Source code: de/laures/cewolf/util/RenderingHelper.java
1 /* ================================================================
2 * Cewolf : Chart enabling Web Objects Framework
3 * ================================================================
4 *
5 * Project Info: http://cewolf.sourceforge.net
6 * Project Lead: Guido Laures (guido@laures.de);
7 *
8 * (C) Copyright 2002, by Guido Laures
9 *
10 * This library is free software; you can redistribute it and/or modify it under the terms
11 * of the GNU Lesser General Public License as published by the Free Software Foundation;
12 * either version 2.1 of the License, or (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
15 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16 * See the GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License along with this
19 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20 * Boston, MA 02111-1307, USA.
21 */
22
23 package de.laures.cewolf.util;
24
25 import java.awt.Color;
26 import java.awt.Font;
27 import java.awt.Graphics;
28 import java.awt.image.BufferedImage;
29 import java.io.IOException;
30 import java.io.OutputStream;
31 import java.io.PrintWriter;
32 import java.io.StringWriter;
33 import java.util.Enumeration;
34 import java.util.StringTokenizer;
35
36 import com.sun.image.codec.jpeg.JPEGCodec;
37 import com.sun.image.codec.jpeg.JPEGEncodeParam;
38 import com.sun.image.codec.jpeg.JPEGImageEncoder;
39
40 /**
41 * Some methods to render messages or exceptions into an image.
42 * @author glaures
43 */
44 public class RenderingHelper {
45
46 private final static int PADDING_X = 5;
47
48 public static String renderMessage(String msg, int width, int height, OutputStream out) throws IOException {
49 BufferedImage image = ImageHelper.createImage(width, height);
50 Graphics gr = image.getGraphics();
51 gr.setColor(Color.white);
52 gr.fillRect(0, 0, width, height);
53 gr.setColor(Color.black);
54 gr.drawString(msg, PADDING_X, height/2 - 7);
55 JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
56 JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(image);
57 param.setQuality(1.0f, true);
58 encoder.encode(image, param);
59 return "image/jpeg";
60 }
61
62 public static String renderException(Throwable ex, int width, int height, OutputStream out) throws IOException {
63 BufferedImage image = ImageHelper.createImage(width, height);
64 Graphics gr = image.getGraphics();
65 gr.setColor(Color.white);
66 gr.fillRect(0, 0, width, height);
67 gr.setColor(Color.red);
68 gr.drawString(ex.getClass().getName() + " raised:", PADDING_X, 15);
69 gr.drawString(String.valueOf(ex.getMessage()), PADDING_X, 30);
70 gr.setColor(Color.black);
71 Font stFont = gr.getFont().deriveFont(9f);
72 gr.setFont(stFont);
73 drawStackTrace(gr, PADDING_X, 50, ex);
74 JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
75 JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(image);
76 param.setQuality(1.0f, true);
77 encoder.encode(image, param);
78 return "image/jpeg";
79 }
80
81 private static void drawStackTrace(Graphics gr, int x, int y, Throwable ex) {
82 final int linePadding = 4;
83 int lineHeight = gr.getFont().getSize() + linePadding;
84 int currY = y;
85 Enumeration lines = new StringTokenizer(getStackTrace(ex), "\n", false);
86 while (lines.hasMoreElements()) {
87 gr.drawString(((String)lines.nextElement()).trim(), x, currY);
88 currY += lineHeight;
89 }
90 }
91
92 private static String getStackTrace(Throwable t) {
93 StringWriter sw = new StringWriter();
94 PrintWriter pw = new PrintWriter(sw);
95 t.printStackTrace(pw);
96 pw.close();
97 return sw.getBuffer().toString();
98 }
99
100 }