Print Preview: Adding UI for margin settings.

chrome/browser/resources/print_preview/margin_line.js

+// Copyright (c) 2011 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.
+
+cr.define('print_preview', function() {
+  'strict';
+
+  function MarginLine(groupName) {
+    var line = document.createElement('div');
+    line.__proto__ = MarginLine.prototype;
+    line.className = MarginLine.CSS_CLASS_DRAGGABLE_AREA;
+    // @type {string} Specifies which margin this line refers to.
+    line.marginGroup = groupName;
+    // @type {print_preview.Rect} A rectangle describing the values of all
+    //     margins.
+    line.rectangle = null;
+    // @type {HTMLDivElement} The dotted line representing the margin.
+    line.visibleLine = document.createElement('div');
+    line.visibleLine.className = MarginLine.CSS_CLASS_MARGIN_LINE;
+
+    line.appendChild(line.visibleLine);
+    return line;
+  }
+
+  MarginLine.CSS_CLASS_MARGIN_LINE = 'margin-line';
+  MarginLine.CSS_CLASS_DRAGGABLE_AREA = 'draggable-area';
+  // Width of the clickable region around each margin line in screen pixels.
+  MarginLine.CLICKABLE_REGION = 20;
+
+  MarginLine.prototype = {
+    __proto__: HTMLDivElement.prototype,
+
+    update: function(marginsRectangle) {
+      this.rectangle = this.getCoordinates_(marginsRectangle);
+    },
+
+    /**
+     * Draws |this| on screen. Essentially two divs are being drawn, the drag
+     * control area (invisible) and the dotted margin line (visible).
+     */
+    draw: function() {
+      this.drawDraggableArea_();
+      this.drawDottedLine_();
+    },
+
+    /**
+     * Draws the dotted line representing the margin.
+     * @private
+     */
+     drawDottedLine_ : function() {
+      var rectangle = this.getVisibleLineCoordinates_();
+      this.visibleLine.style.left = 100 * rectangle.x + '%';
+      this.visibleLine.style.top = 100 * rectangle.y + '%';
+      this.visibleLine.style.width = 100 * rectangle.width + '%';
+      this.visibleLine.style.height = 100 * rectangle.height + '%';
+    },
+
+    /**
+     * Draws the area the draggable area (not visible).
+     * @private
+     */
+    drawDraggableArea_: function() {
+      var width = previewArea.pdfPlugin_.offsetWidth;
+      var height = previewArea.pdfPlugin_.offsetHeight;
+
+      this.style.left = Math.round(this.rectangle.x * width) + 'px';
+      this.style.top = Math.round(this.rectangle.y * height) + 'px';
+      this.style.width = Math.round(this.rectangle.width * width) + 'px';
+      this.style.height = Math.round(this.rectangle.height * height) + 'px';
+    },
+
+    /**
+     * Calculates the coordinates and size of |this|.
+     * @param {print_preview.Rect} marginsRectangle A rectangle describing the
+     *     selected margins values in percentages.
+     * @private
+     */
+    getCoordinates_: function(marginsRectangle) {
+      var pageLocation = previewArea.getPageLocationNormalized();
+      var totalWidth = previewArea.pdfPlugin_.offsetWidth;
+      var totalHeight = previewArea.pdfPlugin_.offsetHeight;
+
+      if (this.isTop_()) {
+        var lineCoordinates = new print_preview.Rect(
+            pageLocation.x,
+            marginsRectangle.y -
+                (MarginLine.CLICKABLE_REGION / 2) / totalHeight,
+            pageLocation.width,
+            MarginLine.CLICKABLE_REGION / totalHeight);
+      } else if (this.isBottom_()) {
+        var lineCoordinates = new print_preview.Rect(
+            pageLocation.x,
+            marginsRectangle.y + marginsRectangle.height -
+                (MarginLine.CLICKABLE_REGION / 2) / totalHeight,
+            pageLocation.width,
+            MarginLine.CLICKABLE_REGION / totalHeight);
+      } else if (this.isRight_()) {
+        var lineCoordinates = new print_preview.Rect(
+            marginsRectangle.x + marginsRectangle.width -
+                (MarginLine.CLICKABLE_REGION / 2) / totalWidth,
+            pageLocation.y,
+            MarginLine.CLICKABLE_REGION / totalWidth,
+            pageLocation.height);
+      } else if (this.isLeft_()) {
+        var lineCoordinates = new print_preview.Rect(
+            marginsRectangle.x - (MarginLine.CLICKABLE_REGION / 2) / totalWidth,
+            pageLocation.y,
+            MarginLine.CLICKABLE_REGION / totalWidth,
+            pageLocation.height);
+      }
+      return lineCoordinates;
+    },
+
+    /**
+     * Calculates the coordinates in percentages and size of the visible margin
+     * line, with respect to |this| div element.
+     * @return {print_preview.Rect} A rectangle describing the position of the
+     *     visible line in percentages.
+     * @private
+     */
+    getVisibleLineCoordinates_: function() {
+      if (this.isHorizontal_())
+        var innerMarginsRect = new print_preview.Rect(0, 0.5, 1, 0);
+      else if (this.isVertical_())
+        var innerMarginsRect = new print_preview.Rect(0.5, 0, 0, 1);
+      return innerMarginsRect;
+    },
+
+    /**
+     * @return {boolean} True if |this| refers to the top margin.
+     * @private
+     */
+    isTop_: function() {
+      return this.marginGroup == print_preview.MarginSettings.TOP_GROUP;
+    },
+
+    /**
+     * @return {boolean} True if |this| refers to the bottom margin.
+     * @private
+     */
+    isBottom_: function() {
+      return this.marginGroup == print_preview.MarginSettings.BOTTOM_GROUP;
+    },
+
+    /**
+     * @return {boolean} True if |this| refers to the left margin.
+     * @private
+     */
+    isLeft_: function() {
+      return this.marginGroup == print_preview.MarginSettings.LEFT_GROUP;
+    },
+
+    /**
+     * @return {boolean} True if |this| refers to the bottom margin.
+     * @private
+     */
+    isRight_: function() {
+      return this.marginGroup == print_preview.MarginSettings.RIGHT_GROUP;
+    },
+
+    /**
+     * @return {boolean} True if |this| is a horizontal line.
+     * @private
+     */
+    isHorizontal_: function() {
+      return this.isTop_() || this.isBottom_() ;
+    },
+
+    /**
+     * @return {boolean} True if |this| is a vertical line.
+     * @private
+     */
+    isVertical_: function() {
+      return this.isLeft_() || this.isRight_();
+    },
+
+  };
+
+  return {
+    MarginLine: MarginLine
+  };
+});