业务要求：
采集用户图片中的位置信息和时间信息，并打上水印展示

实现方案：
采用 exif.js文件解析图片信息，后续水印直接采用阿里云的 OSS 存储自带的打水印方式；需要注意几点；
重点注意：Android 存在权限问题，开始本人是在标准基座调试一切 OK，转到自定义基座发现获取不到经纬度，安卓需要动态申请权限:

 plus.android.requestPermissions(
      [
        "android.permission.READ_MEDIA_IMAGES",
        "android.permission.WRITE_EXTERNAL_STORAGE",
        "android.permission.ACCESS_MEDIA_LOCATION",
      ],
      function (e) {
        console.log("READ_MEDIA_IMAGES", e);
      }
    );

    1，不管是采用 uni.chooseImage 还是 uView 的 upload 组件，需要配置选择的图片是原图；

    2，获取到的经纬度需要转坐标系，不然误差很多；

    3，阿里云 OSS打水印需要按照文档替换编码后的特殊字符；字符长度需要自己控制；

WechatIMG451.jpg

代码：
izExif.js

function getImageData(img) {
    return new Promise(function(resolve, reject) {
        function handleBinaryFile(binFile) {
            var data = findEXIFinJPEG(binFile);
            var iptcdata = findIPTCinJPEG(binFile);
            resolve({
                exif: data || {},
                iptc: iptcdata || {}
            })
        }

        if (/^data\:/i.test(img)) { // Data URI
            var arrayBuffer = base64ToArrayBuffer(img);
            handleBinaryFile(arrayBuffer);
        } else if (/^blob\:/i.test(img)) { // Object URL
            var fileReader = new FileReader();
            fileReader.onload = function(e) {
                handleBinaryFile(e.target.result);
            };
            objectURLToBlob(img, function(blob) {
                fileReader.readAsArrayBuffer(blob);
            });
        } else {
            if (typeof window === 'object' && 'document' in window) {
                var http = new XMLHttpRequest();
                http.onload = function() {
                    if (this.status == 200 || this.status === 0) {
                        handleBinaryFile(http.response);
                    } else {
                        throw "Could not load image";
                    }
                    http = null;
                };
                http.open("GET", img, true);
                http.responseType = "arraybuffer";
                http.send(null);
                return
            }
            if (typeof plus === 'object') {
                plus.io.resolveLocalFileSystemURL(getLocalFilePath(img), function(entry) {
                    entry.file(function(file) {
                        var fileReader = new plus.io.FileReader()
                        fileReader.onload = function(data) {
                            var arrayBuffer = base64ToArrayBuffer(data.target.result);
                            handleBinaryFile(arrayBuffer)
                        }
                        fileReader.onerror = function(error) {
                            reject(error)
                        }
                        fileReader.readAsDataURL(file)
                    }, function(error) {
                        reject(error)
                    })
                }, function(error) {
                    reject(error)
                })
                return
            }
            if (typeof wx === 'object' && wx.canIUse('getFileSystemManager')) {
                wx.getFileSystemManager().readFile({
                    filePath: img,
                    success: function(res) {
                        handleBinaryFile(res.data)
                    },
                    fail: function(error) {
                        reject(error)
                    }
                })
                return
            }
            reject(new Error('not support'))
        }
    })
}

function ToDigital(strDu, strFen, strMiao, len) {
    len = (len > 6 || typeof (len) == "undefined") ? 6 : len;//精确到小数点后最多六位   
    strDu = (typeof (strDu) == "undefined" || strDu == "") ? 0 : parseFloat(strDu);
    strFen = (typeof (strFen) == "undefined" || strFen == "") ? 0 : parseFloat(strFen) / 60;
    strMiao = (typeof (strMiao) == "undefined" || strMiao == "") ? 0 : parseFloat(strMiao) / 3600;
    var digital = strDu + strFen + strMiao;
    if (digital == 0) {
        return "";
    } else {
        return digital.toFixed(len);
    }
}

function getFloatLocationByExif(exif){
    if(!exif.GPSLatitude||!exif.GPSLongitude){
        return null
    }
    let lat = (exif.GPSLatitudeRef == 'S'?-1:1)*ToDigital(exif.GPSLatitude[0],exif.GPSLatitude[1],exif.GPSLatitude[2])
    let lon = (exif.GPSLongitudeRef == 'W'?-1:1)*ToDigital(exif.GPSLongitude[0],exif.GPSLongitude[1],exif.GPSLongitude[2])
    
    return {lat:lat,lon:lon}
}

function getLocalFilePath(path) {
    if (path.indexOf('_www') === 0 || path.indexOf('_doc') === 0 || path.indexOf('_documents') === 0 || path.indexOf('_downloads') === 0) {
        return path
    }
    if (path.indexOf('file://') === 0) {
        return path
    }
    if (path.indexOf('/storage/emulated/0/') === 0) {
        return path
    }
    if (path.indexOf('/') === 0) {
        var localFilePath = plus.io.convertAbsoluteFileSystem(path)
        if (localFilePath !== path) {
            return localFilePath
        } else {
            path = path.substr(1)
        }
    }
    return '_www/' + path
}

function objectURLToBlob(url, callback) {
    var http = new XMLHttpRequest();
    http.open("GET", url, true);
    http.responseType = "blob";
    http.onload = function(e) {
        if (this.status == 200 || this.status === 0) {
            callback(this.response);
        }
    };
    http.send();
}


