JPS6113756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a raster scanning graphic display device,
In particular, it relates to a memory system for rapidly changing the rotation, enlargement, etc. of the figure.

[Conventional technology]

Currently, there are three typical types of CRTs for displaying graphics: random scan type, storage type, and raster scan type.

Among these, raster scanning type CRTs are characterized by being able to easily obtain color figures and area figures and being inexpensive. A typical method of this raster scanning type CRT is the screen dot memory method. In this method, a memory is provided corresponding to each dot on the CRT screen to store its color information. For example, when a straight line figure is desired to be displayed, color information is first written for each dot in the memory of the corresponding screen dot. Next, from this screen dot memory, color information is read out according to the raster scan for display; color information is read out according to the raster scan;
Display on CRT.

However, with this method, when erasing some figures on the CRT screen, if the color information in the screen dot memory corresponding to the figure to be erased is cleared, the straight line to be erased is A phenomenon occurs in which the portions of triangle B (points C and D) that overlap A are cut off.

[Problem that the invention seeks to solve]

For this reason, conventionally, when writing a figure of color information Q to the screen dot memory, the exclusive OR (+) is written to the color information P that was originally written there, and the resulting color information is written. They used logic such as the following formula where R is assumed to be R.

P+Q→R When you want to erase this figure, you write the color information Q again by calculating the exclusive OR, and return to the original color information P as R+Q = (P+Q)Q→P. . However, this method has the disadvantage that the colors of overlapping figures are exclusive ORed, resulting in unexpected colors.

Another conventional technique, as shown in the flowchart of FIG. 8, is to clear the entire screen (that is, the contents of the entire screen dot memory) after modifying the graphic command list, There is a method that reinterprets the command list and writes it to the screen dot memory. In this way, discoloration due to the exclusive OR of color information can be avoided, but it will be necessary to temporarily erase the entire screen.
There are disadvantages such as the processing time required for this and the fact that when the graphic is moved dynamically, erasing the entire screen causes flickering which is unpleasant for humans.

Note that the graphic command list here is a collection of graphic commands that are original data before being expanded to screen dot positions, for example, graphic commands that represent a straight line using the coordinate values of a starting point and an ending point. When this graphical command list is interpreted and written to the screen dot memory (this is called expanding the graphical command list into dots), a corresponding graphic is generated on the CRT screen.

The purpose of the present invention is to
It is an object of the present invention to provide a raster scanning graphics display device capable of changing displayed graphics at high speed.

[Means for solving problems]

The present invention includes a screen dot memory that stores display information in dot format according to a command list of a figure to be displayed, and a screen dot memory that scans the screen dot memory according to a raster scan to read display information and display it on a display section. A raster scanning graphic display device equipped with a display control device includes a screen control memory for storing control information, and when writing, the display information and the control information are respectively stored in the screen dot memory and the screen control memory, Based on the control information in the control memory, only when reading for the first time after writing is completed,
A method is proposed in which information in the screen dot memory and control memory is changed only once.

According to this method, display graphics can be changed at high speed without causing screen flickering.

FIGS. 1a and 1b are diagrams showing the functions of color information and control information handled in two memories, namely, a screen dot memory and a control memory, respectively, which are the main components of the present invention. In each figure, the "X" symbol is
An indication indicating that the information value is irrelevant, "A" is an indication of color information A, and "φ" is an indication that the color has been erased.

(a) FIG. 1a shows the writing process to the screen dot memory 6 and the screen control memory 7 when a graphic command list is expanded into dots. However, 6 and 7 are reference numbers in the block diagram described later. This writing process sets color information "A" and control information "1" specified by the graphic command in the memories 6 and 7, respectively, regardless of the color information and control information before processing corresponding to the dots to be processed. It is processing. In addition,
Regarding color information, it may be set by processing such as logical summation with previous color information, multiplication, color priority, etc., and this will not contradict the following explanation, but here, we will use the hardware of the embodiment described later. The above-mentioned configuration is used to simplify the wear.

