JPH0224783A - Image display device - Google Patents

Abstract

PURPOSE:To output color data reduced at the number of bits from a drawing device in case of drawing with the small number of color sorts by providing an image display device with a conversion table between color data to be used at present and color data to be written in a display memory. CONSTITUTION:The conversion table instructed from a drawing device 1 is written in a color data storing memory 3 through a color data storing memory control circuit 2. The conversion table data to be used for the device 1 at present into data for color data of a display memory 4. The drawing device 1 outputs the addresses of respective picture elements and 3-bit color data respectively to an address line 6 and a data line 7. The addresses re directly applied to the display memory 4 and the 3-bit color data are converted into 16-bit color data by using the conversion table stored in the memory 3, applied to the display memory 4 through a color data line 8 and stored in a picture element memory corresponding to the addresses. The contents stored in the display memory 4 are displayed on a display 9 by a usual method through a display circuit 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention generates color data for each pixel from an image display device, particularly a drawing device, stores it in a display memory, and reads out this memory to display it on a display device. The present invention relates to an image display device for displaying images.

[Conventional technology]

Conventionally, in this type of image display device, display memory is usually provided corresponding to pixels for one screen, and the memory for each pixel is composed of multiple bits for storing color data. The drawing device creates multiple bits of color data for each pixel and stores it in a display memory.

[Problem to be solved by the invention]

The number of memory bits for each pixel of the conventional image display device described above is, for example, 16, taking into account the maximum number of color types to be displayed.
Since each pixel is set to 16 bits, 16 bits of color data must be generated for each pixel, even if only a limited number of colors, e.g. 8 colors corresponding to 3 bits, are used in one or a series of screens. The drawback is that the drawing speed cannot be increased.

[Means to solve the problem]

An image display device according to the present invention generates color data for each pixel from a drawing device, stores it in a display memory, and reads out the contents of this memory to display a color image on a display device. a conversion means for converting color data with a limited number of bits output from a drawing device into color data with a bit number storing the color data in the display memory and outputting the color data to the display memory; and this conversion means and a control circuit that obtains the conversion contents from the drawing device in advance and stores them in the conversion means.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, a color data storage memory 3 is connected to a drawing device 1 via a color data storage memory control circuit 2, and input is separately given to the color data storage memory 3 from the drawing device 1 through a data line 7, and through a data line 8. The output is given to the display memory 4. Further, the display memory 4 is given an address by the address line 6 from the drawing device 1, and gives an output to the display circuit 5, which in turn gives the output to the display 9.

In the above configuration, a conversion table is written into the color data storage memory 3 via the color data storage memory control circuit 2 in response to an instruction from the drawing device 1.

This conversion table is for converting 3-bit data corresponding to, for example, eight colors that the drawing device 1 is currently using into, for example, 16-bit data for the color data of the display memory 4. After storing the conversion table in the color data storage memory 3, the drawing device 1 outputs an address for each pixel and 3-bit color data to an address line 6 and a data line 7, respectively, as output for drawing. The address is given directly to the display memory 4, and the 3-bit color data is converted to 16-bit color data in the color data storage memory 3 using a conversion table, and then sent to the display memory via the color data line 8.
memory 4 and stored in the pixel memory corresponding to the address. The contents stored in the display memory 4 are displayed on the display 9 via the display circuit 5 in a conventional manner.

In the above embodiment, the display memory 4 has 16 bits for color data, but the number of bits may be any number, and 3-bit data is sent to the data line 7. , the data lines 7 can be set to have the same number of bits as the color data bit number of the display memory 4, and only required bit lines can be used arbitrarily.

〔Effect of the invention〕

As explained above, the present invention has a conversion table between the color data to be used for the time being and the color data to be written to the display memory, so that when drawing a small number of color types, the drawing device can output color data with a small number of bits. This has the effect of speeding up drawing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Drawing device, 2... Color data storage memory control circuit, 3... Color data storage memory, 4... Display memory, 5... Display circuit, 6... Address line, 7... ...Data line, 8...Color data line, 9...Display.

Claims (1)

[Claims] In an image display device that generates color data for each pixel from a drawing device, stores it in a display memory, and reads out the contents of this memory to display a color image on a display device, a limited amount of data output from the drawing device is provided. a converting means for converting color data according to the number of bits into color data according to the number of bits stored in the display memory and outputting the converted color data to the display memory; and converting the conversion contents of the converting means from the drawing device in advance. An image display device comprising: a control circuit that is obtained and stored in the conversion means.