php產生圖片縮圖類

php產生圖片縮圖類（支援常用圖片格式）

功能：支援jpg,jpeg,gif,png,bmp圖片格式，支援按原圖片的比例進行縮放，可以選擇在圖片縮放的過程中是否需要對圖片進行裁切，加入了圖片品質控制，可以實現縮圖片品質最高化。完整類的代碼如下：

/** * 功能：php產生縮圖片的類 */    class ResizeImage{        public $type;//圖片類型        public $width;//實際寬度        public $height;//實際高度        public $resize_width;//改變後的寬度        public $resize_height;//改變後的高度        public $cut;//是否裁圖        public $srcimg;//源圖象          public $dstimg;//靶心圖表象地址        public $im;//臨時建立的圖象        public $quality;//圖片品質        function resizeimage($img,$wid,$hei,$c,$dstpath,$quality=100){            $this->srcimg=$img;            $this->resize_width=$wid;            $this->resize_height=$hei;            $this->cut=$c;            $this->quality=$quality;            $this->type=strtolower(substr(strrchr($this->srcimg,'.'),1));//圖片的類型            $this->initi_img();//初始化圖象            $this -> dst_img($dstpath);//靶心圖表象地址            @$this->width=imagesx($this->im);            @$this->height=imagesy($this->im);            $this->newimg();//產生圖象            @ImageDestroy($this->im);        }        function newimg(){            $resize_ratio=($this->resize_width)/($this->resize_height);//改變後的圖象的比例            @$ratio=($this->width)/($this->height);//實際圖象的比例            if(($this->cut)=='1'){//裁圖                if($img_func==='imagepng'&&(str_replace('.','',PHP_VERSION)>=512)){  //針對php版本大於5.12參數變化後的處理情況                    $quality=9;                }                if($ratio>=$resize_ratio){//高度優先                    $newimg=imagecreatetruecolor($this->resize_width,$this->resize_height);                    imagecopyresampled($newimg,$this->im,0,0,0,0,$this->resize_width,$this->resize_height,(($this->height)*$resize_ratio),$this->height);                    imagejpeg($newimg,$this->dstimg,$this->quality);                }                if($ratio<$resize_ratio){//寬度優先                    $newimg=imagecreatetruecolor($this->resize_width,$this->resize_height);                    imagecopyresampled($newimg,$this->im,0,0,0,0,$this->resize_width,$this->resize_height,$this->width,(($this->width)/$resize_ratio));                    imagejpeg($newimg,$this->dstimg,$this->quality);                }            }else{//不裁圖                if($ratio>=$resize_ratio){                    $newimg=imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);                    imagecopyresampled($newimg,$this->im,0,0,0,0,$this->resize_width,($this->resize_width)/$ratio,$this->width,$this->height);                    imagejpeg($newimg,$this->dstimg,$this->quality);                }                if($ratio<$resize_ratio){                    @$newimg=imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);                    @imagecopyresampled($newimg,$this->im,0,0,0,0,($this->resize_height)*$ratio,$this->resize_height,$this->width,$this->height);                    @imagejpeg($newimg,$this->dstimg,$this->quality);                }            }        }        function initi_img(){//初始化圖象            if($this->type=='jpg' || $this->type=='jpeg'){                $this->im=imagecreatefromjpeg($this->srcimg);            }            if($this->type=='gif'){                $this->im=imagecreatefromgif($this->srcimg);            }            if($this->type=='png'){                $this->im=imagecreatefrompng($this->srcimg);            }            if($this->type=='wbm'){                @$this->im=imagecreatefromwbmp($this->srcimg);            }            if($this->type=='bmp'){                $this->im=$this->ImageCreateFromBMP($this->srcimg);            }        }        function dst_img($dstpath){//圖象目標地址            $full_length=strlen($this->srcimg);            $type_length=strlen($this->type);            $name_length=$full_length-$type_length;            $name=substr($this->srcimg,0,$name_length-1);            $this->dstimg=$dstpath;            //echo $this->dstimg;        }                 function ImageCreateFromBMP($filename){ //自訂函數處理bmp圖片            if(!