1 //
2 // PixelGrabber Example
3 //
4 // by Ozgur Balsoy
5 // November 20, 1996
6 //
7 // Reference: Sun On-line documentation.
8 // http://www.arl.hpc.mil/PET/training/IC001/projects/tutorials/Java/
9 // Sun/api/java.awt.image.PixelGrabber.html
10 //
11
12 import java.awt.*;
13 import java.awt.image.*;
14 import java.applet.*;
15 import java.util.*;
16
17 public class grabber extends Applet {
18 private TextField tf;
19 private TextArea ta;
20 private Label status;
21 private Canvas drawarea;
22 private Image img=null;
23 int ppmline=0;
24
25 public void init() {
26
27 setLayout(new GridLayout(1,2));
28
29 Panel left=new Panel();
30 left.setLayout(new BorderLayout());
31
32 Panel topleft = new Panel();
33 topleft.setLayout(new GridLayout(1, 4));
34
35 topleft.add(tf=new TextField());
36
37 Panel buttonsP = new Panel();
38 buttonsP.add(new Button("Load GIF"));
39 buttonsP.add(new Button("PPM Output"));
40 topleft.add(buttonsP);
41
42 left.add("North", topleft);
43
44 left.add("Center", drawarea=new Canvas());
45
46 left.add("South", status=new Label());
47
48 add(left); // left side of the applet.
49 add(ta=new TextArea()); // right side.
50
51 status.setText("See GIF files below.");
52 }
53
54 public void paint(Graphics appletg) {
55
56 Graphics g=drawarea.getGraphics();
57 if (img != null) {
58 g.drawImage(img, 0, 0, this);
59 g.dispose();
60 }
61 }
62
63 public boolean action(Event evt, Object arg) {
64 String s=(String) arg;
65
66 if(s.equals("Load GIF")) {
67 img=getImage(getCodeBase(), tf.getText());
68 repaint();
69 }
70 else if (s.equals("PPM Output")) getPixs();
71
72 return true;
73 }
74
75 void getPixs() {
76
77 int w=30, h=30;
78
79 // PPM output starts.
80 ta.setText("P3\n");
81 ta.appendText(Integer.toString(w) + " " + Integer.toString(h) + "\n");
82 ta.appendText("255\n");
83 handlepixels(img, 0, 0, w, h);
84
85 }
86
87 public void handlesinglepixel(int x, int y, int pixel) {
88
89
90 // pixel is in RGB model. It is a 4-byte long integer.
91 // It is converted into the string representation of PPM pixels.
92 // ie. Hex 0x00102030 becomes "16 32 48"
93 String s= Integer.toString((pixel & 0x00FF0000) >> 16) + " "
94 + Integer.toString((pixel & 0x0000FF00) >> 8) + " "
95 + Integer.toString(pixel & 0x000000FF) + " ";
96 //
97 // If we use PPM RAW format, then we have to use ascii characters instead.
98 //
99 //
100 // char c[]= {(char) ((pixel & 0x00FF0000) >> 16),
101 // (char) ((pixel & 0x0000FF00) >> 8) ,
102 // (char) (pixel & 0x000000FF) };
103 // String s=new String(c);
104
105 if (ppmline++>=3) { // comment out if you use RAW format.
106 ta.appendText(s + "\n"); // comment out if you use RAW format.
107 ppmline=0; // comment out if you use RAW format.
108 } else // comment out if you use RAW format.
109 ta.appendText(s);
110 }
111
112 public void handlepixels(Image img, int x, int y, int w, int h) {
113 int[] pixels = new int[w * h];
114 PixelGrabber pg = new PixelGrabber(img, x, y, w, h, pixels, 0, w);
115 try {
116 pg.grabPixels();
117 } catch (InterruptedException e) {
118 System.err.println("interrupted waiting for pixels!");
119 return;
120 }
121 if ((pg.status() & ImageObserver.ABORT) != 0) {
122 System.err.println("image fetch aborted or errored");
123 return;
124 }
125 for (int j = 0; j < h; j++) {
126 for (int i = 0; i < w; i++) {
127 handlesinglepixel(x+i, y+j, pixels[j * w + i]);
128 }
129 }
130 }
131 }
132
133
134