Displaying Colors; Video Modes - Toshiba Portégé 650CT User Manual

How Does the Screen Display Information?

Displaying Colors

The pel size also determines how many colors the display can pro-
duce. By combining pixels of different colors within a pel, the dis-
play can produce many more colors than are available within a
single pixel. Therefore, larger individual pels increase the number
of colors available to the display.

Video Modes

Video modes are sets of industry-standard rules about resolution
and the maximum number of distinct colors that can be displayed
simultaneously on the screen. Programs that adhere to the rules of
a video mode will run on any system that supports that mode.
Most display adapters provide several video modes. The Portégé
650CT SVGA-compatible display adapter supports all VGA
modes and some SVGA modes.
The video mode required by a program depends on:
whether the program displays graphics or text.
the resolution required for the text or graphics.
the number of colors used.
the font size (in pixels) of the text.
Based on these requirements, computers recognize two categories
of video modes: graphics modes and text modes.
In a graphics mode, programs can turn on and off individual pels
to display a variety of images. The computer controls every pel on
the screen individually. This provides maximum display flexibil-
ity while somewhat reducing the speed at which the display pro-
duces images.
An image produced this way could be a drawing or picture, like a
pie chart, graph or photograph. It could also be an icon or a varia-
tion on a text character, like italics or bold type.
Part I: Getting To Know Your Computer
What's Really Going On?
297