Monday, June 18, 2012

Random Image Display

Many times we get bored without any reason.. if this is one of those moments then don't worry, coding will make the moment a little bit lighter;

We'll create a webpage that'll display a random image on each visit(refresh) to the page. PHP will be the language in which we'll create the webpage.

First of all, the RandomImage class,

class RandomImage {
    private $ImageDir;
    private $FileList;
   
    /* this is list of extension which will be allowed to display as an image */
    private $FilterList = array("jpg", "jpeg", "gif", "png");
   
    /* constructor */
    public function __construct($initDir) {
        $this->ImageDir = $initDir;
        $this->FileList = array();
    }
   
    /* function to filter out files based on extension */
    private function IsFileOkToShow($file){
        $isOk = false;
        /* check if file extension is not in the filter list */
        $matched = false;
        $fileExt = pathinfo($file, PATHINFO_EXTENSION);
        foreach ((array)$this->FilterList as $ext) {
            if(strcasecmp($fileExt, $ext) == 0) {
                $matched = true;
                break;
            }
        }
        if($matched) {
            $isOk = true;
        }
   
        return $isOk;
    }
   
    /* this function will scan through all the directories(in recursive manner)
     * and build the list of files in all directories.
     */
    private function buildImageList($dir) {
        if($handle = opendir($dir)) {
            while(false !== ($entry = readdir($handle))) {
                if($entry == '.' || $entry == '..') {
                    continue;
                }
                $fullPath = $dir.'/'.$entry;
                if(is_dir($fullPath)) {
                    $this->buildImageList($fullPath);
                } else {
                    if($this->IsFileOkToShow($fullPath)) {
                        array_push($this->FileList, $fullPath);
                    }
                }
            }
            closedir($handle);
        }
    }
   
    /* public function to return a random file */
    public function Get() {
        $this->buildImageList($this->ImageDir);
        srand((float)microtime()*1000000);
        $fileCount = count($this->FileList);
        if($fileCount > 0) {
            $randomIndex = rand(0, $fileCount -1);
            return $this->FileList[$randomIndex];
        } else {
            return "foo!";
        }
    }
}

This class is very simple and it has only one public function Get(). Calling the Get() function on an object of this class will scan through the directory and return a random file from it.

Upon receiving the filename, we'll pass this file to 'src' attribute of <img> tag, in order to display it.

<!--  html code to display the image -->
<html>
<head><title>Ignorance is bliss!</title></head>
<body>
<?php
    $image = new RandomImage("PATH_TO_IMAGE_FOLDER");
?>
    <img src="<?php echo $image->Get();?>">
<?php
?>
</body>
</html>

Thats all!
Download the attached source code and start clicking on refresh button!