Scale

You can stretch and squash the graphic of a FlxSprite by using it’s scale property.

Note: scale does not affect the sprite’s dimensions or hitbox, only the graphic.

// sprite will be scaled on the x-axis by 4
sprite.scale.x = 4;

Demonstration

Source

View Source on GitHub 

package;

import flixel.FlxG;
import flixel.FlxSprite;
import flixel.FlxState;

class PlayState extends FlxState
{
	var sprite:FlxSprite;
	var scaleDir:Int = 1;
	
	override function create()
	{
		super.create();
		
		sprite = new FlxSprite("assets/sprite.png");
		sprite.screenCenter();
		sprite.scale.set(0.5, 2);
		add(sprite);
	}
	
	override function update(elapsed:Float)
	{
		sprite.scale.x += elapsed * 5 * scaleDir;
		sprite.scale.y -= elapsed * 5 * scaleDir;
		
		if (sprite.scale.x >= 4 || sprite.scale.x <= 0.5 || sprite.scale.y >= 4 || sprite.scale.y <= 0.5)
			scaleDir *= -1;
			
		super.update(elapsed);
	}
}