apply method

@override void apply(void draw(Canvas), Canvas canvas)

Applies visual effect while drawing on the canvas.

The default implementation is a no-op; all other non-trivial decorators transform the canvas before drawing, or perform some other adjustments.

This method must be implemented by the subclasses, but it is not available to external users: use applyChain instead.

Implementation

@override
void apply(void Function(Canvas) draw, Canvas canvas) {
  _transformMatrix ??= _makeTransform();
  _paint ??= _makePaint();

  canvas.saveLayer(null, _paint!);
  canvas.translate(base.x + _shift, base.y);
  canvas.transform(_transformMatrix!.storage);
  draw(canvas);
  canvas.restore();
  draw(canvas);
}