<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="vue.js"></script>
<style>
#canvas {
border: 1px dotted black;
position: relative;
top: 20px;
left: 20px;
}
</style>
</head>
<body>
<div id="app">
<canvas id="canvas" ref="canvas" @touchstart="touchstart" @touchmove="touchmove" @touchend="touchend"></canvas>
</div>
<script>
let x, y = 0
let canvas_width = 320
let canvas_height = 180
let vm = new Vue({
el: "#app",
data: {
isDrawing: false,
qm_count: 0,
qm_data: null,
qm_image_url: '',
context: null,
rect: null,
},
methods: {
touchstart(e) {
e.preventDefault();
x = e.changedTouches[0].clientX - this.rect.left;
y = e.changedTouches[0].clientY - this.rect.top;
this.isDrawing = true;
},
touchmove(e) {
e.preventDefault();
this.qm_count++
if (this.isDrawing === true) {
this.drawLine(x, y, e.changedTouches[0].clientX - this.rect.left, e.changedTouches[0].clientY - this.rect.top);
x = e.changedTouches[0].clientX - this.rect.left;
y = e.changedTouches[0].clientY - this.rect.top;
}
},
touchend(e) {
e.preventDefault();
if (this.isDrawing === true) {
this.drawLine(x, y, e.changedTouches[0].clientX - this.rect.left, e.changedTouches[0].clientY - this.rect.top);
x = 0;
y = 0;
this.isDrawing = false;
}
},
drawLine(x1, y1, x2, y2) {
this.context.beginPath();
this.context.strokeStyle = 'black';
this.context.lineWidth = 5;
this.context.moveTo(x1, y1);
this.context.lineTo(x2, y2);
this.context.stroke();
this.context.closePath();
},
clear_canvas() {
this.qm_data = null
this.qm_image_url = ''
this.context.fillStyle = "rgb(128, 128, 128)";
this.context.fillRect (0, 0, canvas_width, canvas_height);
this.qm_count = 0
},
},
mounted() {
let canvas = this.$refs.canvas
canvas.width = canvas_width
canvas.height = canvas_height
this.context = canvas.getContext('2d')
this.rect = canvas.getBoundingClientRect()
this.clear_canvas()
}
})
</script>
</body>
</html>
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