这篇文章主要为大家展示了“php如何实现支持imagemagick及gd库两种处理的缩略图生成类”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“php如何实现支持imagemagick及gd库两种处理的缩略图生成类”这篇文章吧。
一、功能:
1.按比例缩小/放大
2.填充背景色
3.按区域裁剪
4.添加水印，包括水印的位置，透明度等
使用imagemagick/GD库实现，imagemagick地址：www.imagemagick.org
需要安装imagemagick，安装方法如下：https://www.jb51.net/article/55528.htm
二、实现方法：
PicThumb.class.php类文件如下：
<?php
/** 缩略图生成类,支持imagemagick及gd库两种处理
* Date: 2013-07-15
* Author: fdipzone
* Ver: 1.2
*
* Func:
* public set_config: 设置参数
* public create_thumb: 生成缩略图
* private fit: 缩略图片
* private crop: 裁剪图片
* private gd_fit: GD库缩略图片
* private gd_crop: GD库裁剪图片
* private get_size: 获取要转换的size
* private get_crop_offset: 获取裁图的偏移量
* private add_watermark: 添加水印
* private check_handler: 判断处理程序是否已安装
* private create_dirs: 创建目录
* private exists: 判断参数是否存在
* private to_log: 记录log
* private hex2rgb: hex颜色转rgb颜色
* private get_file_ext: 获取图片类型
*
* ver: 1.1 增加GD库处理
* ver: 1.2 增加width,height错误参数处理
* 增加当图片colorspace不为RGB时作转RGB处理
* 修正使用crop保存为gif时出现透明无效区域问题，使用+repage参数，删除透明无效区域即可
*
* tips:建议使用imagemagick
* GD库不支持透明度水印,如果必须使用透明水印,请将水印图片做成有透明度。
* GD库输出gif如加透明水印，会有问题。
*/
class PicThumb{ // class start
private $_log = null; // log file
private $_handler = null; // 进行图片处理的程序,imagemagick/gd库
private $_type = 'fit'; // fit or crop
private $_source = null; // 原图路径
private $_dest = null; // 缩略图路径
private $_watermark = null; // 水印图片
private $_opacity = 75; // 水印圖片透明度,gd库不支持
private $_gravity = 'SouthEast'; // 水印摆放位置 NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast
private $_geometry = '+10+10'; // 水印定位,gd库不支持
private $_croppos = 'TL'; // 截图的位置 TL TM TR ML MM MR BL BM BR
private $_bgcolor = null; // 填充的背景色
private $_quality = 90; // 生成的图片质量
private $_width = null; // 指定区域宽度
private $_height = null; // 指定区域高度
// 初始化
public function __construct($logfile=''){
if($logfile!=''){
$this->_log = $logfile;
}
}
// 设置参数
public function set_config($param=array()){
$this->_handler = $this->exists($param, 'handler')? strtolower($param['handler']) : null;
$this->_type = $this->exists($param, 'type')? strtolower($param['type']) : 'fit';
$this->_watermark = $this->exists($param, 'watermark')? $param['watermark'] : null;
$this->_opacity = $this->exists($param, 'opacity')? $param['opacity'] : 75;
$this->_gravity = $this->exists($param, 'gravity')? $param['gravity'] : 'SouthEast';
$this->_geometry = $this->exists($param, 'geometry')? $param['geometry'] : '+10+10';
$this->_croppos = $this->exists($param, 'croppos')? $param['croppos'] : 'TL';
$this->_bgcolor = $this->exists($param, 'bgcolor')? $param['bgcolor'] : null;
$this->_quality = $this->exists($param, 'quality')? $param['quality'] : 90;
$this->_width = $this->exists($param, 'width')? $param['width'] : null;
$this->_height = $this->exists($param, 'height')? $param['height'] : null;
}
/** 创建缩略图
* @param String $source 原图
* @param String $dest 目标图
* @return boolean
*/
public function create_thumb($source, $dest){
// 检查使用的handler是否已安装
if(!$this->check_handler()){
$this->to_log('handler not installed');
return false;
}
// 判断区域宽高是否正确
if(!is_numeric($this->_width) || !is_numeric($this->_height) || $this->_width<=0 || $this->_height<=0){
$this->to_log('width or height invalid');
return false;
}
// 判断源文件是否存在
if(!file_exists($source)){
$this->to_log($source.' not exists');
return false;
}
// 创建目标文件路径
if(!$this->create_dirs($dest)){
$this->to_log(dirname($dest).' create fail');
return false;
}
$this->_source = $source; // 源文件
$this->_dest = $dest; // 目标文件
// 处理图片
switch($this->_type){
case 'fit':
if($this->_handler=='imagemagick'){
return $this->fit();
}else{
return $this->gd_fit();
}
break;
case 'crop':
if($this->_handler=='imagemagick'){
return $this->crop();
}else{
return $this->gd_crop();
}
break;
default:
$this->to_log($this->_type.' not fit and crop');
return false;
}
}
/** 按比例压缩或拉伸图片
* @return boolean
*/
private function fit(){
// 判断是否填充背景
$bgcolor = ($this->_bgcolor!=null)?
