php生成圖片縮略圖類（支持常用圖片格式）
功能：支持jpg,jpeg,gif,png,bmp圖片格式，支持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，加入了圖片質量控制，可以實現縮略圖片質量最高化。完整類的代碼如下：
<?php /**
功能：php生成縮略圖片的類 */ class ResizeImage{
public $type;//圖片類型 public $width;//實際寬度 public $height;//實際高度 public $resize_width;//改變后的寬度 public $resize_height;//改變后的高度 public $cut;//是否裁圖 public $srcimg;//源圖象 public $dstimg;//目標圖象地址 public $im;//臨時創建的圖象 public $quality;//圖片質量 function resizeimage($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));//圖片的類型 $this->initi_img();//初始化圖象 $this -> dst_img($dstpath);//目標圖象地址 @$this->width=imagesx($this->im); @$this->height=imagesy($this->im); $this->newimg();//生成圖象 @ImageDestroy($this->im); } function newimg(){ $resize_ratio=($this->resize_width)/($this->resize_height);//改變后的圖象的比例 @$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版本大于5.12參數變化后的處理情況 $quality=9; } if($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){ //自定義函數處理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; }} ?></pre>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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