浅谈php扩展imagick

php建图通常都用gd库,因为是内置的不需要在服务器上额外安装插件,所以用起来比较省心,但是如果你的程序主要的功能就是处理图像,那麼就不建议用gd了,因为gd不但低效能而且能力也比较弱,佔用的系统资源也颇多,另外gd的creatfrom也有bug,而imagick却是一个很好的替代品,为此最近把我的一个项目由gd改成了imagick,但是改完之后出现了一些状况在此分享给大家.

首先说一下我这边出现的状况:

状况一:需要重写图像操作class

状况二:imagick多线程时会导致cpu使用率暴增到100%

在此顺便提一下imagick在centos6.4的安装方法:

1、安装imagemagick

wget http://soft.vpser.net/web/imagemagick/imagemagick-6.7.1-2.tar.gz
tar zxvf imagemagick-6.7.1-2.tar.gz
cd imagemagick-6.7.1-2/
./configure --prefix=/usr/local/imagemagick --disable-openmp
make && make install
ldconfig

测试imagemagick是否可以正常运行：

/usr/local/imagemagick/bin/convert -version

2、安装php扩展：imagick

wget http://pecl.php.net/get/imagick-3.0.1.tgz
tar zxvf imagick-3.0.1.tgz
cd imagick-3.0.1/
/usr/local/php/bin/phpize
./configure --with-php-config=/usr/local/php/bin/php-config --with-imagick=/usr/local/imagemagick
make && make install
ldconfig
vi /usr/local/php/etc/php.ini
添加：extension = "imagick.so"

重启lnmp

/root/lnmp reload

接下来我们针对上述两个状况分别提出解决办法:

状况一的解决办法如下:

