I'm using the drawing pad (pen tool) plugin of Jquery to draw with different colors and having an image in the canvas as background. My purpose is to have a button to clear the drawing over the canvas. The way I try to do it remove the background image along with the drawing. How can I keep the background and remove the drawing on clicking the clear button ?
My fiddle : https://jsfiddle.net/ub3s9go7/
<script>
$(document).ready(function() {
// set background
var urlBackground = 'https://picsum.photos/id/100/500/400';
var imageBackground = new Image();
imageBackground.src = urlBackground;
imageBackground.setAttribute('crossorigin', 'anonymous');
$("#target").drawpad();
var contextCanvas = $("#target canvas").get(0).getContext('2d');
imageBackground.onload = function(){
contextCanvas.drawImage(imageBackground, 0, 0);
}
// Need to clear only the drawing not the background image
$("#clearDrawing").click(function() {
contextCanvas.clearRect(0, 0, 750, 423);
});
});
</script>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="https://cnbilgin.github.io/jquery-drawpad/jquery-drawpad.css" />
<style>
body {background-color:rgb(248, 255, 227)}
#target {
width:500px;
height:400px;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cnbilgin.github.io/jquery-drawpad/jquery-drawpad.js"></script>
</head>
<body>
<button id="clearDrawing">Clear Drawing</button>
<div id="target" class="drawpad-dashed"></div>
</body>
</html>
This answer is an improvisation on my previous answer at https://stackoverflow.com/a/67155647/3706717
So we have new requirement: delete/clear previous drawings
There are some possible approach here:
#sinisake in comment suggested to reload the background so that we have fresh canvas with only the background intact (but for some reason, white doodle make the background gone)
the library must have "delete" or "erase" doodle feature (which it didn't have)
save each changes of the drawing when user click "save", so that user can "undo" to previous version of the drawing (like git's git commit and git reset command), I'll be using this approach in my answer
Ideally, you should use server-side language and persistent storage (e.g.: database) to store user's doodling history. But in this case, to simulate such thing I'll be using javascript's localStorage API https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage
So every time I'm calling localStorage API, just assume that I'm calling some ajax to some endpoint.
Fiddle: https://jsfiddle.net/0da572jy/3/
Here is stack fiddle (modified because browser didn't allow stack fiddle to use localStorage)
// polyfill for localStorage API
var localStorage1 = {
items: {},
removeItem: function(key) {
window.localStorage1.items[key] = null;
},
getItem: function(key) {
return window.localStorage1.items[key];
},
setItem: function(key, val) {
return window.localStorage1.items[key] = val;
},
}
//window.localStorage = localStorage1;
window.localStorage1 = localStorage1;
$(document).ready(function() {
$("#save").click(function() {
// I already explained the #save logic in https://stackoverflow.com/a/67155647/3706717
//console.log("save");
var base64Image = $("#target canvas").get(0).toDataURL();
//console.log(base64Image);
$("#outputBase64FormInput").val(base64Image);
$("#outputBase64").html(base64Image);
// load/read saved states/histories
var savedImageJson = window.localStorage1.getItem("savedImage");
//console.log(savedImageJson);
// if the history is undefined, create empty array
if(savedImageJson == null || typeof savedImageJson == "undefined") savedImageJson = "[]";
// parse the history
var savedImageArr = JSON.parse(savedImageJson);
// add current state as a new item to history
savedImageArr.push(base64Image);
// save the modified (added history)
window.localStorage1.setItem("savedImage", JSON.stringify(savedImageArr));
$("#numOfSavedHistory").html( savedImageArr.length );
});
// clear button just clears the localStorage (or any kind of API you use for persistent storage
$("#clear").click(function() {
//console.log("save");
window.localStorage1.removeItem("savedImage");
$("#numOfSavedHistory").html( 0 );
});
// undo last change (rollback to last state when you clicked save)
$("#undo").click(function() {
// clear canvas (to prevent white ink bug that also clears the background)
canvas.width = canvas.width;
//console.log("undo");
// load/read saved states/histories
var savedImageJson = window.localStorage1.getItem("savedImage");
//console.log(savedImageJson);
// if the history is undefined, create empty array
if(savedImageJson == null || typeof savedImageJson == "undefined") savedImageJson = "[]";
// parse the history
var savedImageArr = JSON.parse(savedImageJson);
// delete last item in history
savedImageArr.pop();
// save the modified (pop'ed history)
window.localStorage1.setItem("savedImage", JSON.stringify(savedImageArr));
// draw old picture on canvas
var imageOld = new Image();
imageOld.src = savedImageArr[savedImageArr.length-1];
