使用（和保存）各种图像文件类型？答案

【问题标题】：Working with (and saving) various image filetypes?使用（和保存）各种图像文件类型？
【发布时间】：2012-05-24 18:36:42
【问题描述】：

我正在编写一个用于裁剪图像的脚本。它正在处理jpgs。但是有没有办法让它适用于各种文件类型（bmp、png、gif）而不通过各种 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，但没有奏效。

【问题讨论】：

您可能需要考虑为此目的使用ImageMagick - 它比 GD2 灵活得多。

标签： php image crop

【解决方案1】：

imagecreatefromstring 自动检测文件类型，但它需要图像数据作为字符串，但你总是可以这样做

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

【讨论】：

【解决方案2】：

scr - 用于您的源文件 dest - 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
);

【讨论】：