Processing: Creative Coding and Computational Art

In the last example, I created an array of anonymous PImages using the get() command.
This syntax may look odd, as I’m relying on the returned values of the get() calls (which
are PImages) to populate the arrays. You’ll remember that arrays can be instantiated a few
different ways; one such way is to declare and populate the array at the same time, with
the values specified between curly braces, as illustrated in the example.
A more ambitious but interesting thing to do with get() could be to write your own
image-encrypting sketch. The simple encryption procedure will collect the image as
sequential fragments and then re-create the image, reordering the image. I’ll keep it really
simple and just reverse the order of the fragments. You need to use an image of 600
(width) ✕ 400 pixels to run the example (see Figure 10-27):
//Simple Image Encryption
int ENCRYPTION_LOW = 0;
int ENCRYPTION_MEDIUM = 1;
int ENCRYPTION_HIGH = 2;
int ENCRYPTION_VERY_HIGH = 3;
void setup(){
size(600, 400);
PImage img = loadImage("changsha.jpg");
image(img, 0, 0);
// call the fragment function
fragment(ENCRYPTION_HIGH);
}
void fragment(int encryptionLevel){
int fragW = 0;
int fragH = 0;
int frags = 0;
// set size of blocks
switch(encryptionLevel){
case 0:
fragW = width/2;
fragH = height/2;
frags = 4;
break;
case 1:
fragW = width/4;
fragH = height/4;
frags = 16;
break;
case 2:
fragW = width/8;
fragH = height/8;
frags = 64;
break;
case 3:
COLOR AND IMAGING
437
10