Sample code on website no longer works

[tebruno99]

I had use the following code instead of the sample provided otherwise the JVM would crash.

package org.ghost4j.example;

import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

import org.ghost4j.Ghostscript;
import org.ghost4j.GhostscriptException;
import org.ghost4j.display.ImageWriterDisplayCallback;

/**
 * Example showing how to setup a display callback (to interract with the display) for the Ghostscript interpreter.
 * In this example, a simple ImageWriterDisplayCallback is used as callback: it converts page rasters into images and stores them.
 * @author Gilles Grousset (gi.grousset@gmail.com)
 */
public class DisplayCallbackExample {

    public static void main(String[] args) {

        //get Ghostscript instance
        Ghostscript gs = Ghostscript.getInstance();

        //create display callback (capture display output pages as images)
        ImageWriterDisplayCallback displayCallback = new ImageWriterDisplayCallback();

        //set display callback
        gs.setDisplayCallback(displayCallback);

        //prepare Ghostscript interpreter parameters with display device
        String[] gsArgs = new String[9];
        gsArgs[0] = "-dQUIET";
        gsArgs[1] = "-dNOPAUSE";
        gsArgs[2] = "-dBATCH";
        gsArgs[3] = "-dSAFER";
        gsArgs[4] = "-sDEVICE=display";
        gsArgs[5] = "-sDisplayHandle=0";
        gsArgs[6] = "-dDisplayFormat=16#804";
        gsArgs[7] = "-f";
        gsArgs[8] = "input.ps";

        //run PostScript (also works with PDF) and exit interpreter
        try {
            gs.initialize(gsArgs);
            gs.exit();
        } catch (GhostscriptException e) {
            System.out.println("ERROR: " + e.getMessage());
        }

        //write images captured by the display callback to the disk in PNG format
        try {
            for (int i = 0; i < displayCallback.getImages().size(); i++) {
                ImageIO.write((RenderedImage) displayCallback.getImages().get(i), "png", new File((i + 1) + ".png"));
            }
        } catch (IOException e) {
            System.out.println("ERROR: " + e.getMessage());
        }

    }
}

[zippy1978]

Hi,

Thank you.

Could you tell me what you changed and where the JVM crashed in the code ?

[tebruno99]

Ghost4j: 0.4.6, 0.5.0, 0.5.1 and 0.5.2-SNAPSHOT Ghostscript: 9.10 and 9.14 Java: Java6 (Latest), Java7 (Latest)

On OSX I get: Invalid memory access of location 0x0 rip=0x0 at Ghostscript.java (runFile(String fileName): GhostscriptLibrary.instance.gsapi_run_file(getNativeInstanceByRef() .getValue(), fileName, 0, exitCode);

On Linux: # SIGSEGV (0xb) at pc=0x0000000000000000, pid=17329, tid=139761385789184

At: Ghostscript.java:runFile(String fileName) GhostscriptLibrary.instance.gsapi_run_file(getNativeInstanceByRef() .getValue(), fileName, 0, exitCode);

Linux Core Dump & Log: http://www.naveoss.com/ghost4j/issue32/core.zip http://www.naveoss.com/ghost4j/issue32/hs_err_pid11567.log Failing Sample: http://www.naveoss.com/ghost4j/issue32/MainConverter_SEGV.java

Fixed Sample: http://www.naveoss.com/ghost4j/issue32/MainConverter_FIXED.java

[tebruno99]

The same applies to the other sample that uses runFile

[zippy1978]

Thank you.... Something probably changed for runFile in the native API. I will have a look