imageOld.onload = function() {
contextCanvas.drawImage(imageOld, 0, 0);
};
$("#numOfSavedHistory").html( savedImageArr.length );
});
// set background
var urlBackground = 'https://picsum.photos/id/100/500/400';
var imageBackground = new Image();
imageBackground.src = urlBackground;
//imageBackground.crossorigin = "anonymous";
imageBackground.setAttribute('crossorigin', 'anonymous');
$("#target").drawpad();
var canvas = $("#target canvas").get(0);
var contextCanvas = canvas.getContext('2d');
imageBackground.onload = function(){
contextCanvas.drawImage(imageBackground, 0, 0);
$("#clear").trigger("click"); // clear previous drawings when page refreshed
$("#save").trigger("click"); // save the first image (background only)
}
});
body {background-color:rgb(248, 255, 227)}
#target {
width:500px;
height:400px;
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="https://cnbilgin.github.io/jquery-drawpad/jquery-drawpad.css" />
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cnbilgin.github.io/jquery-drawpad/jquery-drawpad.js"></script>
</head>
<body>
<button id="undo">Undo</button>
<button id="save">Save</button>
<button id="clear">Clear Saved Picture</button>
<span id="numOfSavedHistory">0</span>
<div id="target" class="drawpad-dashed"></div>
<div id="outputBase64"></div>
</body>
</html>
Related
I have created a simple html using the draggable marker example from here maps. I have adapted it to support IE 11 by adding reference to legacy js, meta tag and using P2D engine in map options. Also added two url parameters for coordinates. It works perfectly in IE11 and it loads and shows pan and zoom buttons in ms-access webbrowser but it keeps static, it's not draggable, but pan and zoom works.
The curious thing is that if I navigate to wego.here.com in the same webbrowser control then the map is draggable. So they're doing something else in the here maps main page that I'm not doing in my script.
I have also tried using Microsoft Web Browser from the activex controls list in access.
I need it to be draggable so I can pick the coordinates after the user changes the marker position.
This is my script:
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-type" content="text/html;charset=UTF-8">
<title>Draggable Marker</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<link rel="stylesheet" type="text/css" href="https://js.api.here.com/v3/3.1/mapsjs-ui.css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-core.js" type="text/javascript" charset="utf-8"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-core-legacy.js" type="text/javascript" charset="utf-8"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-service.js" type="text/javascript" charset="utf-8"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-service-legacy.js" type="text/javascript" charset="utf-8"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-ui.js" type="text/javascript" charset="utf-8"></script>
<script src="https://js.api.here.com/v3/3.1/mapsjs-mapevents.js" type="text/javascript" charset="utf-8"></script>
<style>
html, body { margin:0px; padding:0px; width: 100%; height: 100%; }
.main { height: 100%; }
</style>
</head>
<body id="markers-on-the-map">
<div class="main" style="width:100%" id="map"></div>
<input type="hidden" id="long" name="long">
<input type="hidden" id="lat" name="lat">
<script>
function addDraggableMarker(map, behavior){
var marker = new H.map.Marker({lat:latitud, lng:longitud}, {volatility: true});
// Ensure that the marker can receive drag events
marker.draggable = true;
map.addObject(marker);
// disable the default draggability of the underlying map
// and calculate the offset between mouse and target's position
// when starting to drag a marker object:
map.addEventListener('dragstart', function(ev) {
var target = ev.target,
pointer = ev.currentPointer;
if (target instanceof H.map.Marker) {
var targetPosition = map.geoToScreen(target.getGeometry());
target['offset'] = new H.math.Point(pointer.viewportX - targetPosition.x, pointer.viewportY - targetPosition.y);
behavior.disable();
}
}, false);
// re-enable the default draggability of the underlying map
// when dragging has completed
map.addEventListener('dragend', function(ev) {
var target = ev.target;
if (target instanceof H.map.Marker) {
$('#long').val(ev.target.b.lng);
$('#lat').val(ev.target.b.lat);
behavior.enable();
}
}, false);
// Listen to the drag event and move the position of the marker
// as necessary
map.addEventListener('drag', function(ev) {
var target = ev.target,
pointer = ev.currentPointer;
if (target instanceof H.map.Marker) {
target.setGeometry(map.screenToGeo(pointer.viewportX - target['offset'].x, pointer.viewportY - target['offset'].y));
}
}, false);
}
/**
* Boilerplate map initialization code starts below:
*/
//Step 1: initialize communication with the platform
// In your own code, replace variable window.apikey with your own apikey
var platform = new H.service.Platform({
apikey: '?????????????????????????????????'
