JPS61221791A - Cursor display system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a bitmap display system (
This invention relates to a cursor display method in workstations (including workstations such as CAD stations that employ the bitmap method).

[Prior art]

A method of displaying a cross pattern cursor in a conventional bitmap display system will be explained with reference to FIG.

A conventional display system includes a video RAMI 2 for two screens. One video RAM1
The display data is expanded into a bitmap by the CPU. The other video RAM 2 is used by the video RAM controller 3 to develop a cursor pattern into a bitmap.

The data in the video RAMI, 2 is logically summed by the logical sum circuit 4, and then transferred to the display device 5 and displayed.

As described above, in the past, in order to display the cranes on the cross, an extra video RAM for one screen was required, which caused the problem that the cost of the entire display system increased. Also, since the cursor pattern is logically combined with the display data transferred from the CPU, if the background (display data transferred from the CPU) and the cursor pattern have the same brightness (or the same color), The cursor becomes invisible.

〔the purpose〕

The object of the present invention is to remove the extra video R for cursor display.
A cursor display method that does not require AM, can always display the cursor clearly regardless of the background, and does not require special preparation of information to restore the background when moving the cursor. Our goal is to provide the following.

〔composition〕

According to the present invention, in a display system in which display data is expanded into a bitmap in a memory.

The cursor pattern data is exclusively ORed with the data at the cursor display position in the memory and written to the memory to be displayed, and when the cursor display position is moved, the data at the cursor display position in the memory is The display position data and the cursor pattern data are exclusive ORed and written into the memory.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of a display system according to an embodiment of the present invention. In this figure, 11 is a CPU for controlling this system, and 12 is a RAM used as a memory for storing programs and a work memory. 13 is an I10 interface for communicating with the host. 14 is a video RAM for bitmap development, and 15 is its controller. 16 is a display device. 18 is a mouse, and 17 is a mouse controller for controlling it. Each part is interconnected by a pass line 19.

Display data such as characters is developed into a bitmap in the video RAM 14 by the CPU 1, transferred to the display device 14 by the video RAM controller 15, and displayed.

In this display system, the cursor is displayed on the display device as a cross pattern. Since the present invention relates to the display of this cursor, it will be described in detail below.

FIG. 1 shows an operation flowchart of the mouse controller 17 and the CPU 11. This flowchart will be referred to below.

First, the CPU II displays the cursor to the cross at the initial position (step 21).This cursor display is based on the pattern data of the vertical line of the cursor to the cross, as shown in the lower right of Fig. 1 in detail. and the cursor initial display position data developed as a bitmap in the video RAM 14, and write the result to that position in the video RAM 14 (step 31), and then write the horizontal line pattern of the crane to the cross. Exclusive OR is performed between the data and the data at that position in the video RAM 14, and the result is
Write to that position of AM14 (step 32), and finally write the dot at the center point of the cross to the video RAM.
This is done by performing an exclusive OR with the dot at the corresponding location in video RAM 14 and writing it to that location in video RAM 14 (step 33). The data in the video RAM 14 is directly transferred to the display device 16 and displayed.

Therefore, 1. For example, the background of the cursor display position is 6L in Figure 3.
If it is black as shown in A, the display of that part is 62A
, 63A, and 64A. If the background of the cursor display position is a white hot water table, the display at that position is 61B and 62B in FIG.

It changes as shown in 63B and 64B. 64A in Figure 3
, 64B, the pattern of the cranes on the cross is clearly displayed regardless of the black and white of the background (display data) at the cursor display position.

The CPU II enters a state of waiting for an interrupt from the mouse controller 17 (step 22).

On the other hand, the mouse controller 17 reads and stores the initial position of the mouse 18 (step 41), sets an initial value to an internal timer (step 42), reads the position of the mouse 18 and compares it with the initial position (step 43), Based on the comparison result, it is checked whether the mouse 18 has moved or not (step 44).

If you move it, remember the position of the mouse 18 in step 4.
8) Interrupt CPUI 1 (step 4)
9).

If the mouse is not moving in step 44, the mouse controller 17 reads the value of the timer (step 45) and checks whether the specified time has elapsed (step 46). This specified time is, for example, 100 milliseconds. In step 46, if the timer has not passed the specified time, the process returns to step 43, but if the specified time has elapsed, the CPU II is interrupted (step 47).

When the CPU II accepts the interrupt from the mouse controller, it starts a routine related to cursor display (step 23), and performs processing to display the cursor at the current cursor display position (step 24). Specifically, steps 31, 32, and 33 are executed. in this case,
Since the data at the cursor display position in the video RAM 14 is the exclusive OR data of the display data and the pattern data of the crane to the cross, the exclusive OR of the pattern data of the crane to the cross is taken again. This will restore the display data.

Next, the CPU 11 performs processing to display a crane on the cross at the new cursor display position (received from the mouse controller 17) (step 25). In fact, for the new cursor display position, steps 31, 32.3
Execute 3. As a result, the red crane will be displayed at the new position. Further, if the mouse 18 does not move and a timer interrupt is accepted from the mouse controller 17, the cursor is displayed at the same position as the previous display position. After that, the CPU 11 again controls the mouse controller 1.
It enters the state of waiting for an interrupt from 7.

In this way, since the cursor pattern data is exclusively ORed with the data at the cursor display position developed in the video RAM 14, the background at the cursor display position is either black, white, or a mixture of black and white. Even if
The cursor becomes clearly distinguishable from the background. Furthermore, when moving the cursor display position, a logical OR scan is performed between the data in the video RAM 14 corresponding to the previous cursor display position and the cursor pattern data, and the display data at the previous display position is automatically Recover.

Therefore, there is no need to prepare special information for restoring background information destroyed by the cursor.

In this embodiment, the processing related to the cursor is executed by a program in the CPU II, but the processing may be executed in the video RAM controller 15, for example.

〔effect〕

As explained above, according to the present invention, there is no need to provide extra video memory for displaying the cursor, and when the cursor is moved, special information is required to restore the background of the previous cursor display position. Therefore, the cost of the display system can be reduced, and the cursor can be clearly displayed regardless of the background.

[Brief explanation of drawings]

FIG. 1 is a flowchart of processing related to cursor display in one embodiment of the present invention, FIG. 2 is a schematic block diagram showing the hardware configuration of one embodiment of the present invention, and FIG. 3 is an explanatory diagram of cursor display. FIG. 4 is a schematic block diagram for explaining the prior art. 11...CPU, 12...RAM. 13...I10 interface. 14...Video RAM, 15...Video RAM
Controller, 16...Display device, 17
... Mouse controller, 18 ... Mouse, 1
9...Pass line. Figure 1 Ma.7 Sufushito O-ra
CPIJ Figure 2 Figure 3

Claims (1)

[Claims] (1) In a display system in which display data is developed as a bitmap in memory, the cursor pattern data is exclusive-ORed with the data at the cursor display position in the memory and written to the memory to display the cursor pattern data. A cursor display method characterized in that, when moving a position, prior to the movement, data at the current display position of the cursor in the memory and pattern data of the cursor are subjected to an exclusive OR and written to the memory.