php图片缩放代码-按比例缩放或截取指定大小的缩略图 非常好用的一个方法
/**********************************************************
* function resize:
*
* = creates a resized image based on the max width
* specified as well as generates a thumbnail from
* a rectangle cut from the middle of the image.
*
* @dir = directory image is stored in
* @newdir = directory new image will be stored in
* @img = the image name
* @newimg = the image new name
* @max_w = the max width of the resized image
* @max_h = the max height of the resized image
* @th_x = The starting point of the x-coordinate
* @th_y = The starting point of the y-coordinate
* @th_w = the width of the thumbnail
* @th_h = the height of the thumbnail
* @cut = Whether to need cut out
* @center = whether cut from the middle of the image
*
**********************************************************/
function resize($dir, $newdir, $img, $newimg, $max_w, $max_h, $th_x = '', $th_y = '', $th_w = '', $th_h = '',$cut = FALSE,$center = FALSE)
{
// set destination directory
if (!$newdir) $newdir = $dir;
if (!$newimg) $newimg = $img;
// get original images width and height
list($or_w, $or_h, $or_t) = getimagesize($dir.$img);
switch($or_t){
// original image
case 1:
$or_image = imagecreatefromgif($dir.$img);
break;
case 2:
$or_image = imagecreatefromjpeg($dir.$img);
break;
case 3:
$or_image = imagecreatefrompng($dir.$img);
break;
default:
return '不支持的图像格式'; www.zzzyk.com
break;
}
// make sure image is a jpeg
// if ($or_t == 2) {
// obtain the image's ratio
// $ratio = ($or_h / $or_w);
$ratio = ($max_h / $max_w);
// original image
// $or_image = imagecreatefromjpeg($dir.$img);
// resize image?
if ($or_w > $max_w || $or_h > $max_h) {
// resize by height, then width (height dominant)
if ($max_h < $max_w) {
$rs_h = $max_h;
$rs_w = $rs_h / $ratio;
}
// resize by width, then height (width dominant)
else {
$rs_w = $max_w;
$rs_h = $ratio * $rs_w;
}
// copy old image to new image
$rs_image = imagecreatetruecolor($rs_w, $rs_h);
imagecopyresampled($rs_image, $or_image, 0, 0, 0, 0, $rs_w, $rs_h, $or_w, $or_h);
}
// image requires no resizing
else {
$rs_w = $or_w;
$rs_h = $or_h;
$rs_image = $or_image;
}
// generate resized image
DrawImage($rs_image, $newdir.$newimg,$or_t,100);
//裁剪生成指定的大小start-------------------
if ($cut){
$th_image = imagecreatetruecolor($th_w, $th_h);
// cut out a rectangle from the resized image and store in thumbnail
if ($center){
$new_w = (($rs_w / 2) - ($th_w / 2));
$new_h = (($rs_h / 2) - ($th_h / 2));
}else {
$new_w = $th_x;
$new_h = $th_y;
}
imagecopyresampled($th_image, $rs_image, 0, 0, $new_w, $new_h, $rs_w, $rs_h, $rs_w, $rs_h);
// generate thumbnail
&
补充：Web开发 , php ,
