使用此img_resize
功能,它适用于最流行的图像格式
function img_resize($src, $dest, $width, $height, $rgb = 0xFFFFFF, $quality = 100)
{
if (!file_exists($src))
return false;
$size = getimagesize($src);
if ($size === false)
return false;
$format = strtolower(substr($size['mime'], strpos($size['mime'], '/') + 1));
$icfunc = "imagecreatefrom" . $format;
if (!function_exists($icfunc))
return false;
$x_ratio = $width / $size[0];
$y_ratio = $height / $size[1];
$ratio = min($x_ratio, $y_ratio);
$use_x_ratio = ($x_ratio == $ratio);
$new_width = $use_x_ratio ? $width : floor($size[0] * $ratio);
$new_height = !$use_x_ratio ? $height : floor($size[1] * $ratio);
$new_left = $use_x_ratio ? 0 : floor(($width - $new_width) / 2);
$new_top = !$use_x_ratio ? 0 : floor(($height - $new_height) / 2);
$isrc = $icfunc($src);
$idest = imagecreatetruecolor($width, $height);
imagefill($idest, 0, 0, $rgb);
if (($format == 'gif') or ($format == 'png')) {
imagealphablending($idest, false);
imagesavealpha($idest, true);
}
if ($format == 'gif') {
$transparent = imagecolorallocatealpha($idest, 255, 255, 255, 127);
imagefilledrectangle($idest, 0, 0, $width, $height, $transparent);
imagecolortransparent($idest, $transparent);
}
imagecopyresampled($idest, $isrc, $new_left, $new_top, 0, 0, $new_width, $new_height, $size[0], $size[1]);
getResultImage($idest, $dest, $size['mime']);
imagedestroy($isrc);
imagedestroy($idest);
return true;
}
function getResultImage($dst_r, $dest_path, $type)
{
switch ($type) {
case 'image/jpg':
case 'image/jpeg':
case 'image/pjpeg':
return imagejpeg($dst_r, $dest_path, 90);
break;
case 'image/png';
return imagepng($dst_r, $dest_path, 2);
break;
case 'image/gif';
return imagegif($dst_r, $dest_path);
break;
default:
return;
}
}