GeezerVison

pixelHeight

When pixelDensity(2) is used to make use of a high resolution display (called a Retina display on OS X or high-dpi on Windows and Linux), the width and height of the sketch do not change, but the number of pixels is doubled. As a result, all operations that use pixels (like loadPixels(), get(), set(), etc.) happen in this doubled space. As a convenience, the variables pixelWidth and pixelHeight hold the actual width and height of the sketch in pixels. This is useful for any sketch that uses the pixels[] array, for instance, because the number of elements in the array will be pixelWidth*pixelHeight, not width*height.

• void setup() {
    size(600, 400);
    pixelDensity(2);
    println(width, height);
    println(pixelWidth, pixelHeight);
  }
  

• void setup() {
    size(600, 400);
    pixelDensity(2);  // Double the pixel density
    println(width, height);
    println(pixelWidth, pixelHeight);
  }
  
  void draw() {
    loadPixels();
    // Fill all the pixels to blue with using
    // pixelWidth and pixelHeight
    for (int i = 0; i < pixelWidth * pixelHeight; i++) {
      pixels[i] = color(0, 0, 255);
    }
    // Fill one quarter of the pixels to yellow
    // because the pixel density is set to 2 in setup()
    // and 'width' and 'height' don't reflect the pixel 
    // dimensions of the sketch
    for (int i = 0; i < width * height; i++) {
      pixels[i] = color(255, 255, 0);
    }
    updatePixels();
    noLoop();
  }
  

• pixelWidth
• pixelDensity()
• displayDensity()