(PHP 4 >= 4.0.7, PHP 5, PHP 7)
imagegd2 — Output GD2 image to browser or file
$image
[, string $filename
[, int $chunk_size
[, int $type = IMG_GD2_RAW
]]] )
Outputs a GD2 image to the given filename.
imageAn image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
filenameThe path to save the file to. If not set or NULL, the raw image stream will be outputted directly.
chunk_sizeChunk size.
type
Either IMG_GD2_RAW or
IMG_GD2_COMPRESSED. Default is
IMG_GD2_RAW.
Returns TRUE on success or FALSE on failure.
Example #1 Outputting a GD2 image
<?php
// Create a blank image and add some text
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);
// Output the image
imagegd2($im);
// Free up memory
imagedestroy($im);
?>
Example #2 Saving a GD2 image
<?php
// Create a blank image and add some text
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);
// Save the gd2 image
// The file format for GD2 images is .gd2, see http://www.libgd.org/GdFileFormats
imagegd2($im, 'simple.gd2');
// Free up memory
imagedestroy($im);
?>
Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).
Note:
The GD2 format is commonly used to allow fast loading of parts of images. Note that the GD2 format is only usable in GD2-compatible applications.
You can use this function in combination with imagecreatefromstring() to clone the gd resource with minimum fuss (no writing to tmp file):
<?php
function cloneGd($gd)
{
ob_start();
imagegd2($gd);
return imagecreatefromstring(ob_get_clean());
}
?>
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
