docs: public void updateBitmapShader() {
  		if (image == null)
  			return;
  
  		shader = new BitmapShader(image, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
  
  		if(canvasSize != image.getWidth() || canvasSize != image.getHeight()) {
  			Matrix matrix = new Matrix();
  			float scale = (float) canvasSize / (float) image.getWidth();
  			matrix.setScale(scale, scale);
  			shader.setLocalMatrix(matrix);
  		}
  	}