(b) FIG. 1b shows the process of reading screen dot memory for display on a CRT screen.

(i) is the normal case. That is, in read processing other than (ii), the color information and control information are not changed before or after the processing.

(ii) is a case of read processing immediately after completion of dot expansion processing of a graphic command list. Here, if the control information before processing is "0", the color information is cleared, and if the control information is "1", the color information is left as is. In either case, the control information after processing is set to "0".

The reading process follows these rules, and the display color is based on the color information before processing.

[Effect]

FIG. 2 chronologically shows the procedure of partially erasing (altering) and dynamically displaying a figure by the function of the control information described above and the CRT screen. In this figure, the shape command list includes triangle A and straight line B.
shows an example in which triangle A is continuously rotated by an angle Δθ.

At initialization, it is assumed that the screen dot memory and screen control memory are cleared. Note that the display on the CRT screen matches the screen dot memory. Here, for convenience, screen dot memory 6
(This is the CRT screen display itself) The part where color information is set and the part where "1" is set in the screen control memory 7 are represented by lines, with A being a triangle and B being a straight line. It is subscripted.

(1) When the figure command is expanded into dots, the dots corresponding to triangle A and straight line B are displayed on the screen.
Color information is set in the memory and "1" is set in the screen control memory.

(2) When the dot expansion process is completed, a completion notification will be issued. When the notification of completion is issued, all "1"s in the screen control memory are cleared during the first reading process thereafter, as shown in FIG. 3b. However, since the color information whose corresponding control information is "1" remains as is, triangle A and straight line B continue to be displayed.

(3) Now, triangle A needs to be rotated by an angle △θ. Therefore, first, the coordinate values of the graphic command representing triangle A in the graphic command list are updated to values rotated by the angle Δθ. At this stage, the display state remains unchanged since dot expansion processing has not yet been performed.

(4) When the graphical command list is updated, in order to display it, the updated graphical command list is expanded into dots. As a result, the previous triangle A and straight line B are stored in the screen dot memory 6.
In addition, rotated triangle A′, straight line B
is set. Here, the shape command for straight line B has not been changed, so they overlap, so the triangle
Only A′ is added and displayed. On the other hand, in the screen control memory 7, which has been completely cleared, "1" is set in the screen control memory area of the dots corresponding to the triangle A' and the straight line B that have been subjected to the dot expansion processing of the current graphic command list.

(5) When the dot expansion process is completed, a completion notification is issued. When the completion notification is issued, all "1"s in the screen control memory 7 are cleared during the first reading process thereafter. However, since the color information for which the corresponding control information was "1" is left as is, the rotated triangle
A′ and straight line B continue to be displayed. On the other hand, the color information in the screen dot memory 6 of the dots that correspond to the previous triangle A and do not intersect with the triangle A' and the straight line B are cleared, and although the triangle A disappears, the intersection point is not erased.

Similarly, the triangle A is successively rotated by an angle Δθ in the order of 6, 7, 8, and so on. Furthermore, from 3 to 4,
When moving from step 6 to step 7, it is necessary to confirm that the completion notification has been received as described later, but the explanation will be omitted here.

As described above with reference to FIGS. 1 and 2, providing the screen control memory 7 corresponding to each dot eliminates the reduction in processing speed and flickering caused by the full screen erasing process of the prior art. , raster scan type suitable for partial deletion and dynamic display of figures
You can get a CRT graphic display.

〔Example〕

Having described the operating principle of the present invention in detail above, one embodiment of the present invention will now be described in more detail using FIGS. 3 to 6.

