How to Snap linestyle in Actionscript 3.0?

Question

Hai, i am a newbie to actionscript.

i am trying to make a brush tool in actionscript 3, where kids can paint colors inside a circle using the brush. i have achieved this using linestyle. Now i want the brush to snap the color when the kid is about to complete(say when they are 95% to complete the painting). How do i know how much the kid has painted on the circle?

Thanks

Answer 1

How do i know how much the kid has painted on the circle?

You can:

• make your circles and other shapes Sprites to get separate container
• render them into bitmap and count number of non-transparent pixels in it (you should know what number corresponds to 100%)
• since counting pixels is heavy operation (can take hundreds of milliseconds, depending of shape size), you don't want to run it on every frame. I suggest to do it on MOUSE_UP, right after kid finishes next stroke.

How to count pixels:

function countPixels(shape:DisplayObject):int
{
    var bd:BitmapData = new BitmapData(shape.width, shape.height);
    bd.draw(shape);

    //here you get sequence of ARGB-packed colors in vector
    var pixels:Vector.<uint> = bd.getVector(bd.rect);

    //AFAIK, fastest method to traverse vector is 'for' loop
    var pixel:uint;
    var filledCount:int = 0;
    for (var i:int = pixels.length - 1; i >= 0; i--)
    {
        pixel = pixels[i];
        //pixel is 32-bit ARGB color value, test upper 8 bits (alpha):
        if ((pixel >> 24) > 0) filledCount++;
    }
    return filledCount;
}

Run this on filled shape to get total pixel count to compare with.
After pixelCount reaches 95%, you can clear kid's drawing and show filled shape.