This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

Linear Image.

Click and drag mouse up and down to control the signal. Press and hold any key to watch the scanning.


PImage img;
int direction = 1;

float signal;

void setup() {
  size(640, 360);
  stroke(255);
  img = loadImage("sea.jpg");
  img.loadPixels();
  loadPixels();
}

void draw() {
  if (signal > img.height-1 || signal < 0) { 
    direction = direction * -1;
  }
  if (mousePressed == true) {
    signal = abs(mouseY % img.height);
  } 
  else {
    signal += (0.3*direction);
  }

  if (keyPressed == true) {
    set(0, 0, img);
    line(0, signal, img.width, signal);
  } 
  else {
    int signalOffset = int(signal)*img.width;
    for (int y = 0; y < img.height; y++) {
      arrayCopy(img.pixels, signalOffset, pixels, y*width, img.width);
    }
    updatePixels();
  }
}