PHP开发:生成图片缩略图类（支持常用图片格式）

/**
 * 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;
	    }
	    
	}
?>