sprintf(" -background '%s' -gravity center -extent '%sx%s' ", $this->_bgcolor, $this->_width, $this->_height) : "";
// 判断是否要转为RGB
$source_info = getimagesize($this->_source);
$colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : '';
// 命令行
$cmd = sprintf("convert -resize '%sx%s' '%s' %s -quality %s %s '%s'", $this->_width, $this->_height, $this->_source, $bgcolor, $this->_quality, $colorspace, $this->_dest);
// 记录执行的命令
$this->to_log($cmd);
// 执行命令
exec($cmd);
// 添加水印
$this->add_watermark($this->_dest);
return is_file($this->_dest)? true : false;
}
/** 裁剪图片
* @return boolean
*/
private function crop(){
// 获取生成的图片尺寸
list($pic_w, $pic_h) = $this->get_size();
// 获取截图的偏移量
list($offset_w, $offset_h) = $this->get_crop_offset($pic_w, $pic_h);
// 判断是否要转为RGB
$source_info = getimagesize($this->_source);
$colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : '';
// 命令行
$cmd = sprintf("convert -resize '%sx%s' '%s' -quality %s %s -crop %sx%s+%s+%s +repage '%s'", $pic_w, $pic_h, $this->_source, $this->_quality, $colorspace, $this->_width, $this->_height, $offset_w, $offset_h, $this->_dest);
// 记录执行的命令
$this->to_log($cmd);
// 执行命令
exec($cmd);
// 添加水印
$this->add_watermark($this->_dest);
return is_file($this->_dest)? true : false;
}
/** GD库按比例压缩或拉伸图片
* @return boolean
*/
private function gd_fit(){
// 获取生成的图片尺寸
list($pic_w, $pic_h) = $this->get_size();
list($owidth, $oheight, $otype) = getimagesize($this->_source);
switch($otype){
case 1: $source_img = imagecreatefromgif($this->_source); break;
case 2: $source_img = imagecreatefromjpeg($this->_source); break;
case 3: $source_img = imagecreatefrompng($this->_source); break;
default: return false;
}
// 按比例缩略/拉伸图片
$new_img = imagecreatetruecolor($pic_w, $pic_h);
imagecopyresampled($new_img, $source_img, 0, 0, 0, 0, $pic_w, $pic_h, $owidth, $oheight);
// 判断是否填充背景
if($this->_bgcolor!=null){
$bg_img = imagecreatetruecolor($this->_width, $this->_height);
$rgb = $this->hex2rgb($this->_bgcolor);
$bgcolor =imagecolorallocate($bg_img, $rgb['r'], $rgb['g'], $rgb['b']);
imagefill($bg_img, 0, 0, $bgcolor);
imagecopy($bg_img, $new_img, (int)(($this->_width-$pic_w)/2), (int)(($this->_height-$pic_h)/2), 0, 0, $pic_w, $pic_h);
$new_img = $bg_img;
}
// 获取目标图片的类型
$dest_ext = $this->get_file_ext($this->_dest);
// 生成图片
switch($dest_ext){
case 1: imagegif($new_img, $this->_dest, $this->_quality); break;
case 2: imagejpeg($new_img, $this->_dest, $this->_quality); break;
case 3: imagepng($new_img, $this->_dest, (int)(($this->_quality-1)/10)); break;
}
if(isset($source_img)){
imagedestroy($source_img);
}
if(isset($new_img)){
imagedestroy($new_img);
}
// 添加水印
$this->add_watermark($this->_dest);
return is_file($this->_dest)? true : false;
}
/** GD库裁剪图片
* @return boolean
*/
private function gd_crop(){
// 获取生成的图片尺寸
list($pic_w, $pic_h) = $this->get_size();
// 获取截图的偏移量
list($offset_w, $offset_h) = $this->get_crop_offset($pic_w, $pic_h);
list($owidth, $oheight, $otype) = getimagesize($this->_source);
switch($otype){
case 1: $source_img = imagecreatefromgif($this->_source); break;
case 2: $source_img = imagecreatefromjpeg($this->_source); break;
