code-boxx/0-JS-SCREENSHOT.MD

## 0-JS-SCREENSHOT.MD

      
    Raw
  

              0-JS-SCREENSHOT.MD
            
          
    JAVASCRIPT TAKE SCREENSHOT


https://code-boxx.com/take-screenshots-javascript/
https://youtu.be/SNiGWSQa2Bo

LICENSE

Copyright by Code Boxx
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.

  
## 1a-html2canvas.html
<!DOCTYPE html>
<html>
  <head>
    <title>Javascript Screenshot Demo</title>
    <link rel="stylesheet" href="x-dummy.css">

    <!-- (A) HTML2CANVAS LIBRARY -->
    <!-- https://github.com/niklasvh/html2canvas -->
    <!-- https://cdnjs.com/libraries/html2canvas -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/html2canvas/1.4.1/html2canvas.min.js"></script>
    <script src="1b-html2canvas.js"></script>
  </head>
  <body>
    <!-- (B) TEST -->
    <h1>TEST</h1>
    <textarea>Dummy Text - Change and see how it captures below!</textarea>
    <input type="button" value="Capture" onclick="capture()">
  </body>
</html>

## 1b-html2canvas.js
function capture () {
  html2canvas(document.body).then(canvas => {
    let a = document.createElement("a");
    a.download = "ss.png";
    a.href = canvas.toDataURL("image/png");
    a.click(); // MAY NOT ALWAYS WORK!
  });
}

## 2a-media.html
<!DOCTYPE html>
<html>
  <head>
    <title>Javascript Screenshot Demo</title>
    <link rel="stylesheet" href="x-dummy.css">

    <!-- (A) LOAD JS -->
    <script src="2b-media.js"></script>
  </head>
  <body>
    <!-- (B) TEST -->
    <h1>TEST</h1>
    <textarea>Dummy Text - Change and see how it captures below!</textarea>
    <input type="button" value="Capture" onclick="capture()">
  </body>
</html>

## 2b-media.js
async function capture () {
  // (A) GET MEDIA STREAM
  const stream = await navigator.mediaDevices.getDisplayMedia({
    preferCurrentTab: true
  });
  /*
  const stream = await navigator.mediaDevices.getDisplayMedia({
    video: { displaySurface: "window" } // window | browser | monitor
  });*/

  // (B) STREAM TO VIDEO
  const vid = document.createElement("video");

  // (C) VIDEO TO CANVAS
  vid.addEventListener("loadedmetadata", function () {
    // (C1) CAPTURE VIDEO FRAME ON CANVAS
    const canvas = document.createElement("canvas"),
          ctx = canvas.getContext("2d");
    ctx.canvas.width = vid.videoWidth;
    ctx.canvas.height = vid.videoHeight;
    ctx.drawImage(vid, 0, 0, vid.videoWidth, vid.videoHeight);

    // (C2) STOP MEDIA STREAM
    stream.getVideoTracks()[0].stop();

    // (C3) "FORCE DOWNLOAD"
    let a = document.createElement("a");
    a.download = "ss.png";
    a.href = canvas.toDataURL("image/png");
    a.click(); // MAY NOT ALWAYS WORK!
  });

  // (D) GO!
  vid.srcObject = stream;
  vid.play();
}

## 3a-upload.js
// (A) APPEND SCREENSHOT TO DATA OBJECT
var data = new FormData();
data.append("screenshot", canvas.toDataURL("image/jpeg", 0.6));

// (B) UPLOAD SCREENSHOT TO SERVER
fetch("3b-upload.php", { method:"post", body:data })
.then(res => res.text())
.then(txt => alert(txt));

## 3b-upload.php
<?php
// https://netcell.netlify.com/blog/2016/04/image-base64.html
$file = fopen("screenshot.jpg", "w");
$data = explode(",", $_POST["screenshot"]);
$data = base64_decode($data[1]);
fwrite($file, $data);
fclose($file);
echo "OK";

