Fabricjs 橡皮擦、取消橡皮擦、繪畫、選擇和噴霧

    case "select": //選擇
      canvas.isDrawingMode = false //取消繪畫模式
      break;
    case "erase": //橡皮擦
      canvas.freeDrawingBrush = new fabric.EraserBrush(canvas);
      canvas.freeDrawingBrush.width = 10;
      canvas.isDrawingMode = true;
      break;
    case "undo": //取消橡皮擦
      canvas.freeDrawingBrush = new fabric.EraserBrush(canvas);
      canvas.freeDrawingBrush.width = 10;
      canvas.freeDrawingBrush.inverted = true //倒轉的
      canvas.isDrawingMode = true
      break;
    case "draw": //繪畫
      canvas.freeDrawingBrush = new fabric.PencilBrush(canvas);
      canvas.freeDrawingBrush.width = 5;
      canvas.isDrawingMode = true;
      break;
    case "spray": //噴霧器
      canvas.freeDrawingBrush = new fabric.SprayBrush(canvas);
      canvas.freeDrawingBrush.width = 35
      canvas.isDrawingMode = true;

代碼是直接復制的，重點是canvas的屬性值