Editing Yesterday

Useful things to refer to.

*[[Variables]]
*[[If statements]]
*[[Coordinates]]
*[[Keycodes]]

The [[API|API page]] has a list of some of the functions you can use such as 

*[[API#setColour.28colourValue.29.3B|setColour()]]
*[[API#clear();|clear()]]
*[[API#fillCircle_.28x.2C_y.2C_radius.29.3B|fillCircle()]] .
*[[API#keyIsDown.28keyCode.29|keyIsDown()]] .


<edcode>var cx=320;
var cy=240;

var maryx=200;
var maryy=240;

var power=0.1;
var penSize=4;

var lastx=cx;
var lasty=cy;

function move() {    
   var dx = cx-lastx;
   var dy = cy-lasty;

   lastx=cx;
   lasty=cy;
  
   cx=cx+dx;
   cy=cy+dy;
  
    // the arrow keys have key codes 37,38,39 and 40
  
   if (keyIsDown(38)) {
     cy-=power; 
   }

   if (keyIsDown(40)) {
     cy+=power;  
   }

   if (keyIsDown(37)) {
     cx-=power;
   }

   if (keyIsDown(39)) {
     cx+=power;
   }  
  
   //keep cx onscreen
   if (cx>640 ) {
     cx=640;
   }
  
   if (cx <0) {
     cx=0; 
   }
  
  //keep cy onScreen
   if (cy>480) {
     cy=480;
   }
    
   if (cy <0) {
     cy=0;
   }
  
   //move mary towards cx,cy
   if (maryy < cy) {
     maryy+=0.3;
   }
  
   if (maryy > cy) {
     maryy-=0.3;
   }
  
   if (maryx <cx) {
     maryx+=0.3;
   }
  
  if (maryx > cx) {
    maryx-=0.3;
  }
  
   if (keyIsDown(32)) {
     clear();
   }
  
    
   setColour("purple");
   fillCircle(cx,cy,penSize);

   setColour("red");
   fillCircle(maryx,maryy,penSize);
  
}

run(move);
</edcode>