case 3: $source_img = imagecreatefrompng($this->_source); break;
default: return false;
}
// 按比例缩略/拉伸图片
$tmp_img = imagecreatetruecolor($pic_w, $pic_h);
imagecopyresampled($tmp_img, $source_img, 0, 0, 0, 0, $pic_w, $pic_h, $owidth, $oheight);
// 裁剪图片
$new_img = imagecreatetruecolor($this->_width, $this->_height);
imagecopyresampled($new_img, $tmp_img, 0, 0, $offset_w, $offset_h, $this->_width, $this->_height, $this->_width, $this->_height);
// 获取目标图片的类型
$dest_ext = $this->get_file_ext($this->_dest);
// 生成图片
switch($dest_ext){
case 1: imagegif($new_img, $this->_dest, $this->_quality); break;
case 2: imagejpeg($new_img, $this->_dest, $this->_quality); break;
case 3: imagepng($new_img, $this->_dest, (int)(($this->_quality-1)/10)); break;
}
if(isset($source_img)){
imagedestroy($source_img);
}
if(isset($tmp_img)){
imagedestroy($tmp_img);
}
if(isset($new_img)){
imagedestroy($new_img);
}
// 添加水印
$this->add_watermark($this->_dest);
return is_file($this->_dest)? true : false;
}
/** 获取目标图生成的size
* @return Array $width, $height
*/
private function get_size(){
list($owidth, $oheight) = getimagesize($this->_source);
$width = (int)($this->_width);
$height = (int)($this->_height);
switch($this->_type){
case 'fit':
$pic_w = $width;
$pic_h = (int)($pic_w*$oheight/$owidth);
if($pic_h>$height){
$pic_h = $height;
$pic_w = (int)($pic_h*$owidth/$oheight);
}
break;
case 'crop':
if($owidth>$oheight){
$pic_h = $height;
$pic_w = (int)($pic_h*$owidth/$oheight);
}else{
$pic_w = $width;
$pic_h = (int)($pic_w*$oheight/$owidth);
}
break;
}
return array($pic_w, $pic_h);
}
/** 获取截图的偏移量
* @param int $pic_w 图宽度
* @param int $pic_h 图高度
* @return Array $offset_w, $offset_h
*/
private function get_crop_offset($pic_w, $pic_h){
$offset_w = 0;
$offset_h = 0;
switch(strtoupper($this->_croppos)){
case 'TL':
$offset_w = 0;
$offset_h = 0;
break;
case 'TM':
$offset_w = (int)(($pic_w-$this->_width)/2);
$offset_h = 0;
break;
case 'TR':
$offset_w = (int)($pic_w-$this->_width);
$offset_h = 0;
break;
case 'ML':
$offset_w = 0;
$offset_h = (int)(($pic_h-$this->_height)/2);
break;
case 'MM':
$offset_w = (int)(($pic_w-$this->_width)/2);
$offset_h = (int)(($pic_h-$this->_height)/2);
break;
case 'MR':
$offset_w = (int)($pic_w-$this->_width);
$offset_h = (int)(($pic_h-$this->_height)/2);
break;
case 'BL':
$offset_w = 0;
$offset_h = (int)($pic_h-$this->_height);
break;
case 'BM':
$offset_w = (int)(($pic_w-$this->_width)/2);
$offset_h = (int)($pic_h-$this->_height);
break;
case 'BR':
$offset_w = (int)($pic_w-$this->_width);
$offset_h = (int)($pic_h-$this->_height);
break;
}
return array($offset_w, $offset_h);
}
/** 添加水印
* @param String $dest 图片路径
*/
private function add_watermark($dest){
if($this->_watermark!=null && file_exists($this->_watermark) && file_exists($dest)){
list($owidth, $oheight, $otype) = getimagesize($dest);
list($w, $h, $wtype) = getimagesize($this->_watermark);
// 水印图比原图要小才加水印
if($w<=$owidth && $h<=$oheight){
if($this->_handler=='imagemagick'){ // imagemagick 添加水印
$cmd = sprintf("composite -gravity %s -geometry %s -dissolve %s '%s' %s %s", $this->_gravity, $this->_geometry, $this->_opacity, $this->_watermark, $dest, $dest);
