ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Using the drawing API
The lineGradientStyle() method works similarly to beginGradientFill() except that in addition to defining the
gradient, you must specify the thickness of the stroke using the lineStyle() method before drawing. The following
code draws a box with a red, green, and blue gradient stroke:
var myShape:Shape = new Shape();
var gradientBoxMatrix:Matrix = new Matrix();
gradientBoxMatrix.createGradientBox(200, 40, 0, 0, 0);
myShape.graphics.lineStyle(5, 0);
myShape.graphics.lineGradientStyle(GradientType.LINEAR, [0xFF0000, 0x00FF00, 0x0000FF], [1,
1, 1], [0, 128, 255], gradientBoxMatrix);
myShape.graphics.drawRect(0, 0, 200, 40);
this.addChild(myShape);
For more information on the Matrix class, see “Using Matrix objects” on page 215.
Using the Math class with drawing methods
Flash Player 9 and later, Adobe AIR 1.0 and later
A Graphics object draws circles and squares, but can also draw more complex forms, particularly when the drawing
methods are used in combination with the properties and methods of the Math class. The Math class contains
constants of common mathematical interest, such as Math.PI (approximately 3.14159265...), a constant for the ratio
of the circumference of a circle to its diameter. It also contains methods for trigonometry functions, including
Math.sin(), Math.cos(), and Math.tan() among others. Drawing shapes using these methods and constants create
more dynamic visual effects, particularly when used with repetition or recursion.
Many methods of the Math class expect circular measurements in units of radians rather than degrees. Converting
between these two types of units is a common use of the Math class:
var degrees = 121;
var radians = degrees * Math.PI / 180;
trace(radians) // 2.111848394913139
The following example creates a sine wave and a cosine wave, to highlight the difference between the Math.sin() and
Math.cos() methods for a given value.
var sinWavePosition = 100;
var cosWavePosition = 200;
var sinWaveColor:uint = 0xFF0000;
var cosWaveColor:uint = 0x00FF00;
var waveMultiplier:Number = 10;
var waveStretcher:Number = 5;
var i:uint;
for(i = 1; i < stage.stageWidth; i++)
{
var sinPosY:Number = Math.sin(i / waveStretcher) * waveMultiplier;
var cosPosY:Number = Math.cos(i / waveStretcher) * waveMultiplier;
}
graphics.beginFill(sinWaveColor);
graphics.drawRect(i, sinWavePosition + sinPosY, 2, 2);
graphics.beginFill(cosWaveColor);
graphics.drawRect(i, cosWavePosition + cosPosY, 2, 2);
Last updated 6/6/2012
230