JPS62226330A - Cursor control method - Google Patents

Abstract

PURPOSE:To eliminate the flicker of the picture plane of a display at the time of the generation and the movement of a cursor, and to perform a cursor process at high speed, by evading the overlapping of the scanning timing of a scanning line, and a processing timing for a cursor display. CONSTITUTION:It is assumed that the cursor whose cursor display line position A is coincided with a scanning line value m1, is moved to the position B of a scanning line value m2. Thus, when an original cursor and the cursor after being moved are overlapped, a small value (m=m1 in this case) in scanning values is set at a cursor position register 21. Also, at a cursor line number register 23 which represents the size of the cursor, the number (n) of lines of a part where two cursors are overlapped, n=n1+m2-m1 is set. In such a case, n1 is a value to represent the size of single cursor. At an offset register 22, the number of lines (l) that is displayed and scanned at the same time of a processing time T1 required for the movement of the cursor from the position A to the position B, is set, and the output of a subtractor 24 goes to (m-l), and that of an adder 25 goes to (m+n).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cursor control method, particularly to a cursor control method in a display device of an information processing terminal.

2. Description of the Related Art In recent display devices for information processing terminals, in order to improve the man-machine interface, a white area 2 is provided on the optical display screen 1 as shown in FIG. A process is performed in which the white outline is displayed in an overlapping manner on part 2. A conventional example of a cursor control device that displays such a cursor is shown in FIG. 5, for example.

This cursor control device includes a central processing unit 11 that performs data processing based on commands input from an input unit 10, a display 15, and a display data storage unit, that is, a bit map, in which various data displayed on the display 15 are stored. A display controller 13 provides address data 201 and a display control signal for reading display data from the bitmap memory 12 in accordance with the display synchronization signal of the memory 12 and the display 15, and a display control unit 13 that provides display control signals and address data 201 for reading display data from the bitmap memory 12; A parallel/serial converter 14 performs parallel/serial conversion on data. Central processing unit 1
Inside the main memory of 1, there is a storage area C for temporarily saving data on display screen 1 for displaying a cursor, and data for generating part 2 of the blank area necessary for displaying a cursor. A storage area E is provided in which data for generating an image of the cursor 3 is stored. Then, move the cursor 3 displayed together with the image on the display screen l of the display 15 to position A in FIG.
When the cursor is moved from to position B, the following processing is performed within the cursor control device.

First, as the first stage of processing, the data saved in the storage area C of the main memory of the central processing unit 11 by the operation of the central processing unit 11, that is, the original data that existed before writing the cursor 3 at position A. is read from the storage area C and placed at position A.
(arrow CA in Figure 6).

As the second stage of processing, the data displayed at position B is stored in memory area C.

As the third stage of processing, the cursor blank data is read from the storage area and written to position B while performing an AND operation with the data at position B (arrow DB in FIG. 6).

In the fourth stage of processing, the cursor blank reads data from the storage area and writes it to position B while performing an OR operation with the data at position B (arrow EB in FIG. 6). This means that the cursor 3 has been moved from position A to position B on the display screen 1 of the display 15.

The data in the bitmap memory 12 that has been rewritten through these procedures is converted into display data by the parallel/serial converter 14, and sent to the display 15 after synchronization with the display synchronization signal 202 sent from the display controller 13. and displayed.

Problems to be Solved by the Invention However, if a cursor is generated using this method, there is a problem in that the display screen of the display 15 flickers when cursor data is rewritten, which significantly reduces the operator's work efficiency.

Such a flickering phenomenon on the display screen 1 becomes most noticeable when the cursor is moved from position A to position B where the cursor display areas overlap as shown in FIG. This is because the central processing unit 11 is not monitoring which line the display control unit 13 is currently scanning and sending data to the display 15, so the original data shown by arrow CA in FIG. 6 is moved to position A. After writing, the scanning period on the display 15 collides between the completion of the cursor generation work indicated by arrows DB and l, and the data is instantaneously rewritten in the overlapping portion in FIG. 7 (indicated by diagonal lines in the figure). This is so that the human eye can catch it.

