//使用的canvans绘制的三角形 drawArrow(){ var canvas = document.createElement('canvas');//创建一个元素 canvas.width = 10; canvas.height = 5; var ctx = canvas.getContext('2d'); this.draw(ctx,0,0,10,0,5,5,'#ecc818','fill'); return canvas; } draw(ctx,x1, y1, x2, y2, x3