基于GD2图形库的PHP生成图片缩略图类代码分享

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$resizeimage = new resizeimage("图片源文件地址", "200", "100", "0","缩略图地址");

//就只用上面的一句话,就能生成缩略图,其中,源文件和缩略图地址可以相同,200,100分别代表宽和高

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//使用如下类就可以生成图片缩略图,

class resizeimage

{

//图片类型

var $type;

//实际宽度

var $width;

//实际高度

var $height;

//改变后的宽度

var $resize_width;

//改变后的高度

var $resize_height;

//是否裁图

var $cut;

//源图象

var $srcimg;

//目标图象地址

var $dstimg;

//临时创建的图象

var $im;

function resizeimage($img, $wid, $hei,$c,$dstpath)

{

$this->srcimg = $img;

$this->resize_width = $wid;

$this->resize_height = $hei;

$this->cut = $c;

//图片的类型

$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));

//初始化图象

$this->initi_img();

//目标图象地址

$this -> dst_img($dstpath);

//--

$this->width = imagesx($this->im);

$this->height = imagesy($this->im);

//生成图象

$this->newimg();

ImageDestroy ($this->im);

}

function newimg()

{

//改变后的图象的比例

$resize_ratio = ($this->resize_width)/($this->resize_height);

//实际图象的比例

$ratio = ($this->width)/($this->height);

if(($this->cut)=="1")

//裁图

{

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);

}

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);

}

}

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);

}

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);

}

}

}

//初始化图象

function initi_img()

{

if($this->type=="jpg")

{

$this->im = imagecreatefromjpeg($this->srcimg);

}

if($this->type=="gif")

{

$this->im = imagecreatefromgif($this->srcimg);

}

if($this->type=="png")

{

$this->im = imagecreatefrompng($this->srcimg);

}

}

//图象目标地址

function dst_img($dstpath)

{

$full_length = strlen($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;

}

}