业务中需要用户在线签名上传到服务器，并且需要横屏操作，签名区域需要有用户名字底纹，开箱即用，实现效果如图
附上签名组件代码
js
<template>
<view class="wrapper" v-if="show">
<view class="handBtn">
<button @click="cancel" class="canBtn">取消</button>
<button @click="retDraw" class="delBtn">清除</button>
<button @click="subCanvas" class="subBtn">确认</button>
</view>
<view class="handCenter">
<view class="watermark-text" ref="water">
<text class="name">
{{ userName }}
</text>
</view>
<canvas
class="handWriting"
disable-scroll="true"
@touchstart="uploadScaleStart"
@touchmove="uploadScaleMove"
@touchend="uploadScaleEnd"
canvas-id="handWriting"
>
</canvas>
</view>
<view class="handRight">
<view class="handTitle">手写板</view>
</view>
<canvas
canvas-id="camCacnvs"
class="handWriting1"
:style="{ position: 'absolute', top: '-9999px', left: '-9999px' }"
></canvas>
</view>
</template>
<script>
export default {
props: {
show: {
type: Boolean,
default: false,
},
userName: {
type: String,
default: "张三",
},
},
data() {
return {
// w: 100
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
signImg: "signImg",
linePrack: [], //划线轨迹 , 生成线条的实际点
};
},
mounted() {
let canvasName = this.canvasName;
let ctx = uni.createCanvasContext(canvasName);
this.ctx = ctx;
var query = uni.createSelectorQuery();
query
.select(".handCenter")
.boundingClientRect((rect) => {
this.canvasWidth = rect.width;
this.canvasHeight = rect.height;
this.setCanvasBg("#fff");
})
.exec();
},
methods: {
// 笔迹开始
uploadScaleStart(e) {
if (e.type != "touchstart") return false;
let ctx = this.ctx;
ctx.setFillStyle(this.lineColor); // 初始线条设置颜色
ctx.setGlobalAlpha(this.transparent); // 设置半透明
let currentPoint = {
x: e.touches[0].x,
y: e.touches[0].y,
};
let currentLine = this.currentLine;
currentLine.unshift({
time: new Date().getTime(),
dis: 0,
x: currentPoint.x,
y: currentPoint.y,
});
this.currentPoint = currentPoint;
if (this.firstTouch) {
this.cutArea = {
top: currentPoint.y,
right: currentPoint.x,
bottom: currentPoint.y,
left: currentPoint.x,
};
this.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.y < this.cutArea.top) {
this.cutArea.top = point.y;
}
if (point.y < 0) this.cutArea.top = 0;
if (point.x > this.cutArea.right) {
this.cutArea.right = point.x;
}
if (this.canvasWidth - point.x <= 0) {
this.cutArea.right = this.canvasWidth;
}
if (point.y > this.cutArea.bottom) {
this.cutArea.bottom = point.y;
}
if (this.canvasHeight - point.y <= 0) {
this.cutArea.bottom = this.canvasHeight;
}
if (point.x < this.cutArea.left) {
this.cutArea.left = point.x;
}
if (point.x < 0) this.cutArea.left = 0;
((this.lastPoint = this.currentPoint), (this.currentPoint = point));
let currentLine = this.currentLine;
currentLine.unshift({
time: new Date().getTime(),
dis: this.distance(this.currentPoint, this.lastPoint),
x: point.x,
y: point.y,
});
this.pointToLine(currentLine);
},
// 笔迹结束
uploadScaleEnd(e) {
if (e.type != "touchend") return 0;
let point = {
x: e.changedTouches[0].x,
y: e.changedTouches[0].y,
};
this.lastPoint = this.currentPoint;
this.currentPoint = point;
let currentLine = this.currentLine;
currentLine.unshift({
time: new Date().getTime(),
dis: this.distance(this.currentPoint, this.lastPoint),
x: point.x,
y: point.y,
});
if (currentLine.length > 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.lineSize,
lineColor: this.lineColor,
};
var chirography = this.chirography;
chirography.unshift(currentChirography);
this.chirography = chirography;
var linePrack = this.linePrack;
linePrack.unshift(this.currentLine);
((this.linePrack = linePrack), (this.currentLine = []));
},
retDraw() {
this.ctx.clearRect(0, 0, 700, 730);
this.ctx.draw();
//设置canvas背景
this.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) {
this.calcBethelLine(line);
return;
},
//计算插值的方式；
calcBethelLine(line) {
if (line.length <= 1) {
