns pixel values (hence, computed), so we're
+    // always dealing with pixels in this method.
+    var styles = _element.getComputedStyle();
+
+    var val = 0;
+
+    for (String measurement in dimensions) {
+      // The border-box and default box model both exclude margin in the regular
+      // height/width calculation, so add it if we want it for this measurement.
+      if (augmentingMeasurement == 'margin') {
+        val += new Dimension._(styles.getPropertyValue(
+            '$augmentingMeasurement-$measurement')).value;
+      }
+
+      // The border-box includes padding and border, so remove it if we want
+      // just the content itself.
+      if (augmentingMeasurement == 'content') {
+        val -= new Dimension._(
+            styles.getPropertyValue('padding-$measurement')).value;
+      }
+
+      // At this point, we don't wan't to augment with border or margin,
+      // so remove border.
+      if (augmentingMeasurement != 'margin') {
+              val -= new Dimension._(styles.getPropertyValue(
+            'border-${measurement}-width')).value;
+      }
+    }
+    return val;
+  }
+
+  final static _HEIGHT = ['top', 'bottom'];
+  final static _WIDTH = ['right', 'left'];
+}
+