e)
              ctx.lineTo(coordinate.x + size, coordinate.y + size)
              ctx.lineTo(coordinate.x - size, coordinate.y + size)
              ctx.closePath()
              ctx.fill()
            },
            drawExtend: function ({ ctx, point, coordinate, viewport, isActive }) {
              if (isActive) {
                ctx.font = 'normal 20px'
                ctx.fillStyle = '#78ccff'
                ctx.fillText('这是一段测试文字', coordinate.x - 40, coordinate.y + 30)
             