Resize Image Function using GD2

[bsgrules]

Well, after hours of looking for a good php class or function that resizes images with GD, I decided to start making one myself.

Here is one that I made that resizes an image to a fixed size while keeping the aspect ratio by applying black padding. Please let me know what you think, I have no idea if this is the most efficient way? Go ahead and put it on your server and try it out. Feel free to ask any questions with the script, or make any corrections.

http://section31.us/scripts/testing/thumb/resize_with_padding_using_gd2_function.php?source

<?php
/**
 * Resizes an image to a fixed size with black padding.
 *
 * @link		http://section31.us/scripts/
 * @param		string	$srcFile		Filename of the image you want resized
 * @param		int		$dstWidth		Resize to Width
 * @param		int		$dstHeight		Resize to Height
 * @param		string	$dstFile		Destination filename
 * @param		int		$jpegQuality	Jpeg Quality Rating

 * Usage:		resizeImage('test.jpg', 640, 480);
 */

function resizeImage($srcFile, $dstWidth = 120, $dstHeight = 90, $dstFile = null, $jpegQuality = 80)
{
	if (!file_exists($srcFile)) {
		echo "$srcFile doesn't exist! ";
		return false;		
	}
	if (!$dstFile) {
		$dstFile = 'tn_' . basename($srcFile);
	}
	if (!is_writable($dstDir = dirname($dstFile))) {
		echo "$dstDir is not a writeable directory! ";
		return false;
	}

list($srcWidth, $srcHeight, $type, ) = getimagesize($srcFile);

switch ($type) {
case 1 :
	$srcHandle = imagecreatefromgif($srcFile);
	break;
case 2 :
	$srcHandle = imagecreatefromjpeg($srcFile);
	break;
case 3 :
	$srcHandle = imagecreatefrompng($srcFile);
	break;
default :
	echo 'File Type Not Supported! ';
	return false;
}
if (!$srcHandle) {
	echo 'Could not execute imagecreatefrom() function! ';
	return false;
}

// Source is wider than the Destination
if ($srcWidth / $srcHeight >= $dstWidth / $dstHeight) {
	$width = $dstWidth;
	$xOffset = 0;

	$height = round(($width / $srcWidth) * $srcHeight);
	$yOffset = round(($dstHeight - $height) / 2);
}
// Source is narrower than the Destination
else {
	$height = $dstHeight;
	$yOffset = 0;

	$width = round(($height / $srcHeight) * $srcWidth);
	$xOffset = round(($dstWidth - $width) / 2);
}

$dstHandle = imagecreatetruecolor($dstWidth, $dstHeight);

// bool imagecopyresampled ( resource dst_image, resource src_image, int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h )
if (!imagecopyresampled($dstHandle, $srcHandle, $xOffset, $yOffset, 0, 0, $width, $height, $srcWidth, $srcHeight)) {
	echo 'Could not execute imagecopyresampled() function! ';
	return false;
}
imagedestroy($srcHandle);

switch ($type) {
case 1 :
	imagegif($dstHandle, $dstFile);
	break;
case 2 :
	imagejpeg($dstHandle, $dstFile, $jpegQuality);
	break;
case 3 :
	imagepng($dstHandle, $dstFile);
	break;
default :
	echo 'File Type Not Supported! ';
	return false;
}

imagedestroy($dstHandle);

return true;
}
?>

[bsgrules]

Here is one that crops from the center. I really would like some help improving these functions...Can someone help.

http://section31.us/scripts/testing/thumb/resize_with_cropping_using_gd2_function.php?source

<?php
/**
 * Resizes an image to a fixed size by cropping from the center.
 *
 * @link		http://section31.us/scripts/testing/thumb/resize_with_cropping_using_gd2_function.php?source
 * @param		string	$srcFile		Filename of the image you want resized
 * @param		int		$dstWidth		Resize to Width
 * @param		int		$dstHeight		Resize to Height
 * @param		string	$dstFile		Destination filename
 * @param		int		$jpegQuality	Jpeg Quality Rating

 * Usage:		resizeImage('test.jpg', 640, 480);
 */

function resizeImage($srcFile, $dstWidth = 120, $dstHeight = 90, $dstFile = null, $jpegQuality = 80)
{
	if (!file_exists($srcFile)) {
		echo "$srcFile doesn't exist! ";
		return false;		
	}
	if (!$dstFile) {
		$dstFile = 'tn_' . basename($srcFile);
	}
	if (!is_writable($dstDir = dirname($dstFile))) {
		echo "$dstDir is not a writeable directory! ";
		return false;
	}

list($srcWidth, $srcHeight, $type, ) = getimagesize($srcFile);

switch ($type) {
case 1 :
	$srcHandle = imagecreatefromgif($srcFile);
	break;
case 2 :
	$srcHandle = imagecreatefromjpeg($srcFile);
	break;
case 3 :
	$srcHandle = imagecreatefrompng($srcFile);
	break;
default :
	echo 'File Type Not Supported! ';
	return false;
}
if (!$srcHandle) {
	echo 'Could not execute imagecreatefrom() function! ';
	return false;
}

