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Name

pixelWidth

Description

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.

Examples

  • 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();
}

Related

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