Instant RaphaelJS Starter

JavaScript bound these two giants together and out of their marriage was born RaphaelJS, inheriting the best charms of both parents. It has the ability to scale almost any browser's turf and dance to any developer's tune.

The solution—RaphaelJS.

Just like the world is of two primary states water and land, graphics are of two primitive types—vector and raster. Vector graphics are drawn using geometrical primitives like lines, curves, ellipses, and so on. Various such primitives join together and form a graphic. Vector graphics are drawn on the screen mathematically. They are scalable without loss in quality. Raster graphics, on the other hand, are pixel-based and are not scalable. The main advantage with vector graphics is that they are scalable and are also real objects, meaning we can fiddle with them and manipulate them dynamically. The following diagram shows the difference between raster (bitmap) and vector graphics:

Difference between raster (bitmap) and vector graphics

RaphaelJS is a vector graphics library, therefore the drawings are real DOM objects. Thus they can be dynamically accessed, manipulated, resized, and practically hammered into anything you want in runtime. Best of all is that they can be assigned events like click, mouseover, mouseleave, and so on. The capabilities of RaphaelJS are just incredible.

Raphael uses vector graphics and HTML 5 Canvas uses raster graphics.

The syntax for creating the Raphael object, which is the base for all other Raphael methods and functions, is as follows:

var raphaelObj = Raphael(x,y,width,height);

The four parameters inside the Raphael function are nothing but x-position, y-position, width, and height of the canvas to be created.

Since it is created in the browser's viewport, the positioning of the canvas will be absolute; therefore, it will overlap any HTML element underneath.

For example:

// Creating the canvas in the browser's viewport
var paper = Raphael(20, 30, 650, 400);

Here the Raphael object is initialized and assigned to a variable called paper. This variable will be christened with all the powers of RaphaelJS. It will, henceforth, become the Raphael Paper Object.

To initiate the Raphael object inside an element, we must add the element ID or the element itself in the place of the positioning coordinates (x, y).

Let's consider the following example:

//The element itself is passed 
//This line creates a Raphael paper inside 'paperDiv', which is 650px in width and 400px in height
var elm= document.getElementById("paperDiv");
var paper = Raphael(elm, 650, 400);
//or 
// The element ID is passed directly
//This line also creates a Raphael paper inside 'paperDiv', which is 650px in width and 400px in height
var paper = Raphael("paperDiv", 650, 400);

That's it; we now have the engine up and running.

Vrooom vrooom.

We now have a smooth circle. It's absolutely fantastic, but wouldn't it be much better if we could add some color and other styles to it? RaphaelJS gives us the option to add styles to the object. It's a fairly straightforward method.

Styles and other customizations to our new circle are done using the attr() method.

This method takes the properties as parameters. The properties are entered as a collection of objects in key-value pairs. If you are familiar with jQuery, then its syntax is identical to jQuery's attr() method. This format is known as JavaScript Object Notation (JSON), to further clarify.

The syntax for this method is as follows:

element.attr({
  "Property1":value1,
  "Property2":value2
})

Let's consider the following example:

//adding the attributes as key value pair
var coloredCircle = paper.circle(35,25,20).attr({
  "fill":"#17A9C6",
  "stroke":"#2A6570",
  "stroke-width":2
});

The output for the preceding code snippet is as shown in the following screenshot:

A circle with styles applied using the attr() method

Raphael's paper allows easy integration of vector graphics in an HTML layout, which makes it even more appealing.

Paper—the shiny new wand.

There are three basic shapes in RaphaelJS, namely circle, ellipse, and rectangle. Since the circle is already covered in the Quick start section, we are going to skip drawing a circle.

Rectangle

We can create a rectangle using the rect() method. This method takes four required parameters and a fifth optional parameter, border-radius. The border-radius parameter will make the rectangle rounded (rounded corners) by the number of pixels specified.

