Oricat Central

With the introduction of flash 8 we had the ability to manipulate bitmaps with filters. Flash player 9 optimises the calculations of these filters and flash player 10 promises to preform these calculations on the clients graphics hardware. I believe that there are many non-graphic applications of these technologies such as path finding.

In the example below I have investigated using a simple convolution filter to expand the area of colour by one pixel. Repetitively applying this filter allowed me to fill a maze like pouring a can of paint in a mouse maze. Once the destination is reached it is a simple process to back track and evaluate the route taken. This route will be the fastest possible.

maze2.zip

This code draws with a predefined brush “brush” onto the screen when the mouse is down and moving. A colour picker allows you to modify the colour. 

import flash.display.BitmapData;
import flash.geom.Rectangle;
import flash.geom.Matrix;
import flash.geom.ColorTransform
import fl.controls.ColorPicker;
import fl.events.ColorPickerEvent;
var ct:ColorTransform = new ColorTransform();
var myBitmapData:BitmapData = new BitmapData(200,200, false, 0xFFCCCCCC);
var myBitmap:Bitmap = new Bitmap(myBitmapData,”auto”,false);
var canvas:Sprite = new Sprite();
var size:Number = brush.width;
var offSet:Number = Math.floor(size/2);
var translateMatrix:Matrix = new Matrix()
var brushData:BitmapData = new BitmapData(int(brush.width), int(brush.height), true, 0×00FF0000);
init();
function init(){
 brushData.draw(brush, new Matrix, new ColorTransform, “normal”, brushData.rect, false);
 brushColour.addEventListener(ColorPickerEvent.CHANGE,updateColour);
 canvas.addChild(myBitmap);
 addChild(canvas)
 canvas.addEventListener(MouseEvent.MOUSE_DOWN, startDraw);
 canvas.addEventListener(MouseEvent.MOUSE_UP, endDraw);
 canvas.addEventListener(MouseEvent.ROLL_OUT, endDraw);
 brushColour.selectedColor = 0xFFFFFF;
}
function updateColour(e:Event){
 ct.color = brushColour.selectedColor;
}
function startDraw(event:MouseEvent):void {
 canvas.addEventListener(MouseEvent.MOUSE_MOVE, drawPoint);
}
function endDraw(event:MouseEvent):void {
 canvas.removeEventListener(MouseEvent.MOUSE_MOVE, drawPoint);
}
function drawPoint(event:MouseEvent):void {
 translateMatrix.tx = canvas.mouseX-offSet;
 translateMatrix.ty = canvas.mouseY-offSet;
 myBitmapData.draw(brushData,translateMatrix,ct,null,null,false)
}

This code draws blue blocks onto the screen when the mouse is down and moving.

import flash.display.BitmapData;
import flash.geom.Rectangle;

var myBitmapData:BitmapData = new BitmapData(200,200, false, 0xFFCCCCCC);
var myBitmap:Bitmap = new Bitmap(myBitmapData,”auto”,false);
var maze:Sprite = new Sprite();
var size:Number = 10;
var offSet:Number = Math.floor(size/2);

maze.addChild(myBitmap);
addChild(maze)
maze.addEventListener(MouseEvent.MOUSE_DOWN, startDraw);
maze.addEventListener(MouseEvent.MOUSE_UP, endDraw);
maze.addEventListener(MouseEvent.ROLL_OUT, endDraw);

function startDraw(event:MouseEvent):void {
 maze.addEventListener(MouseEvent.MOUSE_MOVE, drawPoint);
}
function endDraw(event:MouseEvent):void {
 maze.removeEventListener(MouseEvent.MOUSE_MOVE, drawPoint);
}
function drawPoint(event:MouseEvent):void {
 var rect:Rectangle = new Rectangle(maze.mouseX-offSet, maze.mouseY-offSet,size,size)
 myBitmapData.fillRect(rect,0xFF0000FF);
}