/**
    imagick图像处理类
    用法:
        //引入imagick物件
        if(!defined('class_imagick')){require(inc.'class_imagick.php');}
        $imagick=new class_imagick();
        $imagick->open('a.gif');
        $imagick->resize_to(100,100,'scale_fill');
        $imagick->add_text('1024i.com',10,20);
        $imagick->add_watermark('1024i.gif',10,50);
        $imagick->save_to('x.gif');
        unset($imagick);
/**/
define('class_imagick',true);
class class_imagick{
    private $image=null;
    private $type=null;
    // 构造
    public function __construct(){}
    // 析构
    public function __destruct(){
        if($this->image!==null){$this->image->destroy();}
    }
    // 载入图像
    public function open($path){
        if(!file_exists($path)){
            $this->image=null;
            return ;
        }
        $this->image=new imagick($path);
        if($this->image){
            $this->type=strtolower($this->image->getimageformat());
        }
        $this->image->stripimage();
        return $this->image;
    }
    /**
        图像裁切
    /**/
    public function crop($x=0,$y=0,$width=null,$height=null){
        if($width==null) $width=$this->image->getimagewidth()-$x;
        if($height==null) $height=$this->image->getimageheight()-$y;
        if($width<=0 || $height<=0) return;
        if($this->type=='gif'){
            $image=$this->image;
            $canvas=new imagick();
            $images=$image->coalesceimages();
            foreach($images as $frame){
                $img=new imagick();
                $img->readimageblob($frame);
                $img->cropimage($width,$height,$x,$y);
                $canvas->addimage($img);
                $canvas->setimagedelay($img->getimagedelay());
                $canvas->setimagepage($width,$height,0,0);
            }
            $image->destroy();
            $this->image=$canvas;
        }else{
            $this->image->cropimage($width,$height,$x,$y);
        }
    }
    /**
        更改图像大小
        参数:
            $width:新的宽度
            $height:新的高度
            $fit: 适应大小
                'force': 把图像强制改为$width x $height
                'scale': 按比例在$width x $height内缩放图片,结果不完全等於$width x $height
                'scale_fill':按比例在$width x $height内缩放图片,没有像素的地方填充顏色$fill_color=array(255,255,255)(红,绿,蓝,透明度[0不透明-127全透明])
                其他:智能模式,缩放图片并从正中裁切$width x $height的大小
        注意:
            $fit='force','scale','scale_fill'时输出完整图像
            $fit=图像方位时输出指定位置部份的图像
        字母与图像的对应关系如下:
            north_west   north   north_east
            west         center        east
            south_west   south   south_east
    /**/
    public function resize_to($width=100,$height=100,$fit='center',$fill_color=array(255,255,255,0)){
        switch($fit){
        case 'force':
            if($this->type=='gif'){
                $image=$this->image;
                $canvas=new imagick();
                $images=$image->coalesceimages();
                foreach($images as $frame){
                    $img=new imagick();
                    $img->readimageblob($frame);
                    $img->thumbnailimage($width,$height,false);
                    $canvas->addimage($img);
                    $canvas->setimagedelay($img->getimagedelay());
                }
                $image->destroy();
                $this->image=$canvas;
            }else{
                $this->image->thumbnailimage($width,$height,false);
            }
            break;
        case 'scale':
            if($this->type=='gif'){
                $image=$this->image;
                $images=$image->coalesceimages();
                $canvas=new imagick();
                foreach($images as $frame){
                    $img=new imagick();
                    $img->readimageblob($frame);
                    $img->thumbnailimage($width,$height,true);
                    $canvas->addimage($img);
                    $canvas->setimagedelay($img->getimagedelay());
                }
                $image->destroy();
                $this->image=$canvas;
            }else{
                $this->image->thumbnailimage($width,$height,true);
            }
            break;
        case 'scale_fill':
            $size=$this->image->getimagepage();
            $src_width=$size['width'];
            $src_height=$size['height'];
            $x=0;
            $y=0;
            $dst_width=$width;
            $dst_height=$height;
            if($src_width*$height > $src_height*$width){
                $dst_height=intval($width*$src_height/$src_width);
                $y=intval(($height-$dst_height)/2);
            }else{
                $dst_width=intval($height*$src_width/$src_height);
                $x=intval(($width-$dst_width)/2);
            }
            $image=$this->image;
            $canvas=new imagick();
            $color='rgba('.$fill_color[0].','.$fill_color[1].','.$fill_color[2].','.$fill_color[3].')';
