A free, simple, tunable grayscale function for dynamic image conversion using PHP and the gd library
February 17, 2008
Looking for a simple, tunable grayscale function, one you - or your web site's visitors - can use to dynamically generate grayscale images? Look no further. The following images were all generated from the first, using PHP with the gd graphics library, and Ars Informatica's AI_grayscale() function:
And it's as easy as
... or easier. [ Read more ... ]
Checking for and installing the gd Graphics Library
February 12, 2008
The gd graphics library is open source code for the dynamic creation and manipulation of images that load in real-time in a client's browser. It is part of a standard PHP install - but do you have it? is it active? Today's article tells you how to check for it, how to install and enable this functionality.
We also present a light-weight, nicer, neater gd_info function: one that displays which gd version is installed, what image formats are supported, etc. Output is clean, legible, and easily understood.
[ Read more ... ]
Find the perfect image: 2,500,000 royalty-free stock photographs
July 16, 2007
You need an image - that perfect image - for whatever reason. You know you don't have it. And you need it, well, by yesterday.
Google Images or other Search Engines don't turn up the image you want - and these images aren't yours to begin with. They're copyrighted; you can't just borrow them.
Fortunately, that perfect image is available. Often for free, or for a very nominal fee. Royalty-free stock image sites provide a wealth of images, usable under a variety of licenses. Our three favorite stock image sites host over 2,500,000 images between them, and you're likely to find what you need within minutes.
Image creation and manipulation using the gd Graphics Library
April 1, 2006
The gd Graphics Library is an open source code library use to create and manipulate PNG, JPEG and GIF images. Part of the standard PHP installation, it is available with most MySQL/PHP web hosting packages - if it isn't already available to you, ask for it!
GD is used to dynamically produce charts, graphics, thumbnails, etc., usually by web sites, though it can be incorporated into other programming projects. Create animated GIFs, add FreeType and TrueType text, draw complex graphics, or convert from one image format to another.
GD isn't difficult, but you can't just call a grayscale() function, either. It takes some work. We help you out. [ Read more ... ]
Image creation, conversion and manipulation with ImageMagick
March 26, 2006
ImageMagick consists of a set of powerful, open-source (free!) routines used to create and edit images. These can be called directly, i.e. by web pages, batch programs, software you're writing, or via the appropriate interface for your platform. ImageMagick is available for all major operating systems.
ImageMagick handles over 90 formats, including GIF, JPEG, JPEG-2000, PNG, PDF, PhotoCD and TIFF. Crop, resize, stretch, rotate; sharpen, color-reduce your palette, make the image transparent, or sepia-tone it. Merge images or combine them into an animated GIF. Add text, lines, polygons, ellipses and BΘzier curves.
Of course, nothing is perfect. The number of options are overwhelming: it's almost impossible to visualize the enormous range of possibilities these routines offer. Complex commands take time to craft. And my web hosting service no longer permits the PHP exec() command - it can open the door for crackers. If they can upload one .php file, they can destroy your system. [ Examples of ImageMagick usage, and full review ... ]