SWTUtils


1   /* ===========================================================
2    * JFreeChart : a free chart library for the Java(tm) platform
3    * ===========================================================
4    *
5    * (C) Copyright 2000-2006, by Object Refinery Limited and Contributors.
6    *
7    * Project Info:  http://www.jfree.org/jfreechart/index.html
8    *
9    * This library is free software; you can redistribute it and/or modify it 
10   * under the terms of the GNU Lesser General Public License as published by 
11   * the Free Software Foundation; either version 2.1 of the License, or 
12   * (at your option) any later version.
13   *
14   * This library is distributed in the hope that it will be useful, but 
15   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
16   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
17   * License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
22   * USA.  
23   *
24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
25   * in the United States and other countries.]
26   *
27   * -------------
28   * SWTUtils.java
29   * -------------
30   * (C) Copyright 2006, by Henry Proudhon and Contributors.
31   *
32   * Original Author:  Henry Proudhon (henry.proudhon AT insa-lyon.fr);
33   * Contributor(s):
34   *
35   * Changes
36   * -------
37   * 1 Aug 2006 : New class (HP);
38   * 
39   */
40  
41  package org.jfree.experimental.swt;
42  
43  import javax.swing.JPanel  ;
44  
45  import org.eclipse.swt.SWT;
46  import org.eclipse.swt.graphics.Color;
47  import org.eclipse.swt.graphics.Device;
48  import org.eclipse.swt.graphics.Font;
49  import org.eclipse.swt.graphics.FontData;
50  import org.eclipse.swt.graphics.GC;
51  
52  /**
53   * Utility class gathering some useful and general method.
54   * Mainly convert forth and back graphical stuff between 
55   * awt and swt.
56   */
57  public class SWTUtils {
58      
59      private final static String   Az = "ABCpqr";
60  
61      /**
62       * Create a <code>FontData</code> object which encapsulate 
63       * the essential data to create a swt font. The data is taken 
64       * from the provided awt Font.
65       * <p>Generally speaking, given a font size, the returned swt font 
66       * will display differently on the screen than the awt one.
67       * Because the SWT toolkit use native graphical ressources whenever 
68       * it is possible, this fact is plateform dependent. To address 
69       * this issue, it is possible to enforce the method to return 
70       * a font with the same size (or at least as close as possible) 
71       * as the awt one.
72       * <p>When the object is no more used, the user must explicitely 
73       * call the dispose method on the returned font to free the 
74       * operating system resources (the garbage collector won't do it).
75       * 
76       * @param device The swt device to draw on (display or gc device).
77       * @param font The awt font from which to get the data.
78       * @param ensureSameSize A boolean used to enforce the same size 
79       * (in pixels) between the awt font and the newly created swt font.
80       * @return a <code>FontData</code> object.
81       */
82      public static FontData toSwtFontData(Device device, java.awt.Font   font, 
83              boolean ensureSameSize) {
84          FontData fontData = new FontData();
85          fontData.setName(font.getFamily());
86          int style = SWT.NORMAL;
87          switch (font.getStyle()) {
88              case java.awt.Font.PLAIN:
89                  style |= SWT.NORMAL;
90                  break;
91              case java.awt.Font.BOLD:
92                  style |= SWT.BOLD;
93                  break;
94              case java.awt.Font.ITALIC:
95                  style |= SWT.ITALIC;
96                  break;
97              case (java.awt.Font.ITALIC + java.awt.Font.BOLD):
98                  style |= SWT.ITALIC | SWT.BOLD;
99                  break;
100         }
101         fontData.setStyle(style);
102         // convert the font size (in pt for awt) to height in pixels for swt
103         int height = (int) Math.round(font.getSize() * 72.0 
104                 / device.getDPI().y);
105         fontData.setHeight(height);
106         // hack to ensure the newly created swt fonts will be rendered with the
107         // same height as the awt one
108         if (ensureSameSize) {            
109             GC tmpGC = new GC(device);
110             JPanel   DUMMY_PANEL = new JPanel  ();
111             Font tmpFont = new Font(device, fontData);
112             tmpGC.setFont(tmpFont);
113             if (tmpGC.textExtent(Az).x 
114                     > DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
115                 while (tmpGC.textExtent(Az).x 
116                         > DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
117                     tmpFont.dispose();
118                     height--;
119                     fontData.setHeight(height);
120                     tmpFont = new Font(device, fontData);
121                     tmpGC.setFont(tmpFont);
122                 }
123             }
124             else if (tmpGC.textExtent(Az).x 
125                     < DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
126                 while (tmpGC.textExtent(Az).x 
127                         < DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
128                     tmpFont.dispose();
129                     height++;
130                     fontData.setHeight(height);
131                     tmpFont = new Font(device, fontData);
132                     tmpGC.setFont(tmpFont);
133                 }
134             }
135             tmpFont.dispose();
136             tmpGC.dispose();
137         }
138         return fontData;
139     }
140     
141     /**
142      * Create an awt font by converting as much information 
143      * as possible from the provided swt <code>FontData</code>.
