FULL PRODUCT VERSION :
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b15)
Java HotSpot(TM) Client VM (build 25.45-b02, mixed mode, sharing)

And JDK the same

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.3.9600]

A DESCRIPTION OF THE PROBLEM :
I want to save a snapshot image of a JavaFX Application ImageView to file as type jpg. It seems that there is a bug with jpg (I need jpg, png is not an alternative to me).

Maybe the PixelWriter and PixelFormat seems to me wrong, even if I try to do a PixelFormat<ByteBuffer> format = PixelFormat.getRGBInstance(). But the RGB Format is fully ignored.

If you try the following code, it will show the problem:

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.IntBuffer;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.SplitPane;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelReader;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.image.WritablePixelFormat;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javax.imageio.ImageIO;

public class WritableImageDemo extends Application {

  private Image src;
  private int width;
  private int height;
  ImageView srcView;
  ImageView srcView2;
  ImageView srcView3;

  @Override
  public void start(Stage primaryStage) {
    primaryStage.setTitle("Image");

    src = new Image("http://www.gnu.org/graphics/gnu-head.jpg");
    width = (int) src.getWidth();
    height = (int) src.getHeight();

    srcView = new ImageView(src);
    srcView2 = new ImageView();
    srcView3 = new ImageView();

    ScrollPane scrollPane = new ScrollPane();
    ScrollPane scrollPane2 = new ScrollPane();
    ScrollPane scrollPane3 = new ScrollPane();

    scrollPane.setContent(srcView);
    scrollPane2.setContent(srcView2);
    scrollPane3.setContent(srcView3);

    SplitPane root = new SplitPane(scrollPane, scrollPane2, scrollPane3);

    primaryStage.setScene(new Scene(root, 800, 600));
    primaryStage.show();

    srcView2.setImage(writeToFile());
  }

  private WritableImage writeToFile() {
    WritableImage insert = new WritableImage(width, height);
    WritableImage newimage = new WritableImage(width, height);

    SnapshotParameters parameters = new SnapshotParameters();
    parameters.setFill(Color.TRANSPARENT);
    // make a snapshot
    srcView.snapshot(parameters, insert);

    PixelReader reader = insert.getPixelReader();
    PixelWriter writer = newimage.getPixelWriter();
    WritablePixelFormat<IntBuffer> format = WritablePixelFormat.getIntArgbInstance();

    System.out.println("WritablePixelFormat.getType(): " + format.getType());
    // the following normally creates an exact copy of the original
    for (int x = 0; x < width; x++) {
      for (int y = 0; y < height; y++) {
        int recWidth = 1;
        int recHeight = 1;

        int[] buffer = new int[recWidth * recHeight];
        reader.getPixels(x, y, recWidth, recHeight, format, buffer, 0, recWidth);

        int alpha = 0;
        int red = 0;
        int green = 0;
        int blue = 0;

        for (int color : buffer) {
          alpha += (color >>> 24);
          red += (color >>> 16 & 0xFF);
          green += (color >>> 8 & 0xFF);
          blue += (color & 0xFF);
        }
        alpha = alpha / recWidth / recHeight;
        red = red / recWidth / recHeight;
        green = green / recWidth / recHeight;
        blue = blue / recWidth / recHeight;

        int color = (alpha << 24) + (red << 16) + (green << 8) + blue;
        Arrays.fill(buffer, color);

        writer.setPixels(x, y, recWidth, recHeight, format, buffer, 0, recWidth);
      }

    }
    System.out.println("Reader Type: " + reader.getPixelFormat().getType());
    System.out.println("Writer Type: " + writer.getPixelFormat().getType());

    try {
      BufferedImage b = new BufferedImage(width + 1, height + 1, BufferedImage.OPAQUE);
      BufferedImage bf = SwingFXUtils.fromFXImage(newimage, b);

