php生成图片缩略图类(支持常用图片格式)

jopen 7年前

功能:支持jpg,jpeg,gif,png,bmp图片格式,支持按原图片的比例进行缩放,可以选择在图片缩放的过程中是否需要对图片进行裁切,加入了图片质量控制,可以实现缩略图片质量最高化。完整类的代码如下:

<?php  /**   * 功能:php生成缩略图片的类   */   class ResizeImage{       public $type;//图片类型       public $width;//实际宽度       public $height;//实际高度       public $resize_width;//改变后的宽度       public $resize_height;//改变后的高度       public $cut;//是否裁图       public $srcimg;//源图象         public $dstimg;//目标图象地址       public $im;//临时创建的图象    public $quality;//图片质量       function resizeimage($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));//图片的类型           $this->initi_img();//初始化图象           $this -> dst_img($dstpath);//目标图象地址           @$this->width=imagesx($this->im);           @$this->height=imagesy($this->im);           $this->newimg();//生成图象           @ImageDestroy($this->im);       }       function newimg(){           $resize_ratio=($this->resize_width)/($this->resize_height);//改变后的图象的比例           @$ratio=($this->width)/($this->height);//实际图象的比例           if(($this->cut)=='1'){//裁图      if($img_func==='imagepng'&&(str_replace('.','',PHP_VERSION)>=512)){ //针对php版本大于5.12参数变化后的处理情况       $quality=9;      }               if($ratio>=$resize_ratio){//高度优先                   $newimg=imagecreatetruecolor($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){//宽度优先                   $newimg=imagecreatetruecolor($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,$this->quality);               }           }else{//不裁图               if($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(){//初始化图象           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){//图象目标地址           $full_length=strlen($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){ //自定义函数处理bmp图片        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;       }          }  ?>
使用方法很简单代码如下:
$resizeimage=new ResizeImage('upload/abc.bmp', '120', '90', '0', 'upload/xabc.bmp');