/** Reduce resolution of captured image.
 * @author Mithat Konar
 */

import processing.video.*;

Capture cam;  // The video capture device.
PImage img;   // Buffer image.

// Canvas parameters
final int CANVAS_WIDTH = 320;
final int CANVAS_HEIGHT = 240;
final int CANVAS_FPS = 4;

// Video capture parameters (adjust as neeeded for your 
// platform's available capture options):
final int CAM_WIDTH = 320;
final int CAM_HEIGHT = 240;
final int CAM_FPS = 15;

// Rendering parameters: number of cells the rendered
// image should be in each direction:
final int REDUCED_WIDTH = 128;
final int REDUCED_HEIGHT = 96;

void setup() {
  frameRate(CANVAS_FPS);
  size(CANVAS_WIDTH, CANVAS_HEIGHT);

  if (Capture.list().length == 0) {
    println("There are no cameras available for capture.");
    exit();
  }

  // Instantiate a buffer image used for subsampling, etc.
  img = createImage(REDUCED_WIDTH, REDUCED_HEIGHT, RGB);

  // Instantiate a new Capture object, requesting the specs:
  cam = new Capture(this, CAM_WIDTH, CAM_HEIGHT, CAM_FPS);
  cam.start();  // In Processing 2.0, you need to start the capture device
}

void draw() {
  // Grab a frame
  if (cam.available() == true) {
    cam.read();
  }

  // The following should work but doesn't.
  //  cam.resize(REDUCED_WIDTH, REDUCED_HEIGHT);

  // So we use an interim buffer image instead:
  img.copy(cam, 0, 0, CAM_WIDTH, CAM_HEIGHT, 0, 0, REDUCED_WIDTH, REDUCED_HEIGHT);

  // And draw the image (full canvas):
  image(img, 0, 0, width, height);
  filter(GRAY);  // Render image() in B&W.
}