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Support for images with src of type "Data URI" (Base64) or "Object URL" (Blob). #6

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Support for images with src of type "Data URI" (Base64) or "Object URL" (Blob). #6

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115 changes: 85 additions & 30 deletions exif.js
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Expand Up @@ -57,7 +57,7 @@ var EXIF = (function() {
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", //
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
Expand All @@ -77,7 +77,7 @@ var EXIF = (function() {
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", //
0xA40B : "DeviceSettingDescription", //
0xA40C : "SubjectDistanceRange", // Distance to subject

// other tags
Expand Down Expand Up @@ -294,17 +294,48 @@ var EXIF = (function() {
};

function addEvent(element, event, handler) {
if (element.addEventListener) {
element.addEventListener(event, handler, false);
} else if (element.attachEvent) {
element.attachEvent("on" + 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 base64ToBlob(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);
}
var blob = new Blob([view], {type: contentType});

return blob;
}

function objectURLToBlob (object_url, callback) {
var xhr = new XMLHttpRequest();
xhr.open('GET', object_url, true);
xhr.responseType = 'blob';
xhr.onload = function(e) {
var blob;
if (this.status === 200) {
blob = this.response;
}
callback(blob);
};
xhr.send();
}

function getImageData(img, callback) {
function handleBinaryFile(binFile) {
var data = findEXIFinJPEG(binFile);
Expand All @@ -315,10 +346,34 @@ var EXIF = (function() {
}

if (img instanceof Image) {
BinaryAjax(img.src, function(http) {
handleBinaryFile(http.binaryResponse);
});
} else if (window.FileReader && img instanceof window.File) {
if (/^data\:/i.test(img.src)) { // Data URI
var fileReader = new FileReader();

fileReader.onload = function(e) {
handleBinaryFile(new BinaryFile(e.target.result));
};

var blob = base64ToBlob(img.src);

fileReader.readAsBinaryString(blob);

} else if (/^blob\:/i.test(img.src)) { // Object URL
var fileReader = new FileReader();

fileReader.onload = function(e) {
handleBinaryFile(new BinaryFile(e.target.result));
};

objectURLToBlob(img.src, function (blob) {
fileReader.readAsBinaryString(blob);
});

} else { // HTTP URL
BinaryAjax(img.src, function(http) {
handleBinaryFile(http.binaryResponse);
});
}
} else if (img instanceof Blob || (window.FileReader && img instanceof window.File)) {
var fileReader = new FileReader();

fileReader.onload = function(e) {
Expand Down Expand Up @@ -346,20 +401,20 @@ var EXIF = (function() {

marker = file.getByteAt(offset+1);

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

if (marker == 22400) {
if (debug) console.log("Found 0xFFE1 marker");

return readEXIFData(file, offset + 4, file.getShortAt(offset+2, true)-2);

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

} else if (marker == 225) {
// 0xE1 = Application-specific 1 (for EXIF)
if (debug) console.log("Found 0xFFE1 marker");

return readEXIFData(file, offset + 4, file.getShortAt(offset+2, true)-2);

} else {
Expand All @@ -373,10 +428,10 @@ var EXIF = (function() {

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

for (i=0;i<entries;i++) {
entryOffset = dirStart + i*12 + 2;
tag = strings[file.getShortAt(entryOffset, bigEnd)];
Expand Down Expand Up @@ -526,23 +581,23 @@ var EXIF = (function() {
case "SceneCaptureType" :
case "SceneType" :
case "CustomRendered" :
case "WhiteBalance" :
case "GainControl" :
case "WhiteBalance" :
case "GainControl" :
case "Contrast" :
case "Saturation" :
case "Sharpness" :
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] =

case "ComponentsConfiguration" :
exifData[tag] =
StringValues.Components[exifData[tag][0]]
+ StringValues.Components[exifData[tag][1]]
+ StringValues.Components[exifData[tag][2]]
Expand All @@ -557,10 +612,10 @@ var EXIF = (function() {
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]
case "GPSVersionID" :
gpsData[tag] = gpsData[tag][0]
+ "." + gpsData[tag][1]
+ "." + gpsData[tag][2]
+ "." + gpsData[tag][3];
break;
}
Expand Down Expand Up @@ -591,7 +646,7 @@ var EXIF = (function() {

function getAllTags(img) {
if (!imageHasData(img)) return {};
var a,
var a,
data = img.exifdata,
tags = {};
for (a in data) {
Expand Down Expand Up @@ -627,14 +682,14 @@ var EXIF = (function() {
return findEXIFinJPEG(file);
}


return {
readFromBinaryFile : readFromBinaryFile,
pretty : pretty,
getTag : getTag,
getAllTags : getAllTags,
getData : getData,

Tags : ExifTags,
TiffTags : TiffTags,
GPSTags : GPSTags,
Expand Down