Abstract: A technique for performing clear operations in a region having a subregion. Responsive to a first clear command: perform an initialization in which stale information is eliminated from pixels outside the subregion. Responsive to subsequent clear commands: update a current clear count for the region; and write the updated current clear count into clear count values associated with pixels outside the subregion. Prior to creating the subregion, a conventional fast clear technique may be employed in the region. After creating the subregion and during its life, the inventive technique may be employed. After the subregion is discontinued, the conventional technique may once again be employed. The inventive technique may be employed optionally depending on the percentage of the region's area occupied by the subregion.

Abstract: A method of eliminating stale information from a computer graphics buffer. The method facilitates switching from a fast clear mode to a non fast clear mode during the lifetime of a region of interest such as a window: A clear count value associated with a pixel is read and compared with a current clear count. If the counts are not equal, a replacement value is written into the pixel. The process may be repeated for each pixel in the region. Block transfer hardware and fast clear hardware may be used together to perform the procedure in a high-performance manner: A source region and a destination region for the block transfer operation are both set to the region of interest. As the block transfer proceeds, each pixel is written either with its own value or with a replacement value depending on whether the clear count for the pixel is current.

Abstract: A technique for performing clear operations in a region having a subregion. Responsive to a clear command: a current clear count for the region is left unchanged; a predetermined value is written into the pixels of the subregion; and the current clear count is written into pixel clear counts of the subregion. Prior to creating the subregion, clear commands may be handled according to a conventional fast clear technique. After creating the subregion and during the life of the subregion, clear commands may be handled according to the inventive technique. After the subregion is discontinued, clear commands may once again be handled according to the conventional technique. The inventive technique may be employed optionally depending on the percentage of the region's area occupied by the subregion.

Abstract: A technique for filling a memory area that represents a rectangle. The rectangle or a first section thereof may be divided into i+j horizontal subsections. The i horizontal subsections may be filled in a first pass using i region fill processors. And the j horizontal subsections may be filled in a second pass using j region fill processors. A second section of the rectangle may be filled by dividing the second section into n vertical subsections having equal width and filling the n vertical subsections using n region fill processors.

Abstract: A technique for filling a memory area that represents a rectangle. The rectangle or a first section thereof may be divided into i+j horizontal subsections. The i horizontal subsections may be filled in a first pass using i region fill processors. And the j horizontal subsections may be filled in a second pass using j region fill processors. A second section of the rectangle may be filled by dividing the second section into n vertical subsections having equal width and filling the n vertical subsections using n region fill processors.

Abstract: A technique for performing clear operations in a region having a subregion. Responsive to a first clear command: perform an initialization in which stale information is eliminated from pixels outside the subregion. Responsive to subsequent clear commands: update a current clear count for the region; and write the updated current clear count into clear count values associated with pixels outside the subregion. Prior to creating the subregion, a conventional fast clear technique may be employed in the region. After creating the subregion and during its life, the inventive technique may be employed. After the subregion is discontinued, the conventional technique may once again be employed. The inventive technique may be employed optionally depending on the percentage of the region's area occupied by the subregion.

Abstract: A technique for performing clear operations in a region having a subregion. Responsive to a clear command: a current clear count for the region is left unchanged; a predetermined value is written into the pixels of the subregion; and the current clear count is written into pixel clear counts of the subregion. Prior to creating the subregion, clear commands may be handled according to a conventional fast clear technique. After creating the subregion and during the life of the subregion, clear commands may be handled according to the inventive technique. After the subregion is discontinued, clear commands may once again be handled according to the conventional technique. The inventive technique may be employed optionally depending on the percentage of the region's area occupied by the subregion.

Abstract: A method of eliminating stale information from a computer graphics buffer. The method facilitates switching from a fast clear mode to a non fast clear mode during the lifetime of a region of interest such as a window: A clear count value associated with a pixel is read and compared with a current clear count. If the counts are not equal, a replacement value is written into the pixel. The process may be repeated for each pixel in the region. Block transfer hardware and fast clear hardware may be used together to perform the procedure in a high-performance manner: A source region and a destination region for the block transfer operation are both set to the region of interest. As the block transfer proceeds, each pixel is written either with its own value or with a replacement value depending on whether the clear count for the pixel is current.