});
var defaultLayers = platform.createDefaultLayers();
//url parameters
var query_string = {};
var query = window.location.search.substring(1);
var vars = query.split("&");
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split("=");
if (typeof query_string[pair[0]] === "undefined") {
query_string[pair[0]] = decodeURIComponent(pair[1]);
} else if (typeof query_string[pair[0]] === "string") {
var arr = [ query_string[pair[0]],decodeURIComponent(pair[1]) ];
query_string[pair[0]] = arr;
} else {
query_string[pair[0]].push(decodeURIComponent(pair[1]));
}
}
var latitud=query_string.lat;
var longitud=query_string.long;
//Step 2: initialize a map - this map is centered over Boston
var map = new H.Map(document.getElementById('map'),
defaultLayers.raster.normal.map, {
center: {lat:latitud, lng:longitud},
engineType: H.map.render.RenderEngine.EngineType.P2D,
zoom: 12,
pixelRatio: window.devicePixelRatio || 1
});
// add a resize listener to make sure that the map occupies the whole container
//window.addEventListener('resize', () => map.getViewPort().resize());
window.addEventListener('resize', function () {map.getViewPort().resize(); });
//Step 3: make the map interactive
// MapEvents enables the event system
// Behavior implements default interactions for pan/zoom (also on mobile touch environments)
//var behavior = new H.mapevents.Behavior(new H.mapevents.MapEvents(map));
var behavior = new H.mapevents.Behavior(new H.mapevents.MapEvents(map));
// Step 4: Create the default UI:
var ui = H.ui.UI.createDefault(map, defaultLayers, 'en-US');
// Add the click event listener.
addDraggableMarker(map, behavior);
</script>
</body>
</html>```
Check please on this static page
: your code works for my IE11
I'm trying to print a specific zone on an Arcgis maps with the JS API (not the extend that is displayed).
I didn't find any method or option to do this so I tried to change the extend and then print the map :
var extent = new esri.geometry.Extent(
-620526.0922336339,
5993991.149960931,
108988.90572005256,
6293624.300838808,
myMap.spatialReference
);
myMap.setExtent(extent, true).then(function() {
console.log('setExtend is finished');
var template = new esri.tasks.PrintTemplate();
template.exportOptions = {
width : 500,
height : 500
};
template.format = 'jpg';
template.layout = 'MAP_ONLY';
var params = new esri.tasks.PrintParameters();
params.map = myMap;
params.template = template;
var printTask = new esri.tasks.PrintTask(urlToThePrintServer);
printTask.execute(params);
});
Since setExtent is asynchonous and return a defered I have to use the 'then' method.
I can see the map moving but the defered doesn't seem to works ... (I don't see the console.log()).
is there another way to print a specific extend of a map ?
if not why is the 'then' method never called ?
(I'm using the 3.12 JS API)
Your code looks good to me, though obviously you didn't post all your JavaScript or any of your HTML. Maybe you're not requiring the modules you need. Or maybe your code is trying to run before the map is loaded, though that's unlikely because as you say, the map does move. Or maybe something else is wrong.
