Welcome to Piexifjs’s documentation!¶

https://travis-ci.org/hMatoba/piexifjs.svg?branch=master

Exif manipulations with JavaScript. Writing, reading, and more… For client-side and Node.js. https://github.com/hMatoba/piexifjs

About Piexifjs¶

Notice and Warning!¶

We are implementing v2.0. This version would include a few big changes. If you won’t ready to use, don’t update this library.

add some arguments type checks
stop to support bower
some data types are changed in exif object…?

Some names in this libary will be changed until beta version.

What for?¶

Exif manipulations in JS. Writing, reading, and more…

How to Use¶

There are only just four functions.

load(jpegData) - Get exif data as object.
dump(exifObj) - Get exif binary as string to insert into JPEG.
insert(exifbytes, jpegData) - Insert exif into JPEG.
remove(jpegData) - Remove exif from JPEG.

and some utilities.

Dependency¶

No dependencies.

Environment¶

Both client-side and server-side. Piexifjs is transpiled as Universal Module Definition.

License¶

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Functions¶

Warning

It could set any value in exif without actual value. For example, actual XResolution is 300, whereas XResolution value in exif is 0. Confliction might happen.

Warning

To edit exif tags and values appropriately, read official document from P167-. http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf

load¶

piexif.load(jpegData)¶

Get exif data as object. jpegData must be a string that starts with “data:image/jpeg;base64,”(DataURL), “\xff\xd8”, or “Exif”.

Arguments:	jpegData (string) – JPEG data
Returns:	Exif data({“0th”:object, “Exif”:object, “GPS”:object, “Interop”:object, “1st”:object, “thumbnail”:string})
Return type:	object

let exifObj = piexif.load(jpegData);
for (let ifd in exifObj) {
    if (ifd == "thumbnail") {
        continue;
    }
    console.log("-" + ifd);
    for (let tag in exifObj[ifd]) {
        console.log("  " + piexif.Tags[ifd][tag]["name"] + ":" + exifObj[ifd][tag]);
    }
}

dump¶

piexif.dump(exifObj)¶

Get exif binary as string to insert into JPEG.

Arguments:	exifObj (object) – Exif data({“0th”:0thIFD - object, “Exif”:ExifIFD - object, “GPS”:GPSIFD - object, “Interop”:InteroperabilityIFD - object, “1st”:1stIFD - object, “thumbnail”:JPEG data - string})
Returns:	Exif binary
Return type:	string

let zeroth = {};
let exif = {};
let gps = {};
zeroth[piexif.TagValues.ImageIFD.Make] = "Make";
zeroth[piexif.TagValues.ImageIFD.XResolution] = [777, 1];
zeroth[piexif.TagValues.ImageIFD.YResolution] = [777, 1];
zeroth[piexif.TagValues.ImageIFD.Software] = "Piexifjs";
exif[piexif.TagValues.ExifIFD.DateTimeOriginal] = "2010:10:10 10:10:10";
exif[piexif.TagValues.ExifIFD.LensMake] = "LensMake";
exif[piexif.TagValues.ExifIFD.Sharpness] = 777;
exif[piexif.TagValues.ExifIFD.LensSpecification] = [[1, 1], [1, 1], [1, 1], [1, 1]];
gps[piexif.TagValues.GPSIFD.GPSVersionID] = [7, 7, 7, 7];
gps[piexif.TagValues.GPSIFD.GPSDateStamp] = "1999:99:99 99:99:99";
let exifObj = {"0th":zeroth, "Exif":exif, "GPS":gps};
const exifbytes = piexif.dump(exifObj);

Properties of piexif.TagValues.ImageIFD help to make 0thIFD and 1stIFD. piexif.TagValues.ExifIFD is for ExifIFD. piexif.TagValues.GPSIFD is for GPSIFD. piexif.InteropIFD is for InteroperabilityIFD.

Note

ExifTag(34665), GPSTag(34853), and InteroperabilityTag(40965) in 0thIFD automatically are set appropriate value.

Note

JPEGInterchangeFormat(513), and JPEGInterchangeFormatLength(514) in 1stIFD automatically are set appropriate value.

Note

If ‘thumbnail’ is contained in exifObj, ‘1st’ must be contained – and vice versa. 1stIFD means thumbnail’s information.

insert¶

piexif.insert(exifbytes, jpegData)¶

Insert exif into JPEG.

