Cirrus Logic Inc.

Vernon Dennis Hasz

Karl Scott Mills

Richard Charles Owen

Bradley A May

Mark Emil Bonnelycke

Mark Emill Bonnelycke

A method and apparatus for determining representative values for the chrominance components to be associated with a plurality of luminance components in a horizontally shrunken or stretched image for graphics controllers wherein display image data is stored in a buffer memory in a form associating a single set of U and V chrominance components with a plurality of Y luminance values. For a four to one shrinkage of an image in a format associating one set of chrominance components with four pixel luminance values wherein each pixel luminance value in the shrunken image initially has as associated set of chrominance components U.sub.0, U.sub.1, U.sub.2 and U.sub.3 and V.sub.0, V.sub.1, V.sub.2 and V.sub.3, the multiple values of the chrominance components are sequentially accumulated in a 3/4:1/4 ratio in such a manner as to provide an approximate average value for U and V for each set of four pixel luminance values in the shrunken image. Circuitry for processing the chrominance components making use of interpolation circuitry already used for interpolation between pixels for a stretched image is disclosed.

Method and apparatus for determining representative chrominance

A method and apparatus to stretch video images in a graphics controller chip of a computer system. The graphics controller chip fetches four pixel data comprising two pixel data each from a first scan line and a second scan line of a source video image, and generates a set of additional pixels in a rectangular area defined by the four pixels. The graphics controller chip stores the pixels of rectangular portions in a display memory, and displays the pixel data of the stretched video image in a scan line order.

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Bellevue, WA, United States of America

Vernon Dennis Hasz