JavaFX ImageView repaint stage in while - javafx

Question

I can't redraw imageview in while. Without while is work with single image. May be it will be work if i try to use diffrent thread for image redraw, but i don't kno how to make it. Anybody can give me example for way where i can make it workable^)
package videostepone;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.ByteArrayInputStream;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.core.Scalar;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.objdetect.CascadeClassifier;
/**
*
* #author Анютка
*/
public class FXMLDocumentController implements Initializable {
#FXML
private Label label;
#FXML
private ImageView imageCam1;
#FXML
private void handleButtonAction(ActionEvent event) throws InterruptedException {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
//System.loadLibrary("opencv_java2410");
System.out.println("You clicked me!");
label.setText("Hello World!");
WebCamLive();
}
// Делает снимок с веб-камеры
private void WebCamShot() throws InterruptedException
{
VideoCapture camera = new VideoCapture(0);
Thread.sleep(1000);
camera.open(0); //Useless
if(!camera.isOpened()){
System.out.println("Camera Error");
}
else{
System.out.println("Camera OK?");
}
Mat frame = new Mat();
camera.read(frame);
System.out.println("Captured Frame Width " + frame.width());
Highgui.imwrite("camera.jpg", frame);
System.out.println("OK");
}
// Видео с веб-камеры
private void WebCamLive() throws InterruptedException
{
int i = 0;
VideoCapture camera = new VideoCapture(0);
Thread.sleep(1000);
camera.open(0); //Useless
if(!camera.isOpened()){
System.out.println("Camera Error");
}
else{
System.out.println("Camera OK?");
}
Mat frame = new Mat();
CascadeClassifier faceDetect = new CascadeClassifier("./res/haarcascade_frontalface_default.xml");
while (true)
{
camera.read(frame);
if (!frame.empty())
{
setImageOn(matToImage(frame));
// label.setText("1");
// Thread.sleep(6000);
// label.setText("-");
System.out.println(i++);
}
}
}
#FXML
private void setImageOn(Image img)
{
imageCam1.setImage(img);
}
private Image matToImage(Mat m){
MatOfByte memory = new MatOfByte();
try {
Highgui.imencode(".jpg", m, memory);
return (new Image(new ByteArrayInputStream(memory.toArray())));
} catch (Exception e) {
System.out.println(e);
}
return (new Image(new ByteArrayInputStream(memory.toArray())));
}
#Override
public void initialize(URL url, ResourceBundle rb) {
// TODO
}
}

Answer 1

As ItachiUchiha has pointed out your controller has some threading problems.
Like most other GUI toolkits, JavaFX is a single threaded GUI toolkit and thus all time consuming tasks which might block the GUI Thread should be performed elsewhere. Ohterwise nothings gets painted.
If I read your code correctly WebCamLive() takes a snapshot of the webcam every second?
Now you have two options on how to do this with JavaFX:
If the snapshot is taken rather fast, you can do this with a TimeLine, as shown here: Javafx Not on fx application thread when using timer
If the snapshot takes some time to capture, I would recommend writing a ScheduledService.
For further information on threading in JavaFX refer to the tutorial here: http://docs.oracle.com/javafx/2/threads/jfxpub-threads.htm