uniapp 使用canvas 画海报，有手粘贴即可用

html部分

<view  @click="doposter">下载海报</view>
<canvas canvas-id="myCanvas" type='2d' style="width: 370px; height: 550px;opcity:0;position: fixed;z-index:-1;" id="myCanvas" />

js 部分

 drawBackground() {const canvasId   = 'myCanvas'const ctx        = uni.createCanvasContext(canvasId, this)const title      = this.titleconst goodsCover = this.selcetShareImgUrl // 分享商品图片 需要换成自己的产品图片const goodsTitle = this.goods.name // 商品名称const goodsPrice = '￥ '+this.goods.original_priceconst des1       = '① 长按识别二维码'const des2       = '② 查看商品详情'const qrcode     = this.goods.share.code //二维码地址 需要换成自己的二维码//  绘制背景图ctx.setFillStyle('#fff')ctx.fillRect(0, 0, 370, 550)// 字体颜色ctx.setFontSize(17)ctx.setFillStyle('#111')ctx.fillText(title, 50, 39.9)ctx.fillText(title, 49.9, 40)ctx.fillText(title, 50,40)ctx.fillText(title, 50, 40.1)ctx.fillText(title, 50.1, 40.1)// 商品名称 且拦截页面文字长度let titleGoods = this.goods.name.split('').length <= 20 ? this.goods.name : this.goods.name.substring(0,18)+' ...'ctx.setFontSize(16)ctx.setFillStyle('#111')ctx.fillText(titleGoods , 30 , 420)// 商品价格ctx.setFontSize(18)ctx.setFillStyle('#f36d00')ctx.fillText(goodsPrice, 29.9, 450)ctx.fillText(goodsPrice, 30,450)ctx.fillText(goodsPrice, 30, 450.1)ctx.fillText(goodsPrice, 30.1, 450)//  二维码描述ctx.setFontSize(13)ctx.setFillStyle('#999')ctx.fillText(des1, 30, 490)ctx.setFontSize(13)ctx.setFillStyle('#999')ctx.fillText(des2, 30, 520)uni.downloadFile({url:goodsCover,success: (res) => {// 商品图片ctx.drawImage(res.tempFilePath, 30, 70, 310, 310)//  二维码ctx.drawImage(qrcode, 240, 420, 110, 110)ctx.draw(false, () => {uni.canvasToTempFilePath({canvasId: canvasId,success: (res) => {console.log('临时图片路径：', res.tempFilePath);uni.saveImageToPhotosAlbum({filePath: res.tempFilePath,success: () => {uni.hideLoading()uni.showModal({title: '提示',content: ' 图片保存成功',showCancel: false,confirmText: '知道了',confirmColor: '#f36d00',success: res => {uni.navigateBack()}})}})},fail: (error) => {console.error('转化图片失败：', error);}},this)});}})},async doposter() {uni.showLoading({title: '正在生成海报'});await this.drawBackground();},