From: tmb
This does not look like form output to me.


Platform: Windows 95 or Linux/X11R6, JDK-1.0

The following program generates a white square for the rescaled image
that was generated by off-screen rescaling (see comments in "paint()")
when run as "java Bug2". Running it as "java Bug2 -" demonstrates
that all the other setup is working.

Thomas.

// drawImage with rescaling doesn't seem to work properly when the
// destination is an off-screen pixmap

import java.awt.*;
import java.awt.image.*;
import java.net.*;
import java.applet.*;
import java.util.Vector;
import java.lang.*;
import java.io.*;
import sun.awt.image.FileImageSource;

class Bug2 extends Canvas {
    static double min(double x,double y) { if(x<y) return x; else return y; }

    static Image createImageComplete(Component c,ImageProducer source) {
        Image image = c.createImage(source);
        Bug2Wait w = new Bug2Wait();
        if(!c.prepareImage(image,w)) w.waitfor();
        return image;
    }

    Image scale(Image timage) {
        int nw = 50, nh = 50;
        Image nimage = createImage(nw,nh);
        Graphics ng = nimage.getGraphics();
        Bug2Wait ws;
        if(!no_rescale) {
            ws = new Bug2Wait();
            if(!ng.drawImage(timage,0,0,nw,nh,ws)) ws.waitfor();
        } else {
            D("no rescale");
            ws = new Bug2Wait();
            if(!ng.drawImage(timage,0,0,ws)) ws.waitfor();
        }
        return nimage;
    }

    Image image = null;
    Image image2 = null;
    int count = 1;
    static boolean no_rescale;
    
    public void paint(Graphics g) {
        if(image==null) {
            D("loading image");
            image = createImageComplete(this,new FileImageSource("foo.jpg"));
            D("rescaling");
            image2 = scale(image);
            D("done");
        }
        g.setColor(Color.darkGray);
        g.fillRect(0,0,10000,10000);
        g.drawImage(image,0,0,this); // this works--it draws the original image
        g.drawImage(image2,400,0,this); // this doesn't work--it yields just a white square
        g.drawImage(image,0,200,60,60,this); // this works and draws a rescaled image
        g.setColor(Color.white);
        g.drawString(""+count++,400,200);
    }

    public static void main(String args[]) {
        no_rescale = args.length>0;
        Frame f = new Frame("Test");
        Bug2 c = new Bug2();
        c.resize(800,400);
        f.add("Center",c);
        f.pack();
        f.show();
    }
    static void D(String s) { System.out.println(s); }
}

class Bug2Wait implements ImageObserver {
    boolean done = false;
    int flags = 0;
    // NB: this uses polling because of a bug in notifyAll()
    public boolean imageUpdate(Image img,int infoflags,int x,int y,int width,int height) {
        flags = flags|infoflags;
        if((infoflags&ERROR)!=0) System.out.println("wait: ERROR");
        if((infoflags&ABORT)!=0) System.out.println("wait: ABORT");
        if((infoflags&(ABORT|ALLBITS|ERROR|FRAMEBITS))!=0) {
            done = true;
            return false;
        }
        return true;
    }
    public void waitfor() {
        while(true) {
            if(done) return;
            U.sleep(200);
        }
    }
}