我正在编写一个裁剪图像的脚本。它正在研究jpg。但是有没有办法让它适用于各种文件类型（bmp、png、gif），而无需通过各种 if 子句？
//create the crop
// Original image
$filename = 'uploads/'.$image_name;
$endname = 'uploads/thumbnails/'.$image_name;
// Get dimensions of the original image
list($current_width, $current_height) = getimagesize($filename);
// The x and y coordinates on the original image where we
// will begin cropping the image
$left = 0;
$top = 0;
// This will be the final size of the image (e.g. how many pixels
// left and down we will be going)
$crop_width = 200;
$crop_height = 200;
// Resample the image
$canvas = imagecreatetruecolor($crop_width, $crop_height);
$current_image = imagecreatefromjpeg($filename);
imagecopy($canvas, $current_image, 0, 0, $left, $top, $crop_width, $crop_height);
imagejpeg($canvas, $endname, 100);
我尝试用imagecreate替换imcreatefromjpeg，但这不起作用。
imagecreatefromstring自动检测文件类型，但它需要图像数据作为字符串，但您可以随时这样做
$current_image = imagecreatefromstring(file_get_contents($filename));
scr - 用于源文件 dest - 用于生成的文件
$size = getimagesize($src);
// Detect file format from MIME-information, detected by getimagesize() function
// And select proper imagecreatefrom()-function.
$format = strtolower(substr($size['mime'], strpos($size['mime'], '/')+1));
$icfunc = "imagecreatefrom" . $format;
if (!function_exists($icfunc)){
echo "Function $icfunc doesn't exists!");
}
//Here is the magic: We call function, which name is value of variable
$isrc = $icfunc($src);
// Create new img
$idest = imagecreatetruecolor($width_dest, $height_dest);
// Copy src img to dest img with resizing
imagecopyresampled(
$idest, $isrc, // dest & src img ident
0,0, // dest img (x,y) top left corner
0,0, // src img (x,y) top left corner
$width_dest, $height_dest,
$width_src, $height_src
);