function base64ToArrayBuffer(base64, contentType) {
    contentType = contentType || base64.match(/^data\:([^\;]+)\;base64,/mi)[1] || ''; // e.g. 'data:image/jpeg;base64,...' => 'image/jpeg'
    base64 = base64.replace(/^data\:([^\;]+)\;base64,/gmi, '');
    var binary = atob(base64);
    var len = binary.length;
    var buffer = new ArrayBuffer(len);
    var view = new Uint8Array(buffer);
    for (var i = 0; i < len; i++) {
        view[i] = binary.charCodeAt(i);
    }
    return buffer;
}

function findEXIFinJPEG(file) {
    var dataView = new DataView(file);

    if (debug) console.log("Got file of length " + file.byteLength);
    if ((dataView.getUint8(0) != 0xFF) || (dataView.getUint8(1) != 0xD8)) {
        if (debug) console.log("Not a valid JPEG");
        return false; // not a valid jpeg
    }

    var offset = 2,
        length = file.byteLength,
        marker;

    while (offset < length) {
        if (dataView.getUint8(offset) != 0xFF) {
            if (debug) console.log("Not a valid marker at offset " + offset + ", found: " + dataView.getUint8(offset));
            return false; // not a valid marker, something is wrong
        }

        marker = dataView.getUint8(offset + 1);
        if (debug) console.log(marker);

        // we could implement handling for other markers here,
        // but we're only looking for 0xFFE1 for EXIF data

        if (marker == 225) {
            if (debug) console.log("Found 0xFFE1 marker");

            return readEXIFData(dataView, offset + 4, dataView.getUint16(offset + 2) - 2);

            // offset += 2 + file.getShortAt(offset+2, true);

        } else {
            offset += 2 + dataView.getUint16(offset + 2);
        }

    }

}

function readEXIFData(file, start) {
    if (getStringFromDB(file, start, 4) != "Exif") {
        if (debug) console.log("Not valid EXIF data! " + getStringFromDB(file, start, 4));
        return false;
    }

    var bigEnd,
        tags, tag,
        exifData, gpsData,
        tiffOffset = start + 6;

    // test for TIFF validity and endianness
    if (file.getUint16(tiffOffset) == 0x4949) {
        bigEnd = false;
    } else if (file.getUint16(tiffOffset) == 0x4D4D) {
        bigEnd = true;
    } else {
        if (debug) console.log("Not valid TIFF data! (no 0x4949 or 0x4D4D)");
        return false;
    }

    if (file.getUint16(tiffOffset + 2, !bigEnd) != 0x002A) {
        if (debug) console.log("Not valid TIFF data! (no 0x002A)");
        return false;
    }

    var firstIFDOffset = file.getUint32(tiffOffset + 4, !bigEnd);

    if (firstIFDOffset < 0x00000008) {
        if (debug) console.log("Not valid TIFF data! (First offset less than 8)", file.getUint32(tiffOffset + 4, !bigEnd));
        return false;
    }

    tags = readTags(file, tiffOffset, tiffOffset + firstIFDOffset, TiffTags, bigEnd);

    if (tags.ExifIFDPointer) {
        exifData = readTags(file, tiffOffset, tiffOffset + tags.ExifIFDPointer, ExifTags, bigEnd);
        for (tag in exifData) {
            switch (tag) {
                case "LightSource":
                case "Flash":
                case "MeteringMode":
                case "ExposureProgram":
                case "SensingMethod":
                case "SceneCaptureType":
                case "SceneType":
                case "CustomRendered":
                case "WhiteBalance":
                case "GainControl":
                case "Contrast":
                case "Saturation":
                case "Sharpness":
                case "SubjectDistanceRange":
                case "FileSource":
                    exifData[tag] = StringValues[tag][exifData[tag]];
                    break;

                case "ExifVersion":
                case "FlashpixVersion":
                    exifData[tag] = String.fromCharCode(exifData[tag][0], exifData[tag][1], exifData[tag][2], exifData[tag][3]);
                    break;

                case "ComponentsConfiguration":
                    exifData[tag] =
                        StringValues.Components[exifData[tag][0]] +
                        StringValues.Components[exifData[tag][1]] +
                        StringValues.Components[exifData[tag][2]] +
                        StringValues.Components[exifData[tag][3]];
                    break;
            }
            tags[tag] = exifData[tag];
        }
    }

    if (tags.GPSInfoIFDPointer) {
        gpsData = readTags(file, tiffOffset, tiffOffset + tags.GPSInfoIFDPointer, GPSTags, bigEnd);
        for (tag in gpsData) {
            switch (tag) {
                case "GPSVersionID":
                    gpsData[tag] = gpsData[tag][0] +
                        "." + gpsData[tag][1] +
                        "." + gpsData[tag][2] +
                        "." + gpsData[tag][3];
                    break;
            }
            tags[tag] = gpsData[tag];
        }
    }

