<em>Mac</em>Book项目 2009年学校开始实施<em>Mac</em>Book项目,所有师生配备一本<em>Mac</em>Book,并同步更新了校园无线网络。学校每周进行电脑技术更新,每月发送技术支持资料,极大改变了教学及学习方式。因此2011
2021-06-01 09:32:01
微信小程式實現橫屏和豎屏簽名功能
2022-05-24 18:01:54
本文範例為大家分享了微信小程式實現橫屏和豎屏簽名的具體程式碼，供大家參考，具體內容如下
wxml
<view class="container"> <canvas canvas-id="firstCanvas" id="firstCanvas" bindtouchstart="bindtouchstart" bindtouchmove="bindtouchmove"></canvas> <view class="btn"> <button type="warn" bindtap="clear"> 清除 </button> <button type="primary" bindtap="export"> 確定 </button> </view> </view>
wxss
#firstCanvas{
width: 750rpx;
height: 600rpx;
background-color: #fff;
}js
const app = getApp()
Page({
data: {
context: null,
index: 0,
height: 0,
width: 0
},
/**記錄開始點 */
bindtouchstart: function(e) {
this.data.context.moveTo(e.changedTouches[0].x, e.changedTouches[0].y)
},
/**記錄移動點，重新整理繪製 */
bindtouchmove: function(e) {
this.data.context.lineTo(e.changedTouches[0].x, e.changedTouches[0].y);
this.data.context.stroke();
this.data.context.draw(true);
this.data.context.moveTo(e.changedTouches[0].x, e.changedTouches[0].y);
},
/**清空畫布 */
clear: function() {
this.data.context.clearRect(0, 0, this.data.width, this.data.height);
this.data.context.draw();
this.data.context.setStrokeStyle('#00ff00')
this.data.context.setLineWidth(2)
this.data.context.setFontSize(20)
let str = "簽名區域";
this.data.context.fillText(str, Math.ceil((this.data.width - this.data.context.measureText(str).width) / 2), Math.ceil(this.data.height / 2) - 20)
this.data.context.draw()
},
base64(url, type) {
return new Promise((resolve, reject) => {
wx.getFileSystemManager().readFile({
filePath: url,
encoding: 'base64',
success(res){
resolve('data:img/'+type.toLocaleLowerCase()+':base64,'+res.data)
},
fail(){
reject()
}
})
})
},
/**匯出圖片 */
export: function() {
const that=this;
this.data.context.draw(false, wx.canvasToTempFilePath({
x: 0,
y: 0,
width: that.data.width,
height: that.data.height,
destWidth: that.data.width,
destHeight: that.data.height,
fileType: 'jpg',
canvasId: 'firstCanvas',
success(res) {
let url = res.tempFilePath
that.base64(url, 'jpg').then(res => {
console.log('base64資料流',res);
var pages = getCurrentPages();
var prevPage = pages[pages.length - 2]; //上一個頁面
//直接呼叫上一個頁面的setData()方法，把資料存到上一個頁面中去
prevPage.setData({
sign: {
sign:res,
}
})
wx.navigateBack({//返回
delta: 1
})
})
},
fail() {
wx.showToast({
title: '匯出失敗',
icon: 'none',
duration: 2000
})
}
}))
},
onShow: function() {
let query = wx.createSelectorQuery();
const that = this;
query.select('#firstCanvas').boundingClientRect();
query.exec((rect) => {
let width = rect[0].width;
let height = rect[0].height;
that.setData({
width,
height
});
const context = wx.createCanvasContext('firstCanvas')
that.setData({
context: context
})
that.data.context.setLineWidth(2)
that.data.context.setLineCap('round')
});
},
})效果
橫屏
<view class="wrapper">
<view class="handBtn">
<image catchtap="selectColorEvent" src="{{ selectColor === 'black' ? '../../public/image/index/sign/color_black_selected.png' : '../../public/image/index/sign/color_black.png' }}" class="{{ selectColor === 'black' ? 'color_select' : '' }} black-select" data-color="black"
data-color-value="#1A1A1A"></image>
<image catchtap="selectColorEvent" src="{{ selectColor === 'red' ? '../../public/image/index/sign/color_red_selected.png' : '../../public/image/index/sign/color_red.png' }}" class="{{ selectColor === 'red' ? 'color_select' : '' }} red-select" data-color="red"
data-color-value="#ca262a"></image>
<button catchtap="retDraw" class="delBtn">重寫</button>
<button catchtap="saveCanvasAsImg" class="saveBtn">儲存</button>
<button catchtap="previewCanvasImg" class="previewBtn">預覽</button>
<button catchtap="uploadCanvasImg" class="uploadBtn">上傳</button>
<button catchtap="subCanvas" class="subBtn">完成</button>
