JPH0619442A - Display controller - Google Patents

Abstract

PURPOSE:To switch look-up tables(LUT) for an area of optional size in an optional shape. CONSTITUTION:This display controller is equipped with plural LUTs 16 and 25, an LUT specification information holding means which holds LUT specification information specifying one of the LUTs 16 and 25 in respective storage locations corresponding to respective pixels of a bit map memory 15 and is scanned in synchronism with the scanning of the bit map memory 15, and a means which selects one of the outputs of the look-up tables 16 and 25 specified with the LUT specification information read out of the LUT specification information holding means in response to the information and sends it to a display part 24, and consequently the LUTs 16 and 2S are switched in pixel units. One or plural planes predetermined in the bit map memory 15 are usable as this LUT specification information holding means.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display control device, and more particularly to a display control device in a raster scan type display having a bitmap memory. Most raster scan displays having bitmap memory are also called video look-up tables (color look-up tables, color tables, color maps, etc.). Abbreviated as LUT) (for example, A. vanDam “Fundamentals o
f Interactive Computer Graphics ”pp. 129-135, Add
See ison-Wesley, 1982). LUT is refresh
It is a conversion table that receives a value stored in a bit map memory as a buffer as a table index and generates information for controlling the brightness and color of the CRT. The use of LUTs makes it easy to control a wide variety of color displays with digital information. However, the display color or brightness obtained through the LUT is always the same if the data values on the bitmap memory are the same. If the display color or the brightness of the data of the same value on the bitmap memory can be made different from the other areas in the area of any shape and size, a wider variety of display functions can be enjoyed. LUs to be used in this area and other areas by providing multiple LUTs and designating the area by XY coordinates
Although a method of switching T can be considered, this method can set only an extremely limited area. An object of the present invention is to provide a display in which display attributes such as color and brightness of data having the same value on a bit map memory can be made different from other areas in an area having an arbitrary shape and size. It is to provide a control device. A display control device according to the present invention has a plurality of LUTs and a storage position corresponding to each pixel position of a bitmap memory, and the plurality of LUTs are provided at each storage position. Of the LUT designating information for designating one of the LUT designating information and the LUT designating information holding means which is scanned in synchronization with the scanning of the bitmap memory and the LUT designating information read from the LUT designating information holding means. Means for selecting an output from one of the plurality of look-up tables it designates and sending it to the display. As the LUT designation information holding means, one or a plurality of predetermined planes of the bitmap memory can be used. In synchronization with the sequential reading of data from the successive pixel positions of the bit map memory, the LUT designation information is read from the corresponding position of the LUT designation information holding means and designated by it. The output of the LUT is selected and sent to the display. That is, the LUT can be switched for each pixel. Therefore, in areas of arbitrary shape and size, it is possible to make display attributes such as color and brightness different for data of the same value on the bitmap memory. FIG. 1 shows an embodiment of the present invention. The X counter 13 receives the clock from the clock generator 14 and increments the X address for the bitmap memory 15 by "1". The capacity of the X counter 13 is set equal to the width of the bitmap memory 15, and in response to the overflow of the X counter 13, the content of the Y counter 12 is incremented by "1". The synchronization generator 11 receives outputs of the clock generator 14, the X counter 13, and the Y counter 14, and generates a synchronization signal 127 (horizontal synchronization, vertical synchronization, etc.) for the display unit 24.
The X counter 13 and the Y counter 14 indicate the two-dimensional address (111, 112) for the bitmap memory 15, and since the values are incremented as described above, the contents of the bitmap memory 15 are: The pixels are sequentially scanned from left to right and from top to bottom one pixel at a time in synchronization with the raster scanning of the display section 24, and read. The bit map memory 15 has a depth of M + 2 bits (M ≧ 1) in this embodiment. Of these, the M bit is for display data, and the remaining 2 bits (15p and 15q) are for LUT designating information. Of the M + 2 bit data 113 read from the bit map memory 15, the M bits of the display data include the first LUT (LUTa) 16 and the second LUT.
It is supplied to (LUTb) 25 as a table index. As shown in FIG. 2, each LUT 16, 25 is
Has 2 M entries, and the M-bit display data from the bitmap memory 15 is considered as binary numeric data and specifies one of these entries. Each entry consists of 3N bits (N ≧ 1). This 3N-bit data is divided into three N-bit data and supplied to three selection circuits 18, 19 and 20, respectively (114 to 116, 128 to 130). The M-bit display data read from the bit map memory 15 is also divided into three, and any LUT (16,
25) is also directly supplied to the selection circuits 18 to 20 without passing through. Outputs 121-123 of the selection circuits 18-20
Is supplied to the DA converters (DAC) 21 to 23. The DACs 21 to 23 convert the outputs of the selection circuits 18 to 20 into R (red), G (green), and B (blue) analog signals 124 to 126, respectively, and display 24.
Send to. The display 24 displays these R, G, B
Color display is performed based on the signal and the sync signal 127 from the sync generator 11. The selection by the selection circuits 18 to 20 is controlled by the output signal 120 of the area determination section 17. That is, the area determination unit 17 receives the remaining 2 bits 15p and 15q from the bitmap memory 15 (113p,
113q), these 2 bits are decoded, and the selection circuits 18 to 20 are controlled according to the decode value. For example, depending on the permutation “00”, “01” or “10” of the values of the bits 15p and 15q, the direct outputs 117 to 119 of the bitmap memory 15 and the outputs 114 to 1 of the first LUT 16 are given.
16 or the outputs 128 to 130 of the second LUT 25 may be selected respectively. Instead of providing the special faces 15p and 15q for designating the LUT in the bitmap memory 15, another memory which is sequentially read in synchronization with the bitmap memory 15 may be provided. In this embodiment, it is possible to switch the output of a plurality of LUTs and the direct output of the bit map memory on a pixel-by-pixel basis, so that a more versatile display function is provided. For example, it is easy to freely combine a computer graphics image with a real image such as a photograph, and such combination is effective in games and animations. Although the above-described embodiment has been applied to the case of a color image, the selection circuit 18 to
20 and DACs 21-23 need only be one system. As described above, according to the present invention, a plurality of LUT-converted display images can be selected and used for each pixel with a simple structure, and therefore, an arbitrary shape and size can be obtained. An area can be set so that the display color and brightness in that area can be different from other areas without changing the contents of the bitmap memory. Therefore, extremely versatile display is possible, which contributes to enriching the contents of image processing by a computer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a conceptual diagram of a table structure of a lookup table (LUT). [Description of Codes] 15: Bitmap memories 15p, 15q: Lookup table designation information holding unit 16, 25: Lookup table 17: Area determination unit 18 to 20: Selection circuit 24: Display (display unit)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kunihiro Nomura             1099 Ozenji, Aso-ku, Kawasaki City, Kanagawa Prefecture             Ceremony company Hitachi Systems Development Laboratory

Claims (1)

[Claims] 1. In a display device having a bitmap memory and a raster scanning type display unit, a plurality of look-up tables for receiving the output of the bitmap memory and a storage position corresponding to each pixel position of the bitmap memory are provided. And holding lookup table designation information for designating one of the plurality of lookup tables in each storage location, and holding lookup table designation information scanned in synchronization with the scanning of the bitmap memory. Means, and in response to the lookup table designation information read from the lookup table designation information holding means, selects an output from one of the plurality of look-up tables designated by the lookup table designation information and displays it. And a means for sending to a display unit. 2. The display control device according to claim 1, wherein the lookup table designation information holding means is a predetermined surface of the bit map memory.