How to Draw in a Flash movie

1. Create a new document and set the size to 400 x 300 (“Frame” > “Frame Size”)
2. Set “Frame 1″ to “Stop” (“Frame” > “Frame Delay” and check “Stop”, click OK)
3. Draw the pen cursor using the Shape tool. Select both shapes and choose “Edit” > “Convert to Sprite”. Quit the sprite with “Esc” key.
4. Select the sprite and choose “Item” > “Placement Properties”. Check “ActionScript Target” and rename the item to “PenItem”:
5. Choose “Frame” > “ActionScript” and paste the following code:

   _root.createEmptyMovieClip("myLine", 0);  // create blank movie to draw on
   
   function moveroutine() // this moves the pen to follow the mouse
   {
    PenItem._x = _xmouse;
    PenItem._y = _ymouse - PenItem._height;
   }
   
   function drawroutine() // this draws the line when the button is pressed
   {
     myLine.lineTo(_xmouse, _ymouse);
     moveroutine();
   }
   
   _root.onMouseMove = moveroutine; // initially we only move the pen 
   
   _root.onMouseDown = function() // when the user clicks the button
   {
      myLine.moveTo(_xmouse, _ymouse);
      myLine.lineStyle(2, 0xff0000, 100);
      _root.onMouseMove = drawroutine;
   }
   
   _root.onMouseUp = function() // when the button is released
   {
      _root.onMouseMove = moveroutine;
   }
   

Hit F9 to preview the movie.

NOTE: You have to target Flash Player 6 or above.

Download source project here (4 kb)