$this->to_log($cmd);
exec($cmd);
}else{ // gd 添加水印
switch($wtype){
case 1: $water_img = imagecreatefromgif($this->_watermark); break;
case 2: $water_img = imagecreatefromjpeg($this->_watermark); break;
case 3: $water_img = imagecreatefrompng($this->_watermark); break;
default: return false;
}
switch($otype){
case 1: $dest_img = imagecreatefromgif($dest); break;
case 2: $dest_img = imagecreatefromjpeg($dest); break;
case 3: $dest_img = imagecreatefrompng($dest); break;
default: return false;
}
// 水印位置
switch(strtolower($this->_gravity)){
case 'northwest':
$posX = 0;
$posY = 0;
break;
case 'north':
$posX = ($owidth - $w) / 2;
$posY = 0;
break;
case 'northeast':
$posX = $owidth - $w;
$posY = 0;
break;
case 'west':
$posX = 0;
$posY = ($oheight - $h) / 2;
break;
case 'center':
$posX = ($owidth - $w) / 2;
$posY = ($oheight - $h) / 2;
break;
case 'east':
$posX = $owidth - $w;
$posY = ($oheight - $h) / 2;
break;
case 'southwest':
$posX = 0;
$posY = $oheight - $h;
break;
case 'south':
$posX = ($owidth - $w) / 2;
$posY = $oheight - $h;
break;
case 'southeast':
$posX = $owidth - $w;
$posY = $oheight - $h;
break;
}
imagealphablending($dest_img, true);
imagecopy($dest_img, $water_img, $posX, $posY, 0, 0, $w, $h);
switch($otype){
case 1:imagegif($dest_img, $dest, $this->_quality); break;
case 2:imagejpeg($dest_img, $dest, $this->_quality); break;
case 3:imagepng($dest_img, $dest, (int)(($this->_quality-1)/10)); break;
}
if(isset($water_img)){
imagedestroy($water_img);
}
if(isset($dest_img)){
imagedestroy($dest_img);
}
}
}
}
}
/** 判断处理程序是否已安装
* @return boolean
*/
private function check_handler(){
$handler = $this->_handler;
if(!in_array($handler, array('imagemagick', 'gd', null))){
return false;
}
// 检查是否有安装imagemagick
$imagemagick_installed = strstr(shell_exec('convert -version'),'Version: ImageMagick')!=''? true : false;
// 检查是否有安装gd库
$gd_installed = function_exists('gd_info')? true : false;
switch($handler){
case 'imagemagick':
return $imagemagick_installed;
break;
case 'gd':
return $gd_installed;
break;
case null:
if($imagemagick_installed){
$this->_handler = 'imagemagick';
return true;
}
if($gd_installed){
$this->_handler = 'gd';
return true;
}
break;
}
return false;
}
/** 创建图片目录
* @param String $path
* @return boolean
*/
private function create_dirs($dest){
if(!is_dir(dirname($dest))){
return mkdir(dirname($dest), 0777, true);
}
return true;
}
/** 判断参数是否存在
* @param Array $obj 数组对象
* @param String $key 要查找的key
* @return boolean
*/
private function exists($obj,$key=''){
if($key==''){
return isset($obj) && !empty($obj);
}else{
$keys = explode('.',$key);
for($i=0,$max=count($keys); $i<$max; $i++){
if(isset($obj[$keys[$i]])){
$obj = $obj[$keys[$i]];
}else{
return false;
}
}
return isset($obj) && !empty($obj);
}
}
/** 记录log
* @param String $msg 要记录的log讯息
*/
private function to_log($msg){
if($this->_log){
$msg = '['.date('Y-m-d H:i:s').']'.$msg."\r\n";
file_put_contents($this->_log, $msg, FILE_APPEND);
}
}
/** hex颜色转rgb颜色
* @param String $color hex颜色
* @return Array
*/