            if($this->type=='gif'){
                $images=$image->coalesceimages();
                foreach($images as $frame){
                    $frame->thumbnailimage($width,$height,true);
                    $draw=new imagickdraw();
                    $draw->composite($frame->getimagecompose(),$x,$y,$dst_width,$dst_height,$frame);
                    $img=new imagick();
                    $img->newimage($width,$height,$color,'gif');
                    $img->drawimage($draw);
                    $canvas->addimage($img);
                    $canvas->setimagedelay($img->getimagedelay());
                    $canvas->setimagepage($width,$height,0,0);
                }
            }else{
                $image->thumbnailimage($width,$height,true);
                $draw=new imagickdraw();
                $draw->composite($image->getimagecompose(),$x,$y,$dst_width,$dst_height,$image);
                $canvas->newimage($width,$height,$color,$this->get_type());
                $canvas->drawimage($draw);
                $canvas->setimagepage($width,$height,0,0);
            }
            $image->destroy();
            $this->image=$canvas;
            break;
        default:
            $size=$this->image->getimagepage();
            $src_width=$size['width'];
            $src_height=$size['height'];
            $crop_x=0;
            $crop_y=0;
            $crop_w=$src_width;
            $crop_h=$src_height;
            if($src_width*$height > $src_height*$width){
                $crop_w=intval($src_height*$width/$height);
            }else{
                $crop_h=intval($src_width*$height/$width);
            }
            switch($fit){
                case 'north_west':
                    $crop_x=0;
                    $crop_y=0;
                    break;
                case 'north':
                    $crop_x=intval(($src_width-$crop_w)/2);
                    $crop_y=0;
                    break;
                case 'north_east':
                    $crop_x=$src_width-$crop_w;
                    $crop_y=0;
                    break;
                case 'west':
                    $crop_x=0;
                    $crop_y=intval(($src_height-$crop_h)/2);
                    break;
                case 'center':
                    $crop_x=intval(($src_width-$crop_w)/2);
                    $crop_y=intval(($src_height-$crop_h)/2);
                    break;
                case 'east':
                    $crop_x=$src_width-$crop_w;
                    $crop_y=intval(($src_height-$crop_h)/2);
                    break;
                case 'south_west':
                    $crop_x=0;
                    $crop_y=$src_height-$crop_h;
                    break;
                case 'south':
                    $crop_x=intval(($src_width-$crop_w)/2);
                    $crop_y=$src_height-$crop_h;
                    break;
                case 'south_east':
                    $crop_x=$src_width-$crop_w;
                    $crop_y=$src_height-$crop_h;
                    break;
                default:
                    $crop_x=intval(($src_width-$crop_w)/2);
                    $crop_y=intval(($src_height-$crop_h)/2);
            }
            $image=$this->image;
            $canvas=new imagick();
            if($this->type=='gif'){
                $images=$image->coalesceimages();
                foreach($images as $frame){
                    $img=new imagick();
                    $img->readimageblob($frame);
                    $img->cropimage($crop_w,$crop_h,$crop_x,$crop_y);
                    $img->thumbnailimage($width,$height,true);
                    $canvas->addimage($img);
                    $canvas->setimagedelay($img->getimagedelay());
                    $canvas->setimagepage($width,$height,0,0);
                }
            }else{
                $image->cropimage($crop_w,$crop_h,$crop_x,$crop_y);
                $image->thumbnailimage($width,$height,true);
                $canvas->addimage($image);
                $canvas->setimagepage($width,$height,0,0);
            }
            $image->destroy();
            $this->image=$canvas;
        }
    }
    /**
        添加图片水印
        参数:
            $path:水印图片(包含完整路径)
            $x,$y:水印座标
    /**/
    public function add_watermark($path,$x=0,$y=0){
        $watermark=new imagick($path);
        $draw=new imagickdraw();
        $draw->composite($watermark->getimagecompose(),$x,$y,$watermark->getimagewidth(),$watermark->getimageheight(),$watermark);
        if($this->type=='gif'){
            $image=$this->image;
            $canvas=new imagick();
            $images=$image->coalesceimages();
            foreach($image as $frame){
                $img=new imagick();
                $img->readimageblob($frame);
                $img->drawimage($draw);
