微信小程序bug

一、小程序分享到好友，需要带上path

微信小程序分享给好友

    //分享微信小程序给好友
    onShareAppMessage(res) {
        if (res.from === "button") {
            // 来自页面内转发按钮
            this.isShare = false;
        }
        return {
            title: this.detailData.ProName,
            path:
                "/pages/goods/goodsDetail/goodsDetail?ClubSN=" +
                this.ClubSN +
                "&ProId=" +
                this.ProId
        };
    }

二、canvas画图需要使用本地临时路径

     Taro.downloadFile({
                        url: ShopLogo, //仅为示例，并非真实的资源
                        success: res => {
                            that.ShopLogo = res.tempFilePath;
                            console.log("店铺图标", that.ShopLogo);
                            resolve(1);
                        }
      });

三、canvas不支持base64格式图片，需要先转换

小程序海报 base64在真机中不显示

//base64src.js方法
const fsm = wx.getFileSystemManager();
const FILE_BASE_NAME = 'tmp_base64src'; //自定义文件名

function base64src(base64data, cb) {
    const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(base64data) || [];
    if (!format) {
        return (new Error('ERROR_BASE64SRC_PARSE'));
    }
    const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`;
    const buffer = wx.base64ToArrayBuffer(bodyData);
    fsm.writeFile({
        filePath,
        data: buffer,
        encoding: 'binary',
        success() {
            cb(filePath);
        },
        fail() {
            return (new Error('ERROR_BASE64SRC_WRITE'));
        },
    });
};

export default base64src;

使用

import base64src from "@/utils/base64src.js";

//使用
          base64src(qrCode, res => {
                console.log(res); // 返回图片地址，直接赋值到image标签即可
                let path = res;
                ctx.drawImage(
                    path,
                    0 * rpx,
                    0 * rpx,
                    530 * rpx,
                    530 * rpx,
                    qrCode1,
                    435 * rpx,
                    qrCodeWidth * rpx,
                    qrCodeWidth * rpx
                );
            });

四、canvas获取屏幕宽度，获取自适应单位变量rpx

 <canvas id="poster"
                :style="{width:canvasWidth+'px', height:canvasHeight+'px'}"
                canvasId="poster"
                @longtap="clickCanvas" />

       //获取屏幕宽度，获取自适应单位
            let that = this;
            wx.getSystemInfo({
                success: function(res) {
                    that.rpx = res.windowWidth / 375;
                    that.deviceWidth = res.windowWidth;
                    that.deviceHeight = res.windowHeight;
                    that.canvasWidth = res.windowWidth - 36 * that.rpx;
                    that.canvasHeight = 579 * that.rpx;
                    console.log(that.rpx, "倍");
                    console.log("设备宽", that.deviceWidth);
                    console.log("canvas宽", that.canvasWidth);
                    console.log("canvas高", that.canvasHeight);
                }
            });

//设备像素比
  const dpr = wx.getSystemInfoSync().pixelRatio

  canvas.width = res[0].width * dpr
  canvas.height = res[0].height * dpr