uniapp实现签名功能

html：

<canvas style="width: 300px; height: 400px;" canvas-id="myCanvas" @touchstart="canvasStart($event)" @touchmove="canvasMove($event)">canvas>

JS：

	data() {
		return {
			startX: 0,
			startY: 0
		}
	},
	methods: {
		canvasStart(event) {
			this.startX = event.touches[0].x
			this.startY = event.touches[0].y
		},
		canvasMove(event) {
			event.preventDefault()
			const ctx = uni.createCanvasContext('myCanvas')				
			ctx.beginPath()
			ctx.moveTo(this.startX, this.startY)
			ctx.lineTo(event.touches[0].x, event.touches[0].y)
			ctx.stroke()
			ctx.draw(true)
			this.startX = event.touches[0].x
			this.startY = event.touches[0].y
		}
	}