"Collaborative" Canvas Designer i.e. Canvas-Drawing tool allows you draw bezier/quadratic curves, rectangles, circles and lines. You can also set strokes, back/forth colors and much more. You can draw using pencils, erase drawing, type texts etc. You can easily add your own tools
This project is an improved version of Muaz Khan's original project. Some improvement I'm working in:
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✅ Webpack 5 & ES6 compatible.
-
✅ Support mobile devices, tablets,...
-
✅ Fix existed bugs in zooming.
-
⬜️ And more.
Feel free to use and contribute.
-
Run
npm start
to start webpack server. A debug-friendly version of file is served atlocalhost:8080/widget.min.js
. -
Open html files with
widgetJsURL
param points to your js file. For example:
http://localhost:8000/widget.html?widgetJsURL=http://localhost:8080/widget.min.js
Demo widget: http://kaito-bk.com/canvas-designer/dist/widget.html
Advance Demo: demos/dashboard/
Multiple designers demo: https://www.webrtc-experiment.com/Canvas-Designer/multiple.html
You can check all releases here:
The specialty of this drawing-tool is that, it generates Canvas2D code for you; so simply draw and get the code! That code can be used in any javascript Canvas2D application.
You can submit issues here:
Also, you can collaborate your drawing with up to 15 users; and everything is synced from all users. So, if you draw a line and your friend-A draws quadratic curve and friend-B draws rectangle then everything will be synced among all users!
Gif images:
You can use designer.setSelected
or designer.setTools
for below tools.
line
--- to draw straight linespencil
--- to write/draw shapesdragSingle
--- to drag/ove and especially resize last selected shapedragMultiple
--- to drag/move all shapeseraser
--- to erase/clear specific portion of shapesrectangle
--- to draw rectanglesarc
--- to draw circlesbezier
--- to draw bezier curvesquadratic
--- to draw quadratic curvestext
--- to write texts on single or multiple lines, select font families/sizes and moreimage
--- add external imagesarrow
--- draw arrow linesmarker
--- draw markerslineWidth
--- set line widthcolorsPicker
--- background and foreground colors pickerextraOptions
--- extra options eg. lineCap, lineJoin, globalAlpha, globalCompositeOperation etc.pdf
--- to import PDFcode
--- to enable/disable code viewundo
--- undo recent shapes
The correct name for dragSingle
should be: drag-move-resize last-selected-shape
.
The correct name for dragMultiple
should be: drag-move all-shapes
.
- Allow users to add video-streams or screen-streams or existing-webm-mp4-videos
- Resize all shapes at once (currently you can resize last selected shape only)
-
Draw single or multiple shapes of any kind (according to toolbox)
-
Drag/resize/adjust all the shapes in any possible direction
-
Rectangles and images can be resized in 4-directions
Red transparent small circles helps you understand how to resize.
-
Undo drawings using
ctrl+z
keys (undo all shapes, undo last 10 or specific shapes, undo range of shapes or undo last shape) -
Drag/move single or all the shapes without affecting any single coordinate
More importantly, you can use unlimited designers on a single page. Each will have its own surface and its own tools.
You can install following chrome extension for multi-language input tools:
Now type your own language text in any <input>
box or anywhere, and simply copy that text.
Now click T
tool icon from the tool-box and press ctrl+v
to paste your own language's text.
To repeat it:
- Type your own language texts anywhere and make sure to copy to clipboard using
ctrl+v
- Then click
T
icon, and then pressctrl+v
to paste your copied text
You can paste any text: English, Arabic, Chinese etc.