    // extract thumbnail
    tags['thumbnail'] = readThumbnailImage(file, tiffOffset, firstIFDOffset, bigEnd);

    return tags;
}

function getStringFromDB(buffer, start, length) {
    var outstr = "";
    for (var n = start; n < start + length; n++) {
        outstr += String.fromCharCode(buffer.getUint8(n));
    }
    return outstr;
}

function readTags(file, tiffStart, dirStart, strings, bigEnd) {
    var entries = file.getUint16(dirStart, !bigEnd),
        tags = {},
        entryOffset, tag,
        i;

    for (i = 0; i < entries; i++) {
        entryOffset = dirStart + i * 12 + 2;
        tag = strings[file.getUint16(entryOffset, !bigEnd)];
        if (!tag && debug) console.log("Unknown tag: " + file.getUint16(entryOffset, !bigEnd));
        tags[tag] = readTagValue(file, entryOffset, tiffStart, dirStart, bigEnd);
    }
    return tags;
}

// 
var TiffTags = {
    0x0100: "ImageWidth",
    0x0101: "ImageHeight",
    0x8769: "ExifIFDPointer",
    0x8825: "GPSInfoIFDPointer",
    0xA005: "InteroperabilityIFDPointer",
    0x0102: "BitsPerSample",
    0x0103: "Compression",
    0x0106: "PhotometricInterpretation",
    0x0112: "Orientation",
    0x0115: "SamplesPerPixel",
    0x011C: "PlanarConfiguration",
    0x0212: "YCbCrSubSampling",
    0x0213: "YCbCrPositioning",
    0x011A: "XResolution",
    0x011B: "YResolution",
    0x0128: "ResolutionUnit",
    0x0111: "StripOffsets",
    0x0116: "RowsPerStrip",
    0x0117: "StripByteCounts",
    0x0201: "JPEGInterchangeFormat",
    0x0202: "JPEGInterchangeFormatLength",
    0x012D: "TransferFunction",
    0x013E: "WhitePoint",
    0x013F: "PrimaryChromaticities",
    0x0211: "YCbCrCoefficients",
    0x0214: "ReferenceBlackWhite",
    0x0132: "DateTime",
    0x010E: "ImageDescription",
    0x010F: "Make",
    0x0110: "Model",
    0x0131: "Software",
    0x013B: "Artist",
    0x8298: "Copyright"
};

var GPSTags = {
    0x0000: "GPSVersionID",
    0x0001: "GPSLatitudeRef",
    0x0002: "GPSLatitude",
    0x0003: "GPSLongitudeRef",
    0x0004: "GPSLongitude",
    0x0005: "GPSAltitudeRef",
    0x0006: "GPSAltitude",
    0x0007: "GPSTimeStamp",
    0x0008: "GPSSatellites",
    0x0009: "GPSStatus",
    0x000A: "GPSMeasureMode",
    0x000B: "GPSDOP",
    0x000C: "GPSSpeedRef",
    0x000D: "GPSSpeed",
    0x000E: "GPSTrackRef",
    0x000F: "GPSTrack",
    0x0010: "GPSImgDirectionRef",
    0x0011: "GPSImgDirection",
    0x0012: "GPSMapDatum",
    0x0013: "GPSDestLatitudeRef",
    0x0014: "GPSDestLatitude",
    0x0015: "GPSDestLongitudeRef",
    0x0016: "GPSDestLongitude",
    0x0017: "GPSDestBearingRef",
    0x0018: "GPSDestBearing",
    0x0019: "GPSDestDistanceRef",
    0x001A: "GPSDestDistance",
    0x001B: "GPSProcessingMethod",
    0x001C: "GPSAreaInformation",
    0x001D: "GPSDateStamp",
    0x001E: "GPSDifferential"
};

// EXIF 2.3 Spec
var IFD1Tags = {
    0x0100: "ImageWidth",
    0x0101: "ImageHeight",
    0x0102: "BitsPerSample",
    0x0103: "Compression",
    0x0106: "PhotometricInterpretation",
    0x0111: "StripOffsets",
    0x0112: "Orientation",
    0x0115: "SamplesPerPixel",
    0x0116: "RowsPerStrip",
    0x0117: "StripByteCounts",
    0x011A: "XResolution",
    0x011B: "YResolution",
    0x011C: "PlanarConfiguration",
    0x0128: "ResolutionUnit",
    0x0201: "JpegIFOffset", // When image format is JPEG, this value show offset to JPEG data stored.(aka "ThumbnailOffset" or "JPEGInterchangeFormat")
    0x0202: "JpegIFByteCount", // When image format is JPEG, this value shows data size of JPEG image (aka "ThumbnailLength" or "JPEGInterchangeFormatLength")
    0x0211: "YCbCrCoefficients",
    0x0212: "YCbCrSubSampling",
    0x0213: "YCbCrPositioning",
    0x0214: "ReferenceBlackWhite"
};

