Struggling to convert a base64 image captured using a webcam into a jpeg for upload.
The following capture / display photo works (note that I am using webcam.min.js (which returns base64) and not webcam.js (which returns jpeg but relies on Flash) -
function take_snapshot() {
Webcam.snap( function(data_uri) {
// display results in page
document.getElementById('upload_results').innerHTML =
'<img id="imageprev" src="'+data_uri+'"/>';
} );
}
I have tried the following, which may or may not be converting the base 64image to a blob -
function saveSnap(){
var base64image = document.getElementById("imageprev").src;
alert(base64image)
// convert base64 to raw binary data held in a string
var byteString = atob(base64image.split(',')[1]);
// separate out the mime component
var mimeString = base64image.split(',')[0].split(':')[1].split(';')[0];
// write the bytes of the string to an ArrayBuffer
var ab = new ArrayBuffer(byteString.length);
var dw = new DataView(ab);
for(var i = 0; i < byteString.length; i++) {
dw.setUint8(i, byteString.charCodeAt(i));
alert("arrived here");
// write the ArrayBuffer to a blob, and you're done
return new Blob([ab], {type: mimeString});
}
And this doesn't do anything, except halt the jsp
let image = new Image();
image.src = base64image;
document.body.appendChild(image);
How do I get / see / extract the actual jpeg file so I can then upload it
(it must be something like number.jpeg)
JDK6 / Javascript (no php please)
Any thoughts appreciated.
Regards
Ralph
Create an image object and put the base64 as its source.
let image = new Image();
image.src = 'data:image/png;base64,iVBORw0K...';
document.body.appendChild(image);
var aFilePartss = [image];
var oMyBlob = new Blob(aFileParts, {type : 'image/png'});
// window.open(URL.createObjectURL(oMyBlob));
var fd = new FormData();
fd.append('data', oMyBlob);
$.ajax({
type: 'POST',
url: '/upload.php',
data: fd,
}).done(function(data) {
console.log(data);
});
Here is the basics you need to convert to blob and upload.
const MOCK_DATA_URL = `data:image/jpeg;base64,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`
function takeSnapshotThenUpload() {
//get datauri
let blob = convertToBlob(MOCK_DATA_URL)
return uploadFile(blob)
}
function convertToBlob(base64image) {
// convert base64 to raw binary data held in a string
var byteString = atob(base64image.split(',')[1]);
// separate out the mime component
var mimeString = base64image.split(',')[0].split(':')[1].split(';')[0];
// write the bytes of the string to an ArrayBuffer
var ab = new ArrayBuffer(byteString.length);
var dw = new DataView(ab);
for (var i = 0; i < byteString.length; i++) {
dw.setUint8(i, byteString.charCodeAt(i));
alert("arrived here");
// write the ArrayBuffer to a blob, and you're done
return new Blob([ab], {
type: mimeString
});
}
}
function uploadFile(blob) {
const formData = new FormData()
formData.append('cancel.jpeg', blob)
fetch('/saveImage', {
method: 'POST',
body: formData
})
.then(response => response.json())
.then(data => {
console.log(data)
})
.catch(error => {
console.error(error)
})
}
<button onclick="takeSnapshotThenUpload()">Take screenshot then upload</button>
Remember to fix your takeSnapshotThenUpload to something like:
<script src="webcam.js"></script>
<div id="my_camera" style="width:320px; height:240px;"></div>
<div id="my_result"></div>
<script language="JavaScript">
Webcam.attach( '#my_camera' );
function take_snapshot() {
Webcam.snap( function(data_uri) {
takeSnapshotThenUpload(data_uri)
} );
}
</script>
Take Snapshot
Example code for converting base64 to file (image/jpeg):
async base64ToFile(base64) {
const res = await fetch(base64)
const buf = await res.arrayBuffer()
const file = new File([buf], "capture_camera.jpeg", {
type: 'image/jpeg',
})
return file;
};
Related
I have a requirement where I am cropping the image using ng2-image cropper. But the output is of base64, I want to convert it to image source as I have to send it to some server.