144      * <p>Generally speaking, given a font size, an swt font will 
145      * display differently on the screen than the corresponding awt 
146      * one. Because the SWT toolkit use native graphical ressources whenever 
147      * it is possible, this fact is plateform dependent. To address 
148      * this issue, it is possible to enforce the method to return 
149      * an awt font with the same height as the swt one.
150      * 
151      * @param device The swt device being drawn on (display or gc device).
152      * @param fontData The swt font to convert.
153      * @param ensureSameSize A boolean used to enforce the same size 
154      * (in pixels) between the swt font and the newly created awt font.
155      * @return An awt font converted from the provided swt font.
156      */
157     public static java.awt.Font   toAwtFont(Device device, FontData fontData, 
158             boolean ensureSameSize) {
159         int style;
160         switch (fontData.getStyle()) {
161             case SWT.NORMAL:
162                 style = java.awt.Font.PLAIN;
163                 break;
164             case SWT.ITALIC:
165                 style = java.awt.Font.ITALIC;
166                 break;
167             case SWT.BOLD:
168                 style = java.awt.Font.BOLD;
169                 break;
170             default:
171                 style = java.awt.Font.PLAIN;
172                 break;
173         }
174         int height = (int) Math.round(fontData.height * device.getDPI().y 
175                 / 72.0);
176         // hack to ensure the newly created awt fonts will be rendered with the
177         // same height as the swt one
178         if (ensureSameSize) {
179             GC tmpGC = new GC(device);
180             Font tmpFont = new Font(device, fontData);
181             tmpGC.setFont(tmpFont);
182             JPanel   DUMMY_PANEL = new JPanel  ();
183             java.awt.Font   tmpAwtFont = new java.awt.Font  (fontData.getName(), 
184                     style, height);
185             if (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az) 
186                     > tmpGC.textExtent(Az).x) {
187                 while (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az) 
188                         > tmpGC.textExtent(Az).x) {
189                     height--;                
190                     tmpAwtFont = new java.awt.Font  (fontData.getName(), style, 
191                             height);
192                 }
193             }
194             else if (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az) 
195                     < tmpGC.textExtent(Az).x) {
196                 while (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az) 
197                         < tmpGC.textExtent(Az).x) {
198                     height++;
199                     tmpAwtFont = new java.awt.Font  (fontData.getName(), style, 
200                             height);
201                 }
202             }
203             tmpFont.dispose();
204             tmpGC.dispose();
205         }
206         return new java.awt.Font  (fontData.getName(), style, height);
207     }
208 
209     /**
210      * Create an awt font by converting as much information 
211      * as possible from the provided swt <code>Font</code>.
212      * 
213      * @param device The swt device to draw on (display or gc device).
214      * @param font The swt font to convert.
215      * @return An awt font converted from the provided swt font.
216      */
217     public static java.awt.Font   toAwtFont(Device device, Font font) {
218         FontData fontData = font.getFontData()[0]; 
219         return toAwtFont(device, fontData, true);
220     }
221 
222     /**
223      * Creates an awt color instance to match the rgb values 
224      * of the specified swt color.
225      * 
226      * @param color The swt color to match.
227      * @return an awt color abject.
228      */
229     public static java.awt.Color   toAwtColor(Color color) {
230         return new java.awt.Color  (color.getRed(), color.getGreen(), 
231                 color.getBlue());
232     }
233     
234     /**
235      * Creates a swt color instance to match the rgb values 
236      * of the specified awt paint. For now, this method test 
237      * if the paint is a color and then return the adequate 
238      * swt color. Otherwise plain black is assumed.
239      * 
240      * @param device The swt device to draw on (display or gc device).
241      * @param paint The awt color to match.
242      * @return a swt color object.
243      */
244     public static Color toSwtColor(Device device, java.awt.Paint   paint) {
245         java.awt.Color   color;
246         if (paint instanceof java.awt.Color  ) {
247             color = (java.awt.Color  ) paint;
248         }
249         else {
250             try {
251                 throw new Exception  ("only color is supported at present... " 
252                         + "setting paint to uniform black color" );
253             } 
254             catch (Exception   e) {
255                 e.printStackTrace();
256                 color = new java.awt.Color  (0, 0, 0);
257             }
258         }
259         return new org.eclipse.swt.graphics.Color(device,
260                 color.getRed(), color.getGreen(), color.getBlue());
261     }
262 
263     /**
264      * Creates a swt color instance to match the rgb values 
265      * of the specified awt color. alpha channel is not supported.
266      * Note that the dispose method will need to be called on the 
267      * returned object.
268      * 
269      * @param device The swt device to draw on (display or gc device).
270      * @param color The awt color to match.
271      * @return a swt color object.
272      */
273     public static Color toSwtColor(Device device, java.awt.Color   color) {
274         return new org.eclipse.swt.graphics.Color(device,
275                 color.getRed(), color.getGreen(), color.getBlue());
276     }
277 }
278
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