                $canvas->addimage($img);
                $canvas->setimagedelay($img->getimagedelay());
            }
            $image->destroy();
            $this->image=$canvas;
        }else{
            $this->image->drawimage($draw);
        }
    }
    /**
        添加文字水印
        参数:
            $text:水印文字
            $x,$y:水印座标
    /**/
    public function add_text($text,$x=0,$y=0,$angle=0,$style=array()){
        $draw=new imagickdraw();
        if(isset($style['font'])) $draw->setfont($style['font']);
        if(isset($style['font_size'])) $draw->setfontsize($style['font_size']);
        if(isset($style['fill_color'])) $draw->setfillcolor($style['fill_color']);
        if(isset($style['under_color'])) $draw->settextundercolor($style['under_color']);
        if($this->type=='gif'){
            foreach($this->image as $frame){
                $frame->annotateimage($draw,$x,$y,$angle,$text);
            }
        }else{
            $this->image->annotateimage($draw,$x,$y,$angle,$text);
        }
    }
    /**
        图片存档
        参数:
            $path:存档的位置和新的档案名
    /**/
    public function save_to($path){
        $this->image->stripimage();
        switch($this->type){
        case 'gif':
            $this->image->writeimages($path,true);
            return ;
        case 'jpg':
        case 'jpeg':
            $this->image->setimagecompressionquality($_env['imgq']);
            $this->image->writeimage($path);
            return ;
        case 'png':
            $flag = $this->image->getimagealphachannel();
            // 如果png背景不透明则压缩
            if(imagick::alphachannel_undefined == $flag or imagick::alphachannel_deactivate == $flag){
                $this->image->setimagetype(imagick::imgtype_palette);
                $this->image->writeimage($path);
            }else{
                $this->image->writeimage($path);
            }unset($flag);
            return ;
        default:
            $this->image->writeimage($path);
            return ;
        }
    }
    // 直接输出图像到萤幕
    public function output($header=true){
        if($header) header('content-type: '.$this->type);
        echo $this->image->getimagesblob();
    }
    /**
        建立缩小图
        $fit为真时,将保持比例并在$width x $height内產生缩小图
    /**/
    public function thumbnail($width=100,$height=100,$fit=true){$this->image->thumbnailimage($width,$height,$fit);}
    /**
        给图像添加边框
        $width: 左右边框宽度
        $height: 上下边框宽度
        $color: 顏色
    /**/
    public function border($width,$height,$color='rgb(220,220,220)'){
        $color=new imagickpixel();
        $color->setcolor($color);
        $this->image->borderimage($color,$width,$height);
    }
    //取得图像宽度
    public function get_width(){$size=$this->image->getimagepage();return $size['width'];}
    //取得图像高度
    public function get_height(){$size=$this->image->getimagepage();return $size['height'];}
    // 设置图像类型
    public function set_type($type='png'){$this->type=$type;$this->image->setimageformat($type);}
    // 取得图像类型
    public function get_type(){return $this->type;}
    public function blur($radius,$sigma){$this->image->blurimage($radius,$sigma);} // 模糊
    public function gaussian_blur($radius,$sigma){$this->image->gaussianblurimage($radius,$sigma);} // 高斯模糊
    public function motion_blur($radius,$sigma,$angle){$this->image->motionblurimage($radius,$sigma,$angle);} // 运动模糊
    public function radial_blur($radius){$this->image->radialblurimage($radius);} // 径向模糊
    public function add_noise($type=null){$this->image->addnoiseimage($type==null?imagick::noise_impulse:$type);} // 添加噪点
    public function level($black_point,$gamma,$white_point){$this->image->levelimage($black_point,$gamma,$white_point);} // 调整色阶
    public function modulate($brightness,$saturation,$hue){$this->image->modulateimage($brightness,$saturation,$hue);} // 调整亮度,饱和度,色调
    public function charcoal($radius,$sigma){$this->image->charcoalimage($radius,$sigma);} // 素描效果
    public function oil_paint($radius){$this->image->oilpaintimage($radius);} // 油画效果
    public function flop(){$this->image->flopimage();} // 水平翻转
    public function flip(){$this->image->flipimage();} // 垂直翻转
}

状况二的解决办法如下:

首先用/usr/local/imagemagick/bin/convert -version指令查看一下输出内容是否已经开啟了多线程,features:的值为空说明是单线程,如果features:的值是openmp说明是多线程.imagick的多线程模式有一个bug,他会导致多核心的cpu使用率瞬间飆升到100所以一定要使用它的单线程模式才行.

version: imagemagick 6.7.1-2 2014-05-29 q16 http://www.imagemagick.org
copyright: copyright (c) 1999-2011 imagemagick studio llc
features:  

 上边是我配置正确时显示的结果,如果没有配置正确会显示下边的结果

version: imagemagick 6.7.1-2 2014-05-29 q16 http://www.imagemagick.org
copyright: copyright (c) 1999-2011 imagemagick studio llc
features: openmp

 第一种结果是单线程模式,第二种结果是多线程模式,因为imagick的多线程模式有bug,所以如果您刚开始是用多线程模式安装的imagick那就必须要yum remove imagemagick将其卸载掉重新安装才行.

经过重写class,重装imagick之后一切正常,而且处理图像的效能比之以前有了大幅提升