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      1 /*******************************************************************************
      2  * Copyright (c) 2011 Google, Inc.
      3  * All rights reserved. This program and the accompanying materials
      4  * are made available under the terms of the Eclipse Public License v1.0
      5  * which accompanies this distribution, and is available at
      6  * http://www.eclipse.org/legal/epl-v10.html
      7  *
      8  * Contributors:
      9  *    Google, Inc. - initial API and implementation
     10  *******************************************************************************/
     11 package org.eclipse.wb.core.controls;
     12 
     13 import org.eclipse.swt.SWT;
     14 import org.eclipse.swt.graphics.GC;
     15 import org.eclipse.swt.graphics.Image;
     16 import org.eclipse.swt.graphics.Point;
     17 import org.eclipse.swt.graphics.Rectangle;
     18 import org.eclipse.swt.widgets.Canvas;
     19 import org.eclipse.swt.widgets.Composite;
     20 import org.eclipse.swt.widgets.Event;
     21 import org.eclipse.swt.widgets.Listener;
     22 
     23 /**
     24  * Simple control for displaying image and text.
     25  *
     26  * For unknown reason CLabel shows such things not very good - vertical text alignment is strange
     27  * (bottom?).
     28  *
     29  * @author scheglov_ke
     30  * @coverage core.control
     31  */
     32 public class CImageLabel extends Canvas {
     33   private static final int SPACE = 5;
     34   private Image m_image;
     35   private String m_text;
     36 
     37   ////////////////////////////////////////////////////////////////////////////
     38   //
     39   // Constructor
     40   //
     41   ////////////////////////////////////////////////////////////////////////////
     42   public CImageLabel(Composite parent, int style) {
     43     super(parent, style | SWT.NO_BACKGROUND);
     44     addListener(SWT.Dispose, new Listener() {
     45       public void handleEvent(Event event) {
     46         if (m_backImage != null) {
     47           m_backImage.dispose();
     48           m_backImage = null;
     49         }
     50       }
     51     });
     52     addListener(SWT.Paint, new Listener() {
     53       public void handleEvent(Event event) {
     54         doPaint(event.gc);
     55       }
     56     });
     57   }
     58 
     59   ////////////////////////////////////////////////////////////////////////////
     60   //
     61   // Access
     62   //
     63   ////////////////////////////////////////////////////////////////////////////
     64   public Image getImage() {
     65     return m_image;
     66   }
     67 
     68   public void setImage(Image image) {
     69     m_image = image;
     70     redraw();
     71   }
     72 
     73   public String getText() {
     74     return m_text;
     75   }
     76 
     77   public void setText(String text) {
     78     m_text = text;
     79     redraw();
     80   }
     81 
     82   ////////////////////////////////////////////////////////////////////////////
     83   //
     84   // Paint
     85   //
     86   ////////////////////////////////////////////////////////////////////////////
     87   private Image m_backImage;
     88 
     89   private void doPaint(GC paintGC) {
     90     Rectangle clientArea = getClientArea();
     91     // prepare back image
     92     GC gc;
     93     {
     94       if (m_backImage == null || !m_backImage.getBounds().equals(clientArea)) {
     95         if (m_backImage != null) {
     96           m_backImage.dispose();
     97         }
     98         m_backImage = new Image(getDisplay(), clientArea.width, clientArea.height);
     99       }
    100       //
    101       gc = new GC(m_backImage);
    102       gc.setBackground(paintGC.getBackground());
    103       gc.setForeground(paintGC.getForeground());
    104       gc.fillRectangle(clientArea);
    105     }
    106     //
    107     Point textExtent = m_text == null ? new Point(0, 0) : gc.textExtent(m_text);
    108     Rectangle imageBounds = m_image == null ? new Rectangle(0, 0, 0, 0) : m_image.getBounds();
    109     //
    110     if (m_image != null) {
    111       int x = clientArea.x;
    112       int y = clientArea.y + (clientArea.height - imageBounds.height) / 2;
    113       gc.drawImage(m_image, x, y);
    114     }
    115     if (m_text != null) {
    116       int x = clientArea.x + imageBounds.width + SPACE;
    117       int y = clientArea.y + (clientArea.height - textExtent.y) / 2;
    118       gc.drawText(m_text, x, y);
    119     }
    120     // flush back image
    121     {
    122       paintGC.drawImage(m_backImage, 0, 0);
    123       gc.dispose();
    124     }
    125   }
    126 
    127   @Override
    128   public Point computeSize(int wHint, int hHint, boolean changed) {
    129     // prepare text size
    130     GC gc = new GC(this);
    131     Point textExtent = m_text == null ? new Point(0, 0) : gc.textExtent(m_text);
    132     gc.dispose();
    133     // prepare image size
    134     Rectangle imageBounds = m_image == null ? new Rectangle(0, 0, 0, 0) : m_image.getBounds();
    135     // calculate control size
    136     int width = imageBounds.width + SPACE + textExtent.x;
    137     int height = Math.max(imageBounds.height, textExtent.y);
    138     return new Point(width, height);
    139   }
    140 }
    141