// Source has a horizontal Shape
if($srcHeight < $srcWidth) {
	$ratio = (double)($srcHeight / $dstHeight);
	$cpyWidth = round($dstWidth * $ratio);
	if ($cpyWidth > $srcWidth) {
		$ratio = (double)($srcWidth / $dstWidth);
		$cpyWidth = $srcWidth;
		$cpyHeight = round($dstHeight * $ratio);
		$xOffset = 0;
		$yOffset = round(($srcHeight - $cpyHeight) / 2);
	} 
	else {
		$cpyHeight = $srcHeight;
		$xOffset = round(($srcWidth - $cpyWidth) / 2);
		$yOffset = 0;
	}
}

// Source has a Vertical Shape
else {
	$ratio = (double)($srcWidth / $dstWidth);

	$cpyHeight = round($dstHeight * $ratio);
	if ($cpyHeight > $srcHeight) {
		$ratio = (double)($srcHeight / $dstHeight);
		$cpyHeight = $srcHeight;
		$cpyWidth = round($dstWidth * $ratio);
		$xOffset = round(($srcWidth - $cpyWidth) / 2);
		$yOffset = 0;
	}
	else {
		$cpyWidth = $srcWidth;
		$xOffset = 0;
		$yOffset = round(($srcHeight - $cpyHeight) / 2);
	}
}

$dstHandle = imagecreatetruecolor($dstWidth, $dstHeight);

// bool imagecopyresampled ( resource dst_image, resource src_image, int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h )
if (!imagecopyresampled($dstHandle, $srcHandle, 0, 0, $xOffset, $yOffset, $dstWidth, $dstHeight, $cpyWidth, $cpyHeight)) {
	echo 'Could not execute imagecopyresampled() function! ';
	return false;
}
imagedestroy($srcHandle);

switch ($type) {
case 1 :
	imagegif($dstHandle, $dstFile);
	break;
case 2 :
	imagejpeg($dstHandle, $dstFile, $jpegQuality);
	break;
case 3 :
	imagepng($dstHandle, $dstFile);
	break;
default :
	echo 'File Type Not Supported! ';
	return false;
}

imagedestroy($dstHandle);

return true;
}
?>

[Yari]

Try this one, it resizes an image to any size, (you can specify max height or width) and saves it at a perfect aspect ratio at 90 percent quality. This is an excellent script and has helped me many times.

Enjoy.

/*
		Function checkgd()
		checks the version of gd, and returns "yes" when it's higher than 2
	*/
	function checkgd(){
		$gd2="";
		ob_start();
		phpinfo(8);
		$phpinfo=ob_get_contents();
		ob_end_clean();
		$phpinfo=strip_tags($phpinfo);
		$phpinfo=stristr($phpinfo,"gd version");
		$phpinfo=stristr($phpinfo,"version");
		preg_match('/\d/',$phpinfo,$gd);
		if ($gd[0]=='2'){$gd2="yes";}
		return $gd2;
	}

/*
	Function createthumb($name,$filename,$new_w,$new_h)
	creates a resized image
	variables:
	$name		Original filename
	$filename	Filename of the resized image
	$new_w		width of resized image
	$new_h		height of resized image
*/	
function createthumb($name,$filename,$new_w,$new_h,$yallery){

	global $gd2;
	$system=explode(".",$name);
	if (preg_match("/jpg|jpeg/",$system[1])){$src_img=imagecreatefromjpeg($name);}
	if (preg_match("/png/",$system[1])){$src_img=imagecreatefrompng($name);}

	$old_x=imageSX($src_img);
	$old_y=imageSY($src_img);
	if ($old_x > $old_y) {
		$thumb_w=$new_w;
		$thumb_h=$old_y*($new_h/$old_x);
	}
	if ($old_x < $old_y) {
		$thumb_w=$old_x*($new_w/$old_y);
		$thumb_h=$new_h;
	}
	if ($old_x == $old_y) {
		$thumb_w=$new_w;
		$thumb_h=$new_h;
	}

	// If smaller than max size, make a smaller image
	if ($old_x < $new_w) {
		$thumb_w=$old_x;
		$thumb_h=$old_y;
	}
	if ($old_y < $new_h) {
		$thumb_w=$old_x;
		$thumb_h=$old_y;
	}
	if ($gd2==""){
		$dst_img=ImageCreate($thumb_w,$thumb_h);
		imagecopyresized($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y); 
	} else {

		$dst_img = @imageCreateTrueColor($thumb_w,$thumb_h);
		imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);

	}
	if (preg_match("/png/",$system[1])){
		imagepng($dst_img,$filename);
	} else {
		imagejpeg($dst_img,$filename,90); 
	}
	imagedestroy($dst_img);
	imagedestroy($src_img);
}