这篇文章主要为大家详细介绍了小程序实现手写签名,文中示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
本文实例为大家分享了小程序实现手写签名的具体代码,供大家参考,具体内容如下
方法不是我自己写的,但是也忘记最初的原版出自于哪里了,不过搜索下来就是大同小异,我就附上自己实测有效的!可以直接拿了用,只不过最后保存手写签名图片的方法自己写就可以了,用的就是小程序的图片上传方法。
wxml文件:
手写板
.wxss
/* pages/mine/sign.wxss */ page { background: #fbfbfb; height: auto; overflow: hidden; } .wrapper { width: 100%; height: 95vh; margin: 30rpx 0; overflow: hidden; display: flex; align-content: center; flex-direction: row; justify-content: center; font-size: 28rpx; } .handWriting { background: #fff; width: 100%; height: 95vh; } .handRight { display: inline-flex; align-items: center; } .handCenter { border: 4rpx dashed #e9e9e9; flex: 5; overflow: hidden; box-sizing: border-box; } .handTitle { transform: rotate(90deg); flex: 1; color: #666; } .handBtn button { font-size: 28rpx; } .handBtn { height: 95vh; display: inline-flex; flex-direction: column; justify-content: space-between; align-content: space-between; flex: 1; } .delBtn { position: absolute; top: 52rpx; left: 0rpx; transform: rotate(90deg); color: #666; } .delBtn image { position: absolute; top: 13rpx; left: 25rpx; } .subBtn { position: absolute; bottom: 52rpx; left: -3rpx; display: inline-flex; transform: rotate(90deg); background: #008ef6; color: #fff; margin-bottom: 30rpx; text-align: center; justify-content: center; } .black-select { width: 60rpx; height: 60rpx; position: absolute; top: 30rpx; left: 25rpx; } .black-select.color_select { width: 90rpx; height: 90rpx; top: 30rpx; left: 10rpx; } .red-select { width: 60rpx; height: 60rpx; position: absolute; top:140rpx; left:25rpx; } .red-select.color_select { width: 90rpx; height: 90rpx; top: 120rpx; left: 10rpx; }
.js 方法基本都有标注
// pages/mine/sign.js var app = getApp() Page({ data: { userInfo:{}, form:{}, canvasName: 'handWriting', ctx: '', canvasWidth: 0, canvasHeight: 0, transparent: 1, // 透明度 selectColor: 'black', lineColor: '#1A1A1A', // 颜色 lineSize: 1.5, // 笔记倍数 lineMin: 0.5, // 最小笔画半径 lineMax: 4, // 最大笔画半径 pressure: 1, // 默认压力 smoothness: 60, //顺滑度,用60的距离来计算速度 currentPoint: {}, currentLine: [], // 当前线条 firstTouch: true, // 第一次触发 radius: 1, //画圆的半径 cutArea: { top: 0, right: 0, bottom: 0, left: 0 }, //裁剪区域 bethelPoint: [], //保存所有线条 生成的贝塞尔点; lastPoint: 0, chirography: [], //笔迹 currentChirography: {}, //当前笔迹 linePrack: [] //划线轨迹 , 生成线条的实际点 }, // 笔迹开始 uploadScaleStart (e) { if (e.type != 'touchstart') return false; let ctx = this.data.ctx; ctx.setFillStyle(this.data.lineColor); // 初始线条设置颜色 ctx.setGlobalAlpha(this.data.transparent); // 设置半透明 let currentPoint = { x: e.touches[0].x, y: e.touches[0].y } let currentLine = this.data.currentLine; currentLine.unshift({ time: new Date().getTime(), dis: 0, x: currentPoint.x, y: currentPoint.y }) this.setData({ currentPoint, // currentLine }) if (this.data.firstTouch) { this.setData({ cutArea: { top: currentPoint.y, right: currentPoint.x, bottom: currentPoint.y, left: currentPoint.x }, firstTouch: false }) } this.pointToLine(currentLine); }, // 笔迹移动 uploadScaleMove (e) { if (e.type != 