php生成图片缩略图类

​php生成图片缩略图类（支持常用图片格式）

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：

/**
 * 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,$this->quality);
                }
                if($ratioresize_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($ratioresize_height)*$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']=0)
            {
                $X=0;
                while($X>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');