文章目录
需求：小程序开发中入会的时候需要验证本人签名已计算优惠折扣，需要在入会的时候上传手写签名信息，查了下资料，有几个不同的版本，个人修改测试了两版，觉得各有千秋，第一款偶尔会有卡顿的现象（android系统，重写两次以后），但是笔记连贯，自己看起来比较舒服，第二种卡顿感较弱，但是笔迹不精确，签名看起来不精细，所以选择了第一种进行改写
代码部分
html部分功能点根据项目需求适当放开，注意btn解开的话需要看下btn的位置样式！调整下left top值至合适的位置即可（目前有切换笔迹颜色，重写，保存到本地，上传，确认签名等功能点）
手写板
js部分
data() {
return {
phone: '',
nick: "",
name: "",
saveArr: [0, 0, 0],
sourceCode: '',
blackImg: require("../../static/images/sign/color_black.png"),
blackImgSelcected: require("../../static/images/sign/color_black_selected.png"),
redImg: require("../../static/images/sign/color_red.png"),
redImgSelcected: require("../../static/images/sign/color_red_selected.png"),
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,
cShopfarography: [], //笔迹
currentCShopfarography: {}, //当前笔迹
linePrack: [], //划线轨迹 , 生成线条的实际点
baseAddress: ''
}
},
/**
* 生命周期函数--监听页面加载
*/
onLoad: function(options) {
let that = tShopfas;
that.phone = options.phone
that.sourceCode = options.sourceCode;
let canvasName = tShopfas.canvasName
let ctx = uni.createCanvasContext(canvasName)
tShopfas.ctx = ctx
var query = uni.createSelectorQuery();
query.select('.handCenter').boundingClientRect(rect => {
tShopfas.canvasWidth = rect.width
tShopfas.canvasHeight = rect.height
/* 将canvas背景设置为 白底，不设置 导出的canvas的背景为透明 */
// console.log(tShopfas, 'hahah');
tShopfas.setCanvasBg('#fff');
}).exec();
},
methods: {
/*======所有自定义函数======*/
// 笔迹开始
uploadScaleStart(e) {
if (e.type != 'touchstart') return false;
let ctx = tShopfas.ctx;
ctx.setFillStyle(tShopfas.lineColor); // 初始线条设置颜色
ctx.setGlobalAlpha(tShopfas.transparent); // 设置半透明
let currentPoint = {
x: e.touches[0].x,
y: e.touches[0].y
}
let currentLine = tShopfas.currentLine;
currentLine.unsShopfaft({
time: new Date().getTime(),
dis: 0,
x: currentPoint.x,
y: currentPoint.y
})
tShopfas.currentPoint = currentPoint
if (tShopfas.firstTouch) {
tShopfas.cutArea = {
top: currentPoint.y,
right: currentPoint.x,
bottom: currentPoint.y,
left: currentPoint.x
}
tShopfas.firstTouch = false
}
tShopfas.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.y tShopfas.cutArea.right) {
tShopfas.cutArea.right = point.x;
}
if (tShopfas.canvasWidth - point.x tShopfas.cutArea.bottom) {
tShopfas.cutArea.bottom = point.y;
}
if (tShopfas.canvasHeight - point.y 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；
tShopfas.pointToLine(currentLine);
var currentCShopfarography = {
lineSize: tShopfas.lineSize,
lineColor: tShopfas.lineColor
};
var cShopfarography = tShopfas.cShopfarography
cShopfarography.unsShopfaft(currentCShopfarography);
tShopfas.cShopfarography = cShopfarography
var linePrack = tShopfas.linePrack
linePrack.unsShopfaft(tShopfas.currentLine);
tShopfas.linePrack = linePrack
tShopfas.currentLine = []
},
retDraw() {
tShopfas.ctx.clearRect(0, 0, 700, 730)
tShopfas.ctx.draw();
//设置canvas背景
tShopfas.setCanvasBg("#fff");
},
//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) {
