yes, the gd2 file format does improve the speed of image creations as the data-setup is designed to be native for the GD function - ie, the image doesn't have to be converted to a usable format prior to processing.
you may also note that the newer gd2 format creates much smaller size files than the older imagegd function, certainly for images involving chunks of single colours anyway. you'll probably find this function most useful for saving overlay images or background images used in larger image creation scripts.
to read a ping or jpeg image (.png / .jpg) and save a .gd2 version to server...
$img = $_GET['img'];
if(file_exists($img))
{
$dim = getimagesize($img);
$cr = ($dim[2] < 4) ? ($dim[2] < 3) ? ($dim[2] < 2) ? NULL : imagecreatefromjpeg($img) : imagecreatefrompng($img) : Null;
if($cr !== NULL)
{
imagegd2($cr,substr($img,0,strrpos($img,'.')).'.gd2');
}
}
should save a copy with the same filename and directory using extension .gd2 - which can then be nicely and swiftly read using either imagecreatefromgd2 or imagecreatefromgd2part
imagegd2
说明
bool imagegd2 ( resource image [, string filename [, int chunk_size [, int type]]] )imagegd2() 将一个 GD 图像输出到 filename。image 参数是由 imagecreatetruecolor() 函数返回的。
filename 参数为可选项，如果为空，则原始图像流会被直接输出。
可选的 type 参数可以是 IMG_GD2_RAW 或 IMG_GD2_COMPRESSED。默认为 IMG_GD2_RAW。
注: 可选的 chunk_size 和 type 参数自 PHP 4.3.2 起可用。
注: GD2 格式一般是用来加载图像中的一部分时更快。注意 GD2 格式只能用于兼容于 GD2 的应用程序。
注: 本函数需要 GD 2.0.1 或更高版本。
参见 imagegd()。
add a note
User Contributed Notes
mark at teckis dot com
16-Apr-2003 09:33
16-Apr-2003 09:33
mysterium at gmx _spamsux_ dot ch
11-Feb-2003 06:35
11-Feb-2003 06:35
A little more information: http://www.boutell.com/gd/manual2.0.11.html#gdImageGd2
For me, the gd2 format is intended for faster loading and writing. I didn't test this yet.