生成缩略图是当我们要上传图片时如果图片较大我们需要生成一张指定大小的小图以在列表页面显示，这样可节省资源也是现在常用的做法，下面我来分享一个php生成缩略图类，支持自定义高和宽。还支持按高和宽截图
代码如下 复制代码
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;
}
}
$resizeimage = new resizeimage(11.jpg, 200, 150, 1,17.jpg);
?>
实例二
代码如下 复制代码
$src_w && $height> $src_h) || ($height> $src_h && $width == 0) || ($width> $src_w && $height == 0))
{
$proportion = 1;
}
if($width> $src_w)
{
$dst_w = $width = $src_w;
}
if($height> $src_h)
{
$dst_h = $height = $src_h;
}
if(!$width && !$height && !$proportion)
{
return false;
}
if(!$proportion)
{
if($cut == 0)
{
if($dst_w && $dst_h)
{
if($dst_w/$src_w> $dst_h/$src_h)
{
$dst_w = $src_w * ($dst_h / $src_h);
$x = 0 - ($dst_w - $width) / 2;
}
else
{
$dst_h = $src_h * ($dst_w / $src_w);
$y = 0 - ($dst_h - $height) / 2;
}
}
else if($dst_w xor $dst_h)
{
if($dst_w && !$dst_h) //有宽无高
{
$propor = $dst_w / $src_w;
$height = $dst_h = $src_h * $propor;
}
else if(!$dst_w && $dst_h) //有高无宽
{
$propor = $dst_h / $src_h;
$width = $dst_w = $src_w * $propor;
}
}
}
else
{
if(!$dst_h) //裁剪时无高
{
$height = $dst_h = $dst_w;
}
if(!$dst_w) //裁剪时无宽
{
$width = $dst_w = $dst_h;
}
$propor = min(max($dst_w / $src_w, $dst_h / $src_h), 1);
$dst_w = (int)round($src_w * $propor);
$dst_h = (int)round($src_h * $propor);
$x = ($width - $dst_w) / 2;
$y = ($height - $dst_h) / 2;
}
}
else
{
$proportion = min($proportion, 1);
$height = $dst_h = $src_h * $proportion;
$width = $dst_w = $src_w * $proportion;
}
$src = $createfun($src_img);
$dst = imagecreatetruecolor($width ? $width : $dst_w, $height ? $height : $dst_h);
$white = imagecolorallocate($dst, 255, 255, 255);
imagefill($dst, 0, 0, $white);
if(function_exists('imagecopyresampled'))
{
imagecopyresampled($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
}
else
{
imagecopyresized($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
}
$otfunc($dst, $dst_img);
imagedestroy($dst);
imagedestroy($src);
return true;
}
使用方法
代码如下 复制代码
$src_img = ./rosi_050_002.jpg;
$dst_img = ./rosi_050_002_thumb.jpg;
$stat = img2thumb($src_img, $dst_img, $width = 200, $height = 300, $cut = 0, $proportion = 0);
if($stat){
echo 'resize image success!
';
echo '';
}else{
echo 'resize image fail!';
}
http://www.bkjia.com/phpjc/632963.htmlwww.bkjia.comtruehttp://www.bkjia.com/phpjc/632963.htmltecharticle生成缩略图是当我们要上传图片时如果图片较大我们需要生成一张指定大小的小图以在列表页面显示，这样可节省资源也是现在常用的做法...