In a bit mapped raster scan digital display system, a number of maps each contain a single component of the display data and are read together to provide sets of bytes, each set representing eight pel defining groups. A compare system is provided for determining when a pel group in a set of bytes compares with a reference pel defining group. For the, or each, pair of maps, the compare system compares all bits of the two bytes of data with the associated bit of the reference group to provide outputs when a corresponding bit in each of the bytes compares with the two reference bits. When more than two maps are employed the compare outputs related to all of the pairs of maps are combined to provide an output signal when a pel group in a byte from the maps compares with the reference bits. In a modification of the system the comparison can be made between one or more of the maps and the corresponding bit or bits of the compare data.
A memory storage and accessing device is constituted by a plurality of plane memories. Memory elements are arranged in each plane memory two-dimensionally, and a plurality of image data are stored in a word direction in each plane memory. In addition, plural plane memories are disposed in a pixel direction. Hence, plural image data are stored two-dimensionally in word and pixel directions. The memory device is constituted such that a port connected by a word data bus and another port connected by a pixel data bus are provided therein. Due to these two ports, it is possible to perform an independent access so as to independently read out and write in word data and pixel data. The memory storage and accessing device is capable of masking bits of data and memory units, using both static and dynamic masks. In the static mask, mask data are applied all at once in one memory cycle, or the mask data are supplied to the memory device at plural times in one memory cycle. In the dynamic mask, the mask data are supplied to the memory device at plural times in one memory cycle and the mask positions can be sequentially changed. The memory storage and accessing device of the present invention is also capable of comparing pixel and word data with compare data in each plane memory and in combination with a masking operation.
A method and system of displaying a pattern using a bitmap memory display which acomplishes an overall pattern display by writing to the display memory one copy of the pattern. The logical unit (LU) of the system's graphics adapter (GA) is then used to replicate the pattern throughout the bitmap memory with a reduced number of write operations from the central processing unit (CPU) to the GA.
A method and system of displaying a monochrome bitmap on a color display. In a preferred embodiment, a system according to the present invention accomplishes the display of the monochrome bitmap in any two preselected colors. The multibit representations for the two preselected display colors are compared to identify bitmap planes having common bit values for each color. The input for logic units for the identified planes are then forced to 0. The latch registers for each plane of the bitmap memory are then set to the bit value for the first preselected color in that plane. The input values from the monochrome bitmap, as altered by the force-to-0 operation for common planes, are logically exclusively ORed with the latch register values to produce the bitmap memory values for displays. An alternate embodiment suitable for updating partial bytes within the bitmaps is also provided.
An improved method and system for updating a display bitmap with a character string in a given font is provided. Each character in the font is stored as a character bitmap. Each character comprises a contiguous set of virtual characters. A visible stack is created for each character string to be displayed in the display bitmap. For each character to be displayed, the visible stack contains a pointer to each of its virtual characters. The data in the visible stack is then processed to update efficiently the display bitmap. The display bitmap is updated column by column, each column being one byte side. For each byte in the column, the virtual characters that are to be displayed in that byte are combined to form an output byte that is output to the display bitmap. The combining is accomplished by special-purpose routines based on the number of virtual characters that are to be displayed in a particular column.
A display system having a frame buffer comprising a plurality of memory planes, a display device for visually displaying images written into the frame buffer, and a controller for controlling image data operations. The display system is provided with an extended raster operation circuitry comprising an intraplane operation unit and an interplane operation unit. Operation results of the circuitry are written back to the frame buffer. The respective operation units perform operations specified by the controller. The intraplane operation unit performs operations on image data in each of the memory planes, separately, while the interplane operation unit performs operations on image data in at least two memory planes selected by the controller. There are no restrictions as to the positional relation between the intraplane operation unit and the interplane operation unit.
