canvas設置陰影

canvas設置陰影

1. 屬性

   shadowOffsetX = float           陰影向右偏移量
   shadowOffsetY = float           陰影向下偏移量
   shadowBlur = float              陰影模糊效果
   shadowColor = color             陰影顏色

2. 設置陰影

   const canvas = document.getElementById('canvas');
   const ctx = canvas.getContext('2d');
   
   ctx.shadowOffsetX = 10;
   ctx.shadowOffsetY = 10;
   ctx.shadowBlur = 10;
   ctx.shadowColor = 'rgba(0, 0, 0, 0.5)';
   
   ctx.fillRect(25, 25, 100, 100);