I have searched but didn't found anything compatible with angular 4 .
it can be done by using conversion to Blob
dataURItoBlob(dataURI) {
var binary = atob(dataURI.split(',')[1]);
var array = [];
for (var i = 0; i < binary.length; i++) {
array.push(binary.charCodeAt(i));
}
return new Blob([new Uint8Array(array)], {
type: 'image/jpg'
});
}
enter code here
var myFile:Blob=this.dataURItoBlob(myDataUri);
Please try this another simple way to convert base64 to blob
fetch(base64)
.then(res => {
return res.blob();
})
.then(blob => {
console.log(blob);
});
I am using the File reader in JavaScript,i need to Post my image to WebApi and convert it into byte Array and save it in server,Its working fine,Now my problem is base64 string increasing the size of image, Let say if i upload image of 30Kb, it is storing has 389Kb in server,How i can save in same size or reduce size of image need help
//File Reader
function OnFileEditImageEntry(file) {
var reader = new FileReader();
reader.onloadend = function (evt) {
var ImageBase64 = evt.target.result;
return ImageBase64 ;
};
reader.readAsDataURL(file);
}
//WEB API//
public IHttpActionResult UpdateUserDetails(ImageModel model)
{
try
{
if (model.ImageBase64 != "")
{
var PicDataUrl = "";
string ftpurl = "ftp://xxx.xxxxx.xxxx/";
var username = "xxx";
var password = "xxxxx";
string UploadDirectory = "xxxx/xx";
string FileName =model.ImageFileName;
String uploadUrl = String.Format("{0}{1}/{2}", ftpurl, UploadDirectory,FileName);
FtpWebRequest req = (FtpWebRequest)FtpWebRequest.Create(uploadUrl);
req.Proxy = null;
req.Method = WebRequestMethods.Ftp.UploadFile;
req.Credentials = new NetworkCredential(username, password);
req.EnableSsl = false;
req.UseBinary = true;
req.UsePassive = true;
byte[] data =Convert.FromBase64String(model.ImageBase64);
req.ContentLength = data.Length;
Stream stream = req.GetRequestStream();
stream.Write(data, 0, data.Length);
stream.Close();
}
}
}
Send the raw binary instead of increasing the size ~30% with base64/FileReader
with fetch
// sends the raw binary
fetch('http://example.com/upload', {method: 'post', body: file})
// Append the blob/file to a FormData and send it
var fd = new FormData()
fd.append('file', file, file.name)
fetch('http://example.com/upload', {method: 'post', body: fd})
With XHR
// xhr = new ...
// xhr.open(...)
xhr.send(file) // or
xhr.send(fd) // send the FormData
Normally when uploading files, try to avoid sending a json as many developers tends to to wrong. Binary data in json is equal to bad practice (and larger size) eg:
$.post(url, {
name: '',
data: base64
})
Use the FormData#append as much as possible or if you feel like it:
fd.append('json', json)
I made an simple image manipulation experiment with html, css and javascript/jquery.
We can upload an image from local drive and displayed in browser.
After that we can also edit/tag the displayed image.
I use this jquery image tag plugin.
Then I think about, how can i save/print the edited image?
This is my code snippet :
$(function () {
$(":file").change(function () {
if (this.files && this.files[0]) {
var reader = new FileReader();
reader.onload = imageIsLoaded;
reader.readAsDataURL(this.files[0]);
}
});
});
function imageIsLoaded(e) {
$('#myImg').attr('src', e.target.result);
$('#myImg').imageTag();
};
Here's the real live app : http://nanonimos.com/upload-tag-image/
and this is the source code.
Any clue/advice would be greatly appreciated :)
You can convert the whole div to an canvas then convert the canvas into data uri(png,jpeg).
Check this Fiddlecanvastoimage for more.
Use this function(From Stackoverflow) to convert dataURI to blob:
function dataURItoBlob(dataURI) {
// convert base64/URLEncoded data component to raw binary data held in a string
var byteString;
if (dataURI.split(',')[0].indexOf('base64') >= 0)
byteString = atob(dataURI.split(',')[1]);
else
byteString = unescape(dataURI.split(',')[1]);
// separate out the mime component
var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
// write the bytes of the string to a typed array
var ia = new Uint8Array(byteString.length);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
return new Blob([ia], {type:mimeString});
}
and then whenever you want to save just post this file to server.