Arguments:	exifbytes (string) – Exif binary jpegData (string) – JPEG data
Returns:	JPEG data
Return type:	string

const exifbytes = piexif.dump(exifObj)
const newJpeg = piexif.insert(exifbytes, jpegData)

remove¶

piexif.remove(jpegData)¶

Remove exif from JPEG.

Arguments:	jpegData (string) – JPEG data
Returns:	JPEG data
Return type:	string

const newJpeg = piexif.remove(jpegData)

Constants¶

To set exif values¶

0th IFD and 1st IFD: piexif.TagValues.ImageIFD

Exif IFD: piexif.TagValues.ExifIFD

GPS IFD: piexif.TagValues.GPSIFD

Interoperability IFD: piexif.TagValues.InteropIFD

let zerothIfd = {
    [piexif.TagValues.ImageIFD.ProcessingSoftware]:'piexifjs',
    [piexif.TagValues.ImageIFD.XResolution]:[777, 1],
    [piexif.TagValues.ImageIFD.YResolution]:[777, 1],
    [piexif.TagValues.ImageIFD.Software]:"Piexifjs"
};
let exifIfd = {
    [piexif.TagValues.ExifIFD.DateTimeOriginal]:"2010:10:10 10:10:10",
    [piexif.TagValues.ExifIFD.LensMake]:"LensMake",
    [piexif.TagValues.ExifIFD.Sharpness]:777,
    [piexif.TagValues.ExifIFD.LensSpecification]:[[1, 1], [1, 1], [1, 1], [1, 1]]
};
let gpsIfd = {
    [piexif.TagValues.GPSIFD.GPSVersionID]:[7, 7, 7, 7],
    [piexif.TagValues.GPSIFD.GPSDateStamp]:"1999:99:99 99:99:99"
};
let exifObj = {"0th":zerothIfd, "Exif":exifIfd, "GPS":gpsIfd};

To read exif keys¶

in piexif.Tags

let exifObj = piexif.load(exifBinary);
for (let ifd in exifObj) {
    if (ifd == "thumbnail") {
        continue;
    }
    console.log("-" + ifd);
    for (let tag in exifObj[ifd]) {
        console.log("  " + piexif.Tags[ifd][tag]["name"] + ":" + exifObj[ifd][tag]);
    }
}

Helpers¶

degrees in rational¶

piexif.helper.GPSHelper.degToDmsRational(degrees)¶

Convert degrees(number) to [[deg1, deg2], [min1, min2], [sec1, sec2]].

Arguments:	degrees (number) – degrees
Returns:	degrees as [degrees, minutes, seconds]
Return type:	Array

const degreesRat = piexif.helper.GPSHelper.degToDmsRational(63.2);

degrees in number¶

piexif.helper.GPSHelper.dmsRationalToDeg(degrees, direction)¶

Convert degrees([[deg1, deg2], [min1, min2], [sec1, sec2]]) to number.

Arguments:	degrees (Array) – degrees in [[deg1, deg2], [min1, min2], [sec1, sec2]] direction (string) – “N”, “E”, “W”, or “S”
Returns:	degrees
Return type:	number

const degreesNum = piexif.helper.GPSHelper.dmsRationalToDeg([[60, 1], [10, 1], [10, 1]], "S");

1 to 2¶

piexif.TAGS -> piexif.Tags

piexif.*IFD -> piexif.TagValues.*IFD

Samples¶

Insert Exif into jpeg¶

<input type="file" id="files" />
<script source="/js/piexif.js" />
<script>
function handleFileSelect(evt) {
    var file = evt.target.files[0];

    var zeroth = {};
    var exif = {};
    var gps = {};
    zeroth[piexif.TagValues.ImageIFD.Make] = "Make";
    zeroth[piexif.TagValues.ImageIFD.XResolution] = [777, 1];
    zeroth[piexif.TagValues.ImageIFD.YResolution] = [777, 1];
    zeroth[piexif.TagValues.ImageIFD.Software] = "Piexifjs";
    exif[piexif.TagValues.ExifIFD.DateTimeOriginal] = "2010:10:10 10:10:10";
    exif[piexif.TagValues.ExifIFD.LensMake] = "LensMake";
    exif[piexif.TagValues.ExifIFD.Sharpness] = 777;
    exif[piexif.TagValues.ExifIFD.LensSpecification] = [[1, 1], [1, 1], [1, 1], [1, 1]];
    gps[piexif.TagValues.GPSIFD.GPSVersionID] = [7, 7, 7, 7];
    gps[piexif.TagValues.GPSIFD.GPSDateStamp] = "1999:99:99 99:99:99";
    var exifObj = {"0th":zeroth, "Exif":exif, "GPS":gps};
    var exifbytes = piexif.dump(exifObj);

