I tried to get the image from clipboard when I press ctrl+v on a page, with the code from a gist, which will console.log the image content it gets.
I found the image content is a long base64 string with a special prefix:
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEEAAAAUCAYAAADStFABAAAJHElEQVRYCXVXWXObVxl+Pu2yFsuyLMnxHtdpY8c4pHXptOkEGKBlYDowYXLLLeGSX8D/gBvuErhgmElpJkCZNsswjhPZsbHGJo6Rl1pybMuyZEnWyvsc9xVfMvCOj8457/K8y9k+W5lMpi0EJcuywDn7ZrMJh8OBVqulYsMnT2WqSx3ylWivdnZM6lOPPRuJcpIdQ23IVz2Oyadvl8tlevLUL2XEUFv1Qx2S8lXnjAu4yPhfAdGARJmCaTAMgqS2drkGQrmOKVfHyrP3xFW5vbdj6Jg98eyLoPGTT1KZxklfHDudzk4hyNN8XDqgsT1YBkOi3G5gd8ixBkQHKqMd7SnTADRAlVGXpBjUI6mdYpGvTZNTPcUwhvJjT5oyO5baKJbmx7nZCQrSaDSMQzXQxGhAZXtgylOber1ukqat6qqO4tGeMi0Ie+oQw+6L+vYEFUftdFXZU6Z8xVBb+qKOxkNcEueKybnZCXamHVQB1IDO1AF56pR8DYRyNmIyOfI5VqKdYmhPHfJJ1FV7TZZ88tT2dd9qoxiqz95OikGe3eaVImgyqsy+tL+P9Bdf4sVCCrkXL8BNnDx/HqMzM5i8dg3heLyzDQlOGzpgQNprsTgvHOSwtnAfm2spvNxcNzq9g+cx8uY3ceHyhwj19BkesRiPLgRt7UXhziPv5cEe5pYeIb2xhMxORqxaGB4Yw1sjk3hv5kP09sRewWEs9mLRj5VOp83hpEPDEGClreVlzN2+jZ2nTzDY24PRRL8kCWRyWWwdHGLgyhXM3riB4elpkzwxtAjsX6ft50t4+vkfcPjPOYz0RzAy1G9UMlu7yOweITr1Li5/+7oU5LJJWBfl9aCJzfavjTTuPvgTlraWEB/pw7lBWZB2C7tbOSnwIS4NT+OHH3yCixPTncRZONrqwhDbRSYHFLBXYSGXw+Nbt1FIPcWvPv4IA9/7DlxX35elBhoPHmH73uf4zb2/4ImkEeztRXci8X8LQNxi/iVSf/89sDaHX/7ix4i9/xE8kQ/E2kI9/xAv/3EXt357B4tWG+FoAt29CRMPbUlaYDORn33B+/TBH7F2sIqf37yOH1z8PuLBKSPOlp7hs5V7uPW7O2g/bKEnEkNc8EjMk8SjSmL+zps3b/6aDrjVSKq0/NldbH/6Z9yYegtjM9Owjo7QfJJCK7UIq1BAMBJG8qSM1MIzuKQI56YmO9uYWBq04qXn7qH4+A5+8vE04rPvwapX0Th4hmZ+WSIqwxeNYsBVxOrjBTRCMfQNXTDfAmqvx4JFYeBfzv8ND59/gas/uoJvTb6NIkrYKK1gq7yKCsroC0dRD1aQWlxC2N2NccGz50dc3RUuChRYBeQdLC5gOuBHst5Ac2kF7e4wnD4fRWhWq2gVjpGUal7q8mN/cRH42fUzmRSAOHop6krmt5dwaTCMcMCH5r/XZPuEYXn8xqYlBWmWjo2MOuui63D8FLVarbMzGTAx9SNpfXcVfRdiCIR9SOdWEfSF4XG7DV5N8IqVE3SF/Yi/GQN1LesTI2NsjImLxJ7zzncCnZBUqZnZwoTfh2CpAp/jAI5qBfCdBe2WceukgnalggmvF9nNzVcuMGKQdPWIXTvZwbmhKLw+eZdRhaMpL4oUmNRqVGG1K0ZGnfTuziuBUoeYGhv7fHkX/VN9gN+BmlVDuXWMet1DVdSbNeGdwhJfyeE49ud3OzvdKMiP7gIWwhSBwbq/rqJW2+9xIeT2wh8IwRmU5Lu6IFHSGnA65M8Bv4zDMvXXz95rOuCdQjyuGLE4J3l9Hnh6uuDqCcMdDsESLMvlNTJHQz60vHJrO9rwFKQY+bLh057B6gKxJzZX0ev3IhIMIuj3yy7ww+f0wCuNBaq1nHC6BdPZRiR0iqL/2ODpD3G4y9hTv/NEEpxEB3QeGh9HMbcH9HQDEWlyZiFHwhThuAgc5gH3EYrtJoLRmAGkLXG0EJzTCZ2FYsMotI8x3BWA1RWEQxrc0oSsegktdwlWs4Fjy2MuWvKJo8eJPXFIHCejg2iV6vA7vQh5fHLuw+hyykIJlZtlHNWOTR6tE9HtHjB8xSKOvXWOAxXswYe+MY3s/fsox/rk7Y4AA/Kc9cbOinCwLxF6UHZ7kD2Wsyy6TJbF06SJxyKQOA4nJ7F3eB9VlxMev1t2QkhWX4oqZHGztE9xKrJcpY7u/ilTTAZKW/bE1RiJO9I7geeHT+FtuRCw/Oh2h9AlFyDJVXdKLDVUmhWc7suRTbzdweEiEYc7nz1xHfxhI2kSnCffmUV1bAypU9lOfXE0enrRlsusKa0hK1+M9yFVO0V1dBT9s+8aW9qT6IgYdMJGSp5/RwowjKWNLEpyF9RkB7XkTWeriQ55Sy+yKDuH0D8+a2z4wwIQTwuhSVwcm0HESmI7nWX95I6RI9CWYyqNY/IoiyCJi2OXO/EQk4utuTI+a35+vs3KqhOOKeCZPtnaQvbhA3ikEOfemEAsmZSo5I3ezeKr9eeoyb2RvHoNgUHZmmKjBaUD4hBDC0zHxfwmcmt/hd+dRf9QAjH52iTt7+2ZD5xqox/xie/KzhsxiROTOFpQYiiRv1fYwbONR6ghj9GBEcS/xssJ3sZ2Bt52N2bGryIR+W98xCQRU3O1UqlUWxNQh6w2HXrl5ke5jPzKCg7X1+WOyBqAUCKJqNwZPZOT5sKsyCtBYiHZiGNfPXXokye2WSsi/9UiDrMrKBd3jF0gPIiexCSiAzNwyD3BS8serNpTmXz6IBGv1qpifWcZ2/vrck3JHSZfc9FIAkPxNzDWPymXpV9ejXoHj7aKzUUyeHNzc20NXFdQnZJPxUAgYBzqSlDvVHZHqVRCVb4Z7CtOGxaAPOqRFJ9j8kOhEDwejzmX9MUgmfjJyYnBUxv604DJ0wIQQ4k6QXkluGAaH/HouyAfdfqtQVsuDmNRHO3Nv9K6LdQRewZHJYIQlA50p5Cvcl4wTFoLRxmDVAfkK3FMPAZHIh5xGbBiaME4Vz/kaSMG9dmTxzHjI5b6JTZt6cvOo402xTZ2ymSvRAGVlBiQBkWeBsTx63rkKRb1mCTn1GMjj8GpHuck9pRrUZRPv4yHRLnGpjyNi3MtDnXteelYMSknkU+b/wD4ldY7nz0NzAAAAABJRU5ErkJggg==
How to decode it to binary? I tried to remove the prefix data:image/png;base64, and use a base64 library to decode the rest into binary, and save it to a image.png file. But the file can't be displayed, with invalid format error.
But if I paste the whole string to http://base64online.org/decode/, it can play the image as well.
