Retouching several images in several Task - javafx

Question

Generalities : explanations about my program and its functioning
I am working on a photo-retouching JavaFX application. The final user can load several images. When he clicks on the button REVERSE, a Task is launched for each image using an Executor. Each of these Task executes the reversal algorithm : it fills an ArrayBlockingQueue<Pixel> (using add method).
When the final user clicks on the button REVERSE, as I said, these Task are launched. But just after these statements, I tell the JavaFX Application Thread to draw the Pixel of the ArrayBlockingQueue<Pixel> (using remove method).
Thus, there are parallelism and concurrency (solved by the ArrayBlockingQueue<Pixel>) between the JavaFX Application Thread and the Task, and between the Task themselves.
To draw the Pixel of the ArrayBlockingQueue<Pixel>, the JavaFX Application Thread starts an AnimationTimer. The latter contains the previously-mentionned remove method. This AnimationTimer is started for each image.
I think you're wondering yourself how this AnimationTimer can know to what image belongs the Pixel it has removed ? In fact, each Pixel has an attribute writable_image that specifies the image to what it belongs.
My problems
Tell me if I'm wrong, but my program should work. Indeed :
My JavaFX Application Thread is the only thread that change the GUI (and it's required in JavaFX) : the Task just do the calculations.
There is not concurrency, thanks to the BlockingQueue I use (in particular, there isn't possibility of draining).
The AnimationTimer knows to what image belongs each Pixel.
However, it's (obviously !) not the case (otherwise I wouldn't have created this question haha !).
My problem is that my JavaFX Application freezes (first problem), after having drawn only some reversed pixels (not all the pixels). On the last loaded image moreover (third problem).
A detail that could be the problems' cause
But I would need your opinion.
The AnimationTimer of course doesn't draw the reversed pixels of each image directly : this is animated. The final user can see each pixel of an image being reversed, little by little. It's very practical in other algorithms as the creation of a circle, because the user can "look" how the algorithm works.
But to do that, the AnimationTimer needs to read a variable called max. This variable is modified (writen) in... each Task. But it's an AtomicLong. So IF I AM NOT WRONG, there isn't any problem of concurrency between the Task themselves, or between the JavaFX Application Thread and these Task.
However, it could be the problem : indeed, the max's value could be 2000 in Task n°1 (= in image n°1), and 59 in Task n°2 (= in image n°2). The problem is the AnimationTimer must use 2000 for the image n°1, and 59 for the n°2. But if the Task n°1 et n°2 have finished, the only value known by the AnimationTimer would be 59...
Sources
When the user clicks on the button REVERSE
We launch the several Task and start several times the AnimationTimer. CLASS : RightPane.java
WritableImage current_writable_image;
for(int i = 0; i < this.gui.getArrayListImageViewsImpacted().size(); i++) {
current_writable_image = (WritableImage) this.gui.getArrayListImageViewsImpacted().get(i).getImage();
this.gui.getGraphicEngine().executor.execute(this.gui.getGraphicEngine().createTask(current_writable_image));
}
for(int i = 0; i < this.gui.getArrayListImageViewsImpacted().size(); i++) {
current_writable_image = (WritableImage) this.gui.getArrayListImageViewsImpacted().get(i).getImage();
this.gui.getImageAnimation().setWritableImage(current_writable_image);
this.gui.getImageAnimation().startAnimation();
}
The Task are part of the CLASS GraphicEngine, which contains an Executor :
public final Executor executor = Executors.newCachedThreadPool(runnable -> {
Thread t = new Thread(runnable);
t.setDaemon(true);
return t ;
});
public Task createTask(WritableImage writable_image) {
int image_width = (int) writable_image.getWidth(), image_height = (int) writable_image.getHeight();
Task ret = new Task() {
protected Void call() {
switch(operation_to_do) {
case "reverse" :
gui.getImageAnimation().setMax(image_width*image_height); // USE OF "MAX" VARIABLE
reverseImg(writable_image);
break;
}
return null;
}
};
return ret;
}
The same CLASS, GraphicEngine, also contains the reversal algorithm :
private void reverseImg(WritableImage writable_image) {
int image_width = (int) writable_image.getWidth(), image_height = (int) writable_image.getHeight();
BlockingQueue<Pixel> updates = gui.getUpdates();
PixelReader pixel_reader = writable_image.getPixelReader();
double[] rgb_reversed;
for (int x = 0; x < image_width; x++) {
for (int y = 0; y < image_height; y++) {
rgb_reversed = PhotoRetouchingFormulas.reverse(pixel_reader.getColor(x, y).getRed(), pixel_reader.getColor(x, y).getGreen(), pixel_reader.getColor(x, y).getBlue());
updates.add(new Pixel(x, y, Color.color(rgb_reversed[0], rgb_reversed[1], rgb_reversed[2], pixel_reader.getColor(x, y).getOpacity()), writable_image));
}
}
}
Finally, here is the code of the CLASS AnimationTimer. There is nothing particular. Note the variable max is used here too (and in the CLASS GraphicEngine : setMax).
public class ImageAnimation extends AnimationTimer {
private Gui gui;
private AtomicLong max, speed, max_delay;
private long count, start;
private WritableImage writable_image;
ImageAnimation (Gui gui) {
this.gui = gui;
this.count = 0;
this.start = -1;
this.max = new AtomicLong(Long.MAX_VALUE);
this.max_delay = new AtomicLong(999_000_000);
this.speed = new AtomicLong(this.max_delay.get());
}
public void setMax(long max) {
this.max.set(max);
}
public void setSpeed(long speed) { this.speed.set(speed); }
public double getMaxDelay() { return this.max_delay.get(); }
#Override
public void handle(long timestamp) {
if (start < 0) {
start = timestamp ;
return ;
}
ArrayList<Pixel> list_sorted_pixels = new ArrayList<>();
BlockingQueue<Pixel> updates = this.gui.getUpdates();
for(Pixel new_pixel : updates) {
if(new_pixel.getWritableImage() == writable_image) {
list_sorted_pixels.add(new_pixel);
}
}
while (list_sorted_pixels.size() > 0 && timestamp - start > (count * this.speed.get()) / (writable_image.getWidth()) && !updates.isEmpty()) {
Pixel update = list_sorted_pixels.remove(0);
updates.remove(update);
count++;
if (update.getX() >= 0 && update.getY() >= 0) {
writable_image.getPixelWriter().setColor(update.getX(), update.getY(), update.getColor());
}
}
if (count >= max.get()) {
this.count = 0;
this.start = -1;
this.max.set(Long.MAX_VALUE);
stop();
}
}
public void setWritableImage(WritableImage writable_image) { this.writable_image = writable_image; }
public void startAnimation() {
this.start();
}
}