var StringValues = {
    ExposureProgram: {
        0: "Not defined",
        1: "Manual",
        2: "Normal program",
        3: "Aperture priority",
        4: "Shutter priority",
        5: "Creative program",
        6: "Action program",
        7: "Portrait mode",
        8: "Landscape mode"
    },
    MeteringMode: {
        0: "Unknown",
        1: "Average",
        2: "CenterWeightedAverage",
        3: "Spot",
        4: "MultiSpot",
        5: "Pattern",
        6: "Partial",
        255: "Other"
    },
    LightSource: {
        0: "Unknown",
        1: "Daylight",
        2: "Fluorescent",
        3: "Tungsten (incandescent light)",
        4: "Flash",
        9: "Fine weather",
        10: "Cloudy weather",
        11: "Shade",
        12: "Daylight fluorescent (D 5700 - 7100K)",
        13: "Day white fluorescent (N 4600 - 5400K)",
        14: "Cool white fluorescent (W 3900 - 4500K)",
        15: "White fluorescent (WW 3200 - 3700K)",
        17: "Standard light A",
        18: "Standard light B",
        19: "Standard light C",
        20: "D55",
        21: "D65",
        22: "D75",
        23: "D50",
        24: "ISO studio tungsten",
        255: "Other"
    },
    Flash: {
        0x0000: "Flash did not fire",
        0x0001: "Flash fired",
        0x0005: "Strobe return light not detected",
        0x0007: "Strobe return light detected",
        0x0009: "Flash fired, compulsory flash mode",
        0x000D: "Flash fired, compulsory flash mode, return light not detected",
        0x000F: "Flash fired, compulsory flash mode, return light detected",
        0x0010: "Flash did not fire, compulsory flash mode",
        0x0018: "Flash did not fire, auto mode",
        0x0019: "Flash fired, auto mode",
        0x001D: "Flash fired, auto mode, return light not detected",
        0x001F: "Flash fired, auto mode, return light detected",
        0x0020: "No flash function",
        0x0041: "Flash fired, red-eye reduction mode",
        0x0045: "Flash fired, red-eye reduction mode, return light not detected",
        0x0047: "Flash fired, red-eye reduction mode, return light detected",
        0x0049: "Flash fired, compulsory flash mode, red-eye reduction mode",
        0x004D: "Flash fired, compulsory flash mode, red-eye reduction mode, return light not detected",
        0x004F: "Flash fired, compulsory flash mode, red-eye reduction mode, return light detected",
        0x0059: "Flash fired, auto mode, red-eye reduction mode",
        0x005D: "Flash fired, auto mode, return light not detected, red-eye reduction mode",
        0x005F: "Flash fired, auto mode, return light detected, red-eye reduction mode"
    },
    SensingMethod: {
        1: "Not defined",
        2: "One-chip color area sensor",
        3: "Two-chip color area sensor",
        4: "Three-chip color area sensor",
        5: "Color sequential area sensor",
        7: "Trilinear sensor",
        8: "Color sequential linear sensor"
    },
    SceneCaptureType: {
        0: "Standard",
        1: "Landscape",
        2: "Portrait",
        3: "Night scene"
    },
    SceneType: {
        1: "Directly photographed"
    },
    CustomRendered: {
        0: "Normal process",
        1: "Custom process"
    },
    WhiteBalance: {
        0: "Auto white balance",
        1: "Manual white balance"
    },
    GainControl: {
        0: "None",
        1: "Low gain up",
        2: "High gain up",
        3: "Low gain down",
        4: "High gain down"
    },
    Contrast: {
        0: "Normal",
        1: "Soft",
        2: "Hard"
    },
    Saturation: {
        0: "Normal",
        1: "Low saturation",
        2: "High saturation"
    },
    Sharpness: {
        0: "Normal",
        1: "Soft",
        2: "Hard"
    },
    SubjectDistanceRange: {
        0: "Unknown",
        1: "Macro",
        2: "Close view",
        3: "Distant view"
    },
    FileSource: {
        3: "DSC"
    },

    Components: {
        0: "",
        1: "Y",
        2: "Cb",
        3: "Cr",
        4: "R",
        5: "G",
        6: "B"
    }
};

var ExifTags = {

    // version tags
    0x9000: "ExifVersion", // EXIF version
    0xA000: "FlashpixVersion", // Flashpix format version

    // colorspace tags
    0xA001: "ColorSpace", // Color space information tag

    // image configuration
    0xA002: "PixelXDimension", // Valid width of meaningful image
    0xA003: "PixelYDimension", // Valid height of meaningful image
    0x9101: "ComponentsConfiguration", // Information about channels
    0x9102: "CompressedBitsPerPixel", // Compressed bits per pixel

    // user information
    0x927C: "MakerNote", // Any desired information written by the manufacturer
    0x9286: "UserComment", // Comments by user

    // related file
    0xA004: "RelatedSoundFile", // Name of related sound file

    // date and time
    0x9003: "DateTimeOriginal", // Date and time when the original image was generated
    0x9004: "DateTimeDigitized", // Date and time when the image was stored digitally
    0x9290: "SubsecTime", // Fractions of seconds for DateTime
    0x9291: "SubsecTimeOriginal", // Fractions of seconds for DateTimeOriginal
    0x9292: "SubsecTimeDigitized", // Fractions of seconds for DateTimeDigitized

