People use the term “computer graphics” to mean different things in different contexts. Most simply, computer graphics are pictures that are generated bya computer, also refers to the tools used (hardware and software) to make such pictures.
Within software tools exists some graphics libraries, a collection of graphics routines that produce thepictures themselves, like OpenGL.
Not too long ago, programmers were compelled to use highly device-dependent libraries, designed for use on one specific computer system with one specific displaydevice type. This made it very difficult to port a program to another system or to use it with another device when the need arises.
Now, there are device-independent graphics libraries that allow theprogrammer to use a common set of functions within an application and to run the same application on a variety of systems and displays.
Computer graphics often means the whole field of study thatinvolves these tools and the pictures they produce.
SIGGRAPH, a graphics special interest group in the ACM was formed in 1969 and is very active today around the world.
There are several ways in which thegraphics generated by the program can be delivered:
* Frame-by-frame: a single frame can be drawn while the user waits
* Frame-by-frame under control of the user: A sequence of frames can bedrawn; the user presses a key to move on the next slide, but otherwise has no way of interacting with the slides.
* Animation: A sequence of frames proceeds at a particular rate while the userwatches with delight.
* Interactive program: An interactive graphics presentation is watched, where the user controls the flow from one frame to another using an input device in a manner that wasunpredictable at the time the program was written.
An important aspect of computer graphics is: “Computer graphics has the ability to display objects as if they already physically exist, when in...