本文实例讲述了PHP实现的支持imagemagick及gd库两种处理的缩略图生成类及其用法实例，非常具有实用价值。分享给大家供大家参考。具体如下：
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：
二、实现方法：
PicThumb.class.php类文件如下：
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->_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,$pic_h,$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,$source_img,$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,$bgcolor);
imagecopy($bg_img,$new_img,(int)(($this->_width-$pic_w)/2),(int)(($this->_height-$pic_h)/2),$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->_quality); break;
case 3: imagepng($new_img,(int)(($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,$pic_h);list($owidth,$otype) = getimagesize($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,$oheight);// 裁剪图片
$new_img = imagecreatetruecolor($this->_width,$this->_height);
imagecopyresampled($new_img,$tmp_img,$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,(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,$otype) = getimagesize($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,$w,$h); switch($otype){ case 1:imagegif($dest_img,$this->_quality); break; case 2:imagejpeg($dest_img,$this->_quality); break; case 3:imagepng($dest_img,(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,2)),'g' => hexdec(substr($color,2,'b' => hexdec(substr($color,4,2))
);
} else {
$r = substr($color,1) . substr($color,1);
$g = substr($color,1,1);
$b = substr($color,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：
$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','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',);
$obj = new PicThumb($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','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,透明度50 CMYK格式
$param = array(
'type' => 'crop','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';
}
?>
本文完整实例代码点击此处。
希望本文所述对大家的PHP程序设计有所帮助
原文链接：https://www.f2er.com/php/23776.html