FIG. 3 is a block diagram showing the overall configuration of an embodiment of the present invention. Graphics processor 1
via the interface 11, (1) controls input/output devices such as the keyboard 3 and digitizer 4, and (2) controls the graphics command list 2 stored in a part of the main memory of the graphics processor 1. (3) Controlling corrections, editing, etc., and (3) converting figure commands in figure command list 2 to
The interface 12 captures and interprets the graphics commands one by one, and stores them in the screen dot memory 6 corresponding to the dots on the screen that are to be displayed by the graphics command.
Control is performed to write predetermined color information (dot development processing) through the dot printing process. The graphics processor 1 is composed of a general minicomputer or the like. Control of the device (1) is a well-known technique, and (2) the content of graphical commands and the configuration, modification, and editing of the command list are also well-known techniques for graphic displays that are generally commercialized. moreover,
Regarding the dot expansion processing of the figure command in 3, for example, see Kamae et al.: Regarding the display of straight lines: Telecommunications Society Image Engineering Research Group Material IT72-4 Otakar Blazek et al.: Raster Scan
Graphics with Zoom and Pan: Hewlett−
There are references such as Packard Journal Jan'78.

Further, the graphics processor 1 sends a notification to the display control device 5 by a completion notification signal 14 that the dot expansion processing of the graphic command list 2 has been completed.
There is also a function to notify the display control device 5 that the next screen dot memory 2 is ready for dot expansion processing, by the expansion processing enable signal 15, but these functions are also generally The detailed explanation of the graphics processor 1 will be omitted since it is a well-known technology as a normal function of signal exchange in a minicomputer.

Now, the display control device 5 reads color information to be displayed from the screen dot memory 6 via the interface 13 according to raster scanning, takes in this as a display color signal 16, and outputs it to the video signal line 18. Display images on a raster scanning CRT. At the time of reading for this display, a control information signal 17 is applied from the screen control memory 7 to each screen dot memory 6 in order to carry out the operations described in FIGS. 1 and 2.

Next, the internal configurations of the screen dot memory 6, screen control memory 7, and display control device 5 will be explained in this order.

FIG. 4 is a circuit diagram of the screen dot memory 6. Sixteen memory cells 20 #0 to #15 form the core of the configuration. In this figure, screen dot memory 6 is 1
If the screen dot configuration is 512 x 512 dots, each memory cell 20 requires a storage capacity of 16k bits. The writing process from the graphics processor 1 and the reading process from the display control device 5 are controlled in a time-sharing manner according to display control timing, and are given by a display command signal 32 of the interface 13.

First, a write operation from the graphics processor 1 via the interface 12 will be explained. At this time, the display command signal 32 is dropped. Therefore, the selection circuits 21, 25, 26 respectively output the write color signal 40, write command signal 42,
The memory address signal 43 is selected as the data input, write command input, and address input of the memory cell 20. From Graphics Processor 1,
To write to the screen dot memory 6 corresponding to one dot, a memory address signal 43 and a dot address signal 41 for selecting one of the 16 memory cells 20 are issued. This signal 41 is
A chip select signal 50 is output to only one of the memory cells 20 via the decoder 23 and the NOR gate 24, and designated color information is set at the designated address. Further, when the write command signal 42 is falling, it indicates that the request is a read request for color information from the graphic processor 1.
At this time, the selection circuit 27 selects the read data signal 52 of the memory cell 20 specified by the dot address signal 41, and selects the read color signal 44.
It is output to the graphic processor 1 as . As described above, when the display command signal 42 is falling, the graphics processor 1 displays dots on the screen.
Color information can be written to and read from any one dot in the memory 6.

Next, a reading operation from the display control device 5 via the interface 13 will be explained. At this time, the display command signal 32 is being output, and therefore the selection circuits 21, 25, and 26 respectively input the corrected color information signal 51, the write command signal 31, and the display memory address signal 31 to the data input of the memory cell 20. , write command input, and address input. At this time, the display command signal 32 and the NAND gate 24 cause a chip select signal 50 to be output to all memory cells 20 to enable them to operate.