I put a full working example at http://jsfiddle.net/06jtccx0/ . Hopefully you can compare that to what you're doing and figure out what is wrong with your code. Here's the same code for your convenience:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
<title>Simple Map</title>
<link rel="stylesheet" href="http://js.arcgis.com/3.13/esri/css/esri.css">
<style>
html, body, #map {
height: 100%;
width: 100%;
margin: 0;
padding: 0;
}
body {
background-color: #FFF;
overflow: hidden;
font-family: "Trebuchet MS";
}
</style>
<script src="http://js.arcgis.com/3.13/"></script>
<script>
var myMap;
var urlToThePrintServer = "http://sampleserver6.arcgisonline.com/arcgis/rest/services/Utilities/PrintingTools/GPServer/Export%20Web%20Map%20Task";
require(["esri/map", "dojo/domReady!"], function(Map) {
myMap = new Map("map", {
basemap: "topo", //For full list of pre-defined basemaps, navigate to http://arcg.is/1JVo6Wd
center: [-122.45, 37.75], // longitude, latitude
zoom: 13
});
myMap.on("load", function(map) {
var extent = new esri.geometry.Extent(
-620526.0922336339,
5993991.149960931,
108988.90572005256,
6293624.300838808,
myMap.spatialReference
);
myMap.setExtent(extent, true).then(function() {
console.log('setExtend is finished');
require([
"esri/tasks/PrintTemplate",
"esri/tasks/PrintParameters",
"esri/tasks/PrintTask"
], function(
PrintTemplate,
PrintParameters,
PrintTask
) {
var template = new PrintTemplate();
template.exportOptions = {
width : 500,
height : 500
};
template.format = 'jpg';
template.layout = 'MAP_ONLY';
var params = new PrintParameters();
params.map = myMap;
params.template = template;
var printTask = new PrintTask(urlToThePrintServer);
printTask.execute(params, function(response) {
console.log("The printed document is at " + response.url);
window.open(response.url);
});
});
});
});
});
</script>
</head>
<body>
<div id="map"></div>
</body>
</html>
I have the following HTML and JS. When i click on the image the images zooms. This is working. But then I zoom out I want to retract the image to the original location when It was loaded.
Consider image being dragged to right a little and then zoomed.
What I want is when its zoomed out its relocated to the original location when it was loaded.
What am I doing wrong? I need the effect this page has here. When you drag the image and release it, it will go to its original position.
JS
var isZoom=1;
var stage=new Kinetic.Stage({
container:'container',
width:700,
height:700,
id:'kineticstage',
name:'kineticstage'
});
var layer=new Kinetic.Layer({});
var group = new Kinetic.Group({
width:700,
height:700,
draggable: true
});
layer.add(group);
// set the images
var pages = ["http://197.242.159.63/reader/demo/img/face.jpg"];
var loadedPage = 0;
function loadPage(pageno){
var imageObj = new Image();
imageObj.onload = function() {
var kimage = new Kinetic.Image({
x: 0,
y: 0,
image: imageObj,
width:700,
height:700
});
// add to layer
group.add(kimage);
stage.add(layer);
};
// load the page image
imageObj.src = pages[pageno - 1];
}
// page 1
loadPage(1);
var tween = new Kinetic.Tween({
node: group,
duration: 1.0,
rotation:0,
scaleX: 1.5,
scaleY: 1.5,
easing:Kinetic.Easings.EaseInOut
});
group.on('dblclick dbltap',function(e){
if(isZoom == 1){
tween.play();
}
else{
tween.reverse();
}
layer.batchDraw();
isZoom = (isZoom>0) ? -1 : 1;
});
HTML
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" >
<meta name="apple-mobile-web-app-capable" content="yes" >
</head>
<body>
<div id="container"><!-- --></div>
</body>
<script type="text/javascript" language="javascript" src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.7.0.min.js"></script>
</html>
Fiddle
Dragging your kinetic group will cause its x,y to change.
To "undo" the drag, just reset the group back to its original x,y position:
In your case, you created the group at its default position of 0,0 so reset like this:
group.setX(0);
group.setY(0);
I have created a streaming webcam with html5. At the moment I can take a picture through my web cam, but I would like to know if it is possible to choose media stream device from the list, e.g. I have two web cams I want to choose the webcam to activate. How can I do that with html5 getUserMedia() call?
Thanks!
