// format: 0xRRGGBB
var red:Float = 0xff0000;
var green:Float = 0x00ff00; // or 0xff00
var blue:Float = 0x0000ff; // or 0xff
var white:Float = 0xffffff;
var black:Float = 0x000000; // or simply 0Utilities
The starling.utils package contains several useful little helpers that shouldn’t be overlooked.
Colors
In both conventional OpenFL and Starling, colors are specified in hexadecimal format. Here are a few examples:
The Color class contains a list of named color values; furthermore, you can use it to easily access the components of a color.
var purple:UInt = Color.PURPLE; (1)
var lime:UInt = Color.LIME;
var yellow:UInt = Color.YELLOW;
var color:UInt = Color.rgb(64, 128, 192); (2)
var red:Int = Color.getRed(color); // -> 64 (3)
var green:Int = Color.getGreen(color); // -> 128
var blue:Int = Color.getBlue(color); // -> 192| 1 | A few common colors are predefined. |
| 2 | Any other color can be created with this method. Just pass the RGB values to this method (range: 0 - 255). |
| 3 | You can also extract the integer value of each channel. |
Angles
Starling expects all angles in radians (different to OpenFL, which uses degrees in some places and radians in others).
To convert between degrees and radians, you can use the following simple functions defined on the MathUtil class.
var degrees:Float = MathUtil.rad2deg(Math.PI); // -> 180
var radians:Float = MathUtil.deg2rad(180); // -> PIStringUtil
You can use the format method to format Strings in .Net/C# style.
StringUtil.format("{0} plus {1} equals {2}", 4, 3, "seven");
// -> "4 plus 3 equals seven"The same class also contains methods that trim whitespace from the start and end of a string — a frequent operation whenever you need to process user input.
StringUtil.trim(" hello world\n"); // -> "hello world"SystemUtil
It’s often useful to find out information about the environment an app or game is currently executed in. The SystemUtil contains some methods and properties helping with that task.
SystemUtil.isDesktop; // desktop or mobile?
SystemUtil.isApplicationActive; // in use or minimized?
SystemUtil.platform; // WIN, MAC, LNX, IOS, ANDMathUtil
While that class is mainly designed to help with some geometric problems, it also contains some very useful helper methods for common mathemetical calculations:
var inside:Float = MathUtil.clamp(-5, 1, 10); (1)| 1 | Move the number (first argument) into a specific range. Result: 1 |
Pooling
Now that we touched the topic of temporary objects, it’s the perfect time to introduce you to the Pool class.
Experienced Haxe developers know that any object allocation comes at a price: the object needs to be garbage collected later. This happens completely behind the scenes; you won’t even notice it most of the time.
However, when the cleanup process takes up too much time, your app will freeze for a short moment. If that happens often, it quickly becomes a nuisance to your users.
One tactic to avoid this problem is to recycle your objects and use them repeatedly. For example, classes like Point and Rectangle are often just needed for a short moment: you create them, fill them with some data, and then throw them away.
From now on, let Starling’s Pool class handle those objects.
var point:Point = Pool.getPoint(); (1)
doSomethingWithPoint(point);
Pool.putPoint(point); (2)
var rect:Rectangle = Pool.getRectangle(); (1)
doSomethingWithRectangle(rect);
Pool.putRectangle(rect); (2)| 1 | Get an object from the pool. That replaces calling new on the class. |
| 2 | Put it back into the pool when you do not need it any longer. |
The class also supports Vector3D, Matrix, and Matrix3D, in a similar style.
| Always make sure that the get and put-calls are balanced. If you put too many objects into the pool and never retrieve them, it will fill up over time, using more and more memory. |
Furthermore …
The starling.utils package contains more helpers than I can possibly list here.
For a complete list of methods and classes, refer to the API Reference.
It will definitely pay off to take a look!