php实现图片缩略图的方法
程序员文章站
2024-04-01 23:24:16
本段代码实现功能有这些:
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...
本段代码实现功能有这些:
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');
以上代码是小编给大家分享的php实现图片缩略图的方法,希望对大家有所帮助!
上一篇: Yii核心验证器api详解
下一篇: 23种设计模式(1) java单例模式