JPH02271392A - Image display device - Google Patents

Abstract

PURPOSE:To perform various display operations without increasing the capacity of an internal register and the number of times of reading an image memory by reading attribute corresponding to each scanning line of a display from a storage means and converting display data corresponding to each scanning line. CONSTITUTION:CPU 2 reads the attribute corresponding to each scanning line of the display from an internal storage means and transfers the attribute to a frame memory 3 via an image processing device 4. Display data and attribute data are stored in the memory 3 constituted of plural DRAMs. Then, the memory 3 is read according to the control of the CPU 2 and the display data corresponding to the attribute data is read. The display data is converted according to the readout attribute data and displayed on a CRT 5. Under this constitution, the various display operations can be performed without increasing the capacity of the internal register and the number of the reading times.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an image display device used as a computer terminal device or the like.

"Prior Art" General image display methods include the bitmap graphics method and the character graphics method. In this bitmap graphics method, an image processing device reads dot-by-dot display data stored in an image memory, and performs display processing based on multiple attribute data pre-stored in internal registers of the image processing device. and displays the processing results. This attribute data is, for example, display processing parameters that instruct display color, display position, inversion, and the like. In addition, the character graphics method means that an image processing device reads display data for each character (usually a character pattern consisting of 8x8 dots) and its attribute data stored in the image memory, and displays the data based on this. It performs processing and displays the processing results. This attribute data is, for example, display processing parameters such as character display color, blinking, and underlining.

``Problem to be Solved by the Invention J'' By the way, in the above-mentioned bitmap graphics method, since display data is stored in units of dots, an image memory with a large storage capacity is required. In order to perform detailed display processing, the capacity of the internal register that stores attribute data must be increased.Also, in the character graphics method, attribute data is stored in the middle of the character, so detailed display processing is not possible. If this is done, that is, if attribute data with a large number of bits is stored in the image memory, the number of times the image memory is read during the display period will increase.

This invention was made in view of the above-mentioned circumstances, and allows detailed display processing based on a variety of attribute data without increasing the number of image memory reads during the display period by significantly increasing the capacity of the internal register. The purpose is to provide an image display device.

"Means for Solving the Problem" This invention reads attribute data from a storage means storing attribute data corresponding to each scanning line of a display device and an H storage means, and uses the attribute data for each scanning line. The present invention is characterized by comprising a data conversion means for converting display data into a display data, and a display device for displaying the output from the data conversion means on a screen.

According to this invention, not only display data is stored in the image memory, but also attribute data is stored in correspondence with the scan lines of the display.This reduces the memory capacity much more than in the case where attribute data is stored in correspondence with characters. Therefore, since attribute data is not limited by the capacity of the internal register compared to the case where attribute data is stored in the internal register, a variety of display processing becomes possible.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the basic configuration of an image display device (2) according to an embodiment of the present invention. In this figure, reference numeral 2 denotes a central processing unit (CPIJ), which outputs control data such as commands and processing parameters for controlling the image processing device 4, reads display data and attribute data from a memory (not shown), and displays images. Processing device 4
The data is transferred to the frame memory 3 via. The frame memory 3 is composed of a plurality of DRAMs (dynamic RAMs) and stores display data and attribute data. The image processing device 4 reads display data and attribute data from the frame memory 3 in accordance with control data from the CPU 2, converts the display data based on the read attribute data, and converts the conversion result into an analog RGt3 signal. and outputs it to a CRT (display device) 5.

FIG. 2 is a memory map showing the contents of the frame memory 3. In this figure, storage areas E, ~E+n
contains attribute data D Z corresponding to the 1st to Nth scanning lines.
++~Dz+n are stored, storage area 1', I-Et
n is display data D for displaying the first to Nth scanning lines.
! 1-Dtn are respectively stored.

Next, an image display device with the above configuration! Explain the operation. Incidentally, FIG. 3 shows an outline of this operation.

First, when displaying the first scanning line located at the top of the screen on the CRTS, during the vertical retrace period after the end of the previous frame scan, data is transferred from the frame memory 3 to the storage area E shown in FIG.
The first scanning line attribute data Dz, , of , are read out. Then, during the first scanning line display period, storage areas E! 1st scan line display data D of I
! , performs data conversion according to the attribute data Dzz, converts the data after this data conversion into RGB, and displays the first scanning line. Next, during the horizontal retrace period when the scanning line shifts from the first scanning line to the second scanning line, the second scanning line attribute data Dzl! from the frame memory 3 to the storage area E1! Read out.

Then, during the second scanning line display period, the frame memory 3
2nd scanning line display data D□ of storage area Eat from
is read out, data conversion is performed according to the attribute data DZ+t, and the data after this data conversion is converted into RG B j,: to display the second scanning line.

Thereafter, the 3rd to Nth scanning lines are displayed in the same way,
An image for one frame is generated.

In such an image display device 1, if a plurality of color look-up tables (LUTs; color data conversion tables) are stored in advance in the image processing device 4, and the table numbers are stored in the frame memory 3 as attribute data for each line. ,
It becomes possible to increase the total display colors per I frame. For example, if the display data corresponding to dots is 4 bits (16 color display) and there are 4 types of Lu'r,
A total of 64 colors can be displayed. In addition, if the display start address is stored as attribute data in the image processing device 4, it is possible to easily perform horizontal or vertical scrolling of the screen, multi-window display, line stretching (enlargement of the screen in the vertical direction), etc. .

Note that the storage contents of the frame memory 3 shown in FIG. 2 are as follows:
A memory configuration in which the first scanning line attribute data DZ11 is stored in the storage area E and the first scanning line display data Df+ is stored in the storage area E+t, that is, the attribute data and the display data are sequentially allocated, may be used.

"Effect of the Invention J As explained above, according to the present invention, there is an image memory storing attribute data corresponding to each scanning line of a display device, and an image memory in which attribute data is read out from the image memory. By providing data conversion means for converting display data for each scanning line based on attribute data and a display device for displaying the output from this data conversion means on screen, it is possible to reduce the display period without significantly increasing the capacity of the image memory. This has the effect of allowing detailed display processing based on a variety of attribute data without increasing the number of times the internal image memory is read out.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a memory map diagram showing the storage contents of the frame memory in the same embodiment, and FIG. 3 is a display operation diagram showing the operation in the same embodiment. 1... Image display device, 3... Frame memory, 5... CRT

Claims (1)

[Scope of Claims] Storage means storing attribute data corresponding to each scanning line of a display device, and data conversion for reading attribute data from the storage means and converting display data for each scanning line using the attribute data. An image display device comprising: means; and a display device that displays the output from the data conversion means on a screen.