JPS5831588B2 - Display mode change method in raster scan type display device - Google Patents

Description

[Detailed Description of the Invention] A display screen on a CRT (Cathode Ray Tube) is divided vertically and horizontally, and display data sequentially read out from a display buffer memory according to the display order is converted into a video signal in each divided section. System diagrams, floor diagrams, etc. (hereinafter referred to as figures, etc.) are displayed using a raster-can type display device that converts and displays sequentially. When attempting to change the display mode (color, shape, flicker, etc.) of pixels that are already displayed in the surrounding area or pixels that are to be displayed in the surrounding area, conventionally, the number of pixels to be changed is changed. It was necessary to memorize in advance the position address of each pixel on the CRT display screen, and when changing the display mode, read out the address sequentially and change the display mode of the pixels on the CRT display screen corresponding to the address. .

For example, display the graphic pattern D shown in Figure 1 on a CRT screen, and memorize the position addresses of all CRT screens on which a thick line C indicating the periphery of a specific area A (shaded area) is displayed. It is necessary to keep it.

In the example of FIG. 1, the following addresses need to be stored.

Therefore, if the area in which the display mode is to be changed becomes large and the number of addresses of "surrounding pixels" increases, storing the addresses has the disadvantage that the memory capacity becomes extremely large. .

It is an object of the present invention to eliminate such drawbacks and to provide a new display mode change method that allows the same display mode to be changed with a minimum memory capacity.

FIG. 2 shows an example of a pattern displayed on a CRT screen for explaining the present invention, and is similar in content to FIG. 1.

In FIG. 2, "-pa" and "mouth" are pixels for changing the display mode, and in the present invention, these are stored in advance in the display buffer memory as specific pixel codes, and are read out and displayed. It is.

However, the display is not limited to the display formats of "■" and 10" in this figure, and other display formats may be adopted, or the display format may not be displayed at all at the beginning. The display may be made only when the user wishes to change the information, or vice versa.

In FIG. 2, AI and A2 are start addresses for changing the display mode of pixels around each of areas A1 and B, and in the example shown in the figure, A1 is conventionally used when changing the display mode. It was necessary to store all of the addresses necessary to make the changes as shown in the table above, but in the present invention, only the start addresses AI and A2 are stored.

This has the advantage that even if there are a large number of areas in which the display mode is to be changed, only the start address of each area needs to be memorized, so that the amount of memory prepared for this purpose is extremely reduced.

Next, a method for changing the display mode of the area around area A in FIG. 2 (the part drawn with "maro") will be described.

First, start address AI ((X:Y)=(1:1)
), and then change the display mode of the address A3 ((X:Y)=(2:1)) one place to the right of the start address A1 to "Next".

Then, when changing the display mode from now on, certain rules are established for the order of address readout, and by sequentially executing these rules, the surface mode around area A is automatically changed. It is something.

Next, I will describe the rules.

1) When the address on the current CRT screen moves from the left, the order of the next address is 1st on the bottom, 2nd on the right, 3rd on the top, that is, bottom, right, The above shall be determined in this order.

(The order of ``lower, left, and upper'' means that first, the data at the bottom 1 of the current address is read out, and if there is a specific pixel code there, the ``lower'' is the next address to proceed to.

If there is no specific pixel code at the bottom, the data on the right side -1 of the current address is read out, and it is determined whether there is a specific pixel code there, and if so, move that address to the next address. address.

Similarly, if it is not located at ``down-1'' or ``right,'' it must be at the remaining ``above,'' so the next direction to proceed is determined to be ``above.''

2) If the current address has been moved from "above", the priority order of the next direction is set as left, bottom, right.

3) If the current address moves from the "left", set the priority order of the next direction in the order of top, left, and bottom.

4) If the current address has been moved from "bottom", set the priority of the next direction in the order of right, top, and left.

Continuing the previous description of changing the display mode according to the rules 1) to 4) above, in Figure 2, the start address is AI ((X:Y) = (1:1))
, and the current address after moving one place to the right is A3 ((X:
Y) = (2: 1)), and since it has moved from the left direction, following the law l), the address below the current address ((X:Y) = (2:1)) The data is ((
Read the data of X:Y)(2:2)) and put it here”
It is determined whether a specific pixel code ``'' exists.

In the example of FIG. 2, since the "specific pixel code" is not present here, the data at the address to the right of the current address ((X:Y)=(2:1)) is then read out and the same determination is made.

In the example shown in Figure 2, there is a “specific pixel code” (second
In the figure, the next address to move to is ((X:Y)=(3:1)).

The current address is moved to ((X:Y)=(3:1)), the display mode of the address is changed, and the judgments defined in rules 1) to 4) are performed again.

By continuing the same process, the address becomes “−
'', go around area A clockwise (as shown by arrow E), and finally reach the start address AI (
(X:Y)=(x:1)) and all processing ends.

Similarly, when changing the display mode around area B in FIG. 2, the start address is changed to A2 ((X:Y)=(9
The change can be realized by performing the same processing as :1)).

As described above, according to the method of the present invention, if only the star address address (A1, A2, etc.) is memorized, the display mode can be sequentially changed according to the rules 1) to 4). Since the memory capacity can be omitted, the cost can be greatly reduced by using it for a supervisory display, etc.

In the embodiment of the present invention, the display mode rule is set in the clockwise direction E, but it is also possible to set it in the counterclockwise direction, and in that case, the rules 1) to 4) described above are This can be achieved simply by reversing the priorities of the moving directions: left, right, top, and bottom.

Furthermore, this idea can be extended as follows.

In the above, we have limited the next direction of movement to four directions: earth, down, left, and right, but adding movement in ``diagonal directions'' can be done by simply extending this law. It is something.

Furthermore, in the above explanation, the "specific pixel code" was explained as a clue, but this "specific pixel code" does not limit the present invention, and display data corresponding to the target "surrounding pixels" It is also possible to add a specific bit to the data without indicating it, and use that as a clue to determine.

Furthermore, there is no problem with the starting point being the point of collapse between the eyes in area A.

As described above, the present invention greatly reduces the required memory and has high industrial value.

[Brief explanation of drawings]

Figure 1 shows examples of figures and figure patterns displayed on a CRT screen. FIG. 2 is a similar diagram for explaining the invention. A, B... Area shown, A1. A2...
・Start address.

Claims (1)

[Claims] 1 Raster scan that reads display data from display buffer memory according to a predetermined display order, converts it into a video signal, and displays graphic patterns such as system diagrams and floor diagrams on a CRT using combinations of characters and graphic pixels. In a type display device, a specific pixel code is assigned in advance to display data in the display buffer memory corresponding to "pixels surrounding" a specific area of a graphic pattern that is about to be displayed or has already been displayed. Or, when changing the display mode of the "surrounding pixels" of the specific area by adding a specific bit indicating that it is a display cheater corresponding to the "surrounding pixels", If you specify the position of one of the display data of the "surrounding pixels", all the display data of the "surrounding pixel 1" will be read out in a predetermined address read order using the pixel code or the specific bit as a clue. A raster scan type that is characterized in that it is read out sequentially according to the law of , whereby all the "peripheral pixels" of the specific area are read out in a closed loop, and the display mode is changed. A display mode change method in a display device.