这次给大家带来如何使用Vue2.0调用摄像头进行拍照，使用Vue2.0调用摄像头进行拍照的注意事项有哪些，下面就是实战案例，一起来看一下。

import {Exif} from './exif.js'

export default {

data () {

return {

headerImage:'',picValue:''

}

},

mounted () {

},

methods: {

upload (e) {

let files = e.target.files || e.dataTransfer.files;

if (!files.length) return;

this.picValue = files[0];

this.imgPreview(this.picValue);

console.log(this.picValue)

},

imgPreview (file) {

let self = this;

let Orientation;

//去获取拍照时的信息，解决拍出来的照片旋转问题

Exif.getData(file, function(){

Orientation = Exif.getTag(this, 'Orientation');

});

// 看支持不支持FileReader

if (!file || !window.FileReader) return;

if (/^image/.test(file.type)) {

// 创建一个reader

let reader = new FileReader();

// 将图片2将转成 base64 格式

reader.readAsDataURL(file);

// 读取成功后的回调

reader.onloadend = function () {

let result = this.result;

let img = new Image();

img.src = result;

//判断图片是否大于100K,是就直接上传，反之压缩图片

if (this.result.length <= (100 * 1024)) {

self.headerImage = this.result;

self.postImg();

}else {

img.onload = function () {

let data = self.compress(img,Orientation);

self.headerImage = data;

self.postImg();

}

}

}

}

},

postImg () {

//这里写接口

},

rotateImg (img, direction,canvas) {

//最小与最大旋转方向，图片旋转4次后回到原方向

const min_step = 0;

const max_step = 3;

if (img == null)return;

//img的高度和宽度不能在img元素隐藏后获取，否则会出错

let height = img.height;

let width = img.width;

let step = 2;

if (step == null) {

step = min_step;

}

if (direction == 'right') {

step++;

//旋转到原位置，即超过最大值

step > max_step && (step = min_step);

} else {

step--;

step < min_step && (step = max_step);

}

//旋转角度以弧度值为参数

let degree = step * 90 * Math.PI / 180;

let ctx = canvas.getContext('2d');

switch (step) {

case 0:

canvas.width = width;

canvas.height = height;

ctx.drawImage(img, 0, 0);

break;

case 1:

canvas.width = height;

canvas.height = width;

ctx.rotate(degree);

ctx.drawImage(img, 0, -height);

break;

case 2:

canvas.width = width;

canvas.height = height;

ctx.rotate(degree);

ctx.drawImage(img, -width, -height);

break;

case 3:

canvas.width = height;

canvas.height = width;

ctx.rotate(degree);

ctx.drawImage(img, -width, 0);

break;

}

},

compress(img,Orientation) {

let canvas = document.createElement("canvas");

let ctx = canvas.getContext('2d');

//瓦片canvas

let tCanvas = document.createElement("canvas");

let tctx = tCanvas.getContext("2d");

let initSize = img.src.length;

let width = img.width;

let height = img.height;

//如果图片大于四百万像素，计算压缩比并将大小压至400万以下

let ratio;

if ((ratio = width * height / 4000000) > 1) {

console.log("大于400万像素")

ratio = Math.sqrt(ratio);

width /= ratio;

height /= ratio;

} else {

ratio = 1;

}

canvas.width = width;

canvas.height = height;

// 铺底色

ctx.fillStyle = "#fff";

ctx.fillRect(0, 0, canvas.width, canvas.height);

//如果图片像素大于100万则使用瓦片绘制

let count;

if ((count = width * height / 1000000) > 1) {

console.log("超过100W像素");

count = ~~(Math.sqrt(count) + 1); //计算要分成多少块瓦片

// 计算每块瓦片的宽和高

let nw = ~~(width / count);

let nh = ~~(height / count);

tCanvas.width = nw;

tCanvas.height = nh;

for (let i = 0; i < count; i++) {

for (let j = 0; j < count; j++) {

tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh);

ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh);

}

}

} else {

ctx.drawImage(img, 0, 0, width, height);

}

//修复ios上传图片的时候 被旋转的问题

if(Orientation != "" && Orientation != 1){

switch(Orientation){

case 6://需要顺时针(向左)90度旋转

this.rotateImg(img,'left',canvas);

break;

case 8://需要逆时针(向右)90度旋转

this.rotateImg(img,'right',canvas);

break;

case 3://需要180度旋转

this.rotateImg(img,'right',canvas);//转两次

this.rotateImg(img,'right',canvas);

break;

}

}

//进行最小压缩

let ndata = canvas.toDataURL('image/jpeg', 0.1);

console.log('压缩前：' + initSize);

console.log('压缩后：' + ndata.length);

console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");

tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;

return ndata;

