The Image-Interface

2Describing Graphical Information

Before we represent images and interfaces in a graphical form on a computer screen, the underlying digital information is subject to different processes. Although the surface level is always based on screen pixels, the description of images follows different forms and formats: from bitmap images to 2D and 3D vector graphics, etc. Accordingly, the kind of processes that can be performed varies for each type of image.

When we use a software application to process graphical information, we have at our disposition a series of predefined options, parameters and operations for working with information. This is a practical entry point to start discovering the functionalities harnessed by the software environment. However, we are often also confronted with the necessity of understanding what is happening “under the hood” and sometimes we even want to go further than the given possibilities at hand.

This chapter is devoted to the foundations of graphical information. In this part, we consider images as data and digital information. We look at the technical aspects that define a digital image: from data types and data structures required to render an image on the computer screen to seminal algorithms and image processing techniques. Our aim is to offer a technical overview of how images are handled by the computer and to identify how they are implemented at higher levels of description, that is, in graphical visualizations of data, user interfaces, and ...