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这篇文章主要讲解了“PHP怎么生成等比缩略图类和自定义函数”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“PHP怎么生成等比缩略图类和自定义函数”吧！
共有两种等比例缩略图方法可以借鉴
一、为类文件，实例化之后即可使用
二、为自定义方法，比较轻巧
类文件
复制代码 代码如下:
$resizeimage = new resizeimage("./shawn.jpg", "200", "100", "0","../pic/shawnsun.jpg");
//实例化下面的类,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，第四个参数为可选 0不截图，1为截图
复制代码 代码如下:
class resizeimage{
//图片类型
public $type;
//实际宽度
public $width;
//实际高度
public $height;
//改变后的宽度
public $resize_width;
//改变后的高度
public $resize_height;
//是否裁图
public $cut;
//源图象
public $srcimg;
//目标图象地址
public $dstimg;
//临时创建的图象
public $im;
function resizeimage($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);
//W & H
$this->width = imagesx($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 $this->dstimg;
}
}
?>
自定义方法
复制代码 代码如下:
thumbs('shawn.jpg','shawnsun.jpg',100,100);
//参数属性类似于方法一
复制代码 代码如下:
function thumbs($FileName,$SaveTo,$SetW,$SetH){
$IMGInfo= getimagesize($FileName);
if(!$IMGInfo) return false;
if($IMGInfo['mime']== "image/pjpeg" || $IMGInfo['mime']=="image/jpeg"){
$ThisPhoto= imagecreatefromjpeg($FileName);
}elseif($IMGInfo['mime']== "image/x-png" || $IMGInfo['mime']== "image/png"){
$ThisPhoto= imagecreatefrompng($FileName);
}elseif($IMGInfo['mime']== "image/gif"){
$ThisPhoto=imagecreatefromgif($FileName);
}
$width=$IMGInfo[0];
$height=$IMGInfo[1];
$scalc = max($width/$SetW,$height/$SetH);
$nw = intval($width/$scalc);
$nh = intval($height/$scalc);
echo "缩略大小：w$nw,h$nh
";
if($SetW-$nw == 1){$nw = $SetW;}
if($SetH-$nh == 1){$nh = $SetH;}
echo "+修正1像素： w$nw,h$nh
";
//补宽
if($SetW-$nw > 0){
$nh = $nh +(($nh/$nw) * ($SetW-$nw));
echo "*需补宽".($SetW-$nw).",陪补高".(($nh/$nw) * ($SetW-$nw))."
";
$nw = $SetW;
}
//补高
if($SetH-$nh > 0){
$nw = $nw + (($nw/$nh) * ($SetH-$nh));
echo "*需补高".($SetH-$nh).",陪补宽". (($nw/$nh) * ($SetH-$nh)) ."
";
$nh = $SetH;
}
$nw = intval($nw);
$nh = intval($nh);
echo "+修正大小：w$nw,h$nh
";
$px = ($SetW - $nw)/2;
$py = ($SetH - $nh)/2;
echo "窗口大小：w$SetW,h$SetH
";
echo "+偏移修正：x$px,y$py
";
$NewPhoto=imagecreatetruecolor($SetW,$SetH);
imagecopyresized($NewPhoto,$ThisPhoto,$px,$py,0,0,$nw,$nh,$width,$height);
ImageJpeg ($NewPhoto,$SaveTo);
return true;
}
?>
感谢各位的阅读，以上就是“PHP怎么生成等比缩略图类和自定义函数”的内容了，经过本文的学习后，相信大家对PHP怎么生成等比缩略图类和自定义函数这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是创新互联网站建设公司，，小编将为大家推送更多相关知识点的文章，欢迎关注！