The syntax for this method is:

paper.rect(X,Y,Width,Height,border-radius(optional));

A normal rectangle can be created using the following code snippet:

// creating a raphael paper in 'paperDiv'
var paper = Raphael ("paperDiv", 650,400);
// creating a rectangle with the rect() method. The four required parameters are X,Y,Width & Height
var rect = paper.rect(35,25,170,100).attr({
  "fill":"#17A9C6", //filling with background color
  "stroke":"#2A6570", // border color of the rectangle
  "stroke-width":2 // the width of the border 
});

The output for the preceding code snippet is shown in the following screenshot:

Plain rectangle

Rounded rectangle

The following code will create a basic rectangle with rounded corners:

// creating a raphael paper in 'paperDiv'
var paper = Raphael ("paperDiv", 650,400);
//The fifth parameter will make the rectangle rounded by the number of pixels specified – A rectangle with rounded corners
var rect = paper.rect(35,25,170,100,20).attr({
  "fill":"#17A9C6",//background color of the rectangle
  "stroke":"#2A6570",//border color of the rectangle
  "stroke-width":2 // width of the border
});
//in the preceding code 20(highlighted) is the border-radius of the rectangle.

The output for the preceding code snippet is a rectangle with rounded corners, as shown in the following screenshot:

Rectangle with rounded corners

We can create other basic shapes in the same way. Let's create an ellipse with our magic wand.

Ellipse

An ellipse is created using the ellipse() method and it takes four required parameters, namely x,y, horizontal radius, and vertical radius. The horizontal radius will be the width of the ellipse divided by two and the vertical radius will be the height of the ellipse divided by two.

The syntax for creating an ellipse is:

paper.ellipse(X,Y,rX,rY);
//rX is the horizontal radius & rY is the vertical radius of the ellipse

Let's consider the following example for creating an ellipse:

// creating a raphael paperin 'paperDiv'
var paper = Raphael ("paperDiv", 650,400);
//The ellipse() method takes four required parameters: X,Y, horizontal radius & vertical Radius
var ellipse = paper.ellipse(195,125,170,100).attr({
  "fill":"#17A9C6", // background color of the ellipse
  "stroke":"#2A6570", // ellipse's border color
  "stroke-width":2 // border width
});

The preceding code will create an ellipse of width 170 x 2 and height 100 x 2.

An ellipse created using the ellipse() method is shown in the following screenshot:

An Ellipse

It's pretty easy to create basic shapes, but what about complex shapes such as stars, octagons, or any other shape which isn't a circle, rectangle, or an ellipse.

It's time for the next step of Raphael wizardry.

Complex shapes are created using the path() method which has only one parameter called pathString. Though the path string may look like a long genetic sequence with alphanumeric characters, it's actually very simple to read, understand, and draw with.

Before we get into path drawing, it's essential that we know how it's interpreted and the simple logic behind those complex shapes. Imagine that you are drawing on a piece of paper with a pencil. To draw something, you will place the pencil at a point in the paper and begin to draw a line or a curve and then move the pencil to another point on the paper and start drawing a line or curve again. After several such cycles, you will have a masterpiece—at least, you will call it a masterpiece.

Raphael uses a similar method to draw and it does so with a path string.

A typical path string may look like this: M0,0L26,0L13,18L0,0. Let's zoom into this path string a bit.

The first letter says M followed by 0,0. That's right genius, you've guessed it correctly.

It says move to 0,0 position, the next letter L is line to 26,0. RaphaelJS will move to 0,0 and from there draw a line to 26,0. This is how the path string is understood by RaphaelJS and paths are drawn using these simple notations.

Here is a comprehensive list of commands and their respective meanings:

The uppercase commands are absolute (M20, 20); they are calculated from the 0,0 position of the drawing area (paper). The lowercase commands are relative (m20, 20); they are calculated from the last point where the pen left off.

There are so many commands, which might feel like too much to take in—don't worry; there is no need to remember every command and its format. Because we'll be using vector graphics editors to extract paths, it's essential that you understand the meaning of each and every command so that when someone asks you "hey genius, what does this mean?", you shouldn't be standing there clueless pretending to have not heard it.

