JPS5852230B2 - Display device screen control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in functions for controlling the display state of a display device, ie, scrolling functions, screen switching devices, etc. when performing brightness control, color display, ruled line display, etc.

Screen display control of a display device without a scrolling function, which is a conventional technique, will be explained.

FIG. 1 shows an example of a display screen of a display device that performs display control; 1 is the display screen of the display device;
2 is a space pattern (no display), 3 is a low brightness character, 4
is a high-intensity character.

The conventional technology for displaying a screen as shown in FIG. 1 will be explained using the block diagram in FIG. 2. 5 is a screen memory for storing display information, including character codes, display control information, and graphic codes. It is constituted by flag bit 6 that distinguishes whether it is information or control information.

A character generator 7 outputs a character pattern from a pattern display line 8 by giving a character code.

A control information register 9 stores control information read from the screen memory 5.

10 is a display control circuit that analyzes the control information set in the control information register 9 and outputs the result from the display control line 11.

The general operation of the above configuration will be explained.

In the screen memory 5 of FIG. 2, control information (2) is information for displaying character patterns at low brightness, and control information (2) is information for displaying character patterns at high brightness.

Character code A, character code B, etc. are character codes corresponding to character patterns A, B, etc., respectively.

When performing screen display, information is read from the top address of the screen memory 5.

First, when the control information (■) is read, it is recognized by the flag bit 6 that it is control information, and is set in the control information register 9, and the display control circuit 10 and display control line 11
A display control signal, ie, a signal for low brightness display, is sent.

However, since the information is control information, it is not sent to the character generator 7, so a space is displayed on the screen.

Next, when character code A is read from screen memory 5, the character code is sent to character generator 7 by flag bit 6.
Character pattern A is output by pattern display line 8.

At this time, since low brightness is instructed as the display control, character pattern A is displayed at low brightness.

Similarly, character code B is read and character pattern B is displayed with low brightness.

Next, the control information ■ is read from the screen memory 5, and the control information ■
Character pattern X and character pattern Y are displayed with high brightness in the same manner.

Furthermore, when L, M, and N are displayed with high brightness, the screen returns to the beginning of the screen memory and the above operation is repeated.

In the prior art, control information wraps around.

That is, when control information is set in the control information register 9, the previous information remains until the next control information is provided.

A case will be described in which the prior art is applied as is to a display device whose screen memory is larger than the display screen and which has a screen scrolling function to display a portion of the screen memory.

In Fig. 3, numeral 13 is a screen memory, which is larger than the display screen, and if we consider the case where part A is displayed on the screen, control information ■ (instructing low brightness display) can be used to control
, C, D, E, etc. are displayed with low brightness.

If the screen display section such as the scroll function is switched to the mouth part, the control information (2) for controlling the display of letters C, D, and E will be outside the screen display section.

Considering this case, due to the control information ■, X and Y are displayed with high brightness, and since the next control information does not exist, the character C
, D, and E are displayed with high brightness according to the control information (2).

A problem arises in that characters C, D, E, etc. have high brightness even though they are data to be displayed at low brightness.

An object of the present invention is to provide a method for controlling Omote Kaura IJ in a display device having a scrolling function or a screen switching function, which displays a part of the screen memory on the screen, and also has the function of displaying any screen memory. It is something.

FIG. 4 is a partial sectional view of a display device according to an embodiment of the present invention.

The configuration and operation of the block diagram shown in FIG. 4 are almost the same as the operation of the block diagram of FIG. 2 described in the prior art section, and the differences will be explained below.

As for the configuration, a control information register 14 and a selection circuit 15 are added.

In operation, when displaying a part of the screen memory, if control information regarding the display of character codes in the display area does not exist in the display area but is in a non-display area, that control information is set in the control information register 14. be done.

This means that when the display area is changed from, for example, the state of A in Figure 3 to the state of the mouth, the screen memory before the storage location of the first character code C in the display area is searched, and the first character code C is detected. This is done by setting control information.

In the case of Figure 3, a search is performed for character codes B and A,
When the control information (■) is detected next, this control information (■) is set in the register 14.

Incidentally, this search operation can be performed by simply updating the address on the screen memory, and can be easily performed by operating a known address counter that specifies the address on the screen memory.

The selection circuit 15 selects the contents of either the control information register 9 or 14.

The selection method is to first read the screen memory from the top of the screen, select the control information register 14 until the control information is recognized, and then select the control information register 9 from that point on. The display goes around,
When the screen returns to the top again, the control information register 14 is selected.

This operation will be explained with reference to the example shown in FIG. 3. When the mouth is set as the display area, control information (2) is first set in the control information register 14.

The character pattern is displayed from the top of the screen, that is, from the letter C, but at this time, it is controlled by the contents of the control information [Yes], so the character pattern is displayed at low brightness, and the character pattern is displayed from the beginning to the letter E...
. . . are similarly displayed at low brightness.

Then, when the continuation and the contents of the screen memory are displayed on the screen and the control information ■ is read out, the screen control is controlled by the control information ■
The characters X and Y are displayed with high brightness.

When the screen returns to the top, the contents of the control information ■ will be selected again, and the characters C, D, E...
・is displayed at low brightness.

As described above, according to the present invention, screen display control can be easily performed in a display device that displays a part of the screen memory on the screen, such as a display screen scrolling function or a screen switching function.

[Brief explanation of the drawing]

FIG. 1 is an operational diagram for explaining the prior art, FIG. 2 is a block diagram for explaining the prior art, and FIG. 3 is an operational diagram of a display device with a scroll function etc.
FIG. 4 is a block diagram of an embodiment of the present invention. Explanation of symbols, 1...Display device, 2...
Space, 3...Low brightness characters, 4...
High-intensity characters, 5...Screen memory, 6...
・Control information flag, 7...Character generator, 8...
...Pattern display line, 9...Control information register (1), 10...Display control circuit, 11...
...Display control line, 12...Negation circuit, 13
...Screen memory, 14--Control information register (2), 15--Selection circuit.

Claims (1)

[Claims] 1. In a display device that reads character codes and display control information stored in a drawing memory and displays a character pattern corresponding to a certain character code on the display screen while controlling the display state based on the display control information, It has a storage means for storing display control information for controlling the display state of the character code stored at least at the beginning in a certain area of the screen memory set for display, and each time the display area is changed. A screen control method for a display device, characterized in that the contents of the storage means are rewritten.