JPH01184525A - Display control system - Google Patents

Abstract

PURPOSE:To heighten the degree of freedom of a program which performs display on a window and to improve the operability of a user by providing a logical double buffer at every window in a multi-window system. CONSTITUTION:Image data generated by a processor 1 according to a display instruction read out from a command memory 5 is written on frame memories 6 and 7. In such a case, a write operation is performed on the frame 6 or 7 selected by a frame memory change-over switch 10 for write. By allocating a buffer of two logical planes on respective window in the multi-window system, it is possible to perform the switching of a display buffer and a write buffer by the program on respective window in spite of another window.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a display device with a multi-window function, and is particularly suitable for display control in systems that require smooth display screen change processing such as moving images. Regarding the method.
- [Prior Art] Rusk scan type display devices, which are widely used as display devices capable of displaying graphics, generally have frame memory for one screen for refreshing.

Graphics are displayed by developing drawing commands for displaying line segments and circles into image data using a CPU (central processing unit, drawing processor, etc.) and writing the data into a frame memory.

When changing the display screen by deleting a drawing command or the like, it is difficult to directly change the image data on the frame memory. Therefore, after clearing the frame memory, it is necessary to redeploy from a new drawing command, but in this case, one display screen will be cleared each time one display is changed, and the screen flickering associated with this will occur during the last scan. This has been one of the drawbacks of type display devices.

As a method to solve this drawback, for example, JP-A-56-1
No. 43485 discloses that the refresh frame memory waits for two screens, and while one is used as a frame memory for writing image data, the other is used as a display frame memory for screen refresh, and these are A double buffer method has been proposed in which switching is performed alternately.

On the other hand, as a new technology for a single display device, a multi-window system that allows multiple pieces of information to be operated at once and provides multiple work environments on the same screen is becoming popular.

For multi-window systems, for example,
Information processing; VOL, 25, 1984゜NO, 2J No. 8
It is described on pages 8 to 89.

[Problem that the invention seeks to solve]

When trying to apply the double buffer function described above to one window in a multi-window system,
There are the following problems.

That is, in a multi-window system, when a plurality of windows are displayed on the screen, one of the windows has a frame memory (hereinafter referred to as "frame memory") that is not used for one display due to the display content being changed.

If this memory (referred to as a "non-display frame memory") is switched to writing, the display of other windows will also be drawn in the non-display frame memory, making it impossible to see changes in display.

Also, suppose that in a state where multiple windows are drawing to the non-display frame memory, the current memory is switched by one display frame in order to see the content that one window was drawing to the non-display frame memory.

The result of the display change in other windows that was being drawn to the hidden frame memory becomes visible, and the double buffer function becomes meaningless.

In this way, with conventional methods, when implementing the double buffer function in a multi-window environment, it is necessary to limit the number of windows that can use the double buffer function to one, or to stop displaying on other windows while the double buffer is in use. However, it was necessary to impose restrictions such as the user's ability to use the software, which caused a decrease in operability for the user.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional method and to provide a display control method that allows a double buffer function to be used simultaneously and independently in a plurality of windows.

[Means for solving problems]

In order to achieve the above object, the present invention allocates a logical buffer for two sides to each window, and switches the logical buffer for two sides as a display buffer or a write buffer in each window. do.

On the other hand, a table means is provided to manage the usage state of logical buffers in each window, and when a logical buffer switching or a drawing request to a window is issued in one window, the logical buffer and physical Correspondence with the appropriate buffer is performed based on the storage state of the table means, and control is performed so as to be realized in the form of data output to the application frame buffer or buffer switching.

(Operation) According to the present invention, by allocating two logical buffers to each window, a program on each window can switch between one display buffer and one write buffer without regard to other windows. , which allows double buffering to be used simultaneously and independently in multiple windows.

(Example〕 Hereinafter, one embodiment of the present invention will be described in detail.

FIG. 1 is a system configuration diagram for executing display control according to the present invention. In FIG. 1, l is a processor for controlling each element to be described later, and is operated by programs stored in a system program memory 2 and a user program memory 3. 4 is a data memory for storing data managed by the system program.

5 is a command memory for storing display commands from a user program. Reference numerals 6 and 7 designate frame memories for storing image data to be displayed on the screen, into which image data created by the processor 1 is written in accordance with display commands read from the command memory 5. in this case.

The write operation is performed using the frame memory 6 or 7 selected by the write frame memory changeover switch 10.
It is done for. In addition, the processor 1 reads image data from one frame memory selected by the read frame memory changeover switch 17 and writes it to the other frame memory selected by the switch 10, so that image data can be transferred between the same or different frame memories. image data can be copied.

