创建从uncom $ P $一个PNG pssed原始PNG数据 [英] Creating a PNG from uncompressed raw PNG data
问题描述
我用这 Android的屏幕截图库捕捉屏幕截图。我想表明这张截图的网页浏览器。
我已经写在计算机上的小应用程序接口它连接到Android手机和连接code捕获的屏幕截图为base64。
字符串的base64 = Base64.getEn codeR()带codeToString(字节)。
这Base64是正在通过WebSocket的发送到网页。下面是我的HTML / JS code,应在画布上绘制图像。我已存储在一个文本文件中的base64图像数据测试的目的。
< DIV的风格=背景:AQUA;宽度:500像素,高度:660px;> <帆布风格=宽度:480像素,高度:640像素; ID =SIM卡>
< /帆布>
< / DIV><脚本类型=文/ JavaScript的>
VAR CTX;
VAR WIDTH = 480;
VAR HEIGHT = 640; (函数的start(){
CTX =的document.getElementById(SIM)的getContext(2D)。
loadFromFile();
})(); 功能的LoadImage(数据){ VAR图像=新的图像();
image.onload =功能(){
//这个部分从来没有执行
ctx.drawImage(图像,0,0);
的console.log(图像装!);
} image.src =数据:图像/ PNG; BASE64,+数据;
} 功能loadFromFile(){
//请从** HTTPS获取数据://app.box.com/s/e19ww51fd37h4sy8getjnag31ud6tpp9**
var文件=imagefile.txt; VAR rawFile =新XMLHtt prequest();
rawFile.open(GET,文件,真正的); rawFile.onreadystatechange =功能(){
如果(rawFile.readyState === 4){
如果(rawFile.status === 200 || rawFile.status == 0){
VAR数据= rawFile.responseText;
的console.log(数据加载:+ data.length); 的LoadImage(数据);
}
}
}
rawFile.send(NULL);
}
< / SCRIPT>
为了方便起见,这里是同一code的的jsfiddle 。
请指向正确的算法作为如何产生从原始uncom pressed数据的PNG。 code样品将是巨大的;)
感谢
公共静态字符串连接codeTobase64(位图图像)
{
位图immagex =图像;
ByteArrayOutputStream BAOS =新ByteArrayOutputStream();
immagex.com preSS(Bitmap.Com pressFormat.JPEG,100,BAOS);
字节[] B = baos.toByteArray();
字符串imageEn codeD = Base64.en codeToString(B,Base64.DEFAULT);Log.e(看,imageEn codeD);
返回imageEn codeD;
}公共静态位图德codeBase64(字符串输入){
字节[]德codedByte = Base64.de code(输入,0);
返回BitmapFactory.de codeByteArray的(德codedByte,0,德codedByte.length); }
I am using this Android Screenshot Library to capture screenshots. I want to show this screenshot in web browser.
I have written a small socket app on PC which connects to Android phone and encode the captured screenshot to base64.
String base64 = Base64.getEncoder().encodeToString(bytes);
This base64 is being sent to web page over websocket. Below is my html/JS code which should draw the image on canvas. I have stored the base64 image data in a text file for test purpose.
<div style="background: aqua; width: 500px; height: 660px;">
<canvas style="width: 480px; height: 640px;" id="sim">
</canvas>
</div>
<script type="text/javascript">
var ctx;
var width = 480;
var height = 640;
(function start() {
ctx = document.getElementById("sim").getContext("2d");
loadFromFile();
})();
function loadImage(data) {
var image = new Image();
image.onload = function() {
//this part never executes
ctx.drawImage(image, 0, 0);
console.log("images loaded!");
}
image.src = "data:image/png;base64," + data;
}
function loadFromFile() {
//please get data from **https://app.box.com/s/e19ww51fd37h4sy8getjnag31ud6tpp9**
var file = "imagefile.txt";
var rawFile = new XMLHttpRequest();
rawFile.open("GET", file, true);
rawFile.onreadystatechange = function() {
if (rawFile.readyState === 4) {
if (rawFile.status === 200 || rawFile.status == 0) {
var data = rawFile.responseText;
console.log("data loaded: " + data.length);
loadImage(data);
}
}
}
rawFile.send(null);
}
</script>
For convenience, here is the JsFiddle of same code.
Please point to right algorithm as how to generate the PNG from the raw uncompressed data. code sample would be great ;)
Thanks
public static String encodeTobase64(Bitmap image)
{
Bitmap immagex=image;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
immagex.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] b = baos.toByteArray();
String imageEncoded = Base64.encodeToString(b,Base64.DEFAULT);
Log.e("LOOK", imageEncoded);
return imageEncoded;
}
public static Bitmap decodeBase64(String input)
{
byte[] decodedByte = Base64.decode(input, 0);
return BitmapFactory.decodeByteArray(decodedByte, 0, decodedByte.length); }
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