März 5, 2012

As in loadPixel - 2nd example the picture is modified by the horizontal and vertical mouse movements. Additionally, an alpha parameter in the color allows color mixing/overlaying which creates a painting-like effect. The picture can be reset using the space bar.

PImage img;

int res =5;
int res2 = res;
int rectSize = 4;
boolean flag = true;

long timeStamp = 0;
boolean onOff = false;
int pause = 5;

void setup() {
 background(255);
 rectMode(CENTER);
 size(640, 480);
 img = loadImage("ducks.jpg");
 noStroke();
 smooth();
}
void draw() {

 loadPixels();
 img.loadPixels();

//map resolution bewtween 1..80 from mouse
 res = (int)map(mouseX, 0, width, 1, 80);
 res2 = (int)map(mouseY, 0, height, 1, 80);
 if (millis() - timeStamp > pause) {
 // We must also call loadPixels() on the PImage since we are going to read its pixels. img.loadPixels();
 for (int x = 0; x < img.width; x+=res2) {
 for (int y = 0; y < img.height; y+=res2) {

// Calculate the 1D pixel location
 int loc = x + y*img.width;

// Get the R,G,B values from image
 float r = red(img.pixels[loc]);
 float g = green(img.pixels[loc]);
 float b = blue(img.pixels[loc]);
 fill(r, g, b, 10);

//draw a growing shape (size grows from 1 to 4 to 1)
 if (flag)
 rectSize++;
 if (!flag)
 rectSize--;
 if (rectSize>=res)
 flag = false;
 if (rectSize<=0)
 flag = true;
 rect(x, y, rectSize, rectSize);
 }
 }
 timeStamp = millis();
 }
}
//reset with space bar
void keyPressed() {
 if (key==32) {
 background(255);
 }
}