cyzh-SoundOfMusic-H5/components/works-poster/works-poster.vue

<template>
	<view >
		<view class="postcontent"  v-if="isShow" @click.stop="isShow=false">
			<canvas id='canvas' @click.stop="" :style="{ width: canvasW + 'px', height: canvasH + 'px' }" canvas-id="my-canvas"></canvas>
			<!-- <view class="text-center text-white">长按保存图片</view> -->
		</view>
		<u-popup v-model="imgShow" mode="center" width="640" height="990" >
			<image class="calloutImg" :src="imgUrl" @click="preViewImg(imgUrl)"></image>
			<view class="text-center text-lg text-white" style="line-height: 50upx;background-color: #666666;">点击海报，然后长按图片保存</view>
		</u-popup>
	</view>

</template>

<script>
	import { pathToBase64, base64ToPath } from '@/common/utils/index.js'
	export default{
		props:{
			works: {
				type: Object,
				default: {}
			}
		},
		data(){
			return {
				canvasW: 0,
				canvasH: 0,
				ctx: null,
				isShow: false,
				imgUrl:'',
				imgShow: false,
			}
		},
		methods:{
			//显示
			showCanvas(){
				this.isShow = true;
				this.imgShow = true;
				this.__init()
			},
			//初始化画布
			async __init(){
				uni.showLoading({
				    title: '加载中...',
					mask: true
				})
				this.ctx = uni.createCanvasContext('my-canvas', this)
				// this.canvasW = uni.upx2px(550);
				this.canvasW = uni.getSystemInfoSync().windowWidth-uni.upx2px(120)
				this.canvasH = this.canvasW*2 - uni.upx2px(330)
				//设置画布背景透明
				this.ctx.setFillStyle('rgba(255, 255, 255, 0)')
				//设置画布大小
				this.ctx.fillRect(0,0,this.canvasW,this.canvasH)
				//绘制圆角背景
				this.drawRoundRect(this.ctx, 0, 0, this.canvasW, this.canvasH,uni.upx2px(18),'#FFFFFF')
				//获取标题图片
				let headerImg = await this.getImageInfo(this.works.image)
				let hW = uni.upx2px(560);
				let hH = uni.upx2px(360);
				
				//绘制标题
				//绘制标题
				// this.ctx.setFontSize(12); //设置标题字体大小
				// this.ctx.setFillStyle('#333'); //设置标题文本颜色
				// let titleWidth = this.ctx.measureText(this.works.title).width
				// if(titleWidth > hW){
				// 	this.ctx.fillText(this.works.title.slice(0,25),((this.canvasW-hW) / 2),((this.canvasW-hW) / 2))
				// 	this.ctx.fillText(this.works.title.slice(25,50),((this.canvasW-hW) / 2),((this.canvasW-hW) / 2) + uni.upx2px(46))
				// } else{
				// 	this.ctx.fillText(this.works.title,((this.canvasW-hW) / 2),((this.canvasW-hW) / 2))	
				// }
				
				//绘制标题图
				this.drawRoundImg(this.ctx,headerImg.path,((this.canvasW-hW) / 2-uni.upx2px(10)),((this.canvasW-hW) / 2) - uni.upx2px(10),hW + uni.upx2px(20),hW + uni.upx2px(20),uni.upx2px(6))

				//绘制名称
				this.ctx.setFontSize(24);
				this.ctx.setFillStyle('#000000');
				this.ctx.fillText(this.works.title ,((this.canvasW-hW) / 2) + uni.upx2px(2),(((this.canvasW-hW) / 2) + hH + uni.upx2px(280)))
				//绘制副标题
				this.ctx.setFontSize(12);
				this.ctx.setFillStyle('#c7c7c7');
				this.ctx.fillText("赶紧为你的爱豆打榜吧" ,((this.canvasW-hW) / 2) + uni.upx2px(2),(((this.canvasW-hW) / 2) + hH + uni.upx2px(325)))
				
				//绘制热力值
				this.ctx.setFontSize(24);
				this.ctx.setFillStyle('#000000');
				this.ctx.fillText(this.works.hotValue ,((this.canvasW-hW) / 2) + uni.upx2px(2),(((this.canvasW-hW) / 2) + hH + uni.upx2px(390)))
				
				//绘制排名
				this.ctx.setFontSize(12);
				this.ctx.setFillStyle('#000000');
				this.ctx.fillText("热力榜第 "+this.works.rank ,((this.canvasW-hW) / 2) + uni.upx2px(2),(((this.canvasW-hW) / 2) + hH + uni.upx2px(430)))
				