</view>
<view class="handCenter">
<canvas class="handWriting" disable-scroll="true" bindtouchstart="uploadScaleStart" bindtouchmove="uploadScaleMove"
bindtouchend="uploadScaleEnd" bindtap="mouseDown" canvas-id="handWriting">
</canvas>
</view>
<view class="handRight">
<view class="handTitle">手寫板</view>
</view>
</view>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;
align-items: center;
flex: 1;
}
.delBtn,
.saveBtn,
.previewBtn,
.uploadBtn,
.subBtn{
width: 160rpx !important;
height: 70rpx;
border: 2rpx solid #eeeeee;
transform: rotate(90deg);
color: #666;
}
.delBtn{
position: absolute;
bottom: 850rpx;
}
.saveBtn{
position: absolute;
bottom: 660rpx;
}
.previewBtn{
position: absolute;
bottom: 470rpx;
}
.uploadBtn{
position: absolute;
bottom: 280rpx;
}
.subBtn {
position: absolute;
bottom: 52rpx;
display: inline-flex;
transform: rotate(90deg);
background: #218FFC;
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
Page({
data: {
canvasName: 'handWriting',
ctx: '',
canvasWidth: 0,
canvasHeight: 0,
transparent: 1, // 透明度
selectColor: 'black',
lineColor: '#1A1A1A', // 顏色
lineSize: 1.5, // 筆記倍數
lineMin: 0.5, // 最小筆畫半徑
lineMax: 4, // 最大筆畫半徑
pressure: 1, // 預設壓力
smoothness: 60, //順滑度，用60的距離來計算速度
currentPoint: {},
currentLine: [], // 當前線條
firstTouch: true, // 第一次觸發
radius: 1, //畫圓的半徑
cutArea: { top: 0, right: 0, bottom: 0, left: 0 }, //裁剪區域
bethelPoint: [], //儲存所有線條 生成的貝塞爾點；
lastPoint: 0,
chirography: [], //筆跡
currentChirography: {}, //當前筆跡
signImg: 'signImg',
linePrack: [] //劃線軌跡 , 生成線條的實際點
},
onLoad (options) {
this.setData({
signImg: options.names,
})
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
})
/* 將canvas背景設定為 白底，不設定 匯出的canvas的背景為透明 */
// console.log(this, 'hahah');
this.setCanvasBg('#fff');
}).exec();
},
// 筆跡開始
uploadScaleStart (e) {
if (e.type != 'touchstart') return false;
let ctx = this.data.ctx;
ctx.setFillStyle(this.data.lineColor); // 初始線條設定顏色
ctx.setGlobalAlpha(this.data.transparent); // 設定半透明
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);
},
// 筆跡移動
uploadScaleMove (e) {
if (e.type != 'touchmove') return false;
if (e.cancelable) {
// 判斷預設行為是否已經被禁用
if (!e.defaultPrevented) {
e.preventDefault();
}
}
let point = {
x: e.touches[0].x,
y: e.touches[0].y
}
//測試裁剪
if (point.y < this.data.cutArea.top) {
this.data.cutArea.top = point.y;
}
if (point.y < 0) this.data.cutArea.top = 0;
if (point.x > this.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 < this.data.cutArea.left) {
this.data.cutArea.left = point.x;
}
if (point.x < 0) this.data.cutArea.left = 0;
this.setData({
lastPoint: this.data.currentPoint,
currentPoint: point
})
let currentLine = this.data.currentLine
currentLine.unshift({
time: new Date().getTime(),
dis: this.distance(this.data.currentPoint, this.data.lastPoint),
x: point.x,
y: point.y
})
// this.setData({
// currentLine
// })
this.pointToLine(currentLine);
},
// 筆跡結束
uploadScaleEnd (e) {
if (e.type != 'touchend') return 0;
let point = {
x: e.changedTouches[0].x,
y: e.changedTouches[0].y
}
this.setData({
lastPoint: this.data.currentPoint,
currentPoint: point
})
let currentLine = this.data.currentLine
currentLine.unshift({
time: new Date().getTime(),
dis: this.distance(this.data.currentPoint, this.data.lastPoint),
x: point.x,
y: point.y
})
// this.setData({
// currentLine
// })
if (currentLine.length > 2) {
var info = (currentLine[0].time - currentLine[currentLine.length - 1].time) / currentLine.length;
//$("#info").text(info.toFixed(2));
}
//一筆結束，儲存筆跡的座標點，清空，當前筆跡
//增加判斷是否在手寫區域；
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: []
})
},
retDraw() {
this.data.ctx.clearRect(0, 0, 700, 730)
this.data.ctx.draw();
//設定canvas背景
this.setCanvasBg("#fff");
},
//畫兩點之間的線條；引數為:line，會繪製最近的開始的兩個點；
pointToLine (line) {