The syntax for the path() method is as follows:

paper.path("pathString");

Let's consider the following example:

// creating a raphael paper in 'paperDiv'
var paper = Raphael ("paperDiv", 350,200);
// Creating a shape using the path() method and a path string
var tri = paper.path("M0,0L26,0L13,18L0,0").attr({
  "fill":"#17A9C6", // filling the background color
  "stroke":"#2A6570", // the color of the border
  "stroke-width":2 // the size of the border
});

The output for the previous example is shown in the following screenshot:

A triangle shape drawn using the path string

The vector graphics editors are meant for creating complex shapes with ease and they have some powerful tools in their disposal to help us draw. For this example, we'll create a star shape using an open source editor called Inkscape, and then extract those paths and use Raphael to get out the shape! It is as simple as it sounds, and it can be done in four simple steps.

Step 1 – Creating the shape in the vector editor

Let's create some star shapes in Inkscape using the built-in shapes tool.

Star shapes created using the built-in shapes tool

Step 2 – Saving the shape as SVG

The paths used by SVG and RaphaelJS are similar. The trick is to use the paths generated by the vector graphics editor in RaphaelJS. For this purpose, the shape must be saved as an SVG file.

Saving the shape as an SVG file

Step 3 – Copying the SVG path string

The next step is to copy the path from SVG and paste it into Raphael's path() method.

SVG is a markup language, and therefore it's nested in tags. The SVG path can be found in the <path> and </path> tags. After locating the path tag, look for the d attribute. This will contain a long path sequence. You've now hit the bullseye.

The path string is highlighted

Step 4 – Using the copied path as a Raphael path string

After copying the path string from SVG, paste it into Raphael's path() method.

var newpath=paper.path("copied path string from SVG").attr({
  "fill":"#5DDEF4",
  "stroke":"#2A6570",
  "stroke-width":2
});

That's it! We have created a complex shape in RaphaelJS with absolute simplicity.

Note

Using this technique, we can only extract the path, not the styles. So the background color, shadow, or any other style in the SVG won't apply. We need to add our own styles to the path objects using the attr() method.

A screenshot depicting the complex shapes created in RaphaelJS using the path string copied from an SVG file is shown here:

Complex shapes created in RaphaelJS using path string

Text can be created using the text() method. Raphael gives us a way to add a battery of styles to the text object, right from changing colors to animating physical properties like position and size.

The text() method takes three required parameters, namely, x,y, and the text string.

The syntax for the text() method is as follows:

paper.text(X,Y,"Raphael JS Text");
// the text method with X,Y coordinates and the text string

Let's consider the following example:

// creating a raphael paper in 'paperDiv'
var paper = Raphael ("paperDiv", 650,400);
// creating text
var text = paper.text(40,55,"Raphael Text").attr({
  "fill":"#17A9C6", // font-color
  "font-size":75, // font size in pixels
//text-anchor indicates the starting position of the text relative to the X, Y position.It can be "start", "middle" or  "end" default is "middle"
"text-anchor":"start",
"font-family":"century gothic" // font family of the text
});

I am pretty sure that the text-anchor property is a bit heavy to munch. Well, there is a saying that a picture is worth a thousand words. The following diagram clearly explains the text-anchor property and its usage.

A brief explanation of text-anchor property

A screenshot of the text rendered using the text() method is as follows:

Rendering text using the text() method

By the end of this section, you would know how to transform a shape.

There might be many scenarios wherein you might need to modify a shape dynamically. For example, when the user mouse-overs a circle, you might want to scale up that circle just to give a visual feedback to the user. Shapes can be manipulated in RaphaelJS using the transform() method.

Transformation is done through the transform() method, and it is similar to the path() method where we add the path string to the method. transform() works in the same way, but instead of the path string, it's the transformation string. There is only a moderate difference between a transformation string and a path string.

There are four commands in the transformation string:

The fourth command, M, is of little importance and let's keep it out of the way, to avoid confusion.

As with the path string, the uppercase letters are for absolute transformations and the lowercase for relative transformation. If the transformation string reads r90T100,0, then the element will rotate 90 degrees and move 100 px in the x axis (left). If the same reads r90t100,0, then the element will rotate 90 degrees and since the translation is relative, it will actually move vertically down 100px, as the rotation has tilted its axis.

