1    /** 
2     * WritePPM is a class that takes an Image and saves it to 
3     * a PPM format file. 
4     * 
5     * Victor Silva (victor@bridgeport.edu). 
6     * Modified by D.L. (lyon@DocJava.com) 
7     * 
8     */ 
9    package ip.ppm; 
10    
11   import java.io.BufferedOutputStream; 
12   import java.io.FileOutputStream; 
13   import java.io.IOException; 
14   import java.io.OutputStream; 
15    
16   public class WritePPM { 
17       int width; 
18       int height; 
19    
20       public static void doIt( 
21               short r[][], short g[][], short b[][], 
22               String fn) { 
23           WritePPM wppm = new WritePPM(r.length, r[0].length); 
24           try { 
25               OutputStream os = new BufferedOutputStream( 
26                       new FileOutputStream(fn)); 
27               wppm.writeHeader(os); 
28               //System.out.println("Header OK"); 
29               wppm.writeImage(os, r, g, b); 
30               //System.out.println("Image written"); 
31               os.flush(); 
32               os.close(); 
33           } catch (IOException e) { 
34               System.out.println(e + " IOException"); 
35           } 
36       } 
37    
38    
39       public WritePPM(int w, int h) { 
40           width = w; 
41           height = h; 
42       } 
43    
44    
45       public void writeHeader(OutputStream os) { 
46           writeString(os, "P6\n"); 
47           writeString(os, width + " " + height + "\n"); 
48    
49           // Write the maximum value of each color. 
50           // i.e. r,g,b all vary between 0 and 255. 
51           writeString(os, "255\n"); 
52       } 
53    
54       static void writeString(OutputStream out, String str) { 
55           int len = str.length(); 
56           byte[] buf = new byte[len]; 
57           // now deprecated 
58           // str.getBytes( 0, len, buf, 0 ); 
59           // use the following instead: 
60           buf = str.getBytes(); 
61           try { 
62               out.write(buf); 
63           } catch (Exception e) { 
64               System.out.println(e); 
65           } 
66       } 
67    
68       private void printDimensions(short r[][], 
69                                    String nm) { 
70           System.out.println( 
71                   nm + ".length =" + r.length + " " 
72                   + nm + "[0].length =" + r[0].length); 
73    
74       } 
75    
76       public void writeImage(OutputStream os, 
77                              short r[][], 
78                              short g[][], 
79                              short b[][]) { 
80           int j = 0; 
81           width = r.length; 
82           height = r[0].length; 
83           byte[] ppmPixels = new byte[width * height * 3]; 
84           //System.os.println("Writing image "+width+"x"+height); 
85           // yowsa!! 
86           // tuff error to spot! 
87           // for ( int col = 0; col < width ; ++col ) { is wrong!! 
88           // for ( int col = 0; col < height ; col++ ) { is correct! 
89           try { 
90               for (int col = 0; col < height; col++) { 
91                   for (int row = 0; row < width; row++) { 
92                       ppmPixels[j++] = (byte) r[row][col]; 
93                       ppmPixels[j++] = (byte) g[row][col]; 
94                       ppmPixels[j++] = (byte) b[row][col]; 
95                   } 
96               } 
97           } catch (Exception e) { 
98               e.printStackTrace(); 
99           } 
100          // Write ppm file all at once. 
101          try { 
102              os.write(ppmPixels); 
103          } catch (Exception e) { 
104              System.out.println(e + " os.write"); 
105          } 
106      } 
107  } 
108