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imagecapture.html
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imagecapture.html
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<!DOCTYPE html>
<html>
<link rel="stylesheet" href="w3.css">
<link rel="stylesheet" href="range.css" media="screen" />
<link rel="manifest" href="manifest.json">
<head>
<meta name=viewport content="width=device-width, initial-scale=1">
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>ImageCapture demo</title>
</head>
<body>
<div class="w3-container w3-orange"> Open the system camera and grab frame(s) or take (a) picture(s).</div>
<div class="w3-row">
<div class="w3-light-green w3-quarter">Video source: </div>
<!-- onfocus trick to get onchange events also when nothing changes-->
<select id="videoSource" class="w3-select w3-threequarter w3-green"
onfocus="this.selectedIndex = -1;"></select>
</div>
<div class="w3-row">
<input type="button" id="btn-photo" class="w3-btn-primary w3-teal w3-round"
onclick="takePhoto()" value="takePhoto()">
<input type="button" id="btn-photo" class="w3-btn-primary w3-teal w3-round"
onclick="takePhotoWithFlash()" value="takePhotoWithFlash()">
<input type="button" id="btn-frame" class="w3-btn-primary w3-teal w3-round"
onclick="grabFrame()" value="grabFrame()">
</div>
<br>
<div id="zoom-area" class="w3-row-padding" style="visibility : hidden">
<div class="w3-container w3-quarter">Zoom</div>
<input type="range" id="zoom-slider" name="zoom"
class="w3-input w3-border w3-container w3-quarter">
<output id="zoom-slider-value" class="w3-output w3-border w3-container w3-quarter"></output>
</div>
<div class="w3-row-padding w3-center">
<div class="w3-container w3-half">
<video id="videotag" class="w3-round w3-border w3-card-4"
width="240" height="180" autoplay=true>
</video>
</div>
<div class="w3-container w3-half">
<img id="imagetag" class="w3-round w3-border w3-card-4" width="240"
style="visibility : hidden">
</img>
</div>
</div>
<br>
<div id="height-area" class="w3-row" style="visibility : hidden">
<div class="w3-container w3-quarter">Height (pixels)</div>
<input type="range" id="height-slider" name="height"
class="w3-input w3-border w3-container w3-quarter">
<output id="height-slider-value" class="w3-output w3-border w3-container w3-quarter"></output>
</div>
<footer class="w3-container w3-light-green">Size matters?</footer>
<div>
<label class="w3-validate" id="focusModeLabel">focus: unknown</label>
<input type="button" id="btn-single-shot" class="w3-btn-primary w3-teal w3-round"
onclick="setSingleShotFocus()" value="kick focus single-shot">
<input type="button" id="btn-continuous" class="w3-btn-primary w3-teal w3-round"
onclick="setContinuousFocus()" value="set continuous focus">
</div>
</body>
<script type="text/javascript" src="dimsum.js"></script>
<script>
// Chrome 57 and 58 hadn't implemented the "new" constraints API.
const isChrome57or58 =
navigator.userAgent.match(/Chrome\/(57\.0\.[0-9]+)\./) != null ||
navigator.userAgent.match(/Chrome\/(58\.0\.[0-9]+)\./) != null;
var videoSelect = document.querySelector('select#videoSource');
videoSelect.onchange = getUserMedia;
var focusModeLabel = document.getElementById('focusModeLabel');
var theStream;
var theTrack;
var theImageCapturer;
var theGrabbedFrame;
var theTakenPhoto;
var theCapabilities;
var theImageTag = document.getElementById("imagetag");
document.body.appendChild(document.createElement("br"));
var theZoomSlider = document.getElementById("zoom-slider");
theZoomSlider.name = "zoom";
theZoomSlider.step = 20;
var theZoomSliderValue = document.getElementById("zoom-slider-value");
theZoomSlider.oninput = function() {
theZoomSliderValue.value = theZoomSlider.value;
const zoomConstraint = { zoom : theZoomSlider.value };
if (isChrome57or58)
theImageCapturer.setOptions(zoomConstraint);
else
theTrack.applyConstraints({ advanced: [zoomConstraint]});
}
var theHeightSlider = document.getElementById("height-slider");
theHeightSlider.name = "height";
theHeightSlider.step = 0;
var theHeightSliderValue = document.getElementById("height-slider-value");
theHeightSlider.oninput = function() {
theHeightSliderValue.value = theHeightSlider.value;
theImageCapturer.setOptions({ imageHeight : theHeightSlider.value });
}
document.body.appendChild(document.createElement("br"));
function createImageCapturer() {
theImageCapturer = new ImageCapture(theTrack);
document.getElementById("btn-frame").disabled = false;
document.getElementById("btn-photo").disabled = false;
// getPhotoCapabilities() can be called instantly; the synchronous
// theTrack.getCapabilities() is racy and running in parallel, so wait.
