A histogram is: a graphical display of tabulated frequencies. In our case, color frequencies that appear in an image. In some image manipulation software this can be named also as Levels. ...

Although converting an image (usually in true color) to grayscale can sound like a simple operation if you are used to image processing software, PHP doesn't have a function for this conversion by default. ...

Images, even if they are big or small are usually full of colour. However, in certain situations you may want to check if an image is indeed grayscale or not. You can do this using PHP and its image manipulation functions. ...

There are several ways I’ve seen over the years of interchanging 2 variables. I’ll show you here how you can do it with bitwise operations. This method is most efficient when used in combination with assembler. In C++ it is looked at more like a curiosity than a real method by most. However if you would want to make your C++ code harder to read, then this can be helpful. ...

The initial distributed file was AOL-data.tgz (439MB). Inside it contains a simple readme file and 10 .gz archives, each containing a CSV collection. With a packed size of about 45MB each, when extracted they reveal the true treasure: a nice collection of actual user searches (each file at about 200MB). ...

In the first part of this article I've explained the basics of sessions and how they can be used. It is now time to see how we can implement these theories and create a functional session management system using a database. ...

They are used on most websites, yet very few people know they even exist. They use various technologies like "cookies", "SQL", but not many know they can create their very own session handling systems to handle their own need. I will try to explain the technology behind the sessions and very much how to get your own sessions up and running. ...