The image data on the frame memory is passed through the display frame memory changeover switch 11.

It is read out by the CRT controller 8, converted to an analog signal, and then sent to the display device! ! 9 is output. The above switches 10, 11 and 17 are connected to the command memory 5.
It is possible to switch by a command from the processor 1 when executing a display command read from the processor 1.

In the following explanation, of the frame memories 6 and 7, the frame memory selected by the switch 10 will be referred to as the "write frame memory", and the frame memory selected by the switch 11 will be referred to as the "display frame memory". A frame memory that is not a one-display frame memory is referred to as a "non-display frame memory."

FIG. 2 shows the configuration of a program executed by the system. In this embodiment, the program for operating the processor 1 is a management program 12.window management program 1 stored in the system program memory 2.
3. Double buffer management program 14. It is roughly divided into a drawing processing program 15 and a user program 16 stored in the user program memory 3. After writing the display command into the command memory 5, the user program 16 starts the management program 12.

The activated management program 12 sequentially reads the contents of the command memory 5, analyzes the read instructions, and executes the window management program 13. The double buffer management program 14 and the drawing processing program 15 are started.

Each of the activated programs 13 to 15 writes image data to the frame memory 6 or 7, copies image data on the frame memory, or switches 10. By controlling the switching of the switch 11 and the switch 17, display commands from the user program are executed.

FIG. 3 shows the format of a display command written by the user program to the command memory 5. 100 is a command for creating a new window on the screen, an operation code 106, and an identification number (WN) 107 of the window to be created.
．． The X coordinate 11108 at the lower left corner on the display device 9, the Y coordinate 109, and the X coordinate 110 and Y at the upper right corner.
It is composed of coordinates 111. 101 is a command for deleting a window, which is composed of an operation code 112 and an identification number 113 of the window to be deleted.

102 is a command for drawing a line segment on the window, and operation code 114. Identification number 115 of the window to draw, X coordinate 116 and Y coordinate 117 of the starting point of the line segment
．． and the X coordinate 118 and Y coordinate 119 of the end point. 103 is a command for clearing the inside of the window with the background color, and is composed of an operation code 120 and an identification number 121 of the window to be cleared. Commands 104 and 105 are for double buffer control, and are used to switch between two buffers provided as drawing buffers for each window. 104 is a command for selecting a write buffer, which includes an operation code 122, an identification number 123 of the window for switching the write buffer, and a number 1 of the buffer to be selected.
The line segment drawing command 102 and the clear command 103 draw and clear the buffer selected by the write buffer switching command 104. 1o5 is a command for selecting a display buffer, and OPE2 11251 is the identification number 126 of the window for switching the display buffer. and the selected buffer number 127, and the contents of the buffer selected by the display buffer switching command are displayed on the display device v19.

FIG. 4 shows an example of a display screen using the multi-window method. In this example, 201.202
, 203. In this embodiment, each window on the screen is divided by the overlapping windows, as shown by the diagonal line rectangle 204 in FIG. shall be managed using a rectangle. In FIG. 5, rectangles 204 and 205 represent the displayed area of the window 202 (
(hereinafter referred to as the visible area) is a rectangle 206°207.20
8 represents the visible area of the window 203.

FIG. 6 shows the data structure of the window management information stored in the data memory 4.

In FIG. 6, 300 is a window display priority order data table, and 301 is a window position data (hereinafter referred to as position data) table 30 on the display screen 200.
2 is a table of position data (hereinafter referred to as display position data) for the visible area of the window; 0 display priority data table 300 is a position data table 1 consisting of a window identification number 303 and a pointer 304 to position data 301; 301 is the X coordinate 305 and Y coordinate 306 of the lower left corner of the window, and the X coordinate 307 and Y coordinate of the upper right corner
The 0 display position data table 302 consisting of coordinates 3081 and pointer 309 to the display position data table 302 is the X coordinate 310 and Y coordinate 3 of the lower left column of the rectangle (visible area).
11. X coordinate 312 and Y coordinate 313 of the upper right corner. It consists of a pointer 314 to the next rectangle included in the same window.

The contents of each data table are updated by the window management program in response to the window generation command 100 and window deletion command 101 described above.

