Вот небольшой набор функций, которые позволяют обрабатывать и создавать эскизы легко в PHP. если изображение представляет собой прямоугольник, он срезается центром и обрезается соответствующим образом.
функция подписи
function square_thumbs(string $input_name,array $data_source, array $sizes,int $min_width,$int $min_height)
Возвращаемое значение
возвращает массив имен файлов для создаваемых миниатюр в одном порядке, как $ размеры массивов
Пример использования
list($small,$medium,$large) = square_thumbs('image_file',$_FILES,[60,150,300],120,120);
полный код
function square_thumbs($img_name,$files,$sizes = [60,220,800],$min_width=120,$min_height=120)
{
if(empty($files) || !isset($files[$img_name])){
throw new \exception('You must select an image!');
}
if($files[$img_name]['error'])
{
throw new exception(upload_errors($files[$img_name]['error']));
}
$image_temp = $files[$img_name]['tmp_name'];
@$image_info = getimagesize($image_temp);
$exif = [IMAGETYPE_GIF,IMAGETYPE_JPEG,IMAGETYPE_PNG];
$finfo = ['image/gif','image/png','image/jpeg','image/pjpeg'];
$etype = exif_imagetype($image_temp);
if(!function_exists('finfo_file')){
throw new exception('Unable to determine image mime type.');
}
$type = finfo_file(finfo_open(FILEINFO_MIME_TYPE),$image_temp);
if(!is_uploaded_file($files[$img_name]['tmp_name'])){
throw new exception('bad file input');
}
if(!in_array($etype,$exif) || !in_array($type,$finfo)){
throw new exception('file type not allowed');
}
switch($type){
case 'image/gif':
$type2 = 'gif';
break;
case 'image/png':
$type2 = 'png';
break;
case 'image/jpeg':
case 'image/jpg':
case 'image/pjpeg':
$type2 = 'jpg';
break;
}
if(!$image_info){
throw new exception('invalid image size.');
}
//get the image resource
$image = imagecreatefromstring(file_get_contents($image_temp));
$width = $image_info[0];
$height = $image_info[1];
if($width < $min_width || $height < $min_height){
throw new exception('Images must be atleast '.$min_width.' x '.$min_height.' in size.');
}
//ill admit this code is smelly, but do you have a better idea? lol
if($width != $height){
list($size,$image) = square_img($image,$width,$height);
$width = $height = $size;
}
$size = $width;
//now we have a square image and our image size is updated to reflect this change.
$res = [];
foreach($sizes as $z)
{
$t = imagecreatetruecolor($z,$z);
ob_start();
switch($type){
case 'image/gif':
imagecopyresampled($t,$image,0,0,0,0,$z,$z,$size,$size);
imagegif($t);
break;
case 'image/png':
imagesavealpha($t, true);
$trans_colour = imagecolorallocatealpha($t, 0, 0, 0, 127);
imagefill($t, 0, 0, $trans_colour);
imagecopyresampled($t,$image,0,0,0,0,$z,$z,$size,$size);
imagepng($t,NULL,2); //lossless compression minimal (default is 6)
break;
case 'image/jpeg':
case 'image/jpg':
case 'image/pjpeg':
imagecopyresampled($t,$image,0,0,0,0,$z,$z,$size,$size);
imagejpeg($t,NULL,100); //100% quality (default is 75%)
break;
}
$result_image = ob_get_clean(); //stores the image content as string.
$file_name = md5($result_image).'.'.$type2; //we can create a random distinct file name by md5ing the data and appending the file extension which is stored in $type2 variable.
$res[] = store_image($result_image,$file_name); //store name of the resultant file in result array
}
return $res; //after all the thumbs have been generated, return them all in an array.
}
//calculates the nearest square size of the image
function square_img($image,$width,$height)
{
//horizontal rectangle
if ($width > $height) {
$square = $height; // $square: square side length
$offsetX = ($width - $height)/2; // x offset based on the rectangle
$offsetY = 0; // y offset based on the rectangle
}
// vertical rectangle
elseif ($height > $width) {
$square = $width;
$offsetX = 0;
$offsetY = ($height - $width)/2;
}
$t = imagecreatetruecolor($square,$square);
imagecopyresampled($t, $image, 0, 0, $offsetX, $offsetY, $square, $square, $square, $square);
return [$square,$t];
}
//handle some common upload errors
function upload_errors($err_code) {
switch ($err_code) {
case UPLOAD_ERR_INI_SIZE:
return 'The uploaded file exceeds the upload_max_filesize directive in php.ini';
case UPLOAD_ERR_FORM_SIZE:
return 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form';
case UPLOAD_ERR_PARTIAL:
return 'The uploaded file was only partially uploaded';
case UPLOAD_ERR_NO_FILE:
return 'No file was uploaded';
case UPLOAD_ERR_NO_TMP_DIR:
return 'Missing a temporary folder';
case UPLOAD_ERR_CANT_WRITE:
return 'Failed to write file to disk';
case UPLOAD_ERR_EXTENSION:
return 'File upload stopped by extension';
default:
return 'Unknown upload error';
}
}
//stores the resultant image.
function store_image($image_data,$file_name,$path='')
{
//this is just a basic implementation of storing some data into a file.
$t = fopen($path.$file_name,'w+');
fwrite($t,$image_data);
fclose($t);
return $file_name;
}