参考:
- 小程序canvas手写签名,签名旋转(钉钉/微信) - 简书
- https://juejin.cn/post/7103187449169313823
- https://www.cnblogs.com/fhysy/p/16159711.html
- 移动端H5的屏幕适配 | 金融前端组博客
- https://juejin.cn/post/6908922945901608974
- ...
(样式层面实现的)代码:
下面代码,可以看着二开
<template>
<view class="wrapper">
<view class="handCenter">
<view class="ats">
<canvas
class="canvasOne"
:disable-scroll="true"
@touchstart="uploadScaleStart"
@touchmove="uploadScaleMove"
@touchend="uploadScaleEnd"
canvas-id="canvasOne"
id="canvasOne"
>
</canvas>
<canvas class="handWriting2" id="canvas" canvas-id="canvas"></canvas>
</view>
<view class="handBtn">
<button @click="subCanvas" class="subBtn">完成</button>
<button @click="retDraw" class="delBtn">重置</button>
</view>
</view>
<view class="handRight">
<text class="handTitle">签名</text>
</view>
<u-overlay :show="overlayShow">
<view class="rotate-container">
<view>没有签字内容</view>
</view>
</u-overlay>
</view>
</template>
<script>
import UOverlay from '../../../uni_modules/uview-ui/components/u-overlay/u-overlay.vue';
export default {
name: 'signatureBoard',
components: {UOverlay},
data() {
return {
canvasName: 'canvasOne',
ctx: '',
canvasWidth: 0,
canvasHeight: 0,
transparent: 1, // 透明度
selectColor: 'black',
lineColor: '#1A1A1A', // 颜色
lineSize: 1.5,
lineMin: 0.5,
lineMax: 4,
pressure: 1,
smoothness: 60,
currentPoint: {},
currentLine: [],
firstTouch: true,
radius: 1,
cutArea: {top: 0, right: 0, bottom: 0, left: 0},
bethelPoint: [],
lastPoint: 0,
chirography: [],
currentChirography: {},
linePrack: [],
overlayShow: false,
};
},
onLoad: function (options) {
setTimeout(() => {
let canvasName = this.canvasName;
let newCtx = uni.createCanvasContext(canvasName);
this.ctx = newCtx;
const query = uni.createSelectorQuery();
query
.select('.handCenter')
.boundingClientRect((rect) => {
this.canvasWidth = rect.width;
this.canvasHeight = rect.height;
this.setCanvasBg('#fff');
})
.exec();
}, 300);
},
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 newCurrentPoint = {
x: e.touches[0].x,
y: e.touches[0].y,
};
let currentLine = this.currentLine;
currentLine.unshift({
time: new Date().getTime(),
dis: 0,
x: newCurrentPoint.x,
y: newCurrentPoint.y,
});
this.currentPoint = newCurrentPoint;
if (this.firstTouch) {
this.cutArea = {
top: newCurrentPoint.y,
right: newCurrentPoint.x,
bottom: newCurrentPoint.y,
left: newCurrentPoint.x,
};
this.cutArea = 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) {
// const info =
// (currentLine[0].time - currentLine[currentLine.length - 1].time) /
// currentLine.length;
// //$("#info").text(info.toFixed(2));
// }
//增加判断是否在手写区域;
console.log('结束时额', currentLine);
this.pointToLine(currentLine);
const currentChirography = {
lineSize: this.lineSize,
lineColor: this.lineColor,
};
const chirography = this.chirography;
chirography.unshift(currentChirography);
this.chirography = chirography;
const 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;
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 (color !== undefined) {
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 (is_fill !== undefined) {
ctx.fill();
}
ctx.draw(true);
},
//完成
subCanvas() {
if (this.linePrack.length === 0) {
this.overlayShow = true;
setTimeout(() => {
this.overlayShow = false;
}, 1500);
} else {
this.getImage();
}
},
//设置canvas背景色
setCanvasBg(color) {
this.ctx.rect(0, 0, this.canvasWidth, this.canvasHeight - 4);
this.ctx.setFillStyle(color);
this.ctx.fill(); //设置填充
this.ctx.draw(); //开画
},
// 最终的图片
getImage() {
uni.canvasToTempFilePath({
canvasId: 'canvasOne',
success: (res) => {
console.log('生成的图片', res);
this.drowImage(res.tempFilePath);
},
fail: (err) => {
console.error('绘制失败');
},
});
},
drowImage(path) {
const canvasContext = uni.createCanvasContext('canvas');
canvasContext.scale(0.5, 0.5);
canvasContext.translate(0, 300);
canvasContext.rotate((-90 * Math.PI) / 180);
canvasContext.drawImage(path, 0, 0, 300, 600);
canvasContext.draw(true);
setTimeout(() => {
uni.canvasToTempFilePath({
canvasId: 'canvas',
success(res) {
uni.$emit('signImg', res?.tempFilePath);
uni.navigateBack({
delta: 1,
});
},
});
}, 1000);
},
},
};
</script>
<style scoped lang="scss">
.wrapper {
width: 100%;
height: 95vh;
margin: 30rpx 0;
overflow: hidden;
display: flex;
align-content: center;
flex-direction: row;
justify-content: center;
font-size: 28rpx;
margin-left: 20rpx;
}
//第一个canvas