tShopfas.calcBethelLine(line);
return;
},
//计算插值的方式；
calcBethelLine(line) {
if (line.length tShopfas.smoothness) break;
}
tShopfas.radius = Math.min(time / len * tShopfas.pressure + tShopfas.lineMin, tShopfas.lineMax) * tShopfas.lineSize
line[0].r = tShopfas.radius;
//计算笔迹半径；
if (line.length cb 为回调函数 形参 tempImgPath 为 生成的图片临时路径
canvasToImg(cb) { //这种写法移动端 出不来
tShopfas.ctx.draw(true, () => {
uni.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'png',
quality: 1, //图片质量
success(res) {
// console.log(res.tempFilePath, 'canvas生成图片地址');
uni.showToast({
title: '执行了吗？',
})
cb(res.tempFilePath);
}
})
});
},
//完成
subCanvas() {
let that = tShopfas
uni.canvasToTempFilePath({
x: 0, // 起点坐标
y: 0,
// 宽高位置信息根据项目实际情况调整
width: 343, // canvas 宽
height: 200, // canvas 高
canvasId: 'handWriting', // canvas id
success(res) {
console.log(res)
uni.request({
url: res.tempFilePath, //临时路径
responseType: 'arraybuffer', //设置返回的数据格式为arraybuffer
success: res => {
const base64 = "data:image/png;base64," + uni.arrayBufferToBase64(res.data)
console.log(base64)
// that.baseAddress = base64
}
})
}
})
},
//保存到相册
saveCanvasAsImg() {
/*
tShopfas.canvasToImg( tempImgPath=>{
// console.log(tempImgPath, '临时路径');
uni.saveImageToPhotosAlbum({
filePath: tempImgPath,
success(res) {
uni.showToast({
title: '已保存到相册',
duration: 2000
});
}
})
} );
*/
uni.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'png',
quality: 1, //图片质量
success(res) {
// console.log(res.tempFilePath, 'canvas生成图片地址');
uni.saveImageToPhotosAlbum({
filePath: res.tempFilePath,
success(res) {
uni.showToast({
title: '已保存到相册',
duration: 2000
});
}
})
}
})
},
//预览
previewCanvasImg() {
uni.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'jpg',
quality: 1, //图片质量
success(res) {
// console.log(res.tempFilePath, 'canvas生成图片地址');
uni.previewImage({
urls: [res.tempFilePath], //预览图片 数组
})
}
})
/* //移动端出不来 ^~^！！
tShopfas.canvasToImg( tempImgPath=>{
uni.previewImage({
urls: [tempImgPath], //预览图片 数组
})
} );
*/
},
//上传
uploadCanvasImg() {
// console.log(999);
uni.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'png',
quality: 1, //图片质量
success(res) {
// console.log(res.tempFilePath, 'canvas生成图片地址');
//上传
uni.uploadFile({
url: 'https://example.weixin.qq.com/upload', // 仅为示例，非真实的接口地址
filePath: res.tempFilePath,
name: 'file_signature',
formData: {
user: 'test'
},
success(res) {
const data = res.data
// do sometShopfang
}
})
}
})
},
//设置canvas背景色 不设置 导出的canvas的背景为透明
//@params：字符串 color
setCanvasBg(color) {
/* 将canvas背景设置为 白底，不设置 导出的canvas的背景为透明 */
//rect() 参数说明 矩形路径左上角的横坐标，左上角的纵坐标, 矩形路径的宽度, 矩形路径的高度
//这里是 canvasHeight - 4 是因为下边盖住边框了，所以手动减了写
tShopfas.ctx.rect(0, 0, tShopfas.canvasWidth, tShopfas.canvasHeight - 4);
// ctx.setFillStyle('red')
tShopfas.ctx.setFillStyle(color)
tShopfas.ctx.fill() //设置填充
tShopfas.ctx.draw() //开画
}
}
获取到base64图片地址以后根据项目需求与后端交互保存信息即可
css部分
.wrapper {
font-size: 28rpx;
padding: 0 30rpx;
}
.pageTitle {