FIG. 7 shows a data structure related to the double buffer function. Reference numeral 315 is a data table (hereinafter referred to as double buffer status data) that manages the double buffer status for each window.
From the write buffer designation indicator (LWB) 319, the 1 display buffer designation indicator (LDB) 320, and the update status indicator (AC5) 321 of the image data on the frame memory, among the logical buffers for the area. configured. In this example, the buffer specification indicators 319 and 320 take two logical values, "0" and "1", to represent one of the two buffers, but the correspondence with the frame memory is The update status indicator 321, which does not represent a value, means that the image data in the frame memory 6 is in the latest state when the value is "0", and that the image data in the frame memory 7 is in the latest state when the value is "l". , the value is r-
IJ means that the image data in the two frame memories 6 and 7 are in the same state. Also, 316
and 317 are registers for storing data indicating the write frame memory and the display frame memory, respectively; when the value is "0", the frame memory 6 is used;
1" indicates that each frame memory 7 is selected. 318 indicates the number of windows whose indicators 319 and 320 have different values on the double buffer status data table 315 among the generated windows. This is a register for storing , and its initial value is "0". The contents of the table 315 and the registers 316, 317, and 318 are updated by the double buffer management program in response to the write buffer switching command 104 and the display buffer switching command 105.

Next, with reference to FIG. 8 to FIG. 1O, the display control processing procedure in the embodiment of the present invention will be described. 8, 9, and 10 are processing means executed in response to the line segment drawing command 02, write buffer switching command 104, and display buffer switching command 105 of the display command shown in FIG. 3, respectively. Flowchart is shown. The symbol names used in these flowcharts are the command format in Figure 3,
This corresponds to the symbol name given in each table or register in FIGS. 6 and 7. In addition, in the flowchart, rlsDBJ is rlJ and rlJ when the value of data 317 (SDB) indicating the display frame memory is "0".
In this case, the value is "0", which means non-display frame memory.

The processing procedure in response to the line segment drawing command 102 shown in FIG. Compositional processing that writes image data obtained by dot expansion of line segments (
407), which is selected for each window, must always correspond to the display frame memory in order to display its contents on the screen. Therefore, in the table 315, writing to a window where the logical write buffer LWB and display buffer LDB have equal values is performed to one display frame memory, and writing to a window where the logical write buffer LWB and display buffer LDB are not equal is performed to a non-display frame memory. In FIG. 8, in the process (400 to 406) of determining a physical frame memory for writing display contents, first, a write buffer designation indicator (LWB) 31 corresponding to the window to be controlled is
Compare the value of 9 and the value of the display buffer designation indicator (LDB) 320, and if they are equal to 1 (step 400), operate the switch IO so that the frame memories for writing and displaying are the same frame memory (step 400). 401 and 402), it is stored in the update status indicator (ACS) 321 that the display frame memory has been updated.

If LWB and LDB are not equal, the switch 10 is operated and the ACS is updated so that the frame memory in the non-display state becomes the write frame memory (
Steps 404-406).

The processing procedure for the clear command 103 is the same as the processing procedure shown in FIG. 8, except that the drawing processing step 407 clears the visible area of the designated window with the background color.

FIG. 9 shows the processing procedure for switching the logical write buffer for each window, and displays the buffer number (B N) 124 specified by the switching command and the current write buffer designation for the specified window WN. child (LW)
B) Compare 319 with step 500) if not equal to 1.

The value of LWB 319 is set to the value of the specified buffer (B N
) (step 501), and as a result of the update, if the write buffer designation indicator (LWB) 319 and the display buffer designation indicator (LDB) 320 are equal (step 5
'02), the value of register 318 (D I F F) is r
-1" (step 503), if they are not equal, the value (D I F F) of the register 31g is r+NL,
The updated value (DIFF) is used in the display buffer switching process described later.

FIG. 10 shows the logical display buffer switching processing procedure for each window.
Step 600: Compare the buffer number (BN) 127 specified in step 5 with the current display buffer designation indicator (LDB) 320 of the specified window (WN) 126.
), if they are not equal, compare the values of the write buffer specification indicator (LWB) 319 and display buffer specification indicator (■, DB) 320 of the primary specified window (step 601); if they are equal, register 31
The value of 8 (DIFF) is set as r+IJL (step 602). If this value (DIFF) is ``2'' or more, that is, if the number of windows that currently select the non-display frame memory as a write buffer is 2 or more,
When the display frame memory is switched, image data being processed by a window other than the specified window will be displayed on the screen. Therefore, if the value DIFF is 2 or more (step 603), the image within the visible area of the specified window will be displayed on the screen. Hide data frame memory (lsDI3)
Copy from to display frame memory (SDR) (
step 604), if the value of register 318 (DIF
If the value of F) is "1" or less, only the specified window will use the hidden frame memory, so
In this case, image data within the visible area of the window other than the specified window is stored in the display frame memory (SD
After copying from R) to the non-display frame memory (!5DB) (step 605), one display frame memory is switched (steps 606, 607).

