Abstract: In a compositing window system, as a respective version of the window for an application is written into a window buffer, a corresponding set of per tile signatures indicative of the content of each respective tile in the window buffer is generated and stored. When an updated version of the window is stored into a window buffer, the set of signature values for the updated version is compared to the set of signature values for the previous version in the window buffer to determine which tiles' content has changed. The set of tiles found to have changed is used to generate a set of regions for a window compositor to write to a window in a display frame buffer to update the window in the display frame buffer to display the new version of the window.

Abstract: A transaction elimination hardware unit controls the writing to a frame buffer in a memory of tiles generated by a tile-based graphics processor. The transaction elimination hardware unit has a signature generator that generates a signature representative of the content of the tile for each tile. A signature comparator then compares the signature of a new tile received from the graphics processor with the signatures of one or more tiles already stored in the frame buffer to see if the signatures match. If the signatures do not match, then the signature comparator controls a write controller to write the new tile to the frame buffer. On the other hand, if the signatures match, then no data is written to the frame buffer and the existing tile is allowed to remain in the frame buffer. In this way, a tile is only written to the frame buffer if it is found by the signature comparison to differ from the tile or tiles that are already stored in the frame buffer that it is compared with.

Abstract: A graphics processor 1 includes after its tile rendering logic 40, a transaction elimination unit 5 that includes data block generation logic 41 and block comparison logic 43. The block generation logic 41 generates data blocks from the rendered tiles produced by the tile rendering logic 40. The data blocks are then stored in buffers 42. Comparison logic 43 then compares a new data block with the previous data block (which will already be stored in the buffers 42), and generates an output metadata bit indicating whether the blocks can be considered to be the same or not, on the basis of the comparison. The meta-data output bits are stored appropriately in a meta-data bitmap 45 in main memory 2 that is associated with the output data array in question. If the blocks are determined to be different by the comparison logic then the new data block is written from the buffers 42 to the frame buffer 44 in the main memory 2.

Abstract: A display controller reads blocks of data from a frame buffer and stores them in a local memory buffer of the display controller before outputting the blocks of data to a display. The display controller uses similarity meta-data associated with the output frame in the frame buffer to determine whether a new block of data to be processed for display is similar to a block of data already stored in the local memory of the display controller or not. If it is determined that the data block to be processed is similar to a data block already stored in the local buffer of the display controller, the display controller does not read a new data block from the frame buffer but instead provides the existing data block in its buffer to the display.

Abstract: In a compositing window system, as a respective version of the window for an application is written into a window buffer, a corresponding set of per tile signatures indicative of the content of each respective tile in the window buffer is generated and stored. When an updated version of the window is stored into a window buffer, the set of signature values for the updated version is compared to the set of signature values for the previous version in the window buffer to determine which tiles' content has changed. The set of tiles found to have changed is used to generate a set of regions for a window compositor to write to a window in a display frame buffer to update the window in the display frame buffer to display the new version of the window.

Abstract: A graphics processor 1 includes after its tile rendering logic 40, a transaction elimination unit 5 that includes data block generation logic 41 and block comparison logic 43. The block generation logic 41 generates data blocks from the rendered tiles produced by the tile rendering logic 40. The data blocks are then stored in buffers 42. Comparison logic 43 then compares a new data block with the previous data block (which will already be stored in the buffers 42), and generates an output metadata bit indicating whether the blocks can be considered to be the same or not, on the basis of the comparison. The meta-data output bits are stored appropriately in a meta-data bitmap 45 in main memory 2 that is associated with the output data array in question. If the blocks are determined to be different by the comparison logic then the new data block is written from the buffers 42 to the frame buffer 44 in the main memory 2.

Abstract: A display controller reads blocks of data from a frame buffer and stores them in a local memory buffer of the display controller before outputting the blocks of data to a display. The display controller uses similarity meta-data associated with the output frame in the frame buffer to determine whether a new block of data to be processed for display is similar to a block of data already stored in the local memory of the display controller or not. If it is determined that the data block to be processed is similar to a data block already stored in the local buffer of the display controller, the display controller does not read a new data block from the frame buffer but instead provides the existing data block in its buffer to the display.

Abstract: A transaction elimination hardware unit 5 controls the writing to a frame buffer in a memory 2 of tiles generated by a tile-based graphics processor. The transaction elimination hardware unit 5 has a signature generator 20 that generates a signature representative of the content of the tile for each tile. A signature comparator 23 then compares the signature of a new tile received from the graphics processor with the signatures of one or more tiles already stored in the frame buffer to see if the signatures match. If the signatures do not match, then the signature comparator 23 controls a write controller 24 to write the new tile to the frame buffer. On the other hand, if the signatures match, then no data is written to the frame buffer and the existing tile is allowed to remain in the frame buffer. In this way, a tile is only written to the frame buffer if it is found by the signature comparison to differ from the tile or tiles that are already stored in the frame buffer that it is compared with.