-
Download/link
canvas-designer-widget.js
from this github repository. -
Set
designer.widgetHtmlURL
anddesigner.widgetJsURL
in your HTML file. -
Use this command to append widget in your HTML page:
var designer = new CanvasDesigner();
designer.appendTo(document.body);
<!-- 1st step -->
<script src="https://www.webrtc-experiment.com/Canvas-Designer/canvas-designer-widget.js"></script>
<!-- 2nd step -->
<script>
var designer = new CanvasDesigner();
// both links are mandatory
// widget.html will internally use widget.js
designer.widgetHtmlURL = 'https://www.webrtc-experiment.com/Canvas-Designer/widget.html'; // you can place this file anywhere
designer.widgetJsURL = 'https://www.webrtc-experiment.com/Canvas-Designer/widget.js'; // you can place this file anywhere
</script>
<!-- 3rd i.e. last step -->
<script>
// <iframe> will be appended to "document.body"
designer.appendTo(document.body || document.documentElement);
</script>
var designer = new CanvasDesigner();
websocket.onmessage = function(event) {
designer.syncData( JSON.parse(event.data) );
};
designer.addSyncListener(function(data) {
websocket.send(JSON.stringify(data));
});
designer.setSelected('pencil');
designer.setTools({
pencil: true,
text: true
});
designer.appendTo(document.documentElement);
It is having designer.destroy()
method as well.
Use WebRTC!
webrtc.onmessage = function(event) {
designer.syncData( event.data );
};
designer.addSyncListener(function(data) {
webrtc.send(data);
});
socket.on('message', function(data) {
designer.syncData( data );
});
designer.addSyncListener(function(data) {
socket.emit('message', data);
});
You can place widget.html
file anywhere on your site.
designer.widgetHtmlURL = '/html-files/widget.html';
By default widget.html
is placed in the same directory of index.html
.
// here is default value
designer.widgetHtmlURL = 'widget.html';
Remember, widget.html
is loaded using <iframe>
.
Note: This file is internally used by
widget.html
.
You can place widget.html
file anywhere on your site.
designer.widgetJsURL = '/js-files/widget.min.js';
By default widget.min.js
is placed in the same directory of index.html
.
// here is default value
designer.widgetJsURL = 'widget.min.js';
Remember, widget.js
is loaded using <iframe>
.
Pass array-of-points that are shared by remote users using socket.io or websockets or XMPP or WebRTC.
designer.syncData(arrayOfPoints);
An example to pass custom data on Canvas-Designer:
var x = 0;
var y = 0;
var width = designer.iframe.clientWidth;
var height = designer.iframe.clientHeight;
var image = 'https://www.webrtc-experiment.com/images/RTCMultiConnection-STUN-TURN-usage.png';
var points = [
['image', [image, x, y, width, height, 1], ['2', '#6c96c8', 'rgba(0,0,0,0)', '1', 'source-over', 'round', 'round', '15px "Arial"']]
];
designer.syncData({
startIndex: 0,
points: points
});
Remove and clear all drawings from the canvas:
designer.clearCanvas();
Call this method internally to fix video rendering issues.
designer.renderStream();
This callback is invoked as soon as something new is drawn. An array-of-points is passed over this function. That array MUST be shared with remote users for collaboration.
designer.addSyncListener(function(data) {
designer.send(JSON.stringify(data));
});
This method allows you select specific tools.
- See list of all tools
designer.setSelected('rectangle');
This method allows you choose between tools that should be displayed in the tools-panel.