'touchmove') return false; if (e.cancelable) { // 判断默认行为是否已经被禁用 if (!e.defaultPrevented) { e.preventDefault(); } } let point = { x: e.touches[0].x, y: e.touches[0].y } //测试裁剪 if (point.ythis.data.cutArea.right) { this.data.cutArea.right = point.x; } if (this.data.canvasWidth - point.x <= 0) { this.data.cutArea.right = this.data.canvasWidth; } if (point.y > this.data.cutArea.bottom) { this.data.cutArea.bottom = point.y; } if (this.data.canvasHeight - point.y <= 0) { this.data.cutArea.bottom = this.data.canvasHeight; } if (point.x 2) { var info = (currentLine[0].time - currentLine[currentLine.length - 1].time) / currentLine.length; //$("#info").text(info.toFixed(2)); } //一笔结束,保存笔迹的坐标点,清空,当前笔迹 //增加判断是否在手写区域; this.pointToLine(currentLine); var currentChirography = { lineSize: this.data.lineSize, lineColor: this.data.lineColor }; var chirography = this.data.chirography chirography.unshift(currentChirography); this.setData({ chirography }) var linePrack = this.data.linePrack linePrack.unshift(this.data.currentLine); this.setData({ linePrack, currentLine: [] }) }, onLoad () { let canvasName = this.data.canvasName let ctx = wx.createCanvasContext(canvasName) this.setData({ ctx: ctx }) var query = wx.createSelectorQuery(); query.select('.handCenter').boundingClientRect(rect => { this.setData({ canvasWidth: rect.width, canvasHeight: rect.height }) }).exec(); this.setData({ userInfo:app.globalData.userInfo }) }, retDraw () { this.data.ctx.clearRect(0, 0, 700, 730) this.data.ctx.draw() }, subCanvas(event){ // 保存的方法,这里单独列出 }, //画两点之间的线条;参数为:line,会绘制最近的开始的两个点; pointToLine (line) { this.calcBethelLine(line); return; }, //计算插值的方式; calcBethelLine (line) { if (line.length <= 1) { line[0].r = this.data.radius; return; } let x0, x1, x2, y0, y1, y2, r0, r1, r2, len, lastRadius, dis = 0, time = 0, curveValue = 0.5; if (line.length <= 2) { x0 = line[1].x y0 = line[1].y x2 = line[1].x + (line[0].x - line[1].x) * curveValue; y2 = line[1].y + (line[0].y - line[1].y) * curveValue; //x2 = line[1].x; //y2 = line[1].y; x1 = x0 + (x2 - x0) * curveValue; y1 = y0 + (y2 - y0) * curveValue;; } else { x0 = line[2].x + (line[1].x - line[2].x) * curveValue; y0 = line[2].y + (line[1].y - line[2].y) * curveValue; x1 = line[1].x; y1 = line[1].y; x2 = x1 + (line[0].x - x1) * curveValue; y2 = y1 + (line[0].y - y1) * curveValue; } //从计算公式看,三个点分别是(x0,y0),(x1,y1),(x2,y2) ;(x1,y1)这个是控制点,控制点不会落在曲线上;实际上,这个点还会手写获取的实际点,却落在曲线上 len = this.distance({ x: x2, y: y2 }, { x: x0, y: y0 }); lastRadius = this.data.radius; for (let n = 0; n this.data.smoothness) break; } this.setData({ radius: Math.min(time / len * this.data.pressure + this.data.lineMin, this.data.lineMax) * this.data.lineSize }); line[0].r = this.data.radius; //计算笔迹半径; if (line.length <= 2) { r0 = (lastRadius + this.data.radius) / 2; r1 = r0; r2 = r1; //return; } else { r0 = (line[2].r + line[1].r) / 2; r1 = line[1].r; r2 = (line[1].r + line[0].r) / 2; } let n = 5; let point = []; for (let i = 0; i
测试图片:
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