int k,i;
int dx,dy;
float speed;
float angle;

void setup(){
  size(300,200);
  background(255,255,255);
  k =1;
}

void loop(){

  dx = mouseX - pmouseX;
  dy = mouseY - pmouseY;
  speed = sqrt(dx*dx + dy*dy);
  angle = degrees(atan2(dx,dy));

  if(mousePressed == true){
    if(k == 1){
      for(int i = 0; i < width; i += 10){
        stroke(i/height,i,speed/width,speed);
        strokeWeight(speed/4);
        line(mouseX-angle,pmouseY,speed,angle);
      }
    }
    if(k == 2){
      for(int i = 0; i < 200; i += 20){
        strokeWeight(speed/2);
        stroke(speed/2,speed/width,i,speed);
        line(pmouseX,pmouseY,angle,-angle);
      }
    }
    if(k == 3){
      for(int i = 0; i < width; i += 10){
        stroke(255,255,255,speed);
        line(pmouseX,pmouseY,angle,-angle);
      }
    }
    if(k == 4){
      for(int i = 0; i < width; i += 10){
        stroke(speed/width,i,speed/width,speed);
        ellipse(pmouseX,pmouseY,angle,-angle);
      }
    }
    if(k == 5){
      for(int i = 0; i < width; i += 10){
        stroke(speed/width,i,speed/width,speed);
        line(pmouseX,pmouseY,angle,-angle);
      }
    }
  }
}

void keyPressed(){

  if(key == '-'){
    background(255,255,255);
  }
  if(key == '1'){
    k = 1;
  }
  if(key == '2'){
    k = 2;
  }
  if(key == '3'){
    k = 3;
  }
  if(key == '4'){
    k = 4;
  }
  if(key == '5'){
    k = 5;
  }
  if(key == 's'){
    saveFrame();
  }
}