.vue文件：
结果:
![]()
izExif.js代码：
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 debug = true;
export {
getImageData,
getFloatLocationByExif
}
页面更新：2024-04-19
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