Quickreference: flipping DisplayObjects

This one flips DisplayObjects on a vertical or horizontal axe.

public static function flipHorizontal(obj:DisplayObject):void {
    var m:Matrix = obj.transform.matrix;
    m.transformPoint(new Point(obj.width * .5, obj.height * .5));
    m.tx = (m.a > 0)?obj.width + obj.x:obj.x - obj.width;         
    m.a = -1 * m.a;
    obj.transform.matrix = m;
}
       
public static function flipVertical(obj:DisplayObject):void {
    var m:Matrix = obj.transform.matrix;
    m.transformPoint(new Point(obj.width * .5, obj.height * .5));
    m.ty = (m.d > 0)?obj.y + obj.height:obj.y - obj.height;
    m.d = -1 * m.d;
    obj.transform.matrix = m;
}

Basic random functions

Here are some really basic (but useful) functions that returns random stuff…

The really basic one, is built in the Flash api and it returns a Number between 0 and 1:

var n:Number = Math.random();

A number in  a range

Sometime is more useful to have a random number in a different range, let’s say between 15 and 45, instead of 0 and 1.

public static function randNumber(max:Number = 1, min:Number = 0):Number {
    return Math.random() * (max - min) + min;
}

Random int

and what if we don’t need decimals? Round’em!

public static function randInt(max:Number = 1, min:Number = 0):int {
    return Math.round(Math.random() * (max - min) + min);
}

Random boolean

True or false? Flip a coin.

public static function bool():Boolean {
    return (Math.round(Math.random()) == 0);
}

Random sign

-1 or 1; Useful when you have to random select random rotation verse, for example, -1*45 or 1*45, rotates counterclockwise or clockwise.

public static function sign():Number {
    return (Math.round(Math.random()) == 0):-1:1;
}

Random color

Really useful when drawing debug shapes on screen..

public static function color():uint {
    return Math.random() * 0xFFFFFF;
}

Random point

Inside an area. I like to use the flash.geom.Rectangle struct to describe an area, more than using 4 parameters (Flash api are quite inconsistent about this choice)

public static function point(area:Rectangle):Point {
    return new Point(randInt(area.x, area.x + area.width), randInt(area.y, area.y + area.height));
}

Quickreference: display elements in a circle

How to display elements in a circle? A small function to do that is:


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Parameters are:

  • items: the items to be displayed a a circle
  • center: the center of the circle
  • distance: the distance from the center
  • initialAngle: the angle of the first item. Zero means that the item wil be aligned orizontally with the center, on his right.

Here’s an example:

Tweening global volume in flash

Just a quick reminder on how to shut up the master volume on a flash project. I like a smooth tween to the silence, so I’m using the TweenLite libraries.


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The trick here is to tween the volume property of a throw-away SoundTransform object, and on each step of the Tween apply that object as the SoundMixer.soundTransform Object, with an helper function. Note that I’m not going to write the function inside the TweenLite’s partameter list, as it is gross and dirty.

Tweening the volume back to 1 is so easy that I’m not writing it, to not offend anyone.

Quick reference: Drawing a scaled object in Actionscript

Just as a quick reference, since I usually forgot each time how to do it.

Assume to have a DisplayObject obj, you want to draw in a Bitmap a scaled snapshot of that object.

Just like when you are drawing thumbs.


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