AS3 libraries with a startDrag() equivalent that has non-rectangular boundaries (ie: circular)?

I'm just trying to avoi开发者_JS百科d rolling my own dragging functionality. Does anyone know of any libraries out there that have a startDrag() equivalent where you can use, say, a circular radius for the drag bounds, rather than a rectangular box?

(For circular drag area) - What you need to do is:

a) Mouse_down: Store start position. Start listening to Enter_frame.

b) Enter_Frame: Check distance from mouse position of mouse to start pos (use pythagoras)

c) only move your object if the distance is less than x

d) Mouse_up: Stop listening to enterframe

You can use a simple circular collision detection routine, it works out the hit area using the radius of the objects and distance between them. Maybe you will have to manually do this calculation in your onDrag method and stop the drag on collision with the circular bounds calculated below.

        var deltax : Number = targetCentreCoord.x - hitTestCentreCoord.x;
        var deltay : Number = targetCentreCoord.y - hitTestCentreCoord.y;

        //works out if our circles are colliding, distance between the circles inc radius               
        if (((deltax * deltax) + (deltay * deltay)) <= ((((targetRadius) + (hitTargetRadius)) * ((targetRadius) + (hitTargetRadius))))) 
        {
            Log.info("collision occured with " + candidate.name + " target coords " + targetCentreCoord + " candidate coords " + hitTestCentreCoord);
            return true;
        } 
        return false;

Nope, you need to do pixel-perfect collision (or in this case, mouse clicking) in order to do that. By nature all display objects always have rectangular bounds to them. So basically you'd have to do something like this:

mySprite.addEventListener(MouseEvent.MOUSE_DOWN, mousedDown);

function mousedDown(e:MouseEvent):void
{
    //Draw my sprite to a bitmap, then check the bitmap colour at mouseX/mouseY
    uint colour = myBitmap.getPixel32(mouseX, mouseY);
    if(colour != TRANSPARENT){
        //We've actually clicked on the object, drag it
        Sprite(e.currentTarget).startDrag();
    }
}

Note this is just pseudo code, you'll have to figure out what uint value transparent comes up as, and also you'll have to account for where the origin point of the sprite is when drawing to bitmap. Say you have a sprite and the contents are inside, you're going to need to create a Matrix object that has a X and Y offset that are negative .5 times the width of your sprite in order to draw it properly.

This can be done without ENTER_FRAME event. Have a MOUSE_DOWN listener, check boundaries there, if within boundaries, then add a MOUSE_MOVE listener. Also, start out with a MOUSE_UP listener to remove the MOUSE_MOVE listener.