PHP生成图片缩略图

要使用PHP生成图片缩略图,要保证你的PHP服务器安装了GD2图形库

使用一个类生成图片的缩略图,类的源码见下文

调用此类的方法:

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

//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

//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

{

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;

}

}

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