In normal display processing, as shown in FIG. 1B, since the color information remains unchanged, writing processing is not necessary and only reading processing is required. At this time, the write command signal 31 is of course dropped.
In this case, the read data 52 at the specified address in the screen dot memory 6 is read out from the display control device 5.
It is set in the parallel-to-serial conversion circuit 28 at the specified timing from . This designated timing is when the display dot clock signal 34 is output while the load signal 33 is on.

After loading, the load signal 33 is dropped, and the color information at the addresses designated for display in the 16 memory cells 20 is converted into serial information at the cycle of the display dot clock signal 34 and displayed. The signals are sent one after another to the display control device 5 as color signals 16.

Next, the readout operation for display and color information change operation after the completion of the dot development process of the graphic command list shown in FIG.
The reading operation for display is as described above, but under this condition, the write command signal 31 is issued from the display control device 5 at a certain timing. As a result, the data of the modified color information signal 51, that is, the read data signal 52 and the control information signal 17, are processed by the AND gate 22, and the modified color information according to FIG. 1b- is read out for display. Written to the screen dot memory 6.

Note that even during the write operation, the memory cell 20
It is necessary that the read data signal 52 of the memory cell 2 is fixed, but if the address input is fixed, the output data will remain fixed even during the write operation.
It is assumed that 0 is used.

FIG. 5 shows a circuit diagram of the screen control memory 7. This circuit is almost the same as the screen dot memory 6, and since unnecessary circuits have been removed from the screen dot memory 6, a brief explanation will be provided.

First, during a write operation from the graphics processor 1, color information is set in the corresponding screen dot memory 6, but "0" is always set in the screen control memory 7 via the selection circuit 60. It will operate according to FIG. 1a.

Next, during a normal read operation from the display control device 5, no write processing is performed on the memory cell 20, so the contents of the screen control memory 7 remain unchanged, and the operation is performed according to FIG. 1b-.

Further, when reading the graphic command list after the dot development process is completed, the tag information of the corresponding address is sent to the screen dot memory 6 via the control information signal 17, and at the same time, during the write operation, the tag information is sent to the screen dot memory 6 via the selection circuit 60. "0" is screen control memory 7
and operates according to FIG. 1b.

FIG. 6 is a circuit diagram of the display control device 5. A display dot clock 34 is output from a dot clock generating circuit 70 which defines the display time per dot in raster scanning, and at the same time a horizontal counter 71 that indicates how many dots are displayed in the horizontal direction is counted up. The value of the horizontal counter 71 is set to 16 by the horizontal counter decoder 73 during dot display.
A signal 96 for counting up the address counter 75, a horizontal synchronizing signal 93, and a count-up signal 95 for the vertical counter 72 indicating the number of vertical rasters are output for each dot. Address counter 75 can be replaced by horizontal counter 71 and vertical counter 72 when the number of horizontal dots on the screen is a power of two. The horizontal counter decoder 73 performs timing control for time-sharing access to the screen dot memory 6 between the graphics processor 1 and the display control device 5. That is, the display time of 16 dots is determined by the usage time of the graphics processor 1 and the display control device 5.
The display command signal 32 is set up during the access time of the display control device 5, and the load signal 33 is issued after the read data is determined during the read operation time. During the write operation time, a write timing signal 94 is output, and if a color information correction signal 91 (described later) is on, a write command signal 31 is output via the NAND gate 76. Meanwhile, the value of the vertical counter 72 is decoded by a vertical counter decoder 74, which outputs a vertical synchronization signal 92 when the entire raster scan is completed.

Now, the display color signal 16 is sent from each screen dot memory 6 at the dot timing of the display dot clock 34, as described above. This display color signal 16 is generated by a color video signal generation circuit 77 as red, green, and blue video signals, and the horizontal synchronization signal 93 and vertical synchronization signal 92 are transmitted as synchronization signals via a video signal line 18 in a raster scanning format.
Sent to CRT8.

