What is the GD library in PHP and how to enable it

1.What is GD library?

GD libraryis an extension library forPHPto process graphics. The GD library provides a series ofAPI# for processing images. ##, useGD libraryto process images or generate images. On websites,GD libraryis usually used to generate thumbnails or to add watermarks to images or to generate reports on website data. Cloud virtual host (Linuxoperating system) currently supports the GD library and supportsJPG, GIF, PNG, WBMPformat files. Specific supportedGDversion Since the selectedPHPversion is different, the supportedGDversion is also different.

Using the

library inPHPcan draw various graphic images and statistical charts on the page, if used withAjaxThe combination of technologies can also produce a variety of powerful dynamic charts. There is also the verification code used in the website login page, which can also be implemented using theGDlibrary. It should be noted that the GD library initially supported the GIF format, but because GIF used the copyright-controversialLZW algorithm, it would cause legal issues, so starting from GD library version 1.6, all GIF support Removed, but added back in GD library version 2.0.28. If a version of the GD library between the two is used, theGIFrelated functions are not available.

is installed by default inPHP5and above versions. If you are using a lower version, you can clickDownload address.If you cannot confirm whether you have activated the GD library, you can search for extension = php_gd2.dll in php.in and delete the previous ";".

## Verify whetherGD library

As shown above,GD library

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