Resize Images

<?php
// @fill
// center       - Centers the image without any scaling.  May be smaller than dimensions, or cropped.
// stretch      - Stretches the image to fill dimensions.  May change image proportions.
// squeeze      - Scales the image, maintaining original proportions.  May not fill dimensions.
// trim         - Scales the image, maintaining original proportions, to fill dimensions.  Image may be centered and trimmed.
// trim_rand    - Scales the image, maintaining original proportions, to fill dimensions.  Trimmed randomly.
 
function resize($src_filename, $dst_filename, $dst_width, $dst_height, $fill='squeeze', $quality=80, $png_filters=PNG_NO_FILTER)
{
    if(!file_exists($src_filename)) {
        //throw new Exception("File does not exist: $src_filename");
        return false;
    }
    if(empty($dst_filename)) {
        $dst_filename = $src_filename;
    }
    if($dst_width <= 0) {
        //throw new Exception("Width must be positive: $dst_width");
        return false;
    }
    if($dst_height <= 0) {
        //throw new Exception("Height must be positive: $dst_height");
        return false;
    }
    $src_ext = substr($src_filename,strrpos($src_filename,'.')+1);
    switch(strtolower($src_ext)) {
        case 'gif':
            $src_image = imagecreatefromgif($src_filename);
            break;
        case 'jpe':
        case 'jpeg':
        case 'jpg':
            $src_image = imagecreatefromjpeg($src_filename);
            break;
        case 'png':
            $src_image = imagecreatefrompng($src_filename);
            break;
        default:
            //throw new Exception("Invalid source file extension: $src_ext");
            return false;
    }
    $src_width = imagesx($src_image);
    $src_height = imagesy($src_image);
    switch(strtolower(trim($fill))) {
        case 'center':
            $src_x = round($src_width/2-$dst_width/2);
            $src_y = round($src_height/2-$dst_height/2);
            if($src_x < 0) {
                $dst_width = $src_width;
                $src_x = 0;
            }
            if($src_y < 0) {
                $dst_height = $src_height;
                $src_y = 0;
            }
            $dst_image = imagecreatetruecolor($dst_width, $dst_height);
            imagecopyresampled($dst_image, $src_image, 0, 0, $src_x, $src_y, $dst_width, $dst_height, $dst_width, $dst_height);
            break;
        case 'stretch':
            $dst_image = imagecreatetruecolor($dst_width, $dst_height);
            imagecopyresampled($dst_image, $src_image, 0, 0, 0, 0, $dst_width, $dst_height, $src_width, $src_height);
            break;
        case 'crop':
        case 'crop_center':
        case 'trim_center':
        case 'trim':
            $src_ratio = $src_width/$src_height;
            $dst_ratio = $dst_width/$dst_height;
            if($src_ratio < $dst_ratio) // trim top and bottom
            {
                $ratio = $src_width/$dst_width;
                $crop_height = $dst_height*$ratio;
                $src_y = round(($src_height-$crop_height)/2);
                $crop_width = $src_width;
                $src_x = 0;
            }
            else // trim left and right
            {
                $ratio = $src_height/$dst_height;
                $crop_width = $dst_width*$ratio;
                $src_x = round(($src_width-$crop_width)/2);
                $crop_height = $src_height;
                $src_y = 0;
            }
            $dst_image = imagecreatetruecolor($dst_width, $dst_height);
            imagecopyresampled($dst_image, $src_image, 0, 0, $src_x, $src_y, $dst_width, $dst_height, $crop_width, $crop_height);
            break;
        case 'crop_rand':
        case 'trim_rand':
            $src_ratio = $src_width/$src_height;
            $dst_ratio = $dst_width/$dst_height;
            if($src_ratio < $dst_ratio) // trim top and bottom
            {
                $ratio = $src_width/$dst_width;
                $crop_height = $dst_height*$ratio;
                $src_y = rand(0,$src_height-$crop_height);
                $crop_width = $src_width;
                $src_x = 0;
            }
            else // trim left and right
            {
                $ratio = $src_height/$dst_height;
                $crop_width = $dst_width*$ratio;
                $src_x = rand(0,$src_width-$crop_width);
                $crop_height = $src_height;
                $src_y = 0;
            }
            $dst_image = imagecreatetruecolor($dst_width, $dst_height);
            imagecopyresampled($dst_image, $src_image, 0, 0, $src_x, $src_y, $dst_width, $dst_height, $crop_width, $crop_height);
            break;
        case 'squeeze':
        case 'stretch_prop':
        case 'fit':
            $ratio = max($src_width/$dst_width, $src_height/$dst_height);
            if($ratio < 1) $ratio = 1; // do not enlarge
            $dst_width = round($src_width/$ratio);
            $dst_height = round($src_height/$ratio);
            $dst_image = imagecreatetruecolor($dst_width, $dst_height);
            imagecopyresampled($dst_image, $src_image, 0, 0, 0, 0, $dst_width, $dst_height, $src_width, $src_height);
            break;
        default:
            //throw new Exception("Unrecognized fill type: $fill");
            return false;
    }
    $dst_ext = substr($dst_filename,strrpos($dst_filename,'.')+1);
    if(empty($dst_ext)) {
        $dst_ext = $src_ext;
        $dst_filename .= ".$src_ext";
    }
    switch(strtolower($dst_ext)) {
        case 'gif':
            return imagegif($dst_image, $dst_filename);
        case 'jpe':
        case 'jpeg':
        case 'jpg':
            return imagejpeg($dst_image, $dst_filename, $quality);
        case 'png':
            return imagepng($dst_image, $dst_filename, $quality, $png_filters);
        default:
            //throw new Exception('Invalid destination file extension: $dst_ext');
            return false;
    }
}
 
?>