Coding

 

 

Creating 2-D Animations on Canvas - bouncing ball

In this tutorial, the following will be looked into on HTML5 canvas:

  • How to create a ball on HTML5 Canvas.
  • How to control its movement both horizontally and vertically.
  • How to stop the motion when the ball hits the floor.
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Interactive Bouncing Ball

In this example, several methods of context object are used to create a bouncing ball animation on canvas. It is fully interactive too.

The vertical movement of the ball is controlled by the value of a variable which goes down with the time. At the same time, the horizontal movement of the ball is controlled by another variable, which, increases with the time.





The Code for Interactive Bouncing Ball is as follows:

<script type="text/javascript">
var xx; var a=0; var b=10; var c=100; var x=0;
var canvas = document.getElementById('Canvas_One');
var context = canvas.getContext('2d');
resetting();
// print the title of the animation on canvas
function titling(){
context.font = '20pt Calibri';
context.fillStyle = 'green';
context.fillText('The Bouncing Ball', 100, 30);
}
// code for resetting
function resetting(){
c=100;a=0;x=0;
context.clearRect(0,0,400,300);
titling();
context.beginPath();
context.arc(80,100,20,0,2*Math.PI,false);
var grd = context.createRadialGradient(80, 100, 3, 80, 100, 18);
grd.addColorStop(0, '#8ED6FF');
grd.addColorStop(1, '#004CB3');
context.fillStyle = grd;
context.fill();
context.beginPath();
context.moveTo(0,122);
context.lineTo(100,122);
context.lineWidth=4;
context.strokeStyle="red";
context.stroke();
}
// code for dropping the ball
function dropping(){
a=a+b;
x=x+2.5;
if(a==c){b=-10;}
if(a==0){b=10;c=c-10;}
context.beginPath();
context.moveTo(0,122);
context.lineTo(100,142);
context.lineWidth=4;
context.strokeStyle="green";
context.stroke();
context.clearRect(0,0,400,300);
context.font = '20pt Calibri';
context.fillStyle = 'green';
context.fillText('The Bouncing Ball', 100, 30);
context.beginPath();
context.arc(80+x,180+(100-a),20,0,2*Math.PI,false);
var grd = context.createRadialGradient(80+x, 180+(100-a), 3, 80+x, 180+(100-a), 18);
grd.addColorStop(0, '#8ED6FF');
grd.addColorStop(1, '#004CB3');
context.fillStyle = grd;
context.fill();
if(c==20){window.clearInterval(xx);}
var aud=document.getElementById('audio1');
if(a==0 || a==10){ aud.play();}
}
// code for using the timer
function start_one(){
xx=window.setInterval('dropping()',80);
}
</script>

 

All Canvas Animations

 

 

 

Recommended Reading

Amazon Best Seller

 

Everything is evolving; so is the layout of a text book. By uniquely presenting the rich contents of the book, the author has elevated positive user experience of reading a text book to a new level: the examples are easy to follow and rich in standard. Highly recommended for those who want to master JavaScript and JQuery.

Progressive Web Apps(PWA)


 

The significance of app stores is over; progressive web apps is the next big thing. They are just websites that makes the need of going through app stores and need of storing redundant. They work offline too. If you have a reasonable understanding of HTML, CSS and JavaScript, this is the book for you to learn in no time.

HTML5 Canvas Animations


 

David Geary, in this book, shows how to combine JavaScript and HTML5 Canvas to produce amazing animations; he has set aside a whole chapter to teach you the role of physics in animations. If you want an in-depth understanding about HTML5 Canvas animations, this is a must read.