## x-dummy.css
/* (X) CSS COSMETICS - DOES NOT MATTER */
* {
  font-family: Arial, Helvetica, sans-serif;
  box-sizing: border-box;
}
body { max-width: 300px; }
textarea, input { font-size: 1em; }
textarea {
  display: block;
  width: 100%; height: 200px;
}
input[type=button] {
  color: #fff; background: #9d2631;
  border: 0; padding: 10px; margin-top: 20px;
  cursor: pointer;
}
	<!DOCTYPE html>
	<html>
	<head>
	<title>Javascript Screenshot Demo</title>
	<link rel="stylesheet" href="x-dummy.css">

	<!-- (A) HTML2CANVAS LIBRARY -->
	<!-- https://github.com/niklasvh/html2canvas -->
	<!-- https://cdnjs.com/libraries/html2canvas -->
	<script src="https://cdnjs.cloudflare.com/ajax/libs/html2canvas/1.4.1/html2canvas.min.js"></script>
	<script src="1b-html2canvas.js"></script>
	</head>
	<body>
	<!-- (B) TEST -->
	<h1>TEST</h1>
	<textarea>Dummy Text - Change and see how it captures below!</textarea>
	<input type="button" value="Capture" onclick="capture()">
	</body>
	</html>
	function capture () {
	html2canvas(document.body).then(canvas => {
	let a = document.createElement("a");
	a.download = "ss.png";
	a.href = canvas.toDataURL("image/png");
	a.click(); // MAY NOT ALWAYS WORK!
	});
	}
	async function capture () {
	// (A) GET MEDIA STREAM
	const stream = await navigator.mediaDevices.getDisplayMedia({
	preferCurrentTab: true
	});
	/*
	const stream = await navigator.mediaDevices.getDisplayMedia({
	video: { displaySurface: "window" } // window \| browser \| monitor
	});*/

	// (B) STREAM TO VIDEO
	const vid = document.createElement("video");

	// (C) VIDEO TO CANVAS
	vid.addEventListener("loadedmetadata", function () {
	// (C1) CAPTURE VIDEO FRAME ON CANVAS
	const canvas = document.createElement("canvas"),
	ctx = canvas.getContext("2d");
	ctx.canvas.width = vid.videoWidth;
	ctx.canvas.height = vid.videoHeight;
	ctx.drawImage(vid, 0, 0, vid.videoWidth, vid.videoHeight);

	// (C2) STOP MEDIA STREAM
	stream.getVideoTracks()[0].stop();

	// (C3) "FORCE DOWNLOAD"
	let a = document.createElement("a");
	a.download = "ss.png";
	a.href = canvas.toDataURL("image/png");
	a.click(); // MAY NOT ALWAYS WORK!
	});

	// (D) GO!
	vid.srcObject = stream;
	vid.play();
	}
	// (A) APPEND SCREENSHOT TO DATA OBJECT
	var data = new FormData();
	data.append("screenshot", canvas.toDataURL("image/jpeg", 0.6));

	// (B) UPLOAD SCREENSHOT TO SERVER
	fetch("3b-upload.php", { method:"post", body:data })
	.then(res => res.text())
	.then(txt => alert(txt));
	<?php
	// https://netcell.netlify.com/blog/2016/04/image-base64.html
	$file = fopen("screenshot.jpg", "w");
	$data = explode(",", $_POST["screenshot"]);
	$data = base64_decode($data[1]);
	fwrite($file, $data);
	fclose($file);
	echo "OK";
	/* (X) CSS COSMETICS - DOES NOT MATTER */
	* {
	font-family: Arial, Helvetica, sans-serif;
	box-sizing: border-box;
	}
	body { max-width: 300px; }
	textarea, input { font-size: 1em; }
	textarea {
	display: block;
	width: 100%; height: 200px;
	}
	input[type=button] {
	color: #fff; background: #9d2631;
	border: 0; padding: 10px; margin-top: 20px;
	cursor: pointer;
	}