setTimeout(getCaps, 100);
}
function takePhoto() {
theImageCapturer.takePhoto()
.then((blob) => {
document.getElementsByTagName('footer')[0].innerHTML =
"photo taken " + blob.type + " of size " + (blob.size/1024).toFixed(2)
+ "KiB - ";
theTakenPhoto = blob;
theImageTag.style.visibility = "visible";
theImageTag.src = URL.createObjectURL(theTakenPhoto);
theImageTag.onload = function() {
document.getElementsByTagName('footer')[0].innerHTML +=
"(" + theImageTag.naturalWidth + "x" + theImageTag.naturalHeight +
")";
};
});
}
function takePhotoWithFlash() {
theImageCapturer.setOptions({ fillLightMode: "flash" })
.then(() => { takePhoto(); });
}
function getCaps() {
theImageCapturer.getPhotoCapabilities()
.then(function(caps) {
console.log(" PhotoCapabilities retrieved ", caps);
theCapabilities = caps;
if (theCapabilities.imageHeight) {
theHeightSlider.min = theCapabilities.imageHeight.min;
theHeightSlider.max = theCapabilities.imageHeight.max;
theHeightSlider.value = theCapabilities.imageHeight.current;
theHeightSliderValue.value = theHeightSlider.value;
document.getElementById("height-area").style.visibility = "visible";
theImageCapturer.setOptions({ imageHeight : theHeightSlider.value });
}
if (isChrome57or58) {
if (theCapabilities.zoom.min !== theCapabilities.zoom.max) {
theZoomSlider.min = theCapabilities.zoom.min;
theZoomSlider.max = theCapabilities.zoom.max;
theZoomSlider.value = theCapabilities.zoom.current;
theZoomSlider.step = theCapabilities.zoom.step;
theZoomSliderValue.value = theZoomSlider.value;
document.getElementById("zoom-area").style.visibility = "visible";
}
focusModeLabel.innerHTML = 'focus : ' + theCapabilities.focusMode;
} else { /* ! isChrome57or58 */
var zoom = theTrack.getCapabilities().zoom;
if (zoom) {
theZoomSlider.min = zoom.min;
theZoomSlider.max = zoom.max;
theZoomSlider.step = zoom.step;
theZoomSlider.value = theTrack.getSettings().zoom;
theZoomSliderValue.value = theZoomSlider.value;
document.getElementById("zoom-area").style.visibility = "visible";
}
focusModeLabel.innerHTML =
'focus : ' + theTrack.getCapabilities().focusMode;
}
});
}
function grabFrame() {
theImageCapturer.grabFrame()
.then(function(a) {
console.log(" frame grabbed " + a);
theGrabbedFrame = a;
var canvas = document.createElement("canvas");
document.body.appendChild(canvas);
canvas.width = theGrabbedFrame.width;
canvas.height = theGrabbedFrame.height;
canvas.className = "w3-round w3-border w3-card-16";
var context = canvas.getContext("2d");
context.drawImage(theGrabbedFrame, 0, 0);
console.log(" theGrabbedFrame has been painted (maybe)");
});
}
function setSingleShotFocus() {
const focusConstraint = { focusMode : "single-shot" };
if (isChrome57or58)
theImageCapturer.setOptions(focusConstraint);
else
theTrack.applyConstraints({advanced : [focusConstraint]});
getCaps();
}
function setContinuousFocus() {
const focusConstraint = { focusMode : "continuous" };
if (isChrome57or58)
theImageCapturer.setOptions(focusConstraint);
else
theTrack.applyConstraints({advanced : [focusConstraint]});
getCaps();
}
// Set the points of interest on mouse click.
function onMouseClick(e) {
var videoTag = document.getElementById("videotag");
const rect = this.getBoundingClientRect();
const x_pos = (e.clientX - rect.left) / videoTag.offsetWidth;
const y_pos = (e.clientY - rect.top) / videoTag.offsetHeight;
console.log("mouse click @ " + x_pos + "," + y_pos );
const pointsOfInterestConstraint = {
pointsOfInterest : [ {x : x_pos, y : y_pos} ]
};
if (isChrome57or58)
theImageCapturer.setOptions(pointsOfInterestConstraint);
else
theTrack.applyConstraints({advanced : [pointsOfInterestConstraint]});
e.preventDefault();
}
////////////////////////////////////////////////////////////////////////////////
// getUserMedia() related stuff here below: enumerate cameras, open one.
////////////////////////////////////////////////////////////////////////////////
function refreshSources() {
navigator.mediaDevices.enumerateDevices()
.then((devices) => {
devices.forEach((device) => {
if (device.kind == 'videoinput') {
var option = document.createElement('option');
option.value = device.deviceId;
option.text = device.label || 'Camera #' + (videoSelect.length + 1);
console.log("cam [" + option.text + "] with id: " + option.value);
videoSelect.appendChild(option);
}
});
})
.catch((err) => {
console.log(err.name + ": " + err.message);
});
}
refreshSources();
function gotStream(stream) {
if (theStream)
theStream.getTracks().forEach((track) => { track.stop(); });
theStream = stream;
theTrack = stream.getVideoTracks()[0];
var videoTag = document.getElementById("videotag");
// This is the deprecated, obviously working fine, way. The not deprecated
// (videoTag.srcObject = theStream) doesn't work so well.
videoTag.src = URL.createObjectURL(theStream);
videoTag.addEventListener("mousedown", onMouseClick, false);
createImageCapturer();
}
function getUserMediaFailedCallback(error) {
console.error('User media request denied with error code ' + error.code);
}
function getUserMedia() {
var videoSource = videoSelect.value;
console.log("opening camera with id: " + videoSource);
var constraints = {
"audio": false,
"video": {
deviceId: videoSource ? {exact: videoSource} : undefined,
width: { exact: 320 },
height: { exact : 240 }
}
};
navigator.getUserMedia(constraints, gotStream, getUserMediaFailedCallback);
};
</script>
</html>