line[0].r = this.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.radius;
for (let n = 0; n < line.length - 1; n++) {
dis += line[n].dis;
time += line[n].time - line[n + 1].time;
if (dis > this.smoothness) break;
}
this.radius =
Math.min((time / len) * this.pressure + this.lineMin, this.lineMax) *
this.lineSize;
line[0].r = this.radius;
//计算笔迹半径；
if (line.length <= 2) {
r0 = (lastRadius + this.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 < n; i++) {
let t = i / (n - 1);
let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2;
let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2;
let r = lastRadius + ((this.radius - lastRadius) / n) * i;
point.push({
x: x,
y: y,
r: r,
});
if (point.length == 3) {
let a = this.ctaCalc(
point[0].x,
point[0].y,
point[0].r,
point[1].x,
point[1].y,
point[1].r,
point[2].x,
point[2].y,
point[2].r,
);
a[0].color = this.lineColor;
// let bethelPoint = this.bethelPoint;
// console.log(a)
// console.log(this.bethelPoint)
// bethelPoint = bethelPoint.push(a);
this.bethelDraw(a, 1);
point = [
{
x: x,
y: y,
r: r,
},
];
}
}
this.currentLine = line;
},
//求两点之间距离
distance(a, b) {
let x = b.x - a.x;
let y = b.y - a.y;
return Math.sqrt(x * x + y * y);
},
ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
let a = [],
vx01,
vy01,
norm,
n_x0,
n_y0,
vx21,
vy21,
n_x2,
n_y2;
vx01 = x1 - x0;
vy01 = y1 - y0;
norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2;
vx01 = (vx01 / norm) * r0;
vy01 = (vy01 / norm) * r0;
n_x0 = vy01;
n_y0 = -vx01;
vx21 = x1 - x2;
vy21 = y1 - y2;
norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2;
vx21 = (vx21 / norm) * r2;
vy21 = (vy21 / norm) * r2;
n_x2 = -vy21;
n_y2 = vx21;
a.push({
mx: x0 + n_x0,
my: y0 + n_y0,
color: "#1A1A1A",
});
a.push({
c1x: x1 + n_x0,
c1y: y1 + n_y0,
c2x: x1 + n_x2,
c2y: y1 + n_y2,
ex: x2 + n_x2,
ey: y2 + n_y2,
});
a.push({
c1x: x2 + n_x2 - vx21,
c1y: y2 + n_y2 - vy21,
c2x: x2 - n_x2 - vx21,
c2y: y2 - n_y2 - vy21,
ex: x2 - n_x2,
ey: y2 - n_y2,
});
a.push({
c1x: x1 - n_x2,
c1y: y1 - n_y2,
c2x: x1 - n_x0,
c2y: y1 - n_y0,
ex: x0 - n_x0,
ey: y0 - n_y0,
});
a.push({
c1x: x0 - n_x0 - vx01,
c1y: y0 - n_y0 - vy01,
c2x: x0 + n_x0 - vx01,
c2y: y0 + n_y0 - vy01,
ex: x0 + n_x0,
ey: y0 + n_y0,
});
a[0].mx = a[0].mx.toFixed(1);
a[0].mx = parseFloat(a[0].mx);
a[0].my = a[0].my.toFixed(1);
a[0].my = parseFloat(a[0].my);
for (let i = 1; i < a.length; i++) {
a[i].c1x = a[i].c1x.toFixed(1);
a[i].c1x = parseFloat(a[i].c1x);
a[i].c1y = a[i].c1y.toFixed(1);
a[i].c1y = parseFloat(a[i].c1y);
a[i].c2x = a[i].c2x.toFixed(1);
a[i].c2x = parseFloat(a[i].c2x);
a[i].c2y = a[i].c2y.toFixed(1);
a[i].c2y = parseFloat(a[i].c2y);
a[i].ex = a[i].ex.toFixed(1);
a[i].ex = parseFloat(a[i].ex);
a[i].ey = a[i].ey.toFixed(1);
a[i].ey = parseFloat(a[i].ey);
}
return a;
},
bethelDraw(point, is_fill, color) {
let ctx = this.ctx;
ctx.beginPath();
ctx.moveTo(point[0].mx, point[0].my);
if (undefined != color) {
ctx.setFillStyle(color);
ctx.setStrokeStyle(color);
} else {
ctx.setFillStyle(point[0].color);
ctx.setStrokeStyle(point[0].color);
}
for (let i = 1; i < point.length; i++) {
ctx.bezierCurveTo(
point[i].c1x,
point[i].c1y,
point[i].c2x,
point[i].c2y,
point[i].ex,
point[i].ey,
);
}
ctx.stroke();
if (undefined != is_fill) {
ctx.fill(); //填充图形 ( 后绘制的图形会覆盖前面的图形, 绘制时注意先后顺序 )
}
ctx.draw(true);
},
selectColorEvent(event) {
console.log(event);
var color = event.currentTarget.dataset.colorValue;
var colorSelected = event.currentTarget.dataset.color;
((this.selectColor = colorSelected), (this.lineColor = color));
},
// 设置背景函数
//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
this.ctx.rect(0, 0, this.canvasWidth, this.canvasHeight - 4);
// ctx.setFillStyle('red')
this.ctx.setFillStyle(color);
this.ctx.fill(); //设置填充
this.ctx.draw(); //开画
},
//保存到相册
saveCanvasAsImg() {
