Re: [javacv] Problem with EventKey - JavaCV

[Samuel Audet]

Hello,

On 02/21/2013 08:35 AM, Michele Correa wrote:
> Hi! I am new here... =], And I need some help:
>
> I am trying to write a program that displays a video using JavaCV and I
> want that the window (or the video) closes when ESC is pressed. My code:

CanvasFrame.waitKey() wasn't meant to be called in the EDT thread. Try
to run it in the main thread, i.e.:

public static void main(String[] args) {
CanvasFrame canvas = new CanvasFrame("title)";
while (...) {
if (canvas.waitKey(2).getKeyChar() == VK_ESCAPE) {
break;
}
}
}

Samuel

[Michele Correa]

Hi, thanks for your help ! I tried your suggestion, but when I don't call the CanvasFrame.waitKey() in the EDT thread, the code doesn't compile and "Eclipse" suggests that I call it in the EDT thread or add throws declaration and then the video isn't displayed, =\

Have I done something wrong?

[Samuel Audet]

Hello,

On 02/25/2013 06:33 AM, Michele Correa wrote:
> Hi, thanks for your help ! I tried your suggestion, but when I don't
> call the CanvasFrame.waitKey() in the EDT thread, the code doesn't
> compile and "Eclipse" suggests that I call it in the EDT thread or add
> throws declaration and then the video isn't displayed, =\
>
> Have I done something wrong?

I guess so, I'm not getting any issues doing something like this in the
while() loop of Demo.java:
KeyEvent e = frame.waitKey(2);
if (e != null && e.getKeyChar() == KeyEvent.VK_ESCAPE) {
break;
}
But this probably doesn't do exactly what you're after.. I'll be
updating it shortly so that we can call waitKey(-1), which probably does
something closer to what you're looking for.

Samuel

[Michele Correa]

Hi, thanks again, =]! Now the video is playing, but it doesn't stop when I press ESC. My code:

import java.awt.event.ActionEvent;

import java.awt.event.KeyEvent;

import com.googlecode.javacv.CanvasFrame;

import com.googlecode.javacv.FrameGrabber;

import com.googlecode.javacv.cpp.opencv_core.*;

import com.googlecode.javacv.OpenCVFrameGrabber;

import java.awt.event.ActionListener;

import javax.swing.JDesktopPane;

import javax.swing.JFileChooser;

import javax.swing.JFrame;

import javax.swing.JMenu;

import javax.swing.JMenuBar;

import javax.swing.JMenuItem;

public class VideoJavaCV extends JFrame {  

public static void main (String[] args){

JFrame window = new JFrame("JavaCV");

final JDesktopPane desktop = new JDesktopPane();   

        JMenuBar myMenuBar = new JMenuBar();

        JMenu myMenuFile = new JMenu("File");

        JMenuItem openVideo = new JMenuItem("Open Video");

        myMenuBar.add(myMenuFile);

        myMenuFile.add(openVideo);

        JMenuItem exit = new JMenuItem("Exit");

        exit.addActionListener(new ActionListener() {

        public void actionPerformed(ActionEvent e) {

        System.exit(0);

        }

        });

        

        myMenuFile.add(exit);

        

        openVideo.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {

            String path = "";

            JFileChooser file = new JFileChooser();

            if(file.showOpenDialog(null) == JFileChooser.APPROVE_OPTION) path = file.getSelectedFile().getAbsolutePath();

                final CanvasFrame canvas = new CanvasFrame("Video Canvas"); 

                

                canvas.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);   

                FrameGrabber grabber = new OpenCVFrameGrabber(path);

                canvas.setCanvasSize(grabber.getImageWidth(), grabber.getImageHeight());

                try {      

                grabber.start();

                IplImage img;

               

                while(true){

                img = grabber.grab();

                if(img!=null){

                canvas.showImage(img);

                KeyEvent er = canvas.waitKey(2); 

                        if (er != null && er.getKeyChar() == KeyEvent.VK_ESCAPE) { 

                        return; 

                        }

                }

                }

                }catch (Exception ae) {}

            }

            

        });

        

        

        

        window.add(desktop);

        window.setJMenuBar(myMenuBar);

        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        window.setSize(200, 100);

        window.setVisible(true);

}

}   

[Samuel Audet]

On 03/11/2013 07:32 AM, Michele Correa wrote:
> Hi, thanks again, =]! Now the video is playing, but it doesn't stop when
> I press ESC. My code:

Please try to add the following lines to the end of the while() loop of
the Demo class found in the README.txt file:
KeyEvent e = frame.waitKey(-1);

if (e != null && e.getKeyChar() == KeyEvent.VK_ESCAPE) {
break;
}

Samuel

[Michele Correa]

Hi! I've tried this too, but it didn't work.

I noticed that when I remove all the buttons and menus (JMenuBar, JMenu, JMenuItem etc) everything works perfectly, =]. Is there any incompatibility between them and JavaCV / OpenCV?

Thank you,

Michele.

[Samuel Audet]

On 03/25/2013 06:54 AM, Michele Correa wrote:
> I noticed that when I remove all the buttons and menus (JMenuBar, JMenu,
> JMenuItem etc) everything works perfectly, =]. Is there any
> incompatibility between them and JavaCV / OpenCV?

No, this is just Java. If you're going to add menu bars and stuff you're
probably better off using a KeyListener to do what you want to do:
http://docs.oracle.com/javase/tutorial/uiswing/events/keylistener.html