				//提示文案
				this.ctx.setFontSize(12);
				this.ctx.setFillStyle('#858585');
				this.ctx.fillText('来自 '+ this.works.name +' 的分享',(((this.canvasW-hW) / 2)),(((this.canvasW-hW) / 2) + hH + uni.upx2px(500)))
				//底部广告
				// let BottomAdImg = await this.getImageInfo(this.abImg)
				// this.ctx.drawImage(BottomAdImg.path,(((this.canvasW-hW) / 2)),(((this.canvasW-hW) / 2) + hH + uni.upx2px(310)),uni.upx2px(350),uni.upx2px(110))
				//小程序码
				let qrcodeImg = await this.getImageInfo(this.works.qrcode)
				this.ctx.drawImage(qrcodeImg.path,uni.upx2px(450),(((this.canvasW-hW) / 2) + hH + uni.upx2px(360)), uni.upx2px(150), uni.upx2px(150))
				//延迟渲染
				setTimeout(()=>{
					this.ctx.draw(true,()=>{
						uni.hideLoading()
						this.saveImage();
					})
				},500)
			},
			//绘制实心圆
			drawEmptyRound(ctx,x,y,radius){
				ctx.save()
				ctx.beginPath();
				ctx.arc(x, y, radius, 0, 2 * Math.PI,true);
				ctx.setFillStyle('rgba(0, 0, 0, .4)')
				ctx.fill();
				ctx.restore()
				ctx.closePath()
			},
			//绘制虚线
			drawDashLine(ctx,x1,y1,x2,y2,dashLength){
				ctx.setStrokeStyle("#cccccc")//设置线条的颜色
				ctx.setLineWidth(1)//设置线条宽度
				var dashLen = dashLength,
				xpos = x2 - x1, //得到横向的宽度;
				ypos = y2 - y1, //得到纵向的高度;
				numDashes = Math.floor(Math.sqrt(xpos * xpos + ypos * ypos) / dashLen); 
				//利用正切获取斜边的长度除以虚线长度，得到要分为多少段;
				for(var i=0; i<numDashes; i++){
				 if(i % 2 === 0){
					 ctx.moveTo(x1 + (xpos/numDashes) * i, y1 + (ypos/numDashes) * i); 
					 //有了横向宽度和多少段，得出每一段是多长，起点 + 每段长度 * i = 要绘制的起点；
				  }else{
					  ctx.lineTo(x1 + (xpos/numDashes) * i, y1 + (ypos/numDashes) * i);
				  }
				}
				ctx.stroke();
			},
			//带圆角图片
			drawRoundImg(ctx, img, x, y, width, height, radius){
				ctx.beginPath()
				ctx.save()
				// 左上角
				ctx.arc(x + radius, y + radius, radius, Math.PI, Math.PI * 1.5)
				// 右上角
				ctx.arc(x + width - radius, y + radius, radius, Math.PI * 1.5, Math.PI * 2)
				// 右下角
				ctx.arc(x + width - radius, y + height - radius, radius, 0, Math.PI * 0.5)
				// 左下角
				ctx.arc(x + radius, y + height - radius, radius, Math.PI * 0.5, Math.PI)
				ctx.stroke()
				ctx.clip()
				ctx.drawImage(img, x, y, width, height);
				ctx.restore()
				ctx.closePath()
			},
			//圆角矩形
			drawRoundRect(ctx, x, y, width, height, radius, color){
				ctx.save();
				ctx.beginPath();
				ctx.setFillStyle(color); 
				ctx.setStrokeStyle(color)
				ctx.setLineJoin('round');  //交点设置成圆角
				ctx.setLineWidth(radius);
				ctx.strokeRect(x + radius/2, y + radius/2, width - radius , height - radius );
				ctx.fillRect(x + radius, y + radius, width - radius * 2, height - radius * 2);
				ctx.stroke();
				ctx.closePath();
			},
			//获取图片
			getImageInfo(imgSrc){
				return new Promise((resolve, reject) => {
					uni.getImageInfo({
						src: imgSrc,
						success: (image) => {
							resolve(image);
							console.log('获取图片成功',image)
						},
						fail: (err) => {
							reject(err);
							console.log('获取图片失败',err)
						}
					});
				});
			},
			//保存图片到相册
			saveImage(){
				this.isShow = false;
				uni.canvasToTempFilePath({
					canvasId: 'my-canvas',
					quality: 1,
					success: (res) => {
						base64ToPath(res.tempFilePath).then(res => {
							this.imgUrl = res;
						});
						// this.imgUrl = res.tempFilePath.replace(/[\r\n]/g, "");
					}
				},this);
			},
			preViewImg(url) {
				uni.previewImage({
					urls: [url]
				});
			}
		}
	}
</script>

<style scoped lang="scss">
.postcontent{
	position: fixed;
	top: 0;
	left: 0;
	right: 0;
	bottom: 0;
	background: rgba(0,0,0,.4);
	display: flex;
	flex-direction: column;
	justify-content: center;
	align-items: center;
	z-index: 99999999;
	.save-btn{
		margin-top: 35rpx;
		color: #FFFFFF;
		background: linear-gradient(to right, #FE726B , #FE956B);
		padding: 15rpx 40rpx;
		border-radius: 50rpx;
	}
}
.calloutImg {
	width: 640rpx;
	height: 940rpx;
	-webkit-touch-callout: default;
}
</style>