/* We need to create a BitmapData object in order to work with pixels of a Bitmap object. We want the wallCanvas to be transparent at the beginning, that's why we use the 0x00ffffff value as a parameter. */
var wallCanvas:BitmapData  = new BitmapData(stage.stageWidth,
stage.stageHeight - 100,
true, 0x00ffffff);
 
//Create a Bitmap object to refer to the BitmapData object
var bitmap:Bitmap = new Bitmap(wallCanvas);
 
//Add the bitmap to the stage
addChild (bitmap);
 
//We listen for the mouse down event on the wall
drawingArea.addEventListener (MouseEvent.MOUSE_DOWN, mouseDownHandler);
 
//We listen for the mouse up event for the whole stage
stage.addEventListener (MouseEvent.MOUSE_UP, mouseUpHandler);
 
//This is the color of the spray
var color:uint;
 
//This is the maximum radius of the spray
var maxRadius:Number;
 
//This is the density of the spray
var density:Number;
 
//This is called when the mouse is down on the wall
function mouseDownHandler (event:MouseEvent):void {
        //Add the EVENT_FRAME so we can draw in each frame
        addEventListener (Event.ENTER_FRAME, onEnterFrame);
}
 
//This is called when the mouse is released
function mouseUpHandler (event:MouseEvent):void {
        //We don't need the EVENT_FRAME, if the mouse is released (nothing to draw)
        removeEventListener (Event.ENTER_FRAME, onEnterFrame);
}
 
//This function is responsible for the whole drawing
function onEnterFrame (event:Event):void {
 
        //Get the size from the sizeSlider
        maxRadius = sizeSlider.value;
 
        /* Get the color from the myColorPicker. We add 0xff000000 to the color to make the pixel visible when we draw it (we draw the pixel in the for loop). */
        color = myColorPicker.selectedColor + 0xff000000;
 
        //Get the density from the densitySlider
        density = densitySlider.value;
 
        /* The density defines how many loops we have. In other words, how many pixels are drawn in each frame. */
        for (var i:int = 0; i < density; i++) {
 
                //Calculate a random angle
                var angle:Number = Math.random() * Math.PI * 2;
 
                // Calculate a random radius for the pixel to be drawn
                var radius:Number = Math.random() * maxRadius;
 
                //Calculate the x and y positions
                var xPos:Number = mouseX + Math.cos(angle) * radius;
                var yPos:Number = mouseY + Math.sin(angle) * radius;
 
                //Draw the pixel.
                wallCanvas.setPixel32 (xPos, yPos, color);
        }
}