},

}

}

*{

margin: 0;

padding: 0;

}

.show {

width: 100px;

height: 100px;

overflow: hidden;

position: relative;

border-radius: 50%;

border: 1px solid #d5d5d5;

}

.picture {

width: 100%;

height: 100%;

overflow: hidden;

background-position: center center;

background-repeat: no-repeat;

background-size: cover;

}

引用的exif.js代码(function() {

var debug = false;

var root = this;

var EXIF = function(obj) {

if (obj instanceof EXIF) return obj;

if (!(this instanceof EXIF)) return new EXIF(obj);

this.EXIFwrapped = obj;

};

if (typeof exports !== 'undefined') {

if (typeof module !== 'undefined' && module.exports) {

exports = module.exports = EXIF;

}

exports.EXIF = EXIF;

} else {

root.EXIF = EXIF;

}

var ExifTags = EXIF.Tags = {

// 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

};

var TiffTags = EXIF.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 = EXIF.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"

};

var StringValues = EXIF.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"

}

};

function addEvent(element, event, handler) {

if (element.addEventListener) {

element.addEventListener(event, handler, false);

} else if (element.attachEvent) {

element.attachEvent("on" + event, handler);

}

}

function imageHasData(img) {

return !!(img.exifdata);

}

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 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 getImageData(img, callback) {

function handleBinaryFile(binFile) {

var data = findEXIFinJPEG(binFile);

var iptcdata = findIPTCinJPEG(binFile);

img.exifdata = data || {};

img.iptcdata = iptcdata || {};

if (callback) {

callback.call(img);

}

}

if (img.src) {

if (/^data\:/i.test(img.src)) { // Data URI

var arrayBuffer = base64ToArrayBuffer(img.src);

handleBinaryFile(arrayBuffer);

} else if (/^blob\:/i.test(img.src)) { // Object URL

var fileReader = new FileReader();

fileReader.onload = function(e) {

handleBinaryFile(e.target.result);

};

objectURLToBlob(img.src, function (blob) {

fileReader.readAsArrayBuffer(blob);

});

} else {

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.src, true);

http.responseType = "arraybuffer";

http.send(null);

}

} else if (window.FileReader && (img instanceof window.Blob || img instanceof window.File)) {

var fileReader = new FileReader();

fileReader.onload = function(e) {

if (debug) console.log("Got file of length " + e.target.result.byteLength);

handleBinaryFile(e.target.result);

};

fileReader.readAsArrayBuffer(img);

}

}

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 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;

}

function readTags(file, tiffStart, dirStart, strings, bigEnd) {

var entries = file.getUint16(dirStart, !bigEnd),

tags = {},

entryOffset, tag,

i;

for (i=0;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;

}

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

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

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

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

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

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

vals[n] = file.getInt32(valueOffset + 8*n, !bigEnd) / file.getInt32(valueOffset+4 + 8*n, !bigEnd);

}

return vals;

}

}

}

function getStringFromDB(buffer, start, length) {

var outstr = "";

for (n = start; n < start+length; n++) {

outstr += String.fromCharCode(buffer.getUint8(n));

}

return outstr;

}

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];

}

}

return tags;

}

EXIF.getData = function(img, callback) {

if ((img instanceof Image || img instanceof HTMLImageElement) && !img.complete) return false;

if (!imageHasData(img)) {

getImageData(img, callback);

} else {

if (callback) {

callback.call(img);

}

}

return true;

}

EXIF.getTag = function(img, tag) {

if (!imageHasData(img)) return;

return img.exifdata[tag];

}

EXIF.getAllTags = function(img) {

if (!imageHasData(img)) return {};

var a,

data = img.exifdata,

tags = {};

for (a in data) {

if (data.hasOwnProperty(a)) {

tags[a] = data[a];

}

}

return tags;

}

EXIF.pretty = function(img) {

if (!imageHasData(img)) return "";

var a,

data = img.exifdata,

strPretty = "";

for (a in data) {

if (data.hasOwnProperty(a)) {

if (typeof data[a] == "object") {

if (data[a] instanceof Number) {

strPretty += a + " : " + data[a] + " [" + data[a].numerator + "/" + data[a].denominator + "]\r\n";

} else {

strPretty += a + " : [" + data[a].length + " values]\r\n";

}

} else {

strPretty += a + " : " + data[a] + "\r\n";

}

}

}

return strPretty;

}

EXIF.readFromBinaryFile = function(file) {

return findEXIFinJPEG(file);

}

if (typeof define === 'function' && define.amd) {

define('exif-js', [], function() {

return EXIF;

});

}

}.call(this));

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