I am sure the previous point will confuse most, so let me break it up.

Imagine a rectangle with a head and now this head is at the right side of the rectangle. For the time being, let's forget about absolute and relative transformation; our objective is to:

It's critical to understand that the elements' original values don't change when we translate it, meaning its x and y values will remain the same, no matter how we rotate or move the element.

Now our first requirement is to rotate the rectangle by 90 degrees. The code for that would be rect.transform("r90") where r stands for rotation—fantastic, the rectangle is rotated by 90 degrees. Now pay attention to the next important step. We also need the rectangle to move 100px in the x axis and so we update our previous code to rect.transform("r90t100,0"), where t stands for translation. What happens next is interesting—the translation is done through a lowercase t, which means it's relative. One thing about relative translations is that they take into account any previous transformation applied to the element, whereas absolute translations simply reset any previous transformations before applying their own.

Remember the head of the rectangle on the right side? Well, the rectangle's x axis falls on the right side. So when we say, move 100px on the x axis, it is supposed to move 100px towards its right side, that is, in the direction where its head is pointing. Since we have rotated the rectangle by 90 degrees, its head is no longer on the right side but is facing the bottom.

So when we apply the relative translation, the rectangle will still move 100px to its x axis, but the x axis is now pointing down because of the rotation. That's why the rectangle will move 100px down when you expect it to move to the right.

What happens when we apply absolute translation is something that is entirely different from the previous one. When we again update our code for absolute translation to rect.transform("r90T100,0"), the axis of the rectangle is not taken into consideration. However, the axis of the paper is used, as absolute transformations don't take previous transformations into account, and they simply reset them before applying their own. Therefore, the rectangle will move 100px to the right after rotating 90 degrees, as intended.

Getting a grip on this simple logic will save you a lot of frustration in the future while developing as well as while debugging.

The following is a screenshot depicting relative translation:

Using relative translation

The following is a screenshot depicting absolute translation:

Using absolute translation

Notice the gap on top of the rotated rectangle; it's moved 100px on the one with relative translation and there is no such gap on top of the rectangle with absolute translation.

By default, the transform method will append to any transformation already applied to the element. To reset all transformations, use element.transform(""). Adding an empty string to the transform method will reset all the previous transformations on that element.

It's also important to note that the element's original x,y position will not change when translated. The element will merely assume a temporary position but its original position will remain unchanged. Therefore after translation, if we call for the element's position programmatically, we will get the original x,y, not the translated one, just so we don't jump from our seats and call RaphaelJS dull!

The following is an example of scaling and rotating a triangle:

//creating a Triangle using the path string
var tri = paper.path("M0,0L104,0L52,72L0,0").attr({
  "fill":"#17A9C6",
  "stroke":"#2A6570",
  "stroke-width":2
});
//transforming the triangle.
    tri.animate({
      "transform":"r90t100,0,s1.5"
    },1000);
//the transformation string should be read as rotating the element by 90 degrees, translating it to 100px in the X-axis and scaling up by 1.5 times

The following screenshot depicts the output of the preceding code:

Scaling and rotating a triangle

The triangle is transformed using relative translation (t). Now you know the reason why the triangle has moved down rather than moving to its right.

The mouse click event can be added using the click() method.

Let's consider the following example:

//creating a raphael paper in 'paperDiv'
var paper = Raphael("paperDiv", 650, 400);
var blueStyle={
  "fill":"#5DDEF4",
  "stroke":"#2A6570",
  "stroke-width":2
}
//creating a plain circle
var cir = paper.circle(120,120,30).attr(blueStyle);
cir.click(function(){
  alert('Clicked circle');
})

The following is a screenshot demonstrating the click event handler:

Click event handler

The mouseover event can be added using the mouseover() method.

