zhywpt-sp/utils/util/common/photoCompress.js

function chooseImage(options) {
    const self = options.self;
    uni.chooseImage({
        count: 1,
        sizeType: ['compressed'],
        sourceType: ['album', 'camera'],
        success: (res) => {
            console.log('图片选择成功', new Date().getSeconds());
            let fileSize = res.tempFiles[0].size / 1024;
            console.log('图fileSize', fileSize);
            const endSize = options.endSize || 80;
            console.log('endSize', endSize);

            if (fileSize > endSize) {
                photoCompress(
                    {
                        self: self,
                        path: res.tempFiles[0].path,
                        quality: 8,
                        endSize: endSize
                    },
                    options.success,
                    options.fail
                );
            } else {
                photoHandle(
                    {
                        self: self,
                        endSize: options.endSize,
                        path: res.tempFiles[0].path
                    },
                    options.success,
                    options.fail
                );
            }
        },
        fail: (err) => {
            // console.log(err)
            if (options.fail) options.fail(err);
        }
    });
} // 图片压缩

/*
self  页面this
path  图片地址，uni.getImageInfo要求path是图片的本地路径
quality 图片质量 1-10区间，因为下方会乘以0.1
callback 回调返回 （path, base64）
*/

function photoCompress(options, callback, failCallback) {
    const self = options.self;
    const path = options.path;
    const quality = options.quality;
    const endSize = options.endSize;
    console.log('photoCompress压缩开始', options);
    uni.getImageInfo({
        src: path,
        success: (Infores) => {
            const initW = Infores.width,
                initH = Infores.height;

            if (initW > initH) {
                var width = initW > 800 ? 800 : initW;
                var base = initW / width;
                var height = parseInt(initH / base);
            } else {
                var height = initH > 800 ? 800 : initH;
                var base = initH / height;
                var width = parseInt(initW / base);
            }

            self.setData({
                canvas_quality: quality,
                canvasW: width,
                canvasH: height
            });
            console.log('getImageInfo--', Infores, width, height, base, quality);
            let ctx = uni.createCanvasContext('myCanvas');
            ctx.drawImage(Infores.path, 0, 0, width, height);
            ctx.draw(true, () => {
                setTimeout(() => {
                    uni.canvasToTempFilePath({
                        quality: quality * 0.1,
                        fileType: 'jpg',
                        //quality仅对jpg有效
                        canvasId: 'myCanvas',
                        width: width,
                        height: height,
                        destWidth: width,
                        destHeight: height,
                        success: (res) => {
                            console.log('canvasToTempFilePath--', res);
                            photoHandle(
                                {
                                    self: self,
                                    endSize: endSize,
                                    path: res.tempFilePath
                                },
                                callback,
                                failCallback
                            );
                            ctx.clearRect(0, 0, width, height);
                        },
                        fail: (err) => {
                            console.log('canvasToTempFilePath--fail', err);
                            if (failCallback) failCallback(err);
                        }
                    });
                }, 300);
            });
        },
        fail: (err) => {
            if (failCallback) failCallback(err);
        }
    });
} // 生成base64

function photoHandle(options, callback, failCallback) {
    const self = options.self;
    const path = options.path;
    ``;
    const endSize = options.endSize;
    console.log('photoHandle', options);
    let base64Img = 'data:image/jpg;base64,' + uni.getFileSystemManager().readFileSync(path, 'base64');

    if (showSize(base64Img) / 1 > endSize) {
        console.log('压缩后', showSize(base64Img));
        self.data.canvas_quality = self.data.canvas_quality - 1;

        if (self.data.canvas_quality <= 4) {
            //后面备注该处处理原因
            console.log('跳出压缩', showSize(base64Img));
            callback &&
                callback({
                    path: path,
                    base64: base64Img
                });
            return;
        }

        photoCompress(
            {
                self: self,
                path: path,
                quality: self.data.canvas_quality,
                endSize: endSize
            },
            callback,
            failCallback
        );
    } else {
        console.log('压缩结束', showSize(base64Img));
        callback &&
            callback({
                path: path,
                base64: base64Img
            });
    }
} // 获取base64图片大小，返回kb数字

function showSize(base64url) {
    //把头部去掉
    var str = base64url.replace('data:image/png;base64,', ''); // 找到等号，把等号也去掉

    var equalIndex = str.indexOf('=');

    if (str.indexOf('=') > 0) {
        str = str.substring(0, equalIndex);
    } // 原来的字符流大小，单位为字节

    var strLength = str.length; // 计算后得到的文件流大小，单位为字节

    var fileLength = parseInt(strLength - (strLength / 8) * 2); // 由字节转换为kb

    var size = '';
    size = (fileLength / 1024).toFixed(2);
    var sizeStr = size + ''; //转成字符串

    var index = sizeStr.indexOf('.'); //获取小数点处的索引

    var dou = sizeStr.substr(index + 1, 2); //获取小数点后两位的值

    if (dou == '00') {
        //判断后两位是否为00，如果是则删除00
        return sizeStr.substring(0, index) + sizeStr.substr(index + 3, 2);
    }

    return size;
}

module.exports = {
    chooseImage,
    photoCompress,
    photoHandle
};