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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Eclipse Public License, Version 1.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.eclipse.org/org/documents/epl-v10.php
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.ide.eclipse.adt.internal.editors.layout.gle2;
     18 
     19 import org.eclipse.swt.graphics.Color;
     20 import org.eclipse.swt.graphics.Device;
     21 import org.eclipse.swt.graphics.GC;
     22 import org.eclipse.swt.graphics.Rectangle;
     23 
     24 /**
     25  * The {@link OutlineOverlay} paints an optional outline on top of the layout,
     26  * showing the structure of the individual Android View elements.
     27  */
     28 public class OutlineOverlay extends Overlay {
     29     /** The {@link ViewHierarchy} this outline visualizes */
     30     private final ViewHierarchy mViewHierarchy;
     31 
     32     /** Outline color. Must be disposed, it's NOT a system color. */
     33     private Color mOutlineColor;
     34 
     35     /** Vertical scaling & scrollbar information. */
     36     private CanvasTransform mVScale;
     37 
     38     /** Horizontal scaling & scrollbar information. */
     39     private CanvasTransform mHScale;
     40 
     41     /**
     42      * Constructs a new {@link OutlineOverlay} linked to the given view
     43      * hierarchy.
     44      *
     45      * @param viewHierarchy The {@link ViewHierarchy} to render
     46      * @param hScale The {@link CanvasTransform} to use to transfer horizontal layout
     47      *            coordinates to screen coordinates
     48      * @param vScale The {@link CanvasTransform} to use to transfer vertical layout
     49      *            coordinates to screen coordinates
     50      */
     51     public OutlineOverlay(
     52             ViewHierarchy viewHierarchy,
     53             CanvasTransform hScale,
     54             CanvasTransform vScale) {
     55         super();
     56         mViewHierarchy = viewHierarchy;
     57         mHScale = hScale;
     58         mVScale = vScale;
     59     }
     60 
     61     @Override
     62     public void create(Device device) {
     63         mOutlineColor = new Color(device, SwtDrawingStyle.OUTLINE.getStrokeColor());
     64     }
     65 
     66     @Override
     67     public void dispose() {
     68         if (mOutlineColor != null) {
     69             mOutlineColor.dispose();
     70             mOutlineColor = null;
     71         }
     72     }
     73 
     74     @Override
     75     public void paint(GC gc) {
     76         CanvasViewInfo lastRoot = mViewHierarchy.getRoot();
     77         if (lastRoot != null) {
     78             gc.setForeground(mOutlineColor);
     79             gc.setLineStyle(SwtDrawingStyle.OUTLINE.getLineStyle());
     80             int oldAlpha = gc.getAlpha();
     81             gc.setAlpha(SwtDrawingStyle.OUTLINE.getStrokeAlpha());
     82             drawOutline(gc, lastRoot);
     83             gc.setAlpha(oldAlpha);
     84         }
     85     }
     86 
     87     private void drawOutline(GC gc, CanvasViewInfo info) {
     88         Rectangle r = info.getAbsRect();
     89 
     90         int x = mHScale.translate(r.x);
     91         int y = mVScale.translate(r.y);
     92         int w = mHScale.scale(r.width);
     93         int h = mVScale.scale(r.height);
     94 
     95         // Add +1 to the width and +1 to the height such that when you have a
     96         // series of boxes (in say a LinearLayout), instead of the bottom of one
     97         // box and the top of the next box being -adjacent-, they -overlap-.
     98         // This makes the outline nicer visually since you don't get
     99         // "double thickness" lines for all adjacent boxes.
    100         gc.drawRectangle(x, y, w + 1, h + 1);
    101 
    102         for (CanvasViewInfo vi : info.getChildren()) {
    103             drawOutline(gc, vi);
    104         }
    105     }
    106 
    107 }
    108