private function hex2rgb($hexcolor){
$color = str_replace('#', '', $hexcolor);
if (strlen($color) > 3) {
$rgb = array(
'r' => hexdec(substr($color, 0, 2)),
'g' => hexdec(substr($color, 2, 2)),
'b' => hexdec(substr($color, 4, 2))
);
} else {
$r = substr($color, 0, 1) . substr($color, 0, 1);
$g = substr($color, 1, 1) . substr($color, 1, 1);
$b = substr($color, 2, 1) . substr($color, 2, 1);
$rgb = array(
'r' => hexdec($r),
'g' => hexdec($g),
'b' => hexdec($b)
);
}
return $rgb;
}
/** 获取图片类型
* @param String $file 图片路径
* @return int
*/
private function get_file_ext($file){
$filename = basename($file);
list($name, $ext)= explode('.', $filename);
$ext_type = 0;
switch(strtolower($ext)){
case 'jpg':
case 'jpeg':
$ext_type = 2;
break;
case 'gif':
$ext_type = 1;
break;
case 'png':
$ext_type = 3;
break;
}
return $ext_type;
}
} // class end
?>demo示例代码如下：
<?php
define('ROOT', dirname(__FILE__));
require(ROOT."/PicThumb.class.php");
$logfile = ROOT.'/PicThumb.log';
$source1 = ROOT.'/pic/source.jpg';
$dest1 = ROOT.'/pic/1.jpg';
$dest2 = ROOT.'/pic/2.gif';
$dest3 = ROOT.'/pic/3.png';
$source2 = ROOT.'/pic/source_cmyk.jpg';
$dest4 = ROOT.'/pic/4.jpg';
$dest5 = ROOT.'/pic/5.gif';
$dest6 = ROOT.'/pic/6.png';
$watermark = ROOT.'/pic/watermark.png';
// 按比例生成缩略图
$param = array(
'type' => 'fit',
'width' => 100,
'height' => 100,
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source1, $dest1);
if($flag){
echo '<img src="pic/'.basename($dest1).'">';
}else{
echo 'create thumb fail';
}
// 按比例生成缩略图,不足部分用#FF0000填充
$param = array(
'type' => 'fit',
'width' => 100,
'height' => 100,
'bgcolor' => '#FFFF00'
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source1, $dest2);
if($flag){
echo '<img src="pic/'.basename($dest2).'">';
}else{
echo 'create thumb fail';
}
// 裁剪250x250的缩略图,裁剪位置是底部中间,水印位置西南,透明度50
$param = array(
'type' => 'crop',
'croppos' => 'BM',
'width' => 250,
'height' => 250,
'watermark' => $watermark,
'opacity' => 50,
'gravity' => 'SouthWest'
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source1, $dest3);
if($flag){
echo '<img src="pic/'.basename($dest3).'">';
}else{
echo 'create thumb fail';
}
// 按比例生成缩略图 CMYK格式
$param = array(
'type' => 'fit',
'width' => 100,
'height' => 100,
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source2, $dest4);
if($flag){
echo '<img src="pic/'.basename($dest4).'">';
}else{
echo 'create thumb fail';
}
// 按比例生成缩略图,不足部分用#FF0000填充 CMYK格式
$param = array(
'type' => 'fit',
'width' => 100,
'height' => 100,
'bgcolor' => '#FFFF00'
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source2, $dest5);
if($flag){
echo '<img src="pic/'.basename($dest5).'">';
}else{
echo 'create thumb fail';
}
// 裁剪250x250的缩略图,裁剪位置是底部中间,水印位置西南,透明度50 CMYK格式
$param = array(
'type' => 'crop',
'croppos' => 'BM',
'width' => 250,
'height' => 250,
'watermark' => $watermark,
'opacity' => 50,
'gravity' => 'SouthWest'
);
$obj = new PicThumb($logfile);
$obj->set_config($param);
$flag = $obj->create_thumb($source2, $dest6);
if($flag){
echo '<img src="pic/'.basename($dest6).'">';
}else{
echo 'create thumb fail';
}
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