ATI Technologies RADEON 8500 MAC EDITION Guide de l'utilisateur télécharger pdf (Page 28)

Glossary

Alpha blending When an image has an alpha value for each pixel, this

tells how much to blend the colors from the image with

the background colors. The lower the alpha values the

more transparent the image looks.

Anti-aliasing Method used to remove the jagginess of an image.

When anti-aliasing is used, the edges of an image appear

smooth and usually somewhat blurry.

Anisotropic Filtering This filtering technique uses a rectangular filtering

pattern to render smoother, crisper images.

Aspect Ratio The proportions of a display expressed as a ratio of

width and height. Common ratios include 4:3 for TV

and CRTs, 5:4 for LCDs and 16:9 for widescreen

displays.

Back buffer A type of offscreen memory used to provide smooth

video and 2D graphics acceleration. This technique uses

two frame buffers, often referred to as “double-

buffering”. While one buffer is being displayed, a

second buffer of the same size, the “back” buffer, holds

the frame being worked on.

Once a new frame is ready in the back buffer it is copied

to the front buffer - the display screen. In this way, you

will only see complete, smooth frames, and not the

operations performed on them.

In order to increase performance, all memory used for

back buffers are on your ATI graphics accelerator card.

Bilinear Filtering When texture mapping is performed an image can

become very “blocky” or “pixelated” when the texture is

viewed close up. Bilinear filtering samples four texture

pixels, takes the weighted average of these pixels and

applies the average of these “texels”. This blended color

is used to provide a smoother looking texture.

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ATI Technologies RADEON 8500 MAC EDITION Guide de l'utilisateur Page 28