-
Notifications
You must be signed in to change notification settings - Fork 0
/
captureWebRTCSnapshots.html
262 lines (219 loc) · 6.99 KB
/
captureWebRTCSnapshots.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="robots" content="noindex, nofollow">
<style>
body {
padding: 0;
margin: 0;
}
svg:not(:root) {
display: block;
}
.playable-code {
background-color: #f4f7f8;
border: none;
border-left: 6px solid #558abb;
border-width: medium medium medium 6px;
color: #4d4e53;
height: 100px;
width: 90%;
padding: 10px 10px 0;
}
.playable-canvas {
border: 1px solid #4d4e53;
border-radius: 2px;
}
.playable-buttons {
text-align: right;
width: 90%;
padding: 5px 10px 5px 26px;
}
</style>
<style>
#video {
border: 1px solid black;
box-shadow: 2px 2px 3px black;
width: 300px;
height: 300px;
}
#photo {
border: 1px solid black;
box-shadow: 2px 2px 3px black;
width: 300px;
height: 300px;
}
#canvas {
display: none;
}
.camera {
width: 340px;
display: inline-block;
}
.output {
width: 340px;
display: inline-block;
vertical-align: top;
}
#startbutton {
display: block;
position: relative;
margin-left: auto;
margin-right: auto;
bottom: 32px;
background-color: rgba(0, 150, 0, 0.5);
border: 1px solid rgba(255, 255, 255, 0.7);
box-shadow: 0px 0px 1px 2px rgba(0, 0, 0, 0.2);
font-size: 14px;
font-family: "Lucida Grande", "Arial", sans-serif;
color: rgba(255, 255, 255, 1);
}
.contentarea {
font-size: 16px;
font-family: "Lucida Grande", "Arial", sans-serif;
width: 760px;
}
</style>
<title>Taking still photos with getUserMedia() - demo - code sample</title>
</head>
<body>
<div class="contentarea">
<h1>MDN - navigator.mediaDevices.getUserMedia(): Still photo capture demo</h1>
<p>
This example demonstrates how to set up a media stream using your built-in
webcam, fetch an image from that stream, and create a PNG using that image.
</p>
<div class="camera">
<video id="video">Video stream not available.</video>
<button id="startbutton">Take photo</button>
<a id="download" download="myImage.jpg" href="" onclick="download_img(this);">Download to myImage.jpg</a>
</div>
<canvas id="canvas"> </canvas>
<div class="output">
<img id="photo" alt="The screen capture will appear in this box." />
</div>
<p>
Visit our article
<a href="https://developer.mozilla.org/en-US/docs/Web/API/WebRTC_API/Taking_still_photos">
Taking still photos with WebRTC</a>
to learn more about the technologies used here.
</p>
</div>
<script>
(() => {
// The width and height of the captured photo. We will set the
// width to the value defined here, but the height will be
// calculated based on the aspect ratio of the input stream.
const width = 320; // We will scale the photo width to this
let height = 0; // This will be computed based on the input stream
// |streaming| indicates whether or not we're currently streaming
// video from the camera. Obviously, we start at false.
let streaming = false;
// The various HTML elements we need to configure or control. These
// will be set by the startup() function.
let video = null;
let canvas = null;
let photo = null;
let startbutton = null;
function showViewLiveResultButton() {
if (window.self !== window.top) {
// Ensure that if our document is in a frame, we get the user
// to first open it in its own tab or window. Otherwise, it
// won't be able to request permission for camera access.
document.querySelector(".contentarea").remove();
const button = document.createElement("button");
button.textContent = "View live result of the example code above";
document.body.append(button);
button.addEventListener("click", () => window.open(location.href));
return true;
}
return false;
}
function startup() {
if (showViewLiveResultButton()) {
return;
}
video = document.getElementById("video");
canvas = document.getElementById("canvas");
photo = document.getElementById("photo");
startbutton = document.getElementById("startbutton");
navigator.mediaDevices
.getUserMedia({
video: true,
audio: false
})
.then((stream) => {
video.srcObject = stream;
video.play();
})
.catch((err) => {
console.error(`An error occurred: ${err}`);
});
video.addEventListener(
"canplay",
(ev) => {
if (!streaming) {
height = video.videoHeight / (video.videoWidth / width);
// Firefox currently has a bug where the height can't be read from
// the video, so we will make assumptions if this happens.
if (isNaN(height)) {
height = width / (4 / 3);
}
video.setAttribute("width", width);
video.setAttribute("height", height);
canvas.setAttribute("width", width);
canvas.setAttribute("height", height);
streaming = true;
}
},
false
);
startbutton.addEventListener(
"click",
(ev) => {
takepicture();
ev.preventDefault();
},
false
);
clearphoto();
}
// Fill the photo with an indication that none has been
// captured.
function clearphoto() {
const context = canvas.getContext("2d");
context.fillStyle = "#AAA";
context.fillRect(0, 0, canvas.width, canvas.height);
const data = canvas.toDataURL("image/png");
photo.setAttribute("src", data);
}
// Capture a photo by fetching the current contents of the video
// and drawing it into a canvas, then converting that to a PNG
// format data URL. By drawing it on an offscreen canvas and then
// drawing that to the screen, we can change its size and/or apply
// other changes before drawing it.
function takepicture() {
const context = canvas.getContext("2d");
if (width && height) {
canvas.width = width;
canvas.height = height;
context.drawImage(video, 0, 0, width, height);
const data = canvas.toDataURL("image/png");
photo.setAttribute("src", data);
download_img(this);
} else {
clearphoto();
}
}
// Set up our event listener to run the startup process
// once loading is complete.
window.addEventListener("load", startup, false);
})();
download_img = function(el) {
var image = canvas.toDataURL("image/png");
el.href = image;
};
</script>
</body>
</html>