<?php // vim:ts=4:sw=4:noet
/*====================================================================== 
Copyright (C) 2006-2009, Walter Doekes
This file is part of KjwLib-php45.
 
KjwLib-php45 is free software: you can redistribute it and/or modify 
it under the terms of the GNU General Public License as published by 
the Free Software Foundation, either version 3 of the License, or 
(at your option) any later version. 

KjwLib-php45 is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
GNU General Public License for more details. 

You should have received a copy of the GNU General Public License 
along with KjwLib-php45.  If not, see <http://www.gnu.org/licenses/>. 
======================================================================*/

function kjwimage_create_thumbnail($infile, $outfile, $outx, $outy,
		&$characteristics = array()) {
	assert('strrpos($outfile, ".") !== false');
	$outext = strtolower(substr($outfile, strrpos($outfile, '.') + 1));
	if ($outext == 'jpeg')
		$outext = 'jpg';
	assert('$outext == "gif" || $outext == "jpg" || $outext == "png"');

	// Return-characteristics
	$characteristics = array();

	// Open image
	if (($inimg = @imagecreatefrompng($infile))) {
		$inext = 'png';
	} elseif (($inimg = @imagecreatefromjpeg($infile))) {
		$inext = 'jpg';
	} elseif (($inimg = @imagecreatefromgif($infile))) {
		$inext = 'gif';
	} else {
		return null;
	}

	// Image type
	$characteristics['input.extension'] = $inext;

	// Select scale (if $outx or $outy is null, we use inscale as outscale)
	$inx = imagesx($inimg);
	$iny = imagesy($inimg);
	$inscale = (float)$inx / (float)$iny;
	if ($outx !== null && $outy !== null) {
		$outscale = (float)$outx / (float)$outy;
	} elseif ($outx !== null && $outy === null) {
		$outscale = $inscale;
		$outy = $outx / $outscale;
	} elseif ($outx === null && $outy !== null) {
		$outscale = $inscale;
		$outx = $outy * $outscale;
	} else {
		assert(0);
	}

	// Create new image
	if (!($outimg = @imagecreatetruecolor($outx, $outy))) {
		imagedestroy($inimg);
		return null;
	}

	// In case we save as png, we use a transparent background, otherwise we use a white one.
	if ($outext == 'png') {
		imagesavealpha($outimg, true);
		imagealphablending($outimg, false);
		imagefill($outimg, 0, 0, imagecolorallocatealpha($outimg, 0xff, 0x00, 0xff, 127));
	} else {
		imagefill($outimg, 0, 0, imagecolorallocate($outimg, 0xff, 0xff, 0xff));
	}

	// Image size
	$characteristics['input.width'] = $inx;
	$characteristics['input.height'] = $iny;

	// If small scale difference, use full image and stretch it a bit.
	if (abs($outscale - $inscale) < 0.1) {
		$success = imagecopyresampled($outimg, $inimg, 0, 0, 0, 0, $outx, $outy, $inx, $iny);
	// If the image is too high, add space on the sides.
	} elseif ($outscale < $inscale) {
		$newy = (int)((float)$outx / $inscale);
		$success = imagecopyresampled($outimg, $inimg, 0, (int)(($outy - $newy) / 2), 0, 0, $outx, $newy, $inx, $iny);
	// If the image is too wide, add space on top/bottom.
	} else {
		$newx = (int)((float)$outy * $inscale);
		$success = imagecopyresampled($outimg, $inimg, (int)(($outx - $newx) / 2), 0, 0, 0, $newx, $outy, $inx, $iny);
	}

	imagedestroy($inimg); // Free memory early :)
	
	// Write image
	if ($success) {
		if ($outext == 'jpg') {
			$success = imagejpeg($outimg, $outfile);
		} elseif ($outext == 'png') {
			$success = imagepng($outimg, $outfile);
		} elseif ($outext == 'gif') {
			$success = imagegif($outimg, $outfile);
		} else {
			assert('false');
		}
	}

	imagedestroy($outimg); // Free more
	return $success;
}

?>