The base64 library I used is https://github.com/wstrange/base64, and my code is:
import 'package:base64_codec/base64_codec.dart';
var body = /* the long str above */;
var prefix = "data:image/png;base64,";
var bStr = body.substring(prefix.length);
var bs = Base64Codec.codec.decodeList(bStr.codeUnits);
var file = new File("image.png");
file.writeAsBytesSync(bs);
I don't know where is wrong :(
Try using the crypto package from the Dart SDK. This creates an image.png that opens fine (I believe it's this image... )
library foo;
import 'package:crypto/crypto.dart';
import 'dart:io';
void main() {
var body = "data:image/png;base64,iVBORw0KGgoAAAANSUh... snip";
var prefix = "data:image/png;base64,";
var bStr = body.substring(prefix.length);
var bytes = CryptoUtils.base64StringToBytes(bStr); // using CryptoUtils from Dart SDK
var file = new File("image.png");
file.writeAsBytesSync(bytes);
}
You'll need to add crypto to your pubspec.yaml :
dependencies:
crypto: any
The library linked at https://github.com/wstrange/base64, also notes in the README:
Deprecated
Note: The Dart SDK now includes a Base64 codec with url safe options. Unless you need streaming support, you should use the SDK methods as they are slightly faster.
See CryptoUtils
See also How to native convert string -> base64 and base64 -> string
Decoding as a string and then writing the bytes works:
var prefix = "data:image/png;base64,";
var bStr = body.substring(prefix.length);
var bs = Base64Codec.codec.decodeString(bStr);
var file = new File("image.png");
file.writeAsBytesSync(bs.codeUnits);
The easiest approach is:
import 'dart:convert';
final result = base64Decode(stringValue);
Related
I am playing with the youtube api and I would like to download the thumbnails and process them. I've managed to download them in binary doing a simple http request and I can save them as a .jepec file. What I would like to do is not having to save the image as a file and parse the binary directly into an image all in memory to avoid leaving files behind.
Any idea on hat do I need to do to accompish this?
Here is my code:
#[tokio::main(flavor = "current_thread")]
async fn main() {
let res = reqwest::get("https://i.ytimg.com/vi/dQw4w9WgXcQ/hqdefault.jpg")
.await
.unwrap();
let bytes: Bytes = res.bytes().await.unwrap();
let _ = fs::write("img.jpeg", bin.clone()); // this saves the image correctly
let img = ????::from(bytes); // help here
}
You can use the jpeg_decoder crate:
use jpeg_decoder::Decoder;
let mut decoder = Decoder::new(&*bytes);
let pixels = decoder.decode().expect("jpeg decoding failed");
let info = decoder.info().unwrap(); // image metadata
If you call decode() from an async function, you should do so in a blocking task using tokio::spawn_blocking, as decode() is not itself async.
I need to Convert a xamarin forms image into a base64 format, Can anyone help me with this?
This is how i've being trying to do it, but it doesent work.
var inputStream = signatureImage.Source.GetValue(UriImageSource.UriProperty);
//Getting Stream as a Memorystream
var signatureMemoryStream = inputStream as MemoryStream;
if (signatureMemoryStream == null)
{
signatureMemoryStream = new MemoryStream();
inputStream.CopyTo(signatureMemoryStream);
}
//Adding memorystream into a byte array
var byteArray = signatureMemoryStream.ToArray();
//Converting byte array into Base64 string
base64String = Convert.ToBase64String(byteArray);
"signatureImage" is the image name.
Once you get your file path , you can use the following code that worked for me.
var stream = file.GetStream();
var bytes = new byte [stream.Length];
await stream.ReadAsync(bytes, 0, (int)stream.Length);
string base64 = System.Convert.ToBase64String(bytes);
I found it here
Image is just a control in Xamarin forms to display the image.
It is not something from which you can get your image byte array out.
You will be better of using the Media Plugin and save it to disk. Then load it via memory stream and convert.
You can also use FFImageLoading. It has 2 methods which can be of use for you :
GetImageAsJpgAsync(int quality = 90, int desiredWidth = 0, int desiredHeight = 0)
GetImageAsPngAsync(int desiredWidth = 0, int desiredHeight = 0)
The SO question - Convert Image into byte array in Xamarin.Forms shows how to do it in Platform specific code here.
The forum thread (Convert Image to byte[]) has a good discussion on why you can't get it from the control.
You can do this as below as well
var base64String = Convert.ToBase64String(File.ReadAllBytes(file.Path))
I am new to XCode and work on Android Studio previously. In Android Studio, there is log cat to log different types of messages for debugging purposes.
Is this available in XCode?
All I found is NSLog which prints the date and the statement without coloring like in log cat. Is there an easier way ?
You can use the print method.