- See list of all tools
designer.setTools({
line: true,
arrow: true,
pencil: true,
marker: true,
dragSingle: true,
dragMultiple: true,
eraser: true,
rectangle: true,
arc: true,
bezier: true,
quadratic: true,
text: true,
image: true,
pdf: true,
zoom: true,
lineWidth: true,
colorsPicker: true,
extraOptions: true,
code: true,
undo: true
});
You can force/set your own tool-icons:
designer.icons = {
line: '/icons/line.png',
arrow: '/icons/arrow.png',
pencil: '/icons/pencil.png',
dragSingle: '/icons/dragSingle.png',
dragMultiple: '/icons/dragMultiple.png',
eraser: '/icons/eraser.png',
rectangle: '/icons/rectangle.png',
arc: '/icons/arc.png',
bezier: '/icons/bezier.png',
quadratic: '/icons/quadratic.png',
text: '/icons/text.png',
image: '/icons/image.png',
pdf: '/icons/pdf.png',
pdf_next: '/icons/pdf-next.png',
pdf_prev: '/icons/pdf-prev.png',
marker: '/icons/marker.png',
zoom: '/icons/zoom.png',
lineWidth: '/icons/lineWidth.png',
colorsPicker: '/icons/colorsPicker.png',
extraOptions: '/icons/extraOptions.png',
code: '/icons/code.png'
};
You can set like this as well:
designer.icons.line = '/icons/line.png';
Default values are NULL
to force icons from /dev/data-dris.js
.
CanvasDesigner is a widget; that widget should be appended to a DOM object. This method allows you pass <body>
or any other HTMLDOMElement.
designer.appendTo(document.body || document.documentElement);
// or
designer.appendTo(document.body || document.documentElement, function() {
alert('iframe load callback');
});
The correct name for appendTo
is: append-iframe to target HTML-DOM-element
If you want to remove the widget from your HTMLDOMElement.
designer.destroy();
You can access designer iframe as following:
designer.iframe.style.border = '5px solid red';
window.open(designer.iframe.src);
designer.iframe
will be null/undefined
until you call appendTo
. So always use this code-block:
if(!designer.iframe) {
designer.appendTo(document.body);
}
designer.iframe.style.border = '5px solid red';
Get data-URL of your drawings!
designer.toDataURL('image/png', function(dataURL) {
window.open(dataURL);
});
You can manually sync drawings by invoking designer.sync
method:
designer.sync();
Here is a real usecase:
webrtcDataChannel.onopen = function() {
if(designer.pointsLength > 0) {
// you seems having data to be synced with new user!
designer.sync();
}
};
Get MediaStream
object and share in realtime using RTCPeerConnection.addStream
API.
<script src="dev/webrtc-handler.js"></script>
<script>
designer.captureStream(function(stream) {
var url = URL.createObjectURL(stream);
videoPreview.src = url;
rtcPeerConnection.addStream(stream);
rtcPeerConnection.createOffer(success, failure, params);
});
</script>
Each shape is considered as a point
. This value allows you check number of shapes that are already drawn on the canvas-designer.
(function looper() {
document.getElementById('number-of-shapes').inenrHTML = designer.pointsLength;
setTimeout(looper, 1000);
})();
Or a real usage:
websocket.onopen = function() {
if(designer.pointsLength > 0) {
// you seems having data to be synced with existing users!
designer.sync();
}
};
You can either undo drawings by pressing ctrl+z
on windows and command+z
on Mac; however you can undo using designer.undo
method as well:
designer.undo(); // undo last shape
designer.undo(-1); // undo last shape
// undo shape from specific index
designer.undo(0);
// undo all shapes
designer.undo('all');
// undo last 10 shapes
designer.undo({
numberOfLastShapes: 10
})
// to remove all occurrences of a specific shape
designer.undo('pencil');
designer.undo('arrow');
designer.undo('rect');
designer.pointsLength
shows number of shapes; and designer.undo
accepts shape-index as well.
Open widget.html
and add your new tool-icon HTML.
<div id="tool-box" class="tool-box"> <!-- search for this div; and include your HTML inside this div -->
<canvas id="yourNewToolIcon" width="40" height="40"></canvas> <!-- here is your icon-HTML -->
</div>
Open decorator.js
and decorate your new HTML icon.
var tools = {
yourNewToolIcon: true // add this line to make sure index.html can use it
};
Search for decorateLine
method, and append following snippet quickly after that method:
function decorateYourNewToolIcon() {
var context = getContext('yourNewToolIcon');
context.fillStyle = 'Gray';
context.font = '9px Verdana';
context.fillText('New', 16, 12);
bindEvent(context, 'YourNewToolIconSelected');
}
if (tools.yourNewToolIcon === true) {
decorateYourNewToolIcon();
} else document.getElementById('yourNewToolIcon').style.display = 'none';
Open common.js
and add selection-states for your new tool-icon (i.e. whether your new tool icon is selected or not):
var is = {
isYourNewToolIconSelected: false, // add this line
set: function (shape) {
var cache = this;
cache.isYourNewToolIconSelected = false; // add this line as well.