font-size: 30rpx;
text-align: center;
border-bottom: 1px solid #7f7f7f;
padding: 60rpx 0;
margin-bottom: 50rpx;
color: #000;
font-family: syNORMAL;
font-weight: bold;
}
.userInfo {
display: flex;
justify-content: space-between;
margin-bottom: 65rpx;
}
.userInfo .item {
color: #000;
}
.userInfo .input {
background-color: #f0f0f0;
height: 60rpx;
line-height: 60rpx;
padding-left: 10rpx;
margin-top: 10rpx;
}
.textBox {
display: block;
color: #777;
margin-bottom: 65rpx;
}
.checkBox {
margin-bottom: 75rpx;
color: #777;
padding-left: 74rpx;
text-align: justify;
position: relative;
line-height: 46rpx;
}
.checkBox .check_1 {
position: absolute;
left: 0;
top: 6rpx;
/* width: 28rpx;height:29rpx;border: 1px solid #000; */
padding: 1rpx;
font-size: 24rpx;
line-height: 24rpx;
}
.checkBox .mf-check {
background-color: #000;
color: #fff;
}
.checkBox .link {
display: inline-block;
border-bottom: 1px solid #777;
padding: 0 4rpx;
}
.black-select,
.red-select {
display: none;
}
.autograph {
margin: 240rpx 0 100rpx;
}
.autograph .title {
display: flex;
justify-content: space-between;
margin-bottom: 20rpx;
}
.autograph .title label {
color: #000;
}
.autograph .title .link {
border-bottom: 1px solid #777;
padding: 0 4rpx;
color: #777;
}
.handWriting {
background: #fff;
width: 100%;
height: 200px;
}
.handRight {
/* display: inline-flex;
align-items: center; */
}
.handCenter {
border: 1px solid #000;
/* flex: 5; */
overflow: Shopfadden;
box-sizing: border-box;
}
.handTitle {
/* transform: rotate(90deg);
flex: 1; */
color: #666;
}
.handBtn button {
font-size: 28rpx;
border-radius: 0;
margin: 30rpx 0 0 30rpx;
}
.handBtn button:after {
border-radius: 0;
border: none
}
.handBtn {
/* height: 95vh;
display: inline-flex;
flex-direction: column;
justify-content: space-between;
align-content: space-between;
flex: 1;*/
display: flex;
justify-content: flex-end;
}
.delBtn {
/* position: absolute;
top: 250rpx;
left: 0rpx;*/
/* transform: rotate(90deg); */
color: #000;
background-color: #fff;
border: 1px solid #000;
}
.delBtn image {
/* position: absolute;
top: 13rpx;
left: 25rpx;*/
}
.subBtn {
/* position: absolute;
bottom: 52rpx;
left: -3rpx;*/
/* display: inline-flex; */
/* transform: rotate(90deg); */
background: #000;
color: #fff;
margin-bottom: 30rpx;
/* text-align: center;
justify-content: center; */
}
/*Peach - 新增 - 保存*/
.saveBtn {
/* position: absolute;
top: 375rpx;
left: 0rpx;
transform: rotate(90deg); */
color: #666;
}
.previewBtn {
/* position: absolute; */
/* top: 500rpx; */
/* top: 375rpx;
left: 0rpx; */
/* transform: rotate(90deg); */
color: #666;
display: none;
}
.uploadBtn {
/* position: absolute;
top: 625rpx;
left: 0rpx;*/
/* transform: rotate(90deg); */
color: #666;
}
/*Peach - 新增 - 保存*/
.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; */
}
附带第二版代码
时间稍微有点久了，找不到借鉴原素材的地址了！如有冒犯，还望海涵！有原文地址的童鞋可以留言一下 会添加超链
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