Check out these handy Apple docs.
https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html
using XCodeColors Library https://github.com/robbiehanson/XcodeColors you can log different types of messages each in a unique color so that you can find error logs faster
also i customized the code like this to get coloring, which class, function, and line number did the call
struct RZLog
{
static let ESCAPE = "\u{001b}["
static let RESET_FG = ESCAPE + "fg;" // Clear any foreground color
static let RESET_BG = ESCAPE + "bg;" // Clear any background color
static let RESET = ESCAPE + ";" // Clear any foreground or background color
static let A = "fg255,0,0;"
static let B = "fg0,0,255;"
static let C = "fg16,128,0;"
static func Error<T>(object: T, filename: String = FILE, line: Int = LINE, funcname: String = FUNCTION) {
let ClassName = NSURL(string: filename)!
print("\(ESCAPE)\(A)**ERROR \(ClassName.lastPathComponent!)(\(line)) Func: \(funcname.uppercaseString): \(object) **\(RESET)")
}
static func Debug<T>(object: T, filename: String = FILE, line: Int = LINE, funcname: String = FUNCTION) {
let ClassName = NSURL(string: filename)!
print("\(ESCAPE)\(B)**DEBUG \(ClassName.lastPathComponent!)(\(line)) Func: \(funcname.uppercaseString): \(object) **\(RESET)")
}
static func VIP<T>(object: T, filename: String = FILE, line: Int = LINE, funcname: String = FUNCTION) {
let ClassName = NSURL(string: filename)!
print("\(ESCAPE)\(C)**VIP \(ClassName.lastPathComponent!)(\(line)) Func: \(funcname.uppercaseString): \(object) **\(RESET)")
}
}
If you want to use different CocoaLumberjack:
https://github.com/CocoaLumberjack/CocoaLumberjack
Which provides some more advantages over simple logging. And it can also be used with colors:
http://code.tutsplus.com/tutorials/cocoalumberjack-logging-on-steroids--mobile-15287
You can use Printer a new logging experience in Swift 3.x.
It has many functions to add logs in various ways.
Usage:
To log a success message:
Printer.log.success(details: "This is a Success message.")
Output:
Printer ➞ [✅ Success] [⌚04-27-2017 10:53:28] ➞ ✹✹This is a Success message.✹✹
[Trace] ➞ ViewController.swift ➞ viewDidLoad() #58
Disclaimer: This library has been created by me.
Im new Firefox addon programming.
I want set default file browse location with firefox addon sdk.
Thank you so much.
open scratchpad copy and paste this:
const nsIFilePicker = Components.interfaces.nsIFilePicker;
var fp = Components.classes["#mozilla.org/filepicker;1"]
.createInstance(nsIFilePicker);
var startDir = FileUtils.File('C:\\');
fp.displayDirectory = startDir;
fp.init(window, "Dialog Title", nsIFilePicker.modeOpen);
fp.appendFilters(nsIFilePicker.filterAll | nsIFilePicker.filterText);
var rv = fp.show();
if (rv == nsIFilePicker.returnOK || rv == nsIFilePicker.returnReplace) {
var file = fp.file;
// Get the path as string. Note that you usually won't
// need to work with the string paths.
var path = fp.file.path;
// work with returned nsILocalFile...
}
if thats what you want let me know, then ill put it in a default location
I am using js-sctypes to connect to a shared library in Linux from Firefox.
I am declaring a function from the library as follows:
var read_memory = libc.declare("read_memory", ctypes.default_abi, ctypes.int,
ctypes.uint32_t, ctypes.char.ptr, ctypes.int, ctypes.int);
In C++ library this function is declared as follows:
read_memory(unsigned int address, char *buf, int unit_size, int unit_count)
I am calling the read_memory function in the following way:
var my = new ctypes.char().address();
read_memory(0, my, 4, 1);
st = st + my.readString();
And it works fine, but when I am calling the function with greater unit_size and unit_count, for example read_memory(0, my, 4, 10), the Firefox crashes.
Is it because ctypes.char is limited in size, or there is another reason for this fault?
Any help on this matter would be appreciated.
Thank you.
I had the same problem and the problem is because of character encoding. In my problem I need to convert them from windows-1250 to utf-8.
I used code below:
result = myFunctionToInvoke();
var util = priv.Load("LibToConvert.dll");
var wi12502utf8 = util.declare("win12502utf8", ctypes.default_abi, ctypes.char.ptr, ctypes.char.ptr);
var val = wi12502utf8(result);
result = val.readString();
In this code I created my own lib (LibToConvert.dll) in C++ to convert characters.