畫筆為平滑的邊緣/漸變形狀添加更多定義或混合 brush to add more definition to smooth edges/gradient shapes or to blend
在形狀的邊框邊緣內拖動畫筆以向外擴展紋理,向外拖動畫筆可使紋理擦除邊緣
drag brush within border edge of shape to expand grain outwards and outside to make grain erase the edge