    // picture-taking conditions
    0x829A: "ExposureTime", // Exposure time (in seconds)
    0x829D: "FNumber", // F number
    0x8822: "ExposureProgram", // Exposure program
    0x8824: "SpectralSensitivity", // Spectral sensitivity
    0x8827: "ISOSpeedRatings", // ISO speed rating
    0x8828: "OECF", // Optoelectric conversion factor
    0x9201: "ShutterSpeedValue", // Shutter speed
    0x9202: "ApertureValue", // Lens aperture
    0x9203: "BrightnessValue", // Value of brightness
    0x9204: "ExposureBias", // Exposure bias
    0x9205: "MaxApertureValue", // Smallest F number of lens
    0x9206: "SubjectDistance", // Distance to subject in meters
    0x9207: "MeteringMode", // Metering mode
    0x9208: "LightSource", // Kind of light source
    0x9209: "Flash", // Flash status
    0x9214: "SubjectArea", // Location and area of main subject
    0x920A: "FocalLength", // Focal length of the lens in mm
    0xA20B: "FlashEnergy", // Strobe energy in BCPS
    0xA20C: "SpatialFrequencyResponse", //
    0xA20E: "FocalPlaneXResolution", // Number of pixels in width direction per FocalPlaneResolutionUnit
    0xA20F: "FocalPlaneYResolution", // Number of pixels in height direction per FocalPlaneResolutionUnit
    0xA210: "FocalPlaneResolutionUnit", // Unit for measuring FocalPlaneXResolution and FocalPlaneYResolution
    0xA214: "SubjectLocation", // Location of subject in image
    0xA215: "ExposureIndex", // Exposure index selected on camera
    0xA217: "SensingMethod", // Image sensor type
    0xA300: "FileSource", // Image source (3 == DSC)
    0xA301: "SceneType", // Scene type (1 == directly photographed)
    0xA302: "CFAPattern", // Color filter array geometric pattern
    0xA401: "CustomRendered", // Special processing
    0xA402: "ExposureMode", // Exposure mode
    0xA403: "WhiteBalance", // 1 = auto white balance, 2 = manual
    0xA404: "DigitalZoomRation", // Digital zoom ratio
    0xA405: "FocalLengthIn35mmFilm", // Equivalent foacl length assuming 35mm film camera (in mm)
    0xA406: "SceneCaptureType", // Type of scene
    0xA407: "GainControl", // Degree of overall image gain adjustment
    0xA408: "Contrast", // Direction of contrast processing applied by camera
    0xA409: "Saturation", // Direction of saturation processing applied by camera
    0xA40A: "Sharpness", // Direction of sharpness processing applied by camera
    0xA40B: "DeviceSettingDescription", //
    0xA40C: "SubjectDistanceRange", // Distance to subject

    // other tags
    0xA005: "InteroperabilityIFDPointer",
    0xA420: "ImageUniqueID" // Identifier assigned uniquely to each image
};

function readTagValue(file, entryOffset, tiffStart, dirStart, bigEnd) {
    var type = file.getUint16(entryOffset + 2, !bigEnd),
        numValues = file.getUint32(entryOffset + 4, !bigEnd),
        valueOffset = file.getUint32(entryOffset + 8, !bigEnd) + tiffStart,
        offset,
        vals, val, n,
        numerator, denominator;

    switch (type) {
        case 1: // byte, 8-bit unsigned int
        case 7: // undefined, 8-bit byte, value depending on field
            if (numValues == 1) {
                return file.getUint8(entryOffset + 8, !bigEnd);
            } else {
                offset = numValues > 4 ? valueOffset : (entryOffset + 8);
                vals = [];
                for (n = 0; n < numValues; n++) {
                    vals[n] = file.getUint8(offset + n);
                }
                return vals;
            }

        case 2: // ascii, 8-bit byte
            offset = numValues > 4 ? valueOffset : (entryOffset + 8);
            return getStringFromDB(file, offset, numValues - 1);

        case 3: // short, 16 bit int
            if (numValues == 1) {
                return file.getUint16(entryOffset + 8, !bigEnd);
            } else {
                offset = numValues > 2 ? valueOffset : (entryOffset + 8);
                vals = [];
                for (n = 0; n < numValues; n++) {
                    vals[n] = file.getUint16(offset + 2 * n, !bigEnd);
                }
                return vals;
            }

        case 4: // long, 32 bit int
            if (numValues == 1) {
                return file.getUint32(entryOffset + 8, !bigEnd);
            } else {
                vals = [];
                for (n = 0; n < numValues; n++) {
                    vals[n] = file.getUint32(valueOffset + 4 * n, !bigEnd);
                }
                return vals;
            }

        case 5: // rational = two long values, first is numerator, second is denominator
            if (numValues == 1) {
                numerator = file.getUint32(valueOffset, !bigEnd);
                denominator = file.getUint32(valueOffset + 4, !bigEnd);
                val = new Number(numerator / denominator);
                val.numerator = numerator;
                val.denominator = denominator;
                return val;
            } else {
                vals = [];
                for (n = 0; n < numValues; n++) {
                    numerator = file.getUint32(valueOffset + 8 * n, !bigEnd);
                    denominator = file.getUint32(valueOffset + 4 + 8 * n, !bigEnd);
                    vals[n] = new Number(numerator / denominator);
                    vals[n].numerator = numerator;
                    vals[n].denominator = denominator;
                }
                return vals;
            }

        case 9: // slong, 32 bit signed int
            if (numValues == 1) {
                return file.getInt32(entryOffset + 8, !bigEnd);
            } else {
                vals = [];
                for (n = 0; n < numValues; n++) {
                    vals[n] = file.getInt32(valueOffset + 4 * n, !bigEnd);
                }
                return vals;
            }

        case 10: // signed rational, two slongs, first is numerator, second is denominator
            if (numValues == 1) {
                return file.getInt32(valueOffset, !bigEnd) / file.getInt32(valueOffset + 4, !bigEnd);
            } else {
                vals = [];
                for (n = 0; n < numValues; n++) {
                    vals[n] = file.getInt32(valueOffset + 8 * n, !bigEnd) / file.getInt32(valueOffset + 4 + 8 * n, !bigEnd);
                }
                return vals;
            }
    }
}

