Abstract: An image processing apparatus comprises: a boundary line designating unit which designates a boundary line for dividing a screen into a plurality of regions; and a region selecting unit which selects either one of the inside and the outside of the boundary line designated by the boundary line designator as a region to be processed in which an image is to be processed. The boundary line designating unit designates a region surrounded by a freehand line input via an inputting unit. As a result, it is possible to easily and accurately designate a region which a user desires to subject to an image processing, so as to readily subject the desired region to the image processing.

Abstract: A graphics system reduces fetching from memory of color-key pixels when video pixels from a video-overlay window are displayed. A frame buffer is divided into multi-line, multi-pixel blocks that are arranged in block-rows and block-columns. Each block-row has primary and secondary row indicator bits and each block-column has two column indicator bits. When the primary row indicator bit is cleared, all pixels in the block-row are fetched from a frame-buffer memory. When the primary row indicator is set, a secondary row indicator bit selects either first or second column indicator bits for reading. When the selected column indicator bit for a block-column is set, fetching of pixels from the frame buffer memory is skipped. Instead, dummy color-key pixels are generated and inserted into the pixel stream. These dummy pixels match the color key and cause video pixels to be sent to the display. Memory fetching is reduced.

Abstract: A graphics pipeline has at least one stage that determines operations to be performed on graphics data based at least in part on data processing attributes associated with the graphics data. One application is to permit one or more operations in a stage to be bypassed. Another application is a multi-function stage in which the data operations that are performed depend at least in part on the data type.

Abstract: A memory write section 2 writes texture data in a number capable of being transferred at a time and written in one address, in one of first through fourth texture memories 1a through 1d in common by single write operation. If the V coordinate of texture data to be written is an even number, the texture data is written in the first, second, third and fourth texture memories 1a, 1b, 1c and 1d in this order. If the V coordinate is an odd number, the data is written in the third, fourth, first and second texture memories 1c, 1d, 1a and 1b in this order.

Abstract: Methods and apparatuses for effectively clearing stencil buffers at high speed using surrogate stencil buffer clearing. A hardware register tracks the number of surrogate clears of the stencil buffer since the last actual clear. Bits are reserved in each stencil register for storing the surrogate clear number that cleared other stencil registers the last time the stencil register held an assigned value. A comparison between the contents of the hardware register and the reserved bits in each stencil register determines if each stencil register should be assigned a cleared value. If the numbers do not match the stencil register is assigned a predetermined surrogate clear value. In some applications the number of reserved bits is fixed, while in other applications the number of reserved bits can be set, either by a designer or by software.

Abstract: A frame buffer stores X pixels per line and Y lines and is read using a burst of B pixels. The un-rotated image is rotated by 90 degrees for display by writing and reading pixels from a line buffer. The line buffer stores a block of B*Y pixels. The frame buffer is logically divided into X/B blocks that are B pixels wide. Blocks are read from the frame buffer from the bottom line to the top with a burst of B pixels per line. An offset locate pixels to read in the line buffer. The offset is B for the first block, and increases by a factor of B for each block read, but wraps around modulo B*Y?1. Pixels for a next block are written into the line buffer to locations vacated as pixels are read out. The increasing offset re-orders the pixels for the rotated display order.