hi,

i want to fade in the .png documents
& i don't know how.



help a designstudent..... big thanks




________________________________________________________

PImage karteohne;
PImage karte;
PImage kartegelb;


PImage kreuz;

String k1;
String k2;

float bx;
float by;
int bs = 1266;
int bd = 623;
boolean bover = false;
boolean locked = false;
float bdifx = 0.0;
float bdify = 0.0;


void setup()
{
 size(640, 480);
 frameRate (30);
 karteohne = loadImage("kartenormal.png");
 kartegelb = loadImage("kartegelb.png");
 karte = loadImage("karteinfarbe1 Kopie.png");
 
 kreuz = loadImage("kreuzpfeil.png");
 
 
 bx = width/10.0;

 by = height/10.0;
imageMode(CORNER);
}

void draw()
{
background(0);


 
 // Test if the cursor is over the box
 if (mouseX > bx-bs && mouseX < bx+bs &&
     mouseY > by-bd && mouseY < by+bd) {
   bover = true;  
   if(!locked) {

   }
 } else {
 
 
 //  bover = false;
 }
 
 // Draw the box
   image (karteohne , bx, by, bs, bd);
 
 if (k1=="an") {
 image (karte , bx, by, bs, bd);
 }
 
  if (k2=="an") {

 image (kartegelb, bx, by, bs, bd);
 }
// rect(bx, by, bs, bs);
    fill (150);
 noStroke();
 rect (0, 450, 640, 30);
 fill (255);
 rect (20, 455, 20, 20);
 rect (50, 455, 20, 20);
 
           if (((k1 == "an") &&(checkMouseOverButton (0, 0, 640, 450)==1)) || ((k2 == "an") &&(checkMouseOverButton (0, 0, 640, 450)==1)))
 {
      cursor(CROSS);
    }else {
      cursor(ARROW);
    }
}


void mousePressed() {
 if(bover) {
   locked = true;

 } else {
   locked = false;
 }
 bdifx = mouseX-bx;
 bdify = mouseY-by;
 
    if (checkMouseOverButton (20, 455, 20, 20)==1){
k1 = "an";
k2 = "aus";}


   

     if (checkMouseOverButton (50, 455, 20, 20)==1){
k2 = "an";
k1 = "aus";}


}

void mouseDragged() {
 if(locked) {
   bx = mouseX-bdifx;
   by = mouseY-bdify;
 }
}


int checkMouseOverButton (int xpos, int ypos, int breite, int hoehe) {
 if ((mouseX>xpos) && (mouseX<xpos+breite) && (mouseY>ypos) && (mouseY<ypos+hoehe)) {
   return 1;
 }
 else {
   return 0;
 }
}