uniapp 横屏签名旋转canvas

本是古典何须时尚 2023-09-24 22:17 63阅读 0赞

使用插件[canvas手写板，横屏签名 - DCloud 插件市场][canvas_ - DCloud]

保存后签名是横屏的，上传时需正的

获取到图片路径后创建新的canvas

var t=this;
                uni.canvasToTempFilePath({
                    canvasId: 'designature',
                    fileType: 'png',
                    quality: 1, //图片质量
                    success:function(res) {
                        console.log(res.tempFilePath)
    					//获取到原签名照片
    					t.rotate(res.tempFilePath);
                    },
                    fail(e){
                        console.log(e)
                    }
                },this)

//旋转图片，生成新canvas实例
    				rotate(tempFilePaths){
    					const that = this
    					var _this = this;
    					uni.getImageInfo({
    					  // 获取图片的信息
    					  src: tempFilePaths,
    					  success: (res1) => {
    					    console.log(res1)
    					    // 将canvas1的内容复制到canvas2中
    					    let canvasContext = uni.createCanvasContext('handWriting2',this)
    					    let rate = res1.height / res1.width
    					    let width = 300 / rate
    					    let height = 300
    					    _this.cavWidth = 300 / rate
    					    _this.cavWidth1 = 300
    					    canvasContext.translate(height / 2, width / 2)
    					    canvasContext.rotate((270 * Math.PI) / 180)
    					    canvasContext.drawImage(tempFilePaths, -width / 2, -height / 2, width, height)
    					    canvasContext.draw(false,(data)=>{
    								// 将之前在绘图上下文中的描述（路径、变形、样式）画到 canvas 中
    								uni.canvasToTempFilePath({
    								  // 把当前画布指定区域的内容导出生成指定大小的图片。在 draw() 回调里调用该方法才能保证图片导出成功。
    								  canvasId: 'handWriting2',
    								  fileType: 'png',
    								  quality: 1, //图片质量
    								  success(res2) {
    								    // 调用uni.uploadFile上传图片即可
    								    console.log(res2)
    										_this.$emit('getImg',res2.tempFilePath);
    								  }
    								},_this)
    							});
    					  }
    					})
    				}

获取到图片后转Base64

[image-tools - DCloud 插件市场][image-tools - DCloud]

源码

//f-signature.vue
    
    <template>
        
    	<view class="signa">
            <view class="box">
    			
                <canvas class="canvas" disable-scroll="true" canvas-id="designature" @touchstart="starts"
                 @touchmove="moves" @touchend="end"></canvas>
    						 
    						 <canvas style="position: absolute" canvas-id="handWriting2"></canvas>
                <view class="bottomBox u-flex">
                    
                    <view class="btn" @click="cancel">{
       { $t('specialApplication.fh') }}</view>
                    <view class="btn blue" style="margin-top: 4vw;" @click="clear">{
       { $t('specialApplication.qc') }}</view>
                    <view class="btn" @click="save">{
       { $t('specialApplication.qd') }}</view>
                </view>
            </view>
    	</view>
    </template>
    
    <script>
    export default {
        data() {
            return {
                resultUrl: '',
                dom: null,
                line: [],
                width: '0px',
                height: '0px',
                radius: 0
            }
        },
        created() {
            uni.getSystemInfo({
                success: (res) => {
                    this.width = res.windowWidth - 56 + 'px';
                    this.height = res.windowHeight - 154 + 'px';
                }
            });
            this.dom = uni.createCanvasContext('designature',this);
        },
        methods: {
            cancel(){
                uni.navigateBack()
            },
            end(e) {
    
            },
            distance(a, b) {
                let x = b.x - a.x;
                let y = b.y - a.y;
                return Math.sqrt(x * x + y * y);
            },
            starts(e) {
                this.line.push({
                    points: [{
                        time: new Date().getTime(),
                        x: e.touches[0].x,
                        y: e.touches[0].y,
                        dis: 0
                    }]
                })
                let currentPoint = {
                    x: e.touches[0].x,
                    y: e.touches[0].y
                }
                this.currentPoint = currentPoint
                this.drawer(this.line[this.line.length - 1]);
            },
            moves(e) {
                let point = {
                    x: e.touches[0].x,
                    y: e.touches[0].y
                }
                this.lastPoint = this.currentPoint,
                    this.currentPoint = point
                this.line[this.line.length - 1].points.push({
                    time: new Date().getTime(),
                    x: e.touches[0].x,
                    y: e.touches[0].y,
                    dis: this.distance(this.currentPoint, this.lastPoint)
                })
                this.drawer(this.line[this.line.length - 1])
            },
            drawer(item) {
                let x1, x2, y1, y2, len, radius, r, cx, cy, t = 0.5,
                    x, y;
                var time = 0;
                if (item.points.length > 2) {
                    let lines = item.points[item.points.length - 3];
                    let line = item.points[item.points.length - 2];
                    let end = item.points[item.points.length - 1];
                    x = line.x;
                    y = line.y;
                    x1 = lines.x;
                    y1 = lines.y;
                    x2 = end.x;
                    y2 = end.y;
                    var dis = 0;
                    time = (line.time - lines.time) + (end.time - line.time)
                    dis = line.dis + lines.dis + end.dis;
                    var dom = this.dom;
                    var or = Math.min(time / dis * this.linePressure + this.lineMin, this.lineMax);
                    cx = (x - (Math.pow(1 - t, 2) * x1) - Math.pow(t, 2) * x2) / (2 * t * (1 - t))
                    cy = (y - (Math.pow(1 - t, 2) * y1) - Math.pow(t, 2) * y2) / (2 * t * (1 - t))
                    dom.setLineCap('round')
                    dom.beginPath();
                    dom.setStrokeStyle('black')
                    dom.setLineWidth(5)
                    dom.moveTo(x1, y1);
                    dom.quadraticCurveTo(cx, cy, x2, y2);
                    
