"Text animation" is a broad term in computer graphics that refers to creating moving letters, words or paragraphs. In animation, it relates to creating text that moves in some fashion across the screen, within an area, or by following a pattern of motion. A less frequently used meaning is in the context of an animation that is created using only text characters so each of the elements within the animation are made of letters, numbers, punctuation marks or other symbols. There are a wide range of special effects that can be used with text animation, many of which are identical to traditional three-dimensional (3D) animation effects and two-dimensional (2D) image filters. In professional film and video, broadcast television and in presentations, text is often animated to create interesting transitions from one topic to the next or to accent important information.
Two similar, but ultimately different, methods can be employed to create a text animation with computer graphics applications. The first employs a 3D modeling program that contains a 3D model of each of the letters, which are then placed into virtual space with the correct kerning and spacing. These letters can then be animated in the same fashion that any 3D object is animated, including visual effects such as texture mapping, rotations, morphing and inverse kinetics, to make the individual parts of a letter or word seem to move organically.
Another method used to create a text animation is through a vector-based graphical program. These programs store the information required to draw a letter or font at any resolution and in any style, such as bold or italics. Animation is achieved primarily through the use of paths or Bezier curves along which the text then moves at a defined frame rate. Much of the math behind vector graphics is identical to the algorithms used for 3D animation, so there is sometimes a blurring of the lines between vector-based and 3D text animation.
Some office suites include basic text animation functionality that can be used to create motion within a slide show or other type of presentation. These effects generally are pre-programmed and very basic, such as text entering from one side of a screen and then coming to rest in the center. One benefit in using text animation from an office suite is the ease of use and the portability, because an actual animation sequence does not have to be saved, rendered frame by frame, and then replayed.
In the HyperText Markup Language (HTML), text can be animated through the use of JavaScript® and cascading style sheets (CSS). This can be accomplished by modifying the properties of a block of text, changing the position over time so it appears to move or scroll. Within HTML itself, the marquee tag can be used to create a scrolling line of text within a web page. Finally, separate programs or embedded streaming media also can be used to show moving text.