Learn how to create thumbnail images on the fly using PHP. Furthermore you will learn how to process a whole folder of images and create their thumbnails. Since this requires the GD library, you will need an installation of PHP with at least GD 2.0.1 enabled.
Creating images on the fly can be a very useful skill. PHP has some built-in image generation functions, further more, to generate new images or edit existing images on the fly using PHP, we need to have the GD library installed. In this tutorial we will show you how to get quite interesting and useful effects using image handling functions. We will review two practical tasks: creating security images (captcha) on the fly and building a bar chart using numerical values retrieved from MySQL database.
Image rotation in PHP is handled by a function called imagerotate(), which takes three parameters (and optionally a fourth, which deals with transparency and is beyond the scope of this guide). The first is the resource identifier which you obtain when you load the original image within your script, the second is the angle which you want to rotate the image and the third parameter is used when the image isn't going to be rectangular, and specifies the colour with which to fill the uncovered areas of the rotated image to make it into a rectangle (since all image formats require rectangular images).
This article will tell you how to write text on an existing PNG image using PHP using PHP's image manipulation functions. The image functions require the GD library to be installed. This article is fairly basic, however some more detail on the basic functions used is included in the article, "write text on a dynamically generated image in PHP"
First, we need the source image. In this example, we're using an image called image.png (with dimension 150x150, though this code will work with any size of image) which is shown below:
This tutorial will tell you how to write text to a blank dynamically generated PNG image in PHP. This is fairly simple, so it will just be the first step in a series of tutorials dealing with images in PHP. The image functions require the GD library to be installed.
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