$f1=fopen($filename,"rb"))returnFALSE;            $FILE=unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset",fread($f1,14));            if($FILE['file_type']!=19778)returnFALSE;            $BMP=unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.                    '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.                    '/Vvert_resolution/Vcolors_used/Vcolors_important',fread($f1,40));            $BMP['colors']=pow(2,$BMP['bits_per_pixel']);            if($BMP['size_bitmap']==0)$BMP['size_bitmap']=$FILE['file_size']-$FILE['bitmap_offset'];            $BMP['bytes_per_pixel']=$BMP['bits_per_pixel']/8;            $BMP['bytes_per_pixel2']=ceil($BMP['bytes_per_pixel']);            $BMP['decal']=($BMP['width']*$BMP['bytes_per_pixel']/4);            $BMP['decal']-=floor($BMP['width']*$BMP['bytes_per_pixel']/4);            $BMP['decal']=4-(4*$BMP['decal']);            if($BMP['decal']==4)$BMP['decal']=0;            $PALETTE=array();            if($BMP['colors']<16777216)            {                $PALETTE=unpack('V'.$BMP['colors'],fread($f1,$BMP['colors']*4));            }            $IMG=fread($f1,$BMP['size_bitmap']);            $VIDE=chr(0);            $res=imagecreatetruecolor($BMP['width'],$BMP['height']);            $P=0;            $Y=$BMP['height']-1;            while($Y>=0)            {                $X=0;                while($X<$BMP['width'])                {                    if($BMP['bits_per_pixel']==24)                        $COLOR=unpack("V",substr($IMG,$P,3).$VIDE);                    elseif($BMP['bits_per_pixel']==16)                    {                        $COLOR=unpack("n",substr($IMG,$P,2));                        $COLOR[1]=$PALETTE[$COLOR[1]+1];                    }                    elseif($BMP['bits_per_pixel']==8)                    {                        $COLOR=unpack("n",$VIDE.substr($IMG,$P,1));                        $COLOR[1]=$PALETTE[$COLOR[1]+1];                    }                    elseif($BMP['bits_per_pixel']==4)                    {                        $COLOR=unpack("n",$VIDE.substr($IMG,floor($P),1));                        if(($P*2)%2==0)$COLOR[1]=($COLOR[1]>>4);else$COLOR[1]=($COLOR[1]&0x0F);                        $COLOR[1]=$PALETTE[$COLOR[1]+1];                    }                    elseif($BMP['bits_per_pixel']==1)                    {                        $COLOR=unpack("n",$VIDE.substr($IMG,floor($P),1));                        if(($P*8)%8==0)$COLOR[1]=$COLOR[1]>>7;                        elseif(($P*8)%8==1)$COLOR[1]=($COLOR[1]&0x40)>>6;                        elseif(($P*8)%8==2)$COLOR[1]=($COLOR[1]&0x20)>>5;                        elseif(($P*8)%8==3)$COLOR[1]=($COLOR[1]&0x10)>>4;                        elseif(($P*8)%8==4)$COLOR[1]=($COLOR[1]&0x8)>>3;                        elseif(($P*8)%8==5)$COLOR[1]=($COLOR[1]&0x4)>>2;                        elseif(($P*8)%8==6)$COLOR[1]=($COLOR[1]&0x2)>>1;                        elseif(($P*8)%8==7)$COLOR[1]=($COLOR[1]&0x1);                        $COLOR[1]=$PALETTE[$COLOR[1]+1];                    }                    else                        returnFALSE;                    imagesetpixel($res,$X,$Y,$COLOR[1]);                    $X++;                    $P+=$BMP['bytes_per_pixel'];                }                $Y--;                $P+=$BMP['decal'];            }            fclose($f1);            return$res;        }             }

使用方法很簡單代碼如下：

$resizeimage=new ResizeImage('upload/abc.bmp', '120', '90', '0', 'upload/xabc.bmp');

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