Jakk’s blog

Image Magick คำนี่ผมไม่ได้สะกดผิดหรอกนะ แต่มันเป็นชื่อ library ที่ใช้สำหรับ image processing เหมือนกับ GD library แต่ผมคิดว่า performance ของ Image Magick ดีกว่าและใช้จัดการ resource อย่างเช่น memory ได้ดีกว่า Image Magick สามารถใช้ได้ทั้ง command line หรือ interface สำหรับภาษาต่างๆเช่น PHP, JAVA, .NET และอื่นๆ ปัจจุบันมีถึง version 6 สามารถ download และหาดู document ได้จาก website ทางการ : http://www.imagemagick.org แต่version ที่ผมจะนำมาใช้เป็นตัวอย่างเป็น version 4 ซึ่งเป็น statically linked binary (อันนี้ใครรู้วิธี compile สอนผมที)

test resize 440×504 image by Image Magick
code here:

01
<?php
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function resize($img, $w,  $newfilename) {
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	$path_exe = "convert $img -resize \"$w\" $newfilename";
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	exec($path_exe);
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}
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$time_start = microtime(true);
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$mem_before = memory_get_usage();//this function avaliable in PHP 5.2+
08
 
09
resize('alucard.jpg', 100, 'alucard_0.jpg');
10
 
11
$mem_after = memory_get_peak_usage();//this function avaliable in PHP 5.2+
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$time_end = microtime(true);
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$time = $time_end - $time_start;
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print '<table>
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	   <tr align="center" valign="middle">
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		<td ><image src="alucard.jpg"/></td><td > before</td>
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	  </tr>
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	  <tr align="center" valign="middle">
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		<td ><image src="alucard_0.jpg"/></td><td > after</td>
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	  </tr>
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	</table>';
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print "parse time: $time seconds<br/>";
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print "memory usage before resize: $mem_before<br/> memory peak while resize: $mem_after <br/> memory usage for resize:".($mem_after-$mem_before);
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?>

test resize 440×504 image by GD lib
code here:

01
<?
02
function resize($img, $w, $newfilename) {
03
 
04
 //Get Image size info
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 	$imgInfo = getimagesize($img);
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	$format = ereg_replace(".*\.(.*)$","\\1",$img);
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	$format = strtolower($format);
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 	switch ($format) {
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		case "gif": 	$im = imagecreatefromgif($img); break;
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		case "jpg":
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		case "jpeg":	$im = imagecreatefromjpeg($img);  break;
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		case "png": 	$im = imagecreatefrompng($img); break;
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		default:  trigger_error('Unsupported filetype!', E_USER_WARNING);  break;
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 	}
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	//calculate size
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	if($imgInfo[0]>=$imgInfo[1]){
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		$nWidth = $w;
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		$nHeight = ($nWidth/$imgInfo[0])*$imgInfo[1];
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	}else{
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		$nHeight = $w;
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		$nWidth = ($nHeight/$imgInfo[1])*$imgInfo[0];
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	}
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 	$nWidth = round($nWidth);
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 	$nHeight = round($nHeight);
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	$newImg = imagecreatetruecolor($nWidth, $nHeight);
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 // Check if this image is PNG or GIF, then set if Transparent
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	if(($imgInfo[2]==3)){
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		imagealphablending($newImg, false);
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		imagesavealpha($newImg,true);
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		$transparent = imagecolortransparent($im);  
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		imagefilledrectangle($newImg, 0, 0, $nWidth, $nHeight, $transparent);
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	}elseif(($imgInfo[2] == 1)){
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		imagetruecolortopalette($newImg, false, 255);
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		$idx = imagecolortransparent($im);  
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		$rgba = imagecolorsforindex($im,idx);
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		$transparent = imagecolorallocatealpha($newImg, $rgba['red'], $rgba['green'], $rgba['blue'],$rgba['alpha']);
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		imagecolortransparent($newImg, $transparent);
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		imagefilledrectangle($newImg, 0, 0, $nWidth, $nHeight, $transparent);
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	}
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 	imagecopyresampled($newImg, $im, 0, 0, 0, 0, $nWidth, $nHeight, $imgInfo[0], $imgInfo[1]);
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 //Generate the file, and rename it to $newfilename
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	switch ($imgInfo[2]) {
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		case 1: imagegif($newImg,$newfilename); break;
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		case 2: imagejpeg($newImg,$newfilename);  break;
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		case 3: imagepng($newImg,$newfilename); break;
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		default:  trigger_error('Failed resize image!', E_USER_WARNING);  break;
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	}
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	imagedestroy($im);
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	return $newfilename;
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}
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$time_start = microtime(true);
55
$mem_before = memory_get_usage();//this function avaliable in PHP 5.2+
56
 
57
resize('alucard.jpg', 100, 'alucard_1.jpg');
58
 
59
$mem_after = memory_get_peak_usage();//this function avaliable in PHP 5.2+
60
$time_end = microtime(true);
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$time = $time_end - $time_start;
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print '<table>
63
	  <tr align="center" valign="middle">
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		<td ><image src="alucard.jpg"/></td><td > before</td>
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	  </tr>
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	  <tr align="center" valign="middle">
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		<td ><image src="alucard_1.jpg"/></td><td > after</td>
68
	  </tr>
69
	</table>';
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print "parse time: $time seconds<br/>";
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print "memory usage before resize: $mem_before<br/> memory peak while resize: $mem_after <br/> memory usage for resize:".($mem_after-$mem_before);
72
?>

source code including statically linked Image Magick V4: source

Tags: image processing, PHP

This entry was posted on Friday, March 6th, 2009 at 6:17 pm and is filed under General, PHP. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.