    var reader = new FileReader();
    reader.onload = function(e) {
        var inserted = piexif.insert(exifbytes, e.target.result);

        var image = new Image();
        image.src = inserted;
        image.width = 200;
        var el = $("<div></div>").append(image);
        $("#resized").prepend(el);

    };
    reader.readAsDataURL(file);
}

document.getElementById('files').addEventListener('change', handleFileSelect, false);
</script>

Read Exif Values¶

var reader = new FileReader();
reader.onloadend = function(e) {
    var exifObj = piexif.load(e.target.result);
    for (var ifd in exifObj) {
        if (ifd == "thumbnail") {
            continue;
        }
        console.log("-" + ifd);
        for (var tag in exifObj[ifd]) {
            console.log("  " + piexif.Tags[ifd][tag]["name"] + ":" + exifObj[ifd][tag]);
        }
    }
};
reader.readAsDataURL(file);

Generates Rotated JPEG¶

function postJpeg (binStr) {
    var array = [];
    for (var p=0; p<data.length; p++) {
        array[p] = data.charCodeAt(p);
    }
    var u8array = new Uint8Array(array);

    var req = new XMLHttpRequest();
    req.open("POST", "/jpeg", false);
    req.setRequestHeader('Content-Type', 'image/jpeg');
    req.send(u8array.buffer);
}


function previewJpeg(evt) {
    var files = evt.target.files;
    var previewDiv = $("#preview");
    for (var i=0; i<files.length; i++) {
        var file = files[i];
        if (!file.type.match('image/jpeg.*')) {
            continue;
        }

        var reader = new FileReader();
        reader.onload = function(e) {
            var exif = piexif.load(e.target.result);
            var image = new Image();
            image.onload = function () {
                var orientation = exif["0th"][piexif.TagValues.ImageIFD.Orientation];

                var canvas = document.createElement("canvas");
                canvas.width = image.width;
                canvas.height = image.height;
                var ctx = canvas.getContext("2d");
                var x = 0;
                var y = 0;
                ctx.save();
                if (orientation == 2) {
                    x = -canvas.width;
                    ctx.scale(-1, 1);
                } else if (orientation == 3) {
                    x = -canvas.width;
                    y = -canvas.height;
                    ctx.scale(-1, -1);
                } else if (orientation == 4) {
                    y = -canvas.height;
                    ctx.scale(1, -1);
                } else if (orientation == 5) {
                    canvas.width = image.height;
                    canvas.height = image.width;
                    ctx.translate(canvas.width, canvas.height / canvas.width);
                    ctx.rotate(Math.PI / 2);
                    y = -canvas.width;
                    ctx.scale(1, -1);
                } else if (orientation == 6) {
                    canvas.width = image.height;
                    canvas.height = image.width;
                    ctx.translate(canvas.width, canvas.height / canvas.width);
                    ctx.rotate(Math.PI / 2);
                } else if (orientation == 7) {
                    canvas.width = image.height;
                    canvas.height = image.width;
                    ctx.translate(canvas.width, canvas.height / canvas.width);
                    ctx.rotate(Math.PI / 2);
                    x = -canvas.height;
                    ctx.scale(-1, 1);
                } else if (orientation == 8) {
                    canvas.width = image.height;
                    canvas.height = image.width;
                    ctx.translate(canvas.width, canvas.height / canvas.width);
                    ctx.rotate(Math.PI / 2);
                    x = -canvas.height;
                    y = -canvas.width;
                    ctx.scale(-1, -1);
                }
                ctx.drawImage(image, x, y);
                ctx.restore();

                var dataURL = canvas.toDataURL("image/jpeg", 1.0);
                var jpegBinary = atob(dataURL.split(",")[1]);

                var div = $("<div></div>");
                div.append(canvas);
                var button = $("<button>post this image</button>");
                button.click(function () {
                    //postJpeg(jpegBinary);
                });

                previewDiv.prepend(div).prepend(button);
            };
            image.src = e.target.result;
        };

        reader.readAsDataURL(file);
    }
}

document.getElementById("files").onchange = previewJpeg;

