使用（并保存）各种图像文件类型？

Question

我正在研究用于裁剪图像的脚本。 正在处理jpgs。 但是有没有一种方法可以将其应用于各种文件类型（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 ，但是没有用。

Answer 1

imagecreatefromstring自动检测文件类型，但是它需要图像数据作为字符串，但是您始终可以

$current_image = imagecreatefromstring(file_get_contents($filename));

Answer 2

scr用于源文件dest用于结果文件

     $size = getimagesize($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
);