ActionScript for Flash MX: The Definitive Guide, Second Edition

MovieClip.attachMovie() Method

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not affect their _alpha properties. That is, if we have a clip, square, that contains another

clip,

circle, and we set square._alpha to 50, then circle will be 50% transparent on-screen

but will have an

_alpha of 100. However, if both circle and its parent clip (square) set their

_alpha properties, the effect is cumulative. If each have an _alpha of 50, circle will appear

25% opaque (75% transparent) on-screen. Therefore, don’t set the

_alpha of nested clips

unless they are supposed to have different transparencies from any siblings. To keep it

simple, set the

_alpha of the parent clip instead.

Usage

Note that setting the _alpha of a movie clip affects the aa property of the object returned by

Color.getTransform().

Example

ball_mc._alpha = 60; // Make ball_mc partially transparent

ball_mc._alpha = 0; // Make ball_mc invisible

The following clip event handler makes theClip_mc more transparent as the mouse moves

down the screen:

theClip_mc.onEnterFrame = function () {

this._alpha = 100 - (_root._ymouse / 400) * 100;

}

See Also

The Color class; MovieClip._visible

MovieClip.attachMovie() Method

create a new movie clip instance from an exported Library symbol

Flash 5; initObject and return value added in Flash 6

mc.attachMovie(symbolIdentifier ...