You can get the list of web camera
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Video Camera List</title>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js" ></script>
<style type="text/css" media="screen">
video {
border:1px solid gray;
}
</style>
</head>
<body>
<script>
if (!MediaStreamTrack) document.body.innerHTML = '<h1>Incompatible Browser Detected. Try <strong style="color:red;">Chrome Canary</strong> instead.</h1>';
var videoSources = [];
MediaStreamTrack.getSources(function(media_sources) {
console.log(media_sources);
// alert('media_sources : '+media_sources);
media_sources.forEach(function(media_source){
if (media_source.kind === 'video') {
videoSources.push(media_source);
}
});
getMediaSource(videoSources);
});
var get_and_show_media = function(id) {
var constraints = {};
constraints.video = {
optional: [{ sourceId: id}]
};
navigator.webkitGetUserMedia(constraints, function(stream) {
console.log('webkitGetUserMedia');
console.log(constraints);
console.log(stream);
var mediaElement = document.createElement('video');
mediaElement.src = window.URL.createObjectURL(stream);
document.body.appendChild(mediaElement);
mediaElement.controls = true;
mediaElement.play();
}, function (e)
{
// alert('Hii');
document.body.appendChild(document.createElement('hr'));
var strong = document.createElement('strong');
strong.innerHTML = JSON.stringify(e);
alert('strong.innerHTML : '+strong.innerHTML);
document.body.appendChild(strong);
});
};
var getMediaSource = function(media) {
console.log(media);
media.forEach(function(media_source) {
if (!media_source) return;
if (media_source.kind === 'video')
{
// add buttons for each media item
var button = $('<input/>', {id: media_source.id, value:media_source.id, type:'submit'});
$("body").append(button);
// show video on click
$(document).on("click", "#"+media_source.id, function(e){
console.log(e);
console.log(media_source.id);
get_and_show_media(media_source.id);
});
}
});
}
</script>
</body>
</html>
In the latest Chrome Canary (30.0.1587.2) it looks like you can enable device enumeration in chrome://flags (looks like it might already be enabled) and use the MediaStreamTrack.getSources API to select the camera.
See this WebRTC bug and mailing list post for more details.
I'm trying to use canvas object on iPad; the user need to draw a free curve with the finger and when he releases the finger the system must close the curve and fill it.
Actually I wrote down the following code but the problem is that it draws but it does not close the path on finger release.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=768px, maximum-scale=1.0" />
<title>sketchpad</title>
<script type="text/javascript" charset="utf-8">
window.addEventListener('load',function(){
// get the canvas element and its context
var canvas = document.getElementById('sketchpad');
var context = canvas.getContext('2d');
var img = new Image();
img.src = 'imp_02.jpg';
context.drawImage(img,0,0,600,600);
var colorPurple = "#cb3594";
context.strokeStyle=colorPurple;
context.lineWidth = 5;
context.fillStyle = "red";
// create a drawer which tracks touch movements
var drawer = {
isDrawing: false,
touchstart: function(coors){
context.beginPath();
context.moveTo(coors.x, coors.y);
this.isDrawing = true;
},
touchmove: function(coors){
if (this.isDrawing) {
context.lineTo(coors.x, coors.y);
context.stroke();
}
},
touchend: function(coors){
if (this.isDrawing) {
context.touchmove(coors);
context.closePath();
this.isDrawing = false;
}
}
};
// create a function to pass touch events and coordinates to drawer
function draw(event){
// get the touch coordinates
var coors = {
x: event.targetTouches[0].pageX,
y: event.targetTouches[0].pageY
};
// pass the coordinates to the appropriate handler
drawer[event.type](coors);
}
// attach the touchstart, touchmove, touchend event listeners.
canvas.addEventListener('touchstart',draw, false);
canvas.addEventListener('touchmove',draw, false);
canvas.addEventListener('touchend',draw, false);
// prevent elastic scrolling
document.body.addEventListener('touchmove',function(event){
event.preventDefault();
},false); // end body.onTouchMove
},false); // end window.onLoad
</script>
<style type="text/css"><!--
body{margin:0;padding:0; font-family:Arial;}
#container{position:relative;}
#sketchpad{ border: 1px solid #000;}
--></style>
</head>
<body>
<div id="container">
<canvas id="sketchpad" width="766" height="944">
Sorry, your browser is not supported.
</canvas>
</div>
</body>
</html>
I don't understand what I missed.
Is there anyone who can help me..... I would appreciate a lot!!
You are fetching the touch end co-ordinates from a wrong array.
event object has one more array called changedTouches where you can find the co-ordinates of the point where the touch ended. These end co-ordinates are not in targetTouches array.
So you need
endCoordX = event.changedTouches[0].pageX;
endCoordY = event.changedTouches[0].pageY;
[modify the above code to fit into your scenario. hope you got the concept.... And seriuosly i too got stuck on the same point in the past and wasted more than an hour to know this fact....]