function readThumbnailImage(dataView, tiffStart, firstIFDOffset, bigEnd) {
    // get the IFD1 offset
    var IFD1OffsetPointer = getNextIFDOffset(dataView, tiffStart + firstIFDOffset, bigEnd);

    if (!IFD1OffsetPointer) {
        // console.log('******** IFD1Offset is empty, image thumb not found ********');
        return {};
    } else if (IFD1OffsetPointer > dataView.byteLength) { // this should not happen
        // console.log('******** IFD1Offset is outside the bounds of the DataView ********');
        return {};
    }
    // console.log('*******  thumbnail IFD offset (IFD1) is: %s', IFD1OffsetPointer);

    var thumbTags = readTags(dataView, tiffStart, tiffStart + IFD1OffsetPointer, IFD1Tags, bigEnd)

    // EXIF 2.3 specification for JPEG format thumbnail

    // If the value of Compression(0x0103) Tag in IFD1 is '6', thumbnail image format is JPEG.
    // Most of Exif image uses JPEG format for thumbnail. In that case, you can get offset of thumbnail
    // by JpegIFOffset(0x0201) Tag in IFD1, size of thumbnail by JpegIFByteCount(0x0202) Tag.
    // Data format is ordinary JPEG format, starts from 0xFFD8 and ends by 0xFFD9. It seems that
    // JPEG format and 160x120pixels of size are recommended thumbnail format for Exif2.1 or later.

    if (thumbTags['Compression']) {
        // console.log('Thumbnail image found!');

        switch (thumbTags['Compression']) {
            case 6:
                // console.log('Thumbnail image format is JPEG');
                if (thumbTags.JpegIFOffset && thumbTags.JpegIFByteCount) {
                    // extract the thumbnail
                    var tOffset = tiffStart + thumbTags.JpegIFOffset;
                    var tLength = thumbTags.JpegIFByteCount;
                    //iz
                    // thumbTags['blob'] = new Blob([new Uint8Array(dataView.buffer, tOffset, tLength)], {
                    //     type: 'image/jpeg'
                    // });
                }
                break;

            case 1:
                console.log("Thumbnail image format is TIFF, which is not implemented.");
                break;
            default:
                console.log("Unknown thumbnail image format '%s'", thumbTags['Compression']);
        }
    } else if (thumbTags['PhotometricInterpretation'] == 2) {
        console.log("Thumbnail image format is RGB, which is not implemented.");
    }
    return thumbTags;
}

function getNextIFDOffset(dataView, dirStart, bigEnd) {
    //the first 2bytes means the number of directory entries contains in this IFD
    var entries = dataView.getUint16(dirStart, !bigEnd);

    // After last directory entry, there is a 4bytes of data,
    // it means an offset to next IFD.
    // If its value is '0x00000000', it means this is the last IFD and there is no linked IFD.

    return dataView.getUint32(dirStart + 2 + entries * 12, !bigEnd); // each entry is 12 bytes long
}

function findIPTCinJPEG(file) {
    var dataView = new DataView(file);

    if (debug) console.log("Got file of length " + file.byteLength);
    if ((dataView.getUint8(0) != 0xFF) || (dataView.getUint8(1) != 0xD8)) {
        if (debug) console.log("Not a valid JPEG");
        return false; // not a valid jpeg
    }

    var offset = 2,
        length = file.byteLength;


    var isFieldSegmentStart = function(dataView, offset) {
        return (
            dataView.getUint8(offset) === 0x38 &&
            dataView.getUint8(offset + 1) === 0x42 &&
            dataView.getUint8(offset + 2) === 0x49 &&
            dataView.getUint8(offset + 3) === 0x4D &&
            dataView.getUint8(offset + 4) === 0x04 &&
            dataView.getUint8(offset + 5) === 0x04
        );
    };

    while (offset < length) {

        if (isFieldSegmentStart(dataView, offset)) {

            // Get the length of the name header (which is padded to an even number of bytes)
            var nameHeaderLength = dataView.getUint8(offset + 7);
            if (nameHeaderLength % 2 !== 0) nameHeaderLength += 1;
            // Check for pre photoshop 6 format
            if (nameHeaderLength === 0) {
                // Always 4
                nameHeaderLength = 4;
            }

            var startOffset = offset + 8 + nameHeaderLength;
            var sectionLength = dataView.getUint16(offset + 6 + nameHeaderLength);

            return readIPTCData(file, startOffset, sectionLength);

            break;

        }
        // Not the marker, continue searching
        offset++;