      ImageIO.write(bf, "jpg", new File("C:\\temp\\test1.jpg"));
    } catch (IOException ex) {
      Logger.getLogger(WritableImageDemo.class.getName()).
              log(Level.SEVERE, null, ex);
    }
    try {
      Image img = new Image(new FileInputStream(new File("C:\\temp\\test1.jpg")));
      srcView3.setImage(img);
    } catch (IOException ex) {
      Logger.getLogger(WritableImageDemo.class.getName()).log(Level.SEVERE, null, ex);
    }
    return newimage;
  }

  public static void main(String[] args) {
    launch(args);
  }
}




STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the code

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A jpg file that looks like the original file.
ACTUAL -
A red background fade in color is set.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.IntBuffer;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.SplitPane;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelReader;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.image.WritablePixelFormat;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javax.imageio.ImageIO;

public class WritableImageDemo extends Application {

  private Image src;
  private int width;
  private int height;
  ImageView srcView;
  ImageView srcView2;
  ImageView srcView3;

  @Override
  public void start(Stage primaryStage) {
    primaryStage.setTitle("Image");

    src = new Image("http://www.gnu.org/graphics/gnu-head.jpg");
    width = (int) src.getWidth();
    height = (int) src.getHeight();

    srcView = new ImageView(src);
    srcView2 = new ImageView();
    srcView3 = new ImageView();

    ScrollPane scrollPane = new ScrollPane();
    ScrollPane scrollPane2 = new ScrollPane();
    ScrollPane scrollPane3 = new ScrollPane();

    scrollPane.setContent(srcView);
    scrollPane2.setContent(srcView2);
    scrollPane3.setContent(srcView3);

    SplitPane root = new SplitPane(scrollPane, scrollPane2, scrollPane3);

    primaryStage.setScene(new Scene(root, 800, 600));
    primaryStage.show();

    srcView2.setImage(writeToFile());
  }

  private WritableImage writeToFile() {
    WritableImage insert = new WritableImage(width, height);
    WritableImage newimage = new WritableImage(width, height);

    SnapshotParameters parameters = new SnapshotParameters();
    parameters.setFill(Color.TRANSPARENT);
    // make a snapshot
    srcView.snapshot(parameters, insert);

    PixelReader reader = insert.getPixelReader();
    PixelWriter writer = newimage.getPixelWriter();
    WritablePixelFormat<IntBuffer> format = WritablePixelFormat.getIntArgbInstance();
    
    System.out.println("WritablePixelFormat.getType(): " + format.getType());
    // the following normally creates an exact copy of the original
    for (int x = 0; x < width; x++) {
      for (int y = 0; y < height; y++) {
        int recWidth = 1;
        int recHeight = 1;

        int[] buffer = new int[recWidth * recHeight];
        reader.getPixels(x, y, recWidth, recHeight, format, buffer, 0, recWidth);

        int alpha = 0;
        int red = 0;
        int green = 0;
        int blue = 0;

        for (int color : buffer) {
          alpha += (color >>> 24);
          red += (color >>> 16 & 0xFF);
          green += (color >>> 8 & 0xFF);
          blue += (color & 0xFF);
        }
        alpha = alpha / recWidth / recHeight;
        red = red / recWidth / recHeight;
        green = green / recWidth / recHeight;
        blue = blue / recWidth / recHeight;

        int color = (alpha << 24) + (red << 16) + (green << 8) + blue;
        Arrays.fill(buffer, color);

        writer.setPixels(x, y, recWidth, recHeight, format, buffer, 0, recWidth);
      }

    }
    System.out.println("Reader Type: " + reader.getPixelFormat().getType());
    System.out.println("Writer Type: " + writer.getPixelFormat().getType());

    try {
      BufferedImage b = new BufferedImage(width + 1, height + 1, BufferedImage.OPAQUE);
      BufferedImage bf = SwingFXUtils.fromFXImage(newimage, b);

      ImageIO.write(bf, "jpg", new File("C:\\temp\\test1.jpg"));
    } catch (IOException ex) {
      Logger.getLogger(WritableImageDemo.class.getName()).
              log(Level.SEVERE, null, ex);
    }
    try {
      Image img = new Image(new FileInputStream(new File("C:\\temp\\test1.jpg")));
      srcView3.setImage(img);
    } catch (IOException ex) {
      Logger.getLogger(WritableImageDemo.class.getName()).log(Level.SEVERE, null, ex);
    }
    return newimage;
  }

  public static void main(String[] args) {
    launch(args);
  }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Haven't found anything. I was not able to set the Pixelformat.type of the writer.