How to draw a rect() in a Thread

Geist5000

Hello,

I am trying to draw a rectangle in the window from a Thread.

void setup(){ size(100,100); T thread = new T(); thread.start(); } class T extends Thread{ void run(){ rect(10,10,10,10); } }

But this didn't work. I hobe someone can help me?

Thank you!

koogs

this is a bad idea. only the draw() thread should update the image.

GoToLoop

https://Forum.Processing.org/two/discussion/15473/readme-how-to-format-code-and-text

/**
 * Threaded PGraphics (v1.1.1)
 * GoToLoop (2018/Jan/03)
 *
 * Forum.Processing.org/two/discussion/25799/
 * how-to-draw-a-rect-in-a-thread#Item_2
 */

static final float FPS = 10;
final Layer layer = new Layer();

void setup() {
  size(250, 200);
  smooth(3);
  frameRate(FPS);

  colorMode(RGB);
  imageMode(CORNER);

  layer.start();
  while (layer.pg == null || layer.pg.height != height)  delay(1);
}

void draw() {
  getSurface().setTitle("Frames: " + frameCount);
  background((color) random(#000000));
  image(layer.pg, 0, 0);
}

class Layer extends Thread {
  static final short INTERVAL = 1*1000, TXT_SIZE = 40;
  static final float BOLD = 2.5;
  static final color BORDER = 0, TXT_COLOR = -1;

  PGraphics pg;

  void run() {
    initDisplay();
    displayLoop();
  }

  void initDisplay() {
    pg = createGraphics(width, height, JAVA2D);
    pg.beginDraw();

    pg.smooth(3);
    pg.colorMode(RGB);
    pg.rectMode(CENTER);

    pg.strokeWeight(BOLD);
    pg.stroke(BORDER);

    pg.textSize(TXT_SIZE);
    pg.textAlign(CENTER, CENTER);

    pg.endDraw();
  }

  void displayLoop() {
    final int cx = pg.width>>1, cy = pg.height>>1;

    for (int frames = 1;; delay(INTERVAL), ++frames) {
      pg.beginDraw();

      pg.clear();
      pg.fill((color) random(#000000));
      pg.rect(cx, cy, cx, cy);

      pg.fill(TXT_COLOR);
      pg.text(frames, cx, cy);

      pg.endDraw();
    }
  }
}

GoToLoop

"""
 Threaded PGraphics (v1.1.3)
 GoToLoop (2018/Jan/03)

 Forum.Processing.org/two/discussion/25799/
 how-to-draw-a-rect-in-a-thread#Item_3
"""

from java.lang import Thread

FPS = 10

def setup():
    size(250, 200)
    smooth(3)
    frameRate(FPS)

    colorMode(RGB)
    imageMode(CORNER)

    global layer
    layer = Layer()
    layer.start()
    while not layer.pg or layer.pg.height != height: delay(1)


def draw():
    this.surface.title = 'Frames: ' + `frameCount`
    background(int(random(PImage.ALPHA_MASK)))
    image(layer.pg, 0, 0)


class Layer(Thread):
    INTERVAL, TXT_SIZE = 1*1000, 40
    BOLD, BORDER, TXT_COLOR = 2.5, 0, -1

    def __init__(self): self.pg = None

    def run(self): self.initDisplay(), self.displayLoop()

    def initDisplay(self):
        pg = self.pg = createGraphics(width, height, JAVA2D)
        pg.beginDraw()

        pg.smooth(3)
        pg.colorMode(RGB)
        pg.rectMode(CENTER)

        pg.strokeWeight(Layer.BOLD)
        pg.stroke(Layer.BORDER)

        pg.textSize(Layer.TXT_SIZE)
        pg.textAlign(CENTER, CENTER)

        pg.endDraw()


    def displayLoop(self):
        pg, frames = self.pg, 1
        cx, cy = pg.width>>1, pg.height>>1

        while True:
            pg.beginDraw()

            pg.clear()
            pg.fill(int(random(PImage.ALPHA_MASK)))
            pg.rect(cx, cy, cx, cy)

            pg.fill(Layer.TXT_COLOR)
            pg.text(frames, cx, cy)

            pg.endDraw()

            delay(Layer.INTERVAL)
            frames += 1

KevinWorkman

What koogs said is correct. You should not draw from multiple threads. You can do some processing of data on another thread, but all drawing needs to be done from the animation thread.

Geist5000

Thank you for the anwseres. I solved the problem another way.

Thank you