imagegd2

(PHP 4 >= 4.0.7, PHP 5, PHP 7, PHP 8)

imagegd2 — Output GD2 image to browser or file

Description

imagegd2(
    GdImage $image,
    ?string $file = null,
    int $chunk_size = 128,
    int $mode = IMG_GD2_RAW
): bool

Outputs a GD2 image to the given file.

Parameters

image: A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().
file: The path or an open stream resource (which is automatically closed after this function returns) to save the file to. If not set or null, the raw image stream will be output directly.
chunk_size: Chunk size.
mode: Either IMG_GD2_RAW or IMG_GD2_COMPRESSED. Default is IMG_GD2_RAW.

Return Values

Returns true on success or false on failure.

Caution

However, if libgd fails to output the image, this function returns true.

Changelog

Version	Description
8.0.3	`file` is now nullable.
8.0.0	`image` expects a GdImage instance now; previously, a valid `gd` resource was expected.

Examples

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);
?>

Notes

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.

Warning

The GD and GD2 image formats are proprietary image formats of libgd. They have to be regarded obsolete, and should only be used for development and testing purposes.

User Contributed Notes 2 notes

down

Nick ¶

13 years ago


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());
}
?>

down

mark at teckis dot com ¶

21 years ago


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

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