The following is an example of the mouseover() method:

// creating a circle with blue background
var cir = paper.circle(35,25,20).attr({
  "fill":"#17A9C6",
  "stroke":"#2A6570",
  "stroke-width":2
});
// adding mouseover event to the circle with the mouseover() event handler
cir.mouseover(function(){
cir.animate({
  "fill":"#15EA18",
  "transform":"s2"
  },400)
})
// The preceding code animates the background color and scales up the circle twice on mouseover

These methods can only be used with an element and not directly. For example, rect.click().

element.animate({
  Property1:value,
  Property2:value
},time_in_milliseconds,easing(optional),
callback_function(optional));

rect.animate({
  "width":"300",
  "height":"200"
},500,'bounce',function(){
//something to do after animation
  alert("animation complete")
})

element.attr({
  Property1:value,
  Property2:value
})

// Adding background color and stroke to a rectangle
rect.attr({
  "fill":"#17A9C6",   // Adds a background color
  "stroke":"#2A6570", // the color of the border
  "stroke-width":2    // the width of the border
})

rect.click(function(){
  //something to do when the rectangle is clicked
  alert("clicked rectangle");
})

cir.dblclick(function(){
  //alerts "it's a double click " when double clicked
  alert("It's a double click !");
})

rect.mousedown(function(){
// The rectangle will animate to 200px wide when any mouse button is pressed down
rect.animate({
  'width':'200'
  },400)
})

rect.mouseup(function(){
// The rectangle will animate to 100px wide any mouse button is released
rect.animate({
  'width':'100'
  },400)
})

// increases the size of the rectangle as the mouse moves over the rectangle.
var wd=100 // Intial width
rect.mousemove(function(){
  wd++ // incrementing the width on mouse move
  rect.attr({
    //setting the width of the rectangle with the attr() method
    'width':wd
  });
})

//animating the size of the circle when the mouse enters the circle
cir.mouseover(function(){
  cir.animate({
  transform:'s2' // scaling up the circle twice
  },500,'elastic'); //adding and elastic easing function to the animation
})

// scaling down the size of the circle when the mouse leaves it
cir.mouseout(function(){
  cir.animate({
  transform:'s0.5' // scaling down the circle to half of its original size
  },500,'bounce') //adding and elastic easing function to the animation
})

clone()

There will be situations where we will want to duplicate an element. Some might say, "Ah ! that's easy, I just need to copy the element to a new variable like var newrect=rect". Well, it looks like you have made a copy, but that won't work for sure. The variable acts as a reference to the object, in this case, the rectangle. So when we copy the variable, we are just copying the reference. In reality, the new variable still points to the same old object. Here is an example of the wrong way:

// assigning the rect to a new variable called newRect
var newRect=rect;
newRect.attr({
  fill:'#ddd',
  transform:'t100,100'
})

The following screenshot demonstrates what happens when the variable is duplicated—there is no clone of the rectangle.

Variable is duplicated

It's obvious that copying the variable didn't work, as it's evident that the background color has been applied to the same rectangle, and there is no second rectangle as there is supposed to be.

This problem can be addressed by the clone() method in a simple and elegant way.

//To duplicate a rectangle
var newRect=rect.clone();
newRect.attr({
  fill:'#ddd',
  transform:'t100,100'
})

Using the clone() method instead of duplicating the variable will produce a clone of the rectangle, as depicted in the following screenshot:

Producing a clone using the clone() method

Now, we see two rectangles and the background color of the second rectangle is now gray as intended.

data()

Raphael has an incredibly simple way to assign some data to each and every element and retrieve it on demand. It's as simple as assigning some data to an element while creating it and recalling that data whenever necessary. It's a simple and straightforward way.

Data can be added to an element using the data() method in key value pairs.

The following is an example of the data() method:

//assigning a name to a circle
cir.data('name','Am Raphael JS');
// retrieving the data
cir.click(function(){
  alert(this.data('name'));
})

The following is a screenshot depicting the data contents of the circle when clicked:

Data contents of the circle when clicked

removedata(key)

//removing the name of the circle
cir.removeData('name') // removes the name of the circle

getBBox()

The getBBox() method returns the bounding box of the element. By default, the bounding will take into account any transformations on the element. To get the bounding box before any transformation is applied on the element, the isWithoutTransform parameter must be set to true.

