svg.draw.js

An extension of svg.js which allows to draw elements with your mouse

Demo

For a demo see http://svgdotjs.github.io/svg.draw.js/

Get Started

• Install svg.draw.js using bower:

    bower install svg.draw.js

• Include the script after svg.js into your page

    <script src="svg.js"></script>
    <script src="svg.draw.js"></script>

• Draw your first rectangle using this simple piece of code:

    <div id="myDrawing"></div>
  
    var drawing = new SVG('myDrawing').size(500, 500);
    drawing.rect().draw()	// Here we init a rectangle and start drawing it

Usage

As default the drawing starts with a click on the svg-Element

var drawing = SVG('drawing');
drawing.rect().draw(options);

You can use your own mouse-events. Just pass the event-Object to the draw-Function

var drawing = SVG('myDrawing');
var rect = drawing.rect();

drawing.on('mousedown', function(event){
    rect.draw(event, options);
});
drawing.on('mouseup', function(event){
    rect.draw(event);
});

The addon automatically knows when to start or stop drawing (most shapes start with the first event and stop with the second). However when dealing with e.g. a polygon you are able to set new points with every event. To finish the drawing you have to call the done-function. See the next chapter for that.

Methods

svg.draw.js populates its methods it uses to draw the shape. This is useful in edgecases but generally not needed. However the method done is needed for poly-shapes and cancel can be called on every shape to stop drawing and remove the shape.

// Finishes the poly-shape
polygon.draw('done');

// Cancels drawing of a shape, removes it
polygon.draw('cancel');

/* The following are only useful in edge-cases */

// Draws a new point with the help of (mouse-)event
polygon.draw('point', event)

// Draws the point while moving the mouse (basically the animation)
polygon.draw('update', evnt)

// Stop drawing, cleans up
polygon.draw('stop', event)

Options

The following options can be used to modify the behavior of the addon:

• snapToGrid: Specifies a grid to which a point is aligned (default:1)

Note that you can specify the options only on the first call. When you want to change the options while drawing use polygon.draw('params', key, value) This is useful when you want to activate the grid-option when ctrl or soemthing is pressed.

Events

svg.draw.js fires a few specific events which are:

• drawstart
• drawstop
• drawupdate
• drawpoint
• drawdone
• drawcancel

These events are called at the end of the corresponding method.

Each event-object holds the relative position to the parent-Object of the Shape (which is mostly the SVG-doc itself) as Array

Binding a function to the Event is easy

var draw = SVG('drawing');
var rect = draw.rect().draw();
rect.on('drawstart', function(event){
    console.log(event.detail); // Holds event, current Point-coords and matrix
});

Plugins

Currently svg.draw.js only supports all the basic shapes (line, polyline, polygone, rect, image, circle, ellipse). Any other type you want to draw and is available through SVG.invent (e.g. image or your own element) can be added using a plugin which just serves the functions to draw the shape.

For example:

SVG.Element.prototype.draw.extend('line polyline polygon', {

	// add methods here which should be added to the draw-object
	// e.g.
	foo: function(){
		// can access this
	}

	// or even variables
	bar:5

}

Method calc is always needed which updates the point of the shape.

You also can extend two shape-types at once:

SVG.Element.prototype.draw.extend({

	'line polyline polygon': {
		// add methods here which should be added to the draw-object
		// e.g.
		foo: function(){
			// can access this
		}

		// or even variables
		bar:5
	}


	'circle':{
		// something
	}
}

See the implementation of all shapes as examples.

Changes in svg.draw.js v2

• all shapes implemented as plugins
• drawing takes transformations into account (you can even draw e.g. a rotated rectangle)
• useRadius option is obsolete duo to the implementation of circle in svg.js v2