/** * Transparency.  *  * Move the pointer left and right across the image to change * its position. This program overlays one image over another  * by modifying the alpha value of the image with the tint() function.  */PImage a, b;float offset;void setup() {  size(200, 200);  a = loadImage("construct.jpg");  // Load an image into the program   b = loadImage("wash.jpg");   // Load an image into the program   frameRate(60);}void draw() {   image(a, 0, 0);  float offsetTarget = map(mouseX, 0, width, -b.width/2 - width/2, 0);  offset += (offsetTarget-offset)*0.05;   tint(255, 153);  image(b, offset, 20);}