GPS Coordinates¶

var lat = 59.43553989213321;
var lng = 24.73842144012451;
gpsIfd[piexif.TagValues.GPSIFD.GPSLatitudeRef] = lat < 0 ? 'S' : 'N';
gpsIfd[piexif.TagValues.GPSIFD.GPSLatitude] = piexif.GPSHelper.degToDmsRational(lat);
gpsIfd[piexif.TagValues.GPSIFD.GPSLongitudeRef] = lng < 0 ? 'W' : 'E';
gpsIfd[piexif.TagValues.GPSIFD.GPSLongitude] = piexif.GPSHelper.degToDmsRational(lng);

Node.js¶

var piexif = require("piexifjs");
var fs = require("fs");

var filename1 = "in.jpg";
var filename2 = "out.jpg";

var jpeg = fs.readFileSync(filename1);
var data = jpeg.toString("binary");

var zeroth = {};
var exif = {};
var gps = {};
zeroth[piexif.TagValues.ImageIFD.Make] = "Make";
zeroth[piexif.TagValues.ImageIFD.XResolution] = [777, 1];
zeroth[piexif.TagValues.ImageIFD.YResolution] = [777, 1];
zeroth[piexif.TagValues.ImageIFD.Software] = "Piexifjs";
exif[piexif.TagValues.ExifIFD.DateTimeOriginal] = "2010:10:10 10:10:10";
exif[piexif.TagValues.ExifIFD.LensMake] = "LensMake";
exif[piexif.TagValues.ExifIFD.Sharpness] = 777;
exif[piexif.TagValues.ExifIFD.LensSpecification] = [[1, 1], [1, 1], [1, 1], [1, 1]];
gps[piexif.TagValues.GPSIFD.GPSVersionID] = [7, 7, 7, 7];
gps[piexif.TagValues.GPSIFD.GPSDateStamp] = "1999:99:99 99:99:99";
var exifObj = {"0th":zeroth, "Exif":exif, "GPS":gps};
var exifbytes = piexif.dump(exifObj);

var newData = piexif.insert(exifbytes, data);
var newJpeg = Buffer.from(newData, "binary");
fs.writeFileSync(filename2, newJpeg);

Appendices¶

Exif Data in Piexifjs¶

Each exif tag has appropriate type of the value. BYTE, ASCII, SHORT, or… See the document of Exif. http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf

Exif Type	JavaScript
BYTE	int
ASCII	string
SHORT	int
LONG	int
RATIONAL	[int, int]
UNDEFINED	string
SRATIONAL	[int, int]

If value type is number(BYTE, SHORT, LONG, RATIONAL, or SRATIONAL) and value count is two or more number, it is expressed with Array.

BYTE, SHORT, LONG	[int, int, …]
RATIONAL, SRATIONAL	[[int, int], [int, int], …]

Note

If value type is number and value count is one, array that is length one value(e.g. [int]) also be accepted.

Development¶

start development.

npm install

Source codes are in “./src”.

Codes are written in TypeScript. Transpile with below comand.

npm run build

You can get piexif.js under /dist.

Run tests.

npm run node-test
npm run browser-test

Changelog¶

2.0.0(Not Completed)¶

Some name spaces are changed.
Checking types for some argumetns.

1.03¶

Bug fix. Issues #19.

1.02¶

Bug fix. To remove IFD pointer tag.

1.01¶

Bug fix. https://github.com/hMatoba/piexifjs/issues/9

1.0¶

Release.

Welcome to Piexifjs’s documentation!¶

About Piexifjs¶

Notice and Warning!¶

What for?¶

How to Use¶

Dependency¶

Environment¶

License¶

Functions¶

load¶

dump¶

insert¶

remove¶

Constants¶

To set exif values¶

To read exif keys¶

Helpers¶

degrees in rational¶

degrees in number¶

1 to 2¶

Samples¶

Insert Exif into jpeg¶

Read Exif Values¶

Generates Rotated JPEG¶

GPS Coordinates¶

Node.js¶

Appendices¶

Exif Data in Piexifjs¶

Development¶

Changelog¶

2.0.0(Not Completed)¶

1.03¶

1.02¶

1.01¶

1.0¶

Indices and tables¶