Finally, the dot development processing completion notification signal 14 from the graphics processor 1 is first set in the flip-flop 79 for synchronization. At the first rising edge of the vertical synchronizing signal 92 after the flip-flop 79 is set, the flip-flop 80 is set, thereby outputting the color information correction signal 91 described above, so as to perform the operation shown in FIG. 1b according to the tag information. controlled by. On the other hand, the flip-flop 79 is reset via the NAND gate 79 at the fall of the same vertical synchronizing signal 92. Therefore, the flip-flop 80 is reset at the next rising edge of the vertical synchronizing signal 92. In this way, the color information correction signal 91 is output only during the first one-screen display following the completion notification signal 14, and thereafter is dropped.

A dot expansion processing enable signal 15 is output to the graphics processor 1 via the NOR gate 81 only when both flip-flops 79 and 80 are reset. As a result, the graphics processor 1 detects that it is ready for the next dot development process.

As mentioned above, one embodiment of the present invention has been described. By providing a screen control memory corresponding to each dot in this way, it is possible to eliminate the reduction in processing speed and flicker caused by performing the entire screen erasing process that was associated with the conventional technology. This has the effect that partial deletion and dynamic display of figures can be easily and quickly performed.

In the above embodiment, the screen control memory
Although the command list processing is managed under the control of list processing, this form of command list processing management is not necessarily limited to the embodiment. For example, adding a new shape,
The screen control memory can be actively utilized in the processing process related to graphics. Furthermore, the data set to the screen control memory may be set independently. This allows the screen control memory to play an extremely active role in screen processing. Furthermore, the number of screen control memories does not necessarily have to be one. When a plurality of screens are provided, more complex mutual processing of screens becomes possible. In connection with each of the above modifications, erasing the data in the screen control memory is also the first step after dot processing.
Examples that are not limited to only the number of times can also be considered. Dynamic processing such as writing at any time and erasing at any time is also possible. All of these functions are determined by the form and process of graphic processing and the location of the screen control memory.

〔Effect of the invention〕

According to the present invention, without causing flickering,
A raster scanning graphic display device capable of changing displayed graphics at high speed is obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a flowchart showing an example of the figure changing process of the present invention, FIG. 3 is a system block diagram showing an embodiment of the apparatus of the present invention, and FIG. 4 3 is a circuit diagram of the screen dot memory of the device shown in FIG. 3, FIG. 5 is a circuit diagram of the screen control memory of the device shown in FIG. 3, FIG. 6 is a circuit diagram of the display control device of the device shown in FIG. Conventional screen dots
FIG. 8 is a flowchart illustrating the disadvantages of another conventional example. DESCRIPTION OF SYMBOLS 1... Graphic processor, 2... Graphic command list, 3... Keyboard, 4... Digitizer, 5... Display control device, 6... Screen dot memory, 7... Screen control memory, 8... Raster scan type CRT.

Claims (1)

[Claims] 1. A screen dot memory that stores display information in dot format according to a command list of a figure to be displayed, and a screen dot memory that scans the screen dot memory according to a raster scan to read display information and display it on a display section. In a raster scanning graphic display device equipped with a display control device for displaying, a screen control memory for storing control information is provided, and during writing, the display information and control information are stored in the screen dot memory and the screen control memory, respectively. A raster scanning graphic display device characterized in that the information in the screen dot memory and the control memory is changed only once, based on the control information in the control memory, only during the first reading after completion of writing. 2. In the raster scanning graphic display device according to claim 1, the storage capacity of the image control memory is the same as the capacity of the screen dot memory, and when display information is written to the screen dot memory, the display information can be handled simultaneously. "1" is written as control information in the area of the screen control memory to be used, and when the first display information is read after writing is completed, the control information of the screen control memory is set to "0".
A raster scanning graphic display device characterized in that when the value is "1", the display information of the corresponding screen dot memory is cleared, and when the value is "1", the display information of the corresponding screen dot memory is left behind and only its control information is cleared. .