HTML5 Canvas Slideshow
Here are our demo and downloadable packages:
Live Demodownload in package
Ok, download the source files and let's start coding !
Step 1. HTML
This is the markup of our resulting slideshow page.
index.html<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="utf-8" />
<title>HTML5 Canvas Slideshow | Script Tutorials</title>
<link href="css/main.css" rel="stylesheet" type="text/css" />
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script src="js/pixastic.custom.js"></script>
<script src="js/script.js"></script>
</head>
<body>
<header>
<h2>HTML5 Canvas Slideshow</h2>
<a href="http://www.script-tutorials.com/html5-canvas-slideshow/" class="stuts">Back to original tutorial on <span>Script Tutorials</span></a>
</header>
<div class="container">
<div class="slides">
<img src="images/pic1.jpg" />
<img src="images/pic2.jpg" />
<img src="images/pic3.jpg" />
<img src="images/pic4.jpg" />
<img src="images/pic5.jpg" />
<img src="images/pic6.jpg" />
<img src="images/pic7.jpg" />
</div>
<canvas id="slideshow" width="900" height="300"></canvas>
</div>
</body>
</html>
Step 2. CSS
Here are all the stylesheets:
css/main.css/* page layout styles */
*{
margin:0;
padding:0;
}
body {
background-color:#eee;
color:#fff;
font:14px/1.3 Arial,sans-serif;
}
header {
background-color:#212121;
box-shadow: 0 -1px 2px #111111;
display:block;
height:70px;
position:relative;
width:100%;
z-index:100;
}
header h2{
font-size:22px;
font-weight:normal;
left:50%;
margin-left:-400px;
padding:22px 0;
position:absolute;
width:540px;
}
header a.stuts,a.stuts:visited{
border:none;
text-decoration:none;
color:#fcfcfc;
font-size:14px;
left:50%;
line-height:31px;
margin:23px 0 0 110px;
position:absolute;
top:0;
}
header .stuts span {
font-size:22px;
font-weight:bold;
margin-left:5px;
}
.container {
color: #000;
margin: 20px auto;
position: relative;
width: 900px;
}
#slideshow {
border:1px #000 solid;
box-shadow:4px 6px 6px #444444;
display:block;
margin:0 auto;
height:300px;
width:900px;
}
.container .slides {
display:none;
}
Step 3. JS
js/pixastic.custom.jsPixastic – JavaScript Image Processing Library. I have used it to change the brightness and contrast of our canvas. You can download this library here. Or, you can find this library in our package too.
js/script.jsvar canvas, ctx;
var aImages = [];
var iCurSlide = 0;
var iCnt = 0;
var iSmTimer = 0;
var iContr = 0;
var iEfIter = 50;
$(function(){
// creating canvas objects
canvas = document.getElementById('slideshow');
ctx = canvas.getContext('2d');
// collect all images
$('.slides').children().each(function(i){
var oImg = new Image();
oImg.src = this.src;
aImages.push(oImg);
});
// draw first image
ctx.drawImage(aImages[iCurSlide], 0, 0);
var iTimer = setInterval(changeSlideTimer, 5000); // set inner timer
});
function changeSlideTimer() {
iCurSlide++;
if (iCurSlide == $(aImages).length) {
iCurSlide = 0;
}
clearInterval(iSmTimer);
iSmTimer = setInterval(drawSwEffect, 40); // extra one timer
}
// draw switching effect
function drawSwEffect() {
iCnt++;
if (iCnt <= iEfIter / 2) {
iContr += 0.004;
// change brightness and contrast
Pixastic.process(canvas, 'brightness',
{
'brightness': 2,
'contrast': 0.0 + iContr,
'leaveDOM': true
},
function(img) {
ctx.drawImage(img, 0, 0);
}
);
}
if (iCnt > iEfIter / 2) {
// change brightness
Pixastic.process(canvas, 'brightness',
{
'brightness': -2,
'contrast': 0,
'leaveDOM': true
},
function(img) {
ctx.drawImage(img, 0, 0);
}
);
}
if (iCnt == iEfIter / 2) { // switch actual image
iContr = 0;
ctx.drawImage(aImages[iCurSlide], 0, 0);
Pixastic.process(canvas, 'brightness',
{
'brightness': iEfIter,
'contrast': 0,
'leaveDOM': true
},
function(img) {
ctx.drawImage(img, 0, 0);
}
);
} else if (iCnt == iEfIter) { // end of cycle, clear extra sub timer
clearInterval(iSmTimer);
iCnt = 0;
iContr = 0;
}
}
As you can see – the main functionality is easy. I have defined the main
timer (which will change images), and one inner timer, which will change the brightness and contrast of our canvas.
download in package
Conclusion
I hope that today’s html5 slideshow lesson was interesting for you as always. We have made another nice html5 example. I will be glad to see your thanks and comments. Good luck!
Source: http://www.script-tutorials.com/html5-canvas-slideshow/
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