Techniques in Pixel Graphics

There are many techniques available for the creation and manipulation of pixel graphic files. This section discusses some of those techniques.

Image Creation

Pixel graphics can be created by a number of means. What is required from the creation method is to specify the color of all the pixels in the image.

Pixel graphics can be created using simple ‘Paint’ programs, which allow the creator to draw on a canvas representing the bitmap. Depending upon the program used, there are tools of varying sophistication available. It is not an easy process to create pixel graphics by hand, however. It requires the same artistic ability as sketching on paper, but can be greatly aided by the use of specialized pointing devices, such as drawing tablets. These specialized devices are a phenomenal improvement on the desktop mouse.

Pixel graphics are well suited to images such as photographs. This type of image, capturing a real-world scene, can easily be converted to a bitmap with appropriate hardware and software. Scanners and digital cameras are the tools generally used to achieve this, and are a worthy investment since they allow anything which can be drawn on paper or photographed to be used as a bitmap.

The final main technique for pixel graphic creation is to use computer-generated imaging (CGI). CGI ranges from simple programs that create patterns, tessellations, and fractals, to complicated modelers, animators and raytracers, which can be used to create the objects and special effects for the motion picture industry. Some of these advanced techniques are discussed below under 3D graphics.

Editing Procedures

Because pixel graphics define the value of the color of every pixel in an image, they lend themselves well to editing techniques that alter all the color values in a particular area of the image.

Color modification procedures are probably the most common and useful editing which are performed on bitmaps. It is possible to edit the brightness and contrast of an image, as well as the relative strength of the red, green, and blue components. A wide variety of other color modification procedures are also available in different software packages, but all of these color modifications can be expressed as the sum of at most three functions – one each for the red, green, and blue components.

Pixel mask procedures can also be used readily on bitmap images. These procedures apply a given function, which relies on surrounding pixels, to each pixel in the bitmap. This can include procedures for such things as blurring, softening, sharpening, or finding the edges in an image.

A Blurred Image	Edge Detection in an Image

Finally, parts of images can be edited by hand, cut, copied and pasted, and blended with other images using various software packages.

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