this.calcBethelLine(line);
return;
},
//計算插值的方式；
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;
}
//從計算公式看，三個點分別是(x0,y0),(x1,y1),(x2,y2) ；(x1,y1)這個是控制點，控制點不會落在曲線上；實際上，這個點還會手寫獲取的實際點，卻落在曲線上
len = this.distance({ x: x2, y: y2 }, { x: x0, y: y0 });
lastRadius = this.data.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.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;
//計算筆跡半徑；
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 < 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.data.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.data.lineColor;
// let bethelPoint = this.data.bethelPoint;
// console.log(a)
// console.log(this.data.bethelPoint)
// bethelPoint = bethelPoint.push(a);
this.bethelDraw(a, 1);
point = [{ x: x, y: y, r: r }];
}
}
this.setData({
currentLine: line
})
},
//求兩點之間距離
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.data.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(); //填充圖形 ( 後繪製的圖形會覆蓋前面的圖形, 繪製時注意先後順序 )
}
ctx.draw(true)
},
selectColorEvent (event) {
console.log(event)
var color = event.currentTarget.dataset.colorValue;
var colorSelected = event.currentTarget.dataset.color;
this.setData({
selectColor: colorSelected,
lineColor: color
})
},
// 設定背景函數
//設定canvas背景色 不設定 匯出的canvas的背景為透明
//@params：字串 color
setCanvasBg(color){
/* 將canvas背景設定為 白底，不設定 匯出的canvas的背景為透明 */
//rect() 引數說明 矩形路徑左上角的橫座標，左上角的縱座標, 矩形路徑的寬度, 矩形路徑的高度
//這裡是 canvasHeight - 4 是因為下邊蓋住邊框了，所以手動減了寫
this.data.ctx.rect(0, 0, this.data.canvasWidth, this.data.canvasHeight - 4);
// ctx.setFillStyle('red')
this.data.ctx.setFillStyle( color )
this.data.ctx.fill() //設定填充
this.data.ctx.draw() //開畫
},
//儲存到相簿
saveCanvasAsImg(){
wx.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'png',
quality: 1, //圖片質量
success(res) {
// console.log(res.tempFilePath, 'canvas生成圖片地址');
wx.saveImageToPhotosAlbum({
filePath: res.tempFilePath,
success(res) {
wx.showToast({
title: '已儲存到相簿',
duration: 2000
});
}
})
}
})
},
//預覽
previewCanvasImg(){
wx.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'jpg',
quality: 1, //圖片質量
success(res) {
// console.log(res.tempFilePath, 'canvas生成圖片地址');
wx.previewImage({
urls: [res.tempFilePath], //預覽圖片 陣列
})
}
})
},
//上傳
uploadCanvasImg() {
wx.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'png',
quality: 1, //圖片質量
success(res) {
// console.log(res.tempFilePath, 'canvas生成圖片地址');
//上傳
wx.uploadFile({
url: 'https://example.weixin.qq.com/upload', // 僅為範例，非真實的介面地址
filePath: res.tempFilePath,
name: 'file_signature',
formData: {
user: 'test'
},
success(res) {
const data = res.data
// do something
}
})
}
})
},
// 完成 匯出圖片
base64(url, type) {
return new Promise((resolve, reject) => {
wx.getFileSystemManager().readFile({
filePath: url,
encoding: 'base64',
success(res){
resolve('data:image/'+type.toLocaleLowerCase()+';base64,'+res.data)
},
fail(){
reject()
}
})
})
},
subCanvas(){
const that=this;
this.data.ctx.draw(false, wx.canvasToTempFilePath({
canvasId: 'handWriting',
fileType: 'jpg',
quality: 1, //圖片質量
success(res) {
let url = res.tempFilePath
that.base64(url, 'jpg').then(res => {
var pages = getCurrentPages();
var prevPage = pages[pages.length - 2]; //上一個頁面
//直接呼叫上一個頁面的setData()方法，把資料存到上一個頁面中去
prevPage.setSign(res)
wx.navigateBack({//返回
delta: 1
})
})
},
fail() {
wx.showToast({
title: '匯出失敗',
icon: 'none',
duration: 2000
})
}
})
)
}
})呼叫頁面引入
wxml
<view class="sign" bindtap="signName">
<view class="sign-title">檢查員簽名：
</view>
<view class="sign-img">
<image src="{{base64ImgUrl}}"></image>
</view>
</view>js
// 跳簽名板頁面
setSign(value) {
wx.setStorageSync('signImg2', value)
this.setData({
base64ImgUrl: value
})
},
signName() {
wx.navigateTo({
url: '../sign_name/index?names=signImg2',
})
},效果
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