In order to eliminate flickering on the display screen 1, the central processing section 11 should constantly monitor the scanning lines of the display control section 13 and move the cursor within a time period in which the scanning periods do not conflict. However, in this case, the central processing unit 11 cannot perform other processing during the monitoring period, resulting in a decrease in system efficiency.

Another method is to set up a larger cursor movement work area outside the bitmap memory 12, as shown by the dashed line in FIG. There are ways to store data. However, in this case, there are problems such as an extra storage unit for the work area is required, and additional time is required to store the data in the work area in the bitmap memory 12.

The present invention has been made in view of these conventional problems, and its object is to provide a cursor control method that can generate a cursor in a short processing time without flickering the screen. .

Means for Solving the Problems In order to achieve the above object, the present invention provides a cursor control device with a value obtained by subtracting the number of lines scanned by the processing time required to generate the cursor from the scan line value at which cursor display is started. A value obtained by adding a line value indicating the size of the cursor to a scanning line value for starting cursor display is stored, and a cursor generation process is performed in the central processing unit based on the above two values and the value of the scanning line counter. The gist of this is to control the timing of.

Operation The present invention has the above-described configuration, so that the current scanning line counter value is larger than the value obtained by subtracting the number of lines scanned by the processing time required to generate the cursor from the scanning line value at which cursor display is started, and When the value is smaller than the sum of the scanning line value at which cursor display is started and the number of lines indicating the size of the cursor, a cursor generation processing prohibition signal is issued to the central processing unit. Then, when the scanning of the display screen progresses and the value goes out of the range of the calculated value, the cursor generation prohibition signal is stopped to the central processing unit. Generation (movement) processing is started. When this cursor generation process prohibition signal is used as an interrupt, the central processing section can perform cursor generation process and other processes at any time after the prohibition signal is released until the next interrupt occurs. Therefore, cursor generation can be performed on a high-quality screen while maintaining good work efficiency of the central processing unit.

Embodiment FIG. 1 is a block diagram showing the configuration of a cursor control device according to an embodiment of the present invention. In this figure, 11 is a central processing unit (same as shown in FIG. 5), 21 is a cursor position register that indicates the cursor display line position, and 2
2 is an offset register that stores a value indicating the number of lines scanned in the time required for cursor generation processing; 23 is a cursor line number register that stores the number of lines according to the size of the cursor; each register 21, 22 ,2
3 is set with a stored value from the central processing unit ii. 24
is a subtracter that subtracts the value of the offset register 22 from the value of the cursor position register 21 to determine the generation timing position of the cursor generation inhibit signal.

Further, 25 is an adder that adds the cursor line value to the value of the cursor position register 21 to determine the release timing position of the cursor generation prohibition signal. Note that the operations of the subtracter 24 and the adder 25 can of course be performed by the PU. Reference numeral 26 is a scanning line counter that indicates which line is currently displayed on the display screen of the display 15. A comparator 27 compares the output of the subtracter 24 with the output of the scanning line counter 26, and outputs a "true" value signal 101 when the scanning line counter value is smaller than the value of the subtracter 24. , 28 is a comparator that compares the output of the adder 25 and the output of the scanning line counter 26;
When the output of the scanning line counter value is greater than the value of the adder 25, a signal 102 with a true value is output.

Reference numeral 29 denotes an OR gate that performs a logical sum between the output of the comparator 27 and the output of the comparator 28, and the output signal of the OR gate 29 is input to the central processing section 11.

The operation of the cursor control device having such a configuration will be explained. As shown in FIG. 2, it is assumed that the cursor whose cursor display line position A matches the scanning line value m1 is moved to the position B of the scanning line value m2. In this way, when the original cursor and the moved cursor overlap, the smaller scanning line value (m=town in this case) is set in the cursor position register 21. In addition, the cursor line number register 23, which indicates the size of the cursor, contains the number of lines where two cursors overlap, n = nl −1
-m2-ml is set.

here, nl: A value indicating the size of a single cursor.

However, the value n does not have to be set to a very strict value as long as it is larger than the nl value, and may be set to n:2 nl to simplify calculation.

In the offset register 22, the number l of lines to be displayed and scanned in the same time as the processing time Tl required to move the cursor from position A to position B is set.

With the above set of values, the output of the subtracter 24 is m
-/! , the output of the adder 25 becomes m+n.