In HTML5 you can do like this:
var blob = dataURItoBlob(data);
var fd = new FormData();
fd.append("imageFile", blob);
Then send it with ajax like this:
$.ajax({
type: "POST",
url:"url to file",
data: fd,
success: function(result){
//check success
};
});
How can I encode the data:image/jpeg;base64 data url to be transmitted correctly through an AJAX POST. I have the following code xhr.open('POST', 'http://url-sent-to/image/' + saveImage + '&imageid=' + imageid.value, true); that is doing so now.
However, the URL http://url-sent-to/image/data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD…RRQAUUUUAFFFFABRRRQAUUUUAFFFFABRRRQAUUUUAFFFFAH/2Q==&imageid=testimagedata does not look like it will be correct, especially since it has = in it.
$(function () {
var fileInput = document.getElementById("file")
, renderButton = $("#renderButton")
, imgly = new ImglyKit({
container: "#container",
ratio: 1 / 1
});
// As soon as the user selects a file...
fileInput.addEventListener("change", function (event) {
var file;
var fileToBlob = event.target.files[0];
var blob = new Blob([fileToBlob], {"type":fileToBlob.type});
// do stuff with blob
console.log(blob);
// Find the selected file
if(event.target.files) {
file = event.target.files[0];
} else {
file = event.target.value;
}
// Use FileReader to turn the selected
// file into a data url. ImglyKit needs
// a data url or an image
var reader = new FileReader();
reader.onload = (function(file) {
return function (e) {
data = e.target.result;
// Run ImglyKit with the selected file
try {
imgly.run(data);
} catch (e) {
if(e.name == "NoSupportError") {
alert("Your browser does not support canvas.");
} else if(e.name == "InvalidError") {
alert("The given file is not an image");
}
}
};
})(file);
reader.readAsDataURL(file);
});
// As soon as the user clicks the render button...
// Listen for "Render final image" click
renderButton.click(function (event) {
var dataUrl;
imgly.renderToDataURL("image/jpeg", { size: "1200" }, function (err, dataUrl) {
// `dataUrl` now contains a resized rendered image with
// a width of 300 pixels while keeping the ratio
//Convert DataURL to Blob to send over Ajax
function dataURItoBlob(dataUrl) {
// convert base64 to raw binary data held in a string
// doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
var byteString = atob(dataUrl.split(',')[1]);
// separate out the mime component
var mimeString = dataUrl.split(',')[0].split(':')[1].split(';')[0];
// write the bytes of the string to an ArrayBuffer
var ab = new ArrayBuffer(byteString.length);
var ia = new Uint8Array(ab);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
// write the ArrayBuffer to a blob, and you're done
//var bb = new BlobBuilder();
//bb.append(ab);
//return bb.getBlob(mimeString);
}
var blob = dataURItoBlob(dataUrl);
var fd = new FormData(document.forms[0]);
var xhr = new XMLHttpRequest();
var saveImage = dataUrl;
//console.log(saveImage);
fd.append("myFile", blob);
xhr.open('POST', 'http://url-sent-to/image/' + saveImage + '&imageid=' + imageid.value, true);
xhr.send(fd);
I have a fiddle setup for an example of what I'm doing. Essentially, the user will select an image, enter a description, and hit render. When you check the Javascript console, you'll see a Blob is created, and the POST message at the bottom: http://jsfiddle.net/mattography/Lgduvce1/2/
You're looking for encodeURI(), which will do exactly what you're looking for.
Note that you're missing a ? to start your querystring.
Also note that making URLs that long is a bad idea; you should send a POST request instead.
Using FileReader's readAsDataURL() I can transform arbitrary data into a Data URL. Is there way to convert a Data URL back into a Blob instance using builtin browser apis?