// ..... don't modify anything else
cache['is' + shape] = true;
}
};
You merely need to set isYourNewToolIconSelected:true
also cache.isYourNewToolIconSelected=false
.
Create new file in the dev
directory. Name this file as yourNewToolIcon-handler.js
.
This file MUST look like this:
var yourNewToolIconHandler = {
ismousedown: false,
mousedown: function(e) {
this.ismousedown = true;
},
mouseup: function(e) {
this.ismousedown = false;
},
mousemove: function(e) {
if(this.ismousedown) { ... }
}
};
You can check other *-handler.js
from dev
directory to get the idea how exactly it works.
Now open Gruntfile.js#L43
and add link to your new file: dev/events-handler.js
.
Now compile all your changes using grunt
.
Open events-handler.js
and make sure that your above yourNewToolIconHandler
object is called for mouse up/down/move events.
addEvent(canvas, isTouch ? 'touchstart' : 'mousedown', function (e) {
// you merely need to add this line at the end of this method
else if (is.isYourNewToolIconSelected) yourNewToolIconHandler.mousedown(e);
});
addEvent(document, isTouch ? 'touchend' : 'mouseup', function (e) {
// you merely need to add this line at the end of this method
else if (is.isYourNewToolIconSelected) yourNewToolIconHandler.mouseup(e);
});
addEvent(canvas, isTouch ? 'touchmove' : 'mousemove', function (e) {
// you merely need to add this line at the end of this method
else if (is.isYourNewToolIconSelected) yourNewToolIconHandler.mousemove(e);
});
First of all, we are checking whether your tool-icon is selected or not: is.isYourNewToolIconSelected
Then we are calling yourNewToolIconHandler
dot mousedown/mouseup/mousemove
events respectively.
Open draw-helper.js
. Make sure that your new tool-icon can be drawn on the <canvas>
surface.
yourNewToolIcon: function(context, point, options) {
context.beginPath();
context.moveTo(point[0], point[1]);
context.whateverYouWantToDoHere(point[2], point[3]);
this.handleOptions(context, options);
}
Usually point[0]
is x
coordinates; point[1]
is y
coordinates; point[2]
is width
and point[3]
is height
.
Different shapes can handle these points differently.
There is NO-limit for point[index]
. You can add as many points as you want.
Complex shapes can add 10 or 20 points.
Open drag-helper.js
and make sure that your new shape can be dragged/resized/move.
Search for p[0] === 'line'
and add similar code-blocks for your shape (new-tool-icon) as well.
Open common.js
and make sure that your new shape (tool-icon) is printed on the <textarea>
as well.
This allows end-users to copy your shape's code and use anywhere on their own web-pages.
Open common.js
file; there is a function updateTextArea
inside the "common" object – which is aimed to output into textarea element.
You don't have to change updateTextArea
. For simplicity purpose, code is separated in different functions/properties that you've to edit:
Search for p[0] === 'line'
and add similar code-blocks for your shape (new-tool-icon) as well.
ctrl+t (to display text-fonts box)
ctrl+z (to undo last-single shape)
ctrl+a (to select all shapes)
ctrl+c (copy last-selected shape)
ctrl+v (paste last-copied shape)
ctrl+mousedown
allows you quickly copy/paste all shapes. (i.e. ctrl button + mouse down)
Please make pull-request to update this list.
Canvas Designer is released under MIT license . Copyright (c) Muaz Khan.