Custom ScaleMode class: can't modify FlxG.width / FlxG.height

Hello !
I tried to make a custom BaseScaleMode subclass to disable the scaling, but I can't modify FlxG.width and FlxG.height from my subclass of BaseScaleMode.

class MyScaleMode extends BaseScaleMode {
    override public function onMeasure(width:Int, height:Int) {
        FlxG.width = width;
        FlxG.height = height;
    }
} 

Gives me the error

[ERROR] src/PlayState.hx:18: characters 14-19

 18 |         FlxG.width = width;
    |              ^^^^^
    | This expression cannot be accessed for writing

[ERROR] src/PlayState.hx:19: characters 14-20

 19 |         FlxG.height = height;
    |              ^^^^^^
    | This expression cannot be accessed for writing

(Here is the error with Haxe 5 but I also have the error with Haxe 4).

The FlxG width / height fields are defined like this:

@:allow(flixel.system.scaleModes)
	public static var width(default, null):Int;

I can make a PR adding a method setFlxGWidth / setFlxGHeight in BaseScaleMode to allow this modification, is this a good solution for you ?

Have a nice day !

Start with BaseScaleMode.onMeasure and the FlxG width and height declarations shown in the issue. Check how the scale-mode package is granted access and use the compiler error as the initial validation. Done means a custom BaseScaleMode can update both dimensions without write-access errors while existing scaling behavior remains intact.