My english is not very well,so ,I will do my best to describe it clearly:

The picture can move fluently from one side to the other side in the following programe,but if I imported a movie ,it can not move fluently.I don't know what the reason is on earth?             I really appreciate for your any help.

I have another question ,which function can be used to take picture in a programe?

float px=0;

float  py;

float s=1;

 

void setup(){

  size(600,400);

  rectMode(CENTER);

   stroke(1);

  smooth();

  py=random(0,height);

}

void draw(){

  background(123,123,38);

   fill(23,255,50);

 if(px>680){

    px=0;

    py=random(0,height);

  }

  rect(px,py,80,80);

  px=px+s;//指定移动速度

 

    if(mousePressed&&mouseX<px+40&& mouseX> px - 40&&mouseY<py+40&&mouseY>py-40){

    px=mouseX;

    py=mouseY;//与鼠标互动

  }

 }