    }

}
var IptcFieldMap = {
    0x78 : 'caption',
    0x6E : 'credit',
    0x19 : 'keywords',
    0x37 : 'dateCreated',
    0x50 : 'byline',
    0x55 : 'bylineTitle',
    0x7A : 'captionWriter',
    0x69 : 'headline',
    0x74 : 'copyright',
    0x0F : 'category'
  };
  function readIPTCData(file, startOffset, sectionLength){
    var dataView = new DataView(file);
    var data = {};
    var fieldValue, fieldName, dataSize, segmentType, segmentSize;
    var segmentStartPos = startOffset;
    while(segmentStartPos < startOffset+sectionLength) {
      if(dataView.getUint8(segmentStartPos) === 0x1C && dataView.getUint8(segmentStartPos+1) === 0x02){
        segmentType = dataView.getUint8(segmentStartPos+2);
        if(segmentType in IptcFieldMap) {
          dataSize = dataView.getInt16(segmentStartPos+3);
          segmentSize = dataSize + 5;
          fieldName = IptcFieldMap[segmentType];
          fieldValue = getStringFromDB(dataView, segmentStartPos+5, dataSize);
          // Check if we already stored a value with this name
          if(data.hasOwnProperty(fieldName)) {
            // Value already stored with this name, create multivalue field
            if(data[fieldName] instanceof Array) {
              data[fieldName].push(fieldValue);
            }
            else {
              data[fieldName] = [data[fieldName], fieldValue];
            }
          }
          else {
            data[fieldName] = fieldValue;
          }
        }
 
      }
      segmentStartPos++;
    }
    return data;
  }
var debug = true;

export {
    getImageData,
    getFloatLocationByExif
}

geoParse.js

import { getImageData, getFloatLocationByExif } from "@/common/izExif.js";
/**
 * WGS84转GCj02
 * @param lng
 * @param lat
 * @returns {*[]}
 */
var wgs84togcj02 = function wgs84togcj02(lng, lat) {
  var lat = +lat;
  var lng = +lng;
  if (out_of_china(lng, lat)) {
    return [lng, lat];
  } else {
    var dlat = transformlat(lng - 105.0, lat - 35.0);
    var dlng = transformlng(lng - 105.0, lat - 35.0);
    var radlat = (lat / 180.0) * PI;
    var magic = Math.sin(radlat);
    magic = 1 - ee * magic * magic;
    var sqrtmagic = Math.sqrt(magic);
    dlat = (dlat * 180.0) / (((a * (1 - ee)) / (magic * sqrtmagic)) * PI);
    dlng = (dlng * 180.0) / ((a / sqrtmagic) * Math.cos(radlat) * PI);
    var mglat = lat + dlat;
    var mglng = lng + dlng;
    return [mglng, mglat];
  }
};

/**
 * GCJ02 转换为 WGS84
 * @param lng
 * @param lat
 * @returns {*[]}
 */
var x_PI = (3.14159265358979324 * 3000.0) / 180.0;
var PI = 3.1415926535897932384626;
var a = 6378245.0;
var ee = 0.00669342162296594323;
const gcj02towgs84 = function gcj02towgs84(lng, lat) {
  var lat = +lat;
  var lng = +lng;
  if (out_of_china(lng, lat)) {
    return [lng, lat];
  } else {
    var dlat = transformlat(lng - 105.0, lat - 35.0);
    var dlng = transformlng(lng - 105.0, lat - 35.0);
    var radlat = (lat / 180.0) * PI;
    var magic = Math.sin(radlat);
    magic = 1 - ee * magic * magic;
    var sqrtmagic = Math.sqrt(magic);
    dlat = (dlat * 180.0) / (((a * (1 - ee)) / (magic * sqrtmagic)) * PI);
    dlng = (dlng * 180.0) / ((a / sqrtmagic) * Math.cos(radlat) * PI);
    var mglat = lat + dlat;
    var mglng = lng + dlng;
    return [lng * 2 - mglng, lat * 2 - mglat];
  }
};

var transformlat = function transformlat(lng, lat) {
  var lat = +lat;
  var lng = +lng;
  var ret =
    -100.0 +
    2.0 * lng +
    3.0 * lat +
    0.2 * lat * lat +
    0.1 * lng * lat +
    0.2 * Math.sqrt(Math.abs(lng));
  ret +=
    ((20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) *
      2.0) /
    3.0;
  ret +=
    ((20.0 * Math.sin(lat * PI) + 40.0 * Math.sin((lat / 3.0) * PI)) * 2.0) /
    3.0;
  ret +=
    ((160.0 * Math.sin((lat / 12.0) * PI) + 320 * Math.sin((lat * PI) / 30.0)) *
      2.0) /
    3.0;
  return ret;
};

var transformlng = function transformlng(lng, lat) {
  var lat = +lat;
  var lng = +lng;
  var ret =
    300.0 +
    lng +
    2.0 * lat +
    0.1 * lng * lng +
    0.1 * lng * lat +
    0.1 * Math.sqrt(Math.abs(lng));
  ret +=
    ((20.0 * Math.sin(6.0 * lng * PI) + 20.0 * Math.sin(2.0 * lng * PI)) *
      2.0) /
    3.0;
  ret +=
    ((20.0 * Math.sin(lng * PI) + 40.0 * Math.sin((lng / 3.0) * PI)) * 2.0) /
    3.0;
  ret +=
    ((150.0 * Math.sin((lng / 12.0) * PI) +
      300.0 * Math.sin((lng / 30.0) * PI)) *
      2.0) /
    3.0;
  return ret;
};