The following is an example of the getBBox() method:

cir.getBBox() // returns the bounding box 
cir.getBBox({
isWithoutTransform:true // this will return the bouding box values before any transformation that has been applied on the element. It will still return the old values ignoring the transformations
})

The getBBox() method returns an object with the following values:

Value	Type	Description
X	Number	Top-left corner's x position
Y	Number	Top-left corner's y position
X2	Number	Bottom-right corner's x position
Y2	Number	Bottom-right corner's y position
Width	Number	Width of the bounding box
Height	Number	Height of the bounding box

getPointAtLength(path,length)

toFront()

The toFront() method brings the element to the forefront on top of all other elements. Its function is similar to CSS z-index. It doesn't take any parameters.

The following is an example of the toFront() method:

cir.toFront();//brings the circle on top of all the elements

The following screenshot demonstrates the use of the toFront() method. The circle is brought to the front by using the toFront() method; therefore, it overlaps the rectangle.

Circle brought to the front using the toFront() method

rect.toBack() // moves the rect behind all the elements

rect.hide()

rect.show()

transform([transformationString]);

rect.transform("s1.5t100,100,r90");
//scales the rectangle to 1.5 times larger and then translates it to 100px in the X-axis, 100px in the Y-axis and finally rotating it by 90 degrees
//Transformation can also be done using the attr() method.
element.attr('transform','s1.5t100,100,r90');

rect.remove();
//the preceding line removes the rect from Raphael paper

The paper methods can only be used with the Raphael paper object.

circle(x,y,radius);

var cir=paper.circle(100,50,20);

ellipse(x,y,rx,ry);

var ell = paper.ellipse(15,30,80,50);

rect(x,y,width,height,radius(optional));

// A rectangle with a border radius of 5px
var rectangle = paper.rect(10,10,50,70,5);

paper.clear()

var img=paper.image("images/world.png",10,15,80,100);
//imports an image called world.png and places it at 10,15 position. Sets the image's width to 80px and height to 100px

paper.setSize(width,height);

paper.setSize(500,600);
//500 and 600 will be the new width and height of the paper.

paper.set()

The paper.set() method groups several Raphael objects, and any action performed on this set will apply to all the elements. The set() method merely groups the elements, it doesn't create any copies of the elements. Deleting a set will have no effect on the elements.

It is worth mentioning that sets in RaphaelJS are ordered. This varies from the set type in Python, which is a group of unordered objects.

The following is the syntax for this method:

var raphaelSet=paper.set();
raphaelSet.push(element1,element2, ...);

The following is an example of the paper.set() method:

// the following code will create a new set called raphaelSet, add elements to it and change the color of the set to red
var raphaelSet=paper.set();//creating a new set
// adding elements to the set using the push() method 
raphaelSet.push(circle,rect,ellipse);
//changing the color of the set – this will affect all the elements in the set.
raphaelSet.attr('fill','red');

The following is a screenshot demonstrating the use of the paperset() method in RaphaelJS.

Changing the color of the set to red changes the color of all the elements in the set.

The set methods can only be used with the set object, created using the set() method.

var raphaelSet=paper.set();
//raphaelSet is now a set object to which all the set methods apply.

Set.clear();

raphaelSet.clear();
// The preceding code will remove the set called raphaelSet, not its elements

set.exclude(element);

raphaelSet.exclude(rect);
//The preceding code removes the element called 'rect' from the set 'raphaelSet'

set.forEach(callback_function,thisArg);

raphaelSet.forEach(function(elm){
  elm.attr('fill','green');
})
// The preceding code will loop through all the elements in the raphaelSet and change the background color of each and every element to green.

raphaelSet.pop();
// the preceding code will remove the last element from the raphaelSet and return the removed element.

set.splice(index, count, element);

var rect=paper.rect(10,10,50,100).attr('fill','green');
raphaelSet.splice(1,2,rect);
// The preceding code will remove two elements from the index position of 1 and add a rect element.