Assuming that the scanning line counter value is Zl in FIG. 2, the condition of the comparator 27 is satisfied, so that the signal 101 shows the "true" value and the signal 103 also shows the "true" value.

Next, if the scanning line counter value is Z2 or Z3 in FIG. 2, the conditions of comparators 27 and 28 are both not satisfied, so signal line 103 does not indicate a "true" value. Further, when the scan line counter value reaches Z4, the condition of the comparator 28 is satisfied, and the signal 102 becomes the "true" value, and the signal 10 becomes the "true" value.
3 would also indicate a "true" value.

As is clear from the above explanation based on FIG.
If the cursor data rewriting process is started when 03 does not indicate the "true" value, the display screen of the display 15 flickers.

Next, if the cursors do not overlap as shown in Figure 3, the cursor generation process can be divided into two operations: restoring the original data to position A and creating a new cursor to position B. good. That is, first, cursor position register 2
Set m3 to 1, 01 to the cursor line number register 23, 1a (J3<l) to the offset register 22, and if the signal 103 indicates the true value, write the original data at position A. Next, set m4 in the cursor position register 21, the number of cursor lines, 01 in the disc 23, and 14 (14) in the offset register 22. If the signal 103 shows a "true" value, the cursor creation process at position B is performed. With the above processing, even when the cursors do not overlap, the cursor generation processing can be performed without flickering the screen.

If the signal 103 does not indicate a "true" value, whether the cursors overlap or not, if this signal 103 is used for an interrupt, it is not necessary to constantly monitor this signal 103. can also perform cursor generation processing.

In this embodiment, a method for performing cursor generation processing in the central processing unit 11 has been exemplified. However, if the display control unit 13 is equipped with a logical operation circuit (for example, an ALU) and the cursor generation processing is performed, the central processing unit 11 can perform cursor generation processing. 11 is reduced, and a display terminal capable of faster processing is constructed.

The cursor control method described above can also be used in such display terminals without changing the configuration.

Effects of the Invention As is clear from the above description, the present invention stores in the cursor control device a value that is the number of lines scanned in the processing time required to generate the cursor, which is less than the scan line value at which cursor display is started. A register that adds the number of lines indicating the size of the cursor to the scanning line value at which cursor display starts is provided to prevent the scanning timing of the scanning line and the processing timing for cursor display from overlapping. The display screen will not flicker when the cursor is generated or moved, and the cursor can be processed at high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a control device for carrying out the cursor control method of the present invention, and FIG. 2 is a block diagram showing how the cursor control device shown in FIG. 1 moves the cursor within an overlapping range. FIG. 3 is a diagram showing the processing operation of moving the cursor between sufficiently distant positions by the cursor control device shown in FIG. 1, and FIG. FIG. 5 is a diagram showing a general configuration of a conventional cursor control device, and FIG. 6 is a diagram showing an example.
This figure shows a conventional cursor movement processing procedure, and FIG. 7 shows a conventional cursor movement process within an overlapping range. DESCRIPTION OF SYMBOLS 1...Display screen, 2...White area, 3...Cursor, 11...Central processing unit, 12...Bitmap memory (display data storage unit), 13...Display control unit, 14
...Parallel/serial converter, 15...Display, 21゜22, 23...Register, 24...
...Subtractor, 25...Adder, 26...Scanning line counter, 27.28...Comparator, 29...OR gate, 103...Cursor processing prohibition signal, 201-...
Display data read address signal, 202... synchronization signal. Name of agent: Patent attorney Toshio Nakao Haka 1st person
2 Figure Figure 3/l) 3 A word Figure 4

Claims (1)

[Claims] A display, a storage unit that stores image data displayed on the display, and controls the transfer of image data from the storage unit to the display, holds cursor data, and controls display of the cursor on the display as necessary. means for subtracting the number of lines scanned during the processing time required to generate the cursor from the scan line value at which to start displaying the cursor on the display; and a scanning line counter for counting the current display scanning line, and compares the scanning line counter value with the subtraction value and addition value to determine the scanning line display timing and the cursor display processing timing. 2. A cursor control method characterized in that, if the cursor control method matches, the central processing unit is instructed to prohibit processing.