/**
 * 判断是否在国内，不在国内则不做偏移
 * @param lng
 * @param lat
 * @returns {boolean}
 */
var out_of_china = function out_of_china(lng, lat) {
  var lat = +lat;
  var lng = +lng;
  // 纬度3.86~53.55,经度73.66~135.05
  return !(lng > 73.66 && lng < 135.05 && lat > 3.86 && lat < 53.55);
};

function isJPEG(filePath) {
  return (
    filePath.toLowerCase().endsWith(".jpg") ||
    filePath.toLowerCase().endsWith(".jpeg")
  );
}

function haversine(lon1, lat1, lon2, lat2) {
  // 转换为弧度
  lon1 = radians(lon1);
  lat1 = radians(lat1);
  lon2 = radians(lon2);
  lat2 = radians(lat2);

  // 计算经度和纬度的差值
  const dlon = lon2 - lon1;
  const dlat = lat2 - lat1;

  // Haversine 公式
  const a =
    Math.sin(dlat / 2) ** 2 +
    Math.cos(lat1) * Math.cos(lat2) * Math.sin(dlon / 2) ** 2;
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

  // 地球半径（千米）
  const R = 6371;

  // 计算距离
  return R * c;
}

function radians(degrees) {
  return degrees * (Math.PI / 180);
}

// 高德-逆地理编码
const geoParse = (lon, lat) => {
  // https://restapi.amap.com/v3/geocode/geo?parameters
  const [lon3, lat3] = wgs84togcj02(lon, lat);
  console.log(lon3, lat3);
  const obj = {
    output: "JSON",
    location: `${lon3},${lat3}`,
    key: "高德 key",
    radius: 300,
    extensions: "base", //all | base
    roadlevel: 1,
  };

  return new Promise((resolve, reject) => {
    uni
      .request({
        url: `https://restapi.amap.com/v3/geocode/regeo`,
        data: obj,
        method: "GET",
      })
      .then((res) => {
        const { data, statusCode } = res;
        if (statusCode === 200 && data && data.regeocode) {
          const { addressComponent, formatted_address } = data.regeocode;
          if (formatted_address && addressComponent) {
            const { city } = addressComponent;
            const splitByCity = formatted_address.split(city);
            console.log(splitByCity);
            if (splitByCity.length > 0) {
              let formatted_address_new = splitByCity[1];
              resolve(formatted_address_new);
            }
          }
          resolve(formatted_address);
        }
        reject("");
      })
      .catch((err) => {
        reject("");
      })
      .finally(() => {});
  });
};

const parseImage = (filePath, cb) => {
  uni.showLoading({
    title: "获取照片信息中...",
  });
  uni.saveFile({
    tempFilePath: filePath,
    success: function (file) {
      // 调用izExif的方法，解析照片的EXIF信息
      // fileList1.value.push({
      //    url: file.savedFilePath
      // })
      getImageData(file.savedFilePath)
        .then(async (res) => {
          // 得到拍摄时间
          // time.value = res.exif.DateTime
          // 调用izExif的方法，解析照片的EXIF信息里的经纬度
          const lnglat = getFloatLocationByExif(res.exif);
          const address = await geoParse(lnglat.lon, lnglat.lat);
          console.log(address);
          if (lnglat === null) {
            uni.showToast({
              title: "此照片没有位置信息！",
            });
            return null;
          }
          const obj = {
            lat: lnglat.lat,
            lon: lnglat.lon,
            address: address,
            dateTime: res.exif.DateTime,
            filePath: filePath,
          };
          cb(obj);
        })
        .catch((e) => {
          //e : cannot read propty 'lat' of null
          // uni.showModal({
          //    content: 'getImageData catch error' + e
          // })
          // uni.showToast({
          //    title: '此照片没有位置信息！'
          // })
          const obj = {
            lat: "",
            lon: "",
            address: "",
            dateTime: "",
            filePath: filePath,
          };
          cb(obj);
        })
        .finally(() => {
          uni.hideLoading();
        });
    },
    fail: function (error) {
      console.log("存储失败", error);
      uni.showToast({
        title: "存储失败！",
      });
    },
  });
};

export { wgs84togcj02, gcj02towgs84, parseImage };

调用

uni.chooseImage({
    count: 1,
    sourceType: ["album", "camera"],
    // 这里不要压缩，否则可能得不到EXIF信息
    sizeType: ["original"],
    success: (res) => {
      parseImage(res.tempFilePaths[0], (exifData) => {
        address.value = exifData.address;
        time.value = exifData.dateTime;
        lat.value = exifData.lat;
        lon.value = exifData.lon;
        const waterMaskAddress = await makeWaterMask(address.value);
        const waterMaskTime = await makeWaterMask(time.value);
        const waterMaskUrl =
        aliOss +
        `?x-oss-process=image/watermark,size_32,color_000000,text_${waterMaskAddress}/watermark,text_${waterMaskTime},y_60`;
        fileList1.value.push({
            url: waterMaskUrl,
        });

      });
    },
  });

const makeWaterMask = (str) => {
  return new Promise((resolve, reject) => {
    str = str.slice(0, 20);
    let txt = new Buffer(str).toString("base64");
    console.log("txt", txt);
    // 全部替换 / -> _  + -> -  = -> ''
    txt = txt.replace(/\//g, "_").replace(/\+/g, "-").replace(/=/g, "");
    //长度不超过20个字符
    console.log("txt", txt);
    //encodeURIComponent() 函数可以把字符串作为 URI 组件进行编码并且不会对 ASCII 字母和数字进行编码，也不会对这些 ASCII 标点符号进行编码
    const urltxt = encodeURIComponent(txt);
    resolve(urltxt);
  });
};