                    dom.stroke();
                    dom.draw(true)
                }
    
            },
            clear() {
                this.dom.clearRect(0, 0, 1000, 1000)
                this.dom.draw()
            },
            save() {
                var t=this;
                uni.canvasToTempFilePath({
                    canvasId: 'designature',
                    fileType: 'png',
                    quality: 1, //图片质量
                    success:function(res) {
                        console.log(res.tempFilePath)
    										debugger
    										t.rotate(res.tempFilePath);
                        // t.$emit('getImg',res.tempFilePath)
                    },
                    fail(e){
                        console.log(e)
                    }
                },this)
            },
    				//旋转图片，生成新canvas实例
    				rotate(tempFilePaths){
    					const that = this
    					var _this = this;
    					uni.getImageInfo({
    					  // 获取图片的信息
    					  src: tempFilePaths,
    					  success: (res1) => {
    					    console.log(res1)
    					    // 将canvas1的内容复制到canvas2中
    					    let canvasContext = uni.createCanvasContext('handWriting2',this)
    					    let rate = res1.height / res1.width
    					    let width = 300 / rate
    					    let height = 300
    					    _this.cavWidth = 300 / rate
    					    _this.cavWidth1 = 300
    					    canvasContext.translate(height / 2, width / 2)
    					    canvasContext.rotate((270 * Math.PI) / 180)
    					    canvasContext.drawImage(tempFilePaths, -width / 2, -height / 2, width, height)
    					    canvasContext.draw(false,(data)=>{
    								// 将之前在绘图上下文中的描述（路径、变形、样式）画到 canvas 中
    								uni.canvasToTempFilePath({
    								  // 把当前画布指定区域的内容导出生成指定大小的图片。在 draw() 回调里调用该方法才能保证图片导出成功。
    								  canvasId: 'handWriting2',
    								  fileType: 'png',
    								  quality: 1, //图片质量
    								  success(res2) {
    								    // 调用uni.uploadFile上传图片即可
    								    console.log(res2)
    										_this.$emit('getImg',res2.tempFilePath);
    								  }
    								},_this)
    							});
    					  }
    					})
    				},
        }
    }
    </script>
    
    <style scoped lang="scss">
    .signa {
        height: 100%;
    	width: 100%;
        .box{
            background-color: #fff;
            width: 100%;
    		height: 100%;
        }
        .canvas {
            position: relative;
            // z-index: 9999;
    		width: 100%;
    		height: 100%;
        }
        .bottomBox{
            flex-direction: column;
            justify-content: center;
            width: 80px;
            height: 80vw;
            padding: 10px;
            // background-color: #007AFF;
            position: fixed;
            left: 50%;
            bottom: -40vw;
            transform: rotate(90deg);
            margin-left: -50px;
            margin-bottom: 72px;
            .tip{
                font-size: 11px;
                color: #FF6F77;
            }
            .btn{
                width: 100%;
                background: #c70019;
                border-radius: 6px;
                margin-top: 14px;
                text-align: center;
                color: #fff;
                font-size: 24rpx;
    			padding: 12px 0;
                &.blue{
                    background: #fff;
    				color: #c70019;
    				border: solid 1px #c70019;
                }
            }
        }
    }
    </style>

在需要的地方引入

<template>
    	<view>
    		<view class="autograph-canvas">
    			<f-signature @getImg="signature"></f-signature>
    		</view>
    	</view>
    </template>
    
    <script>
    	import fSignature from '@/components/f-signature/f-signature';
    	
    	import {
    			pathToBase64,   
    			base64ToPath
    		} from 'image-tools'
    	export default {
    		data() {
    			return {
    			}
    		},
    		components: {fSignature},
    		methods: {
    			signature(dataImg){
    				this.$store.commit('getValue', dataImg);
    				pathToBase64(dataImg).then(data => {
    					uni.setStorageSync('imgSig',data);
    				})
    				uni.navigateBack()
    			}
    		},
    	}
    </script>
    
    <style scoped>
    	.autograph-canvas {
    	    position: fixed;
    	    top: 0;
    	    left: 0;
    	    right: 0;
    	    width: 100%;
    	    height: 100%;
    	    background: #fff;
    	    z-index: 9999;
    	}
    </style>

[canvas_ - DCloud]: https://ext.dcloud.net.cn/plugin?id=9055
[image-tools - DCloud]: https://ext.dcloud.net.cn/plugin?id=123