Copying image data on the visible area (step 604.
605), the value (AC3) of the register 321 indicating the updated state of the copied window is set to "-1", and the value of the register 321 is changed to "-1" at the next copying opportunity.
1, the copying process can be omitted. If drawing is performed on the window after copying, copying of the image data is guaranteed because the value (AC8) of the status indicator 321 has been updated as described in FIG. When the above-mentioned processing is completed, the value of the indicator 319 (LWB) and the value of the indicator 320 (LDB) are compared (step 608).
, if the value of register 318 (D T
Step 609), indicator 3
The value of 20 (LDB) and the specified buffer number (BN) 12
A value of 7 is assigned (step 610).

For example, a sequence of display commands (700 to 71O) as shown in FIG.
), the command string (702
~704) and the command string indicated by arrow B (707~70
In 9), display is suppressed during the drawing process, and the drawing result appears on the screen after the drawing is completed. In other words, the progress of display changes can be hidden from the user. Also,
Even when a plurality of windows execute a sequence of display commands as shown in FIG. 11, the processing routines shown in FIGS. 8 to 10 can suppress screen display during the drawing of each window. Therefore, according to the above embodiment, the process of changing the display contents of each window can be performed without the user seeing it.

Discomfort caused by flickering on the display screen can be eliminated. Furthermore, since the double buffer function can be used with multiple windows, the degree of freedom of programs that use windows can be increased and the operability can be improved.

In the above embodiment, when switching display buffers, there are two cases: copying only the image data of the target window, and copying image data other than the target window and switching one display frame memory. Generally, in a multi-window system, the most important window is given top priority in display order, and this window often occupies the main area of the display screen. In this case, the processing time required to copy image data can be reduced by using the double buffer function only in the window of interest.

Similarly, in the above embodiment, the buffer update status is managed for each window, but even if there are multiple windows on the screen at the same time, if there are many windows whose display is not changed, the image data The time required for copying can be reduced. Note that although the above example shows an example of processing in an environment where there is only one user process, exclusive control may be performed to suppress the execution of other processes while the processes shown in Figures 8 to 10 are being executed. For example, the present invention can be applied even in a multi-process environment.

〔Effect of the invention〕

As described above, according to the present invention, a logical double buffer can be provided for each window in a multi-window system, thereby increasing the degree of freedom of programs that display on windows and improving operability for users. can.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing the configuration of a display system according to the present invention, FIG. 2 is a diagram for explaining the relationship between programs for implementing the present invention, FIG. 3 is a diagram showing the format of display commands, and FIG. 4 and 5 are diagrams for explaining multi-windows, and FIG. 6 is a diagram showing a table for window management. FIG. 7 is an explanatory diagram of tables and registers for buffer memory management, FIGS. 8 to 10 are flowcharts of control procedures showing an embodiment of the present invention, and FIG. 11 is a diagram showing specific command sequences. It is. l... Processor, 2... System program memory, 3... User program memory, 4... Data memory, 5... Command memory, 6, 7... Frame memory, 8... CRT controller, 9...Display device, lO...Switch for switching frame memory for writing, 11...Switch for switching frame memory for display. Leather 7 m /2σノ2/ /2ri/,? 7/27 ￥ 4- times

Claims (1)

[Claims] 1. In a multi-window system including a display screen on which a plurality of windows are set, and first and second frame memories for refreshing the display screen, each window is displayed separately. Alternatively, allocate two logical buffer memories for use in writing, store the usage status of the two buffer memories in each window using management table means, and use the logical data from the program corresponding to one window. When a request for buffer memory switching or display occurs, the table means determines the usage status of the buffer memory by other windows, and the first or second frame is displayed in correspondence according to the determination result. A display control method characterized by switching memory states. 2. When the request occurs, image data corresponding to a partial area on the display screen allocated to the window is copied from one of the two frame memories to the other according to the storage contents of the table means. The display control method according to item 1, characterized in that: 3. When the request occurs, image data corresponding to an area other than the partial area on the display screen allocated to the window is transferred from one of the two frame memories according to the storage contents of the table means. 2. The display control method according to claim 1, wherein the display is copied to the other side.