User Matt has proposed the following code a year ago ( How to convert dataURL to file object in javascript? ) which might help you
EDIT: As some commenters reported, BlobBuilder has been deprecated some time ago. This is the updated code:
function dataURItoBlob(dataURI) {
// convert base64 to raw binary data held in a string
// doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
var byteString = atob(dataURI.split(',')[1]);
// separate out the mime component
var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]
// write the bytes of the string to an ArrayBuffer
var ab = new ArrayBuffer(byteString.length);
// create a view into the buffer
var ia = new Uint8Array(ab);
// set the bytes of the buffer to the correct values
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
// write the ArrayBuffer to a blob, and you're done
var blob = new Blob([ab], {type: mimeString});
return blob;
}
Like #Adria method but with Fetch api and just smaller [caniuse?]
Don't have to think about mimetype since blob response type just works out of the box
Warning: Can violate the Content Security Policy (CSP)
...if you use that stuff
var url = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="
fetch(url)
.then(res => res.blob())
.then(blob => console.log(blob))
Don't think you could do it any smaller then this without using lib's
In modern browsers one can use the one liner suggested by Christian d'Heureuse in a comment:
const blob = await (await fetch(dataURI)).blob();
dataURItoBlob : function(dataURI, dataTYPE) {
var binary = atob(dataURI.split(',')[1]), array = [];
for(var i = 0; i < binary.length; i++) array.push(binary.charCodeAt(i));
return new Blob([new Uint8Array(array)], {type: dataTYPE});
}
input dataURI is Data URL and dataTYPE is the file type and then output blob object
XHR based method.
function dataURLtoBlob( dataUrl, callback )
{
var req = new XMLHttpRequest;
req.open( 'GET', dataUrl );
req.responseType = 'arraybuffer'; // Can't use blob directly because of https://crbug.com/412752
req.onload = function fileLoaded(e)
{
// If you require the blob to have correct mime type
var mime = this.getResponseHeader('content-type');
callback( new Blob([this.response], {type:mime}) );
};
req.send();
}
dataURLtoBlob( 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==', function( blob )
{
console.log( blob );
});
try:
function dataURItoBlob(dataURI) {
if(typeof dataURI !== 'string'){
throw new Error('Invalid argument: dataURI must be a string');
}
dataURI = dataURI.split(',');
var type = dataURI[0].split(':')[1].split(';')[0],
byteString = atob(dataURI[1]),
byteStringLength = byteString.length,
arrayBuffer = new ArrayBuffer(byteStringLength),
intArray = new Uint8Array(arrayBuffer);
for (var i = 0; i < byteStringLength; i++) {
intArray[i] = byteString.charCodeAt(i);
}
return new Blob([intArray], {
type: type
});
}
Since none of these answers support base64 and non-base64 dataURLs, here's one that does based on vuamitom's deleted answer:
// from https://stackoverflow.com/questions/37135417/download-canvas-as-png-in-fabric-js-giving-network-error/
var dataURLtoBlob = exports.dataURLtoBlob = function(dataurl) {
var parts = dataurl.split(','), mime = parts[0].match(/:(.*?);/)[1]
if(parts[0].indexOf('base64') !== -1) {
var bstr = atob(parts[1]), n = bstr.length, u8arr = new Uint8Array(n)
while(n--){
u8arr[n] = bstr.charCodeAt(n)
}
return new Blob([u8arr], {type:mime})
} else {
var raw = decodeURIComponent(parts[1])
return new Blob([raw], {type: mime})
}
}
Note: I'm not sure if there are other dataURL mime types that might have to be handled differently. But please let me know if you find out! Its possible that dataURLs can simply have any format they want, and in that case it'd be up to you to find the right code for your particular use case.
Create a blob using XHR API:
function dataURLtoBlob( dataUrl, callback )
{
var req = new XMLHttpRequest;
req.open( 'GET', dataUrl );
req.responseType = 'blob';
req.onload = function fileLoaded(e)
{
callback(this.response);
};
req.send();
}
var dataURI = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=='
dataURLtoBlob(dataURI , function( blob )
{
console.log( blob );
});
If you need something that works server-side on Google Apps Script, try:
function dataURItoBlob(dataURI) {
// convert base64 to Byte[]
// doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
var data = Utilities.base64Decode(dataURI.split(',')[1]);
// separate out the mime component
var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]
var blob = Utilities.newBlob(data);
blob.setContentType(mimeString);
return blob;
}
use
FileReader.readAsArrayBuffer(Blob|File)
rather than
FileReader.readAsDataURL(Blob|File)