.canvasOne {
position: relative;
background: #fff;
width: 98%;
z-index: 99;
height: 83vh;
border: 4rpx dashed #e9e9e9;
}
.ats {
position: relative;
}
//第二个canvas
.handWriting2 {
position: absolute;
z-index: 9;
width: 600rpx;
height: 300rpx;
top: 0;
left: 0;
/* transform: rotate(90deg); */
background-color: #fff;
}
.handRight {
display: flex;
height: 100%;
align-items: center;
justify-content: center;
text-align: center;
width: 100rpx;
}
.handCenter {
display: flex;
width: 620rpx;
flex-direction: column;
overflow: hidden;
box-sizing: border-box;
}
.handTitle {
display: flex;
color: #000000;
font-size: 33rpx;
font-weight: bold;
transform: rotate(90deg);
align-items: center;
justify-content: center;
text-align: center;
}
.handBtn button {
font-size: 28rpx;
}
.handBtn {
display: inline-flex;
flex-direction: row;
justify-content: space-between;
align-content: space-between;
text-align: center;
flex: 1;
}
.delBtn {
display: flex;
width: 120rpx;
height: 75rpx;
transform: rotate(90deg);
color: #666;
align-items: center;
justify-content: center;
margin-top: 60rpx;
}
.delBtn image {
position: absolute;
top: 13rpx;
left: 25rpx;
}
.subBtn {
width: 120rpx;
height: 75rpx;
display: inline-flex;
transform: rotate(90deg);
background: linear-gradient(133deg, #5e69ff 0%, #2e37a8 100%);
box-shadow: 0rpx 6rpx 12rpx rgba(0, 0, 0, 0.16);
opacity: 1;
border-radius: 13rpx;
color: #fff;
align-items: center;
justify-content: center;
margin-top: 60rpx;
}
.rotate-container {
position: relative;
top: 50%;
left: 50%;
transform: rotate(90deg) translate(-50%, 57%);
width: 200rpx;
height: auto;
color: #ffffff;
font-size: 28rpx;
}
</style>
效果图:
问题:
有人可能会问,为什么要通过css实现页面横屏,这样会多做很多事...只能说问的好,原因是自己通过配置使用框架的配置项(从系统层)已经实现了页面横屏,但无奈组里负责发版的人不会发版,只能删代码,推倒重来...做了无用功!
(系统层面实现的)代码:
这种方式实现的话可能需要让用户去应用商店下载新版应用;
// 安卓机型横竖屏切换
//页面显示时切换为横屏配置
onShow() {
// #ifdef APP-PLUS
uni.showLoading({
title: "加载中..."
})
setTimeout(() => {
plus.screen.unlockOrientation();
plus.screen.lockOrientation('landscape-primary');
uni.hideLoading();
}, 1200)
//#endif
},
//页面卸载时切换为竖屏配置
onUnload() {
// #ifdef APP-PLUS
plus.screen.lockOrientation('portrait-primary'); //锁死屏幕方向为竖屏
// #endif
}
// **************************************************
// 小程序横竖屏配置只需要在page.json中相关页面的style中配置"pageOrientation": "landscape"
{
"path": "collection/index",
"style": {
"navigationBarTitleText": "我的收藏",
"pageOrientation": "landscape"
}
}
// *****************************************************
// ios想要横竖屏切换需要配置manifest.json文件中的app-plus对象中的screenOrientation属性,值为['rtrait-primary','andscape-secondary'];distribute对象的distribute属性的orientation属性的值['portrait-primary', 'andscape-secondary']
压缩图片以及转base64相应的代码:
// 注意转base64时,需要获取文件管理器,然后就是注意app与小程序的差异性,这一点很重要;
// 获取文件系统管理器
// #ifdef MP-WEIXIN
const fs = uni.getFileSystemManager();
// #endif
// 压缩
uni.compressImage({
src: this.autographedPhotoList[0].thumb,
width: '50%',
height: '50%',
quality: 10,
success: (res) => {
const tempAddress = (
this.addressInfo.region + this.addressInfo.address
).trim();
// #ifdef APP-PLUS
plus.io.resolveLocalFileSystemURL(
res.tempFilePath,
(entry) => {
// 可通过entry对象操作test.html文件
entry.file((file) => {
const fileReader = new plus.io.FileReader();
fileReader.readAsDataURL(file, 'base64');
fileReader.onloadend = (e) => {
base64Url = `${e.target.result}`;
console.log('最终的base64', base64Url);
if (base64Url) {
this.helpFunc(
tempAddress,
this.removeBase64Header(base64Url),
);
}
};
});
},
function (e) {
uni.showToast({
title: e.message,
duration: 1000,
});
throw new Error(e.message);
},
);
// #endif
// 转成base64
// #ifdef MP-WEIXIN
fs.readFile({
filePath: res.tempFilePath,
encoding: 'base64',
success: (readRes) => {
base64Url = `${readRes.data}`;
this.helpFunc(tempAddress, base64Url);
},
fail(err) {
uni.showToast({
title:
typeof err === 'object'
? JSON.stringify(err)
: err ?? '签约错误',
duration: 1000,
});
throw new Error(JSON.stringify(err));
},
});
// #endif
},
});
对于https链接的图片转换为base64的方法:(app\小程序通用)
// https://cloud.tencent.com/developer/article/1597234
uni.request({
url: "https://s0.2mdn.net/simgad/10657937226496242109",
method: 'GET',
responseType: 'arraybuffer',
success: (res) => {
let base64 = wx.arrayBufferToBase64(res.data);
let userImageBase64 = 'data:image/jpg;base64,' + base64;
console.log(userImageBase64); // 打印base64格式图片
// 如果需要使用本地缓存图片,请参照第一步
}
})