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
subCanvas() {
if (this.linePrack.length === 0 && this.chirography.length === 0) {
uni.showToast({
title: '请先签名',
icon: 'none',
duration: 2000
});
return; // 阻止后续提交
}
let that = this;
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");
// 旋转
that.roateImg(res.tempFilePath);
},
});
},
// 旋转图片
roateImg(path) {
const that = this;
const ctx = uni.createCanvasContext("camCacnvs", this);
ctx.translate(0, this.canvasWidth);
ctx.rotate((-90 * Math.PI) / 180);
ctx.drawImage(path, 0, 0, this.canvasWidth, this.canvasHeight);
ctx.draw();
setTimeout(() => {
uni.canvasToTempFilePath(
{
canvasId: "camCacnvs",
success: function (res) {
var tempFilePath = res.tempFilePath;
console.log(tempFilePath, "222222");
that.$emit("subUrl", tempFilePath);
},
fail: (err) => {
console.log("fail", err);
},
},
this,
);
}, 200);
},
//上传
uploadCanvasImg() {
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");
//上传流程
},
});
},
// 取消签名
cancel() {
this.$emit("cancel");
},
// subCanvas() {
// const that = this;
// this.ctx.draw(false, uni.canvasToTempFilePath({
// canvasId: 'handWriting',
// fileType: 'jpg',
// quality: 1, //图片质量
// success(res) {
// let url = res.tempFilePath
// console.log(url,'url');
// that.$emit('subUrl',url)
// // that.roateImg(url)
// },
// fail() {
// uni.showToast({
// title: '生成图片失败',
// icon: 'none',
// duration: 2000
// })
// }
// }))
// }
},
};
</script>
<style>
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;
}
.handWriting1 {
background: #fff;
width: 95vh;
height: calc(100vw / 7 * 5);
}
.handRight {
display: inline-flex;
align-items: center;
}
.handCenter {
border: 4rpx dashed #e9e9e9;
flex: 5;
overflow: hidden;
box-sizing: border-box;
position: relative;
}
.handTitle {
transform: rotate(90deg);
flex: 1;
color: #666;
}
.handBtn button {
font-size: 28rpx;
}
.handBtn {
height: 95vh;
display: inline-flex;
flex-direction: column;
align-items: center;
flex: 1;
}
.canBtn,
.delBtn,
.saveBtn,
.previewBtn,
.uploadBtn,
.subBtn {
width: 20vh !important;
height: 70rpx;
border: 2rpx solid #eeeeee;
transform: rotate(90deg);
color: #666;
}
.canBtn {
position: absolute;
/* bottom: 90vh; */
bottom: 80vh;
}
.delBtn {
position: absolute;
/* bottom: 60vh; */
bottom: 48vh;
}
.subBtn {
position: absolute;
/* bottom: 52rpx; */
/* bottom: 30vh; */
bottom: 16vh;
display: inline-flex;
transform: rotate(90deg);
background: #ab004f;
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;
}
.watermark-text {
width: 100%;
height: 100%;
position: absolute;
font-family: "STKaiti", "楷体", serif;
font-size: 144rpx;
color: rgba(44, 62, 80, 0.15);
letter-spacing: 60rpx;
font-weight: bold;
pointer-events: none;
z-index: 2;
display: inline-flex;
align-items: center;
/* transform: rotate(90deg);
transform-origin: center center; */
/* writing-mode: sideways-rl; */
text-align: center;
justify-content: center;
.name {
transform: rotate(90deg);
white-space: nowrap;
/* flex: 1; */
}
}
</style>父组件使用方法
js
<view class="form-step">
<u-button color="#AB004F" @click="showSignature = true"
>签名</u-button
>
<view v-if="signatureLocalPath" class="signature-result">
<p class="result-title flight-btn">签名结果</p>
<image
:src="signatureLocalPath"
mode="widthFix"
class="result-image"
></image>
<u-button @click="clearResult" class="clear-button"
>清除签名</u-button
>
</view>
<u-modal
:show="showSignature"
class="signModal"
:showConfirmButton="false"
>
<signaturePopup
:show="showSignature"
@cancel="onSignatureCancel"
@subUrl="receiveUrl"
:user-name="step1FormData.passengerName"
/>
</u-modal>
</view>签名完成点击"确认"，父组件接收图片
js
receiveUrl(url) {
this.signatureLocalPath = url;
this.showSignature = false;
},取消及清除
js
onSignatureCancel() {
this.showSignature = false;
},
clearResult() {
this.signatureLocalPath = "";
this.signaturePath = "";
},