JPS59136783A - Multiwindow bit map display unit - 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 The present invention relates to a bitmap memory device for a rask scan type display, and more particularly to a bitmap memory device for a multi-window type display in which the screen is divided into a plurality of display sections.

When windows overlap in a multi-window display, a vertical relationship occurs between the windows, similar to stacking two sheets of paper, and the overlapping part of the ``bottom'' window is masked off. In the most basic bitmap memory, such a display is normally achieved by replacing the information in the masked-off portion with the information in the window above.

In this case, the information of the masked off part is lost from the bitmap memory, so when the window 1 above that masked off the relevant area is removed, the figure in the same area must be recreated and rewritten. However, it is common to
Converting all the graphical information stored in a computer as a data structure into a bead pattern requires a considerable amount of calculation and time. In order to save on processing, it is preferable to also store information on the masked-off portion in the bitmap memory. For this purpose, devices with multi-layer bitmap memories have been developed. In such a device,
Which of the multiple layers of information is displayed is determined according to the priority designation of each layer.

For example, if the bit of the layer with the highest priority is '0', white can be displayed, and if it is '1', heat can be displayed at the corresponding point on the display. However, in this method, the contents of the lower layer bitmap memory are not displayed at all, and as a result, it cannot be used for multi-windows created by an operator. In order to accommodate overlapping windows, it is necessary to display transparency (displaying information from lower-priority bitmaps) in addition to white and black, and in the end, each layer is divided into two bits per dot display point (pixel). It needs to be configured with.

That is, twice as many layers as the number of windows to support are required, and when the maximum number of windows is in the dozens, the amount of memory required becomes considerably large. Therefore, there is a need for a bitmap memory that uses a smaller amount of memory and has similar effects.

SUMMARY OF THE INVENTION An object of the present invention is to obtain a multilayer bitmap memory which is capable of handling three-valued data of transparent, white, and black isometrically with a small capacity.

These methods are necessary when the shape of the window is irregular, but in normal usage the window is rectangular, and in such cases the above methods are inefficient. In addition, when keeping the position of the window on the display constant and changing the area of data displayed within the window (that is, changing the readout area on the bitmap memory), the above method uses memory rewriting. I can't deal with the outside world.

In reality, multiple rectangular windows can be opened on a display, and these windows can be moved to any position on the display without changing their display content, and can overlap each other. It is necessary to satisfy the following conditions: the top relation can be easily changed, and the range of data visible through the window can be easily changed (for example, by scrolling from left to right or top) while the window position remains constant. .

An object of the present invention is to provide an effective bitmap display device that satisfies the above conditions.

According to the present invention, in a multi-window bitmap display device having a bitmap memory corresponding to each window, the size of the bitmap memory is larger than the size of the window, and each bitmap memory has a bitmap memory corresponding to each window. a window register that indicates the position on the display (hereinafter referred to as display position) and the display priority, a yap register that indicates the relationship between the relative position within the window and the position on the bitmap memory (hereinafter referred to as memory position), and display display timing. The display controller has a display controller that generates coordinates indicating the display position of the display point at each timing, and at each display timing, the display controller that generates the coordinates indicating the display position of the display point at the relevant timing, To obtain an apparatus characterized in that a bitmap memory corresponding to a window with a high display priority is selected, and a bit corresponding to the display point out of the contents of the bitmap memory is controlled to be output.

Next, the operating principle of the device according to the invention will be explained.

In the device according to the present invention, as in other conventional bitmap display devices, display is performed by sending data bits to be displayed to the display in accordance with the scan timing of the display. At this time, the display position coordinates (eg, x, y) of the display dots generated by the display controller are sent to the entire bitmap memory. The window register contains the window position (for example, the coordinates of the upper left and lower right points (xly Yx), (x2t y2))
given, and the display display position coordinates are
The coordinates of the two points are compared. As a result, if the display position is contained within the window (e.g.
If both l<X<X2 and yt<Y<y2 hold true)
, the display priority in the window register is output. Alternatively, the difference between the display position coordinates and the window position (for example, X-Xl).

Yyt) is the contents of the map register (for example, the memory location coordinates (xm) corresponding to the upper left point of the window).

ym)) and the result (for example, (X
X1+ Xm, Y X1+ Ym ) )
Display data is read from the bitmap memory using the memory location coordinates. On the other hand, among the display priorities output for each bitmap memory, the bitmap memory with the highest priority is selected,
Of the read display data, only that of the selected bitmap memory is sent to the display.

In the device according to the present invention, the display position of a window can be changed by changing the window coordinates of the window register, the vertical relationship of overlapping windows can be changed by changing the display priority of the window register, and the vertical relationship of overlapping windows can be changed by changing the pine register. The range of data visible through the window can be changed extremely quickly and easily without rewriting the n1 graphic data.

An embodiment of the present invention will be described below with reference to the drawings. In Figures 1 and 2, there are timing signal lines for sending data from the image memory to the display at the correct timing, map registers, window registers, and signal/data lines for reading and writing data from the CPU to the image memory. etc. are omitted because they are not related to the essence of the present invention and their methods are well known, and the following description will also mainly relate to display on a display.

First, the window setting conditions in the present invention will be described. In this embodiment, it is assumed that the origin of both the display and the image memory is the upper left corner, and the coordinate value increases toward the lower right corner.

Window 1 on the display 1000 shown in Figure 3
001 is set, and its position is in the upper left corner (x + t
yt) The lower right corner is (x2.yt). Also, the contents of the image memory that can be seen through this window (displayed within the window) are as follows in the image memory 2000:
(Xs+Ys) is (xt p Ys) of the window
). These window information are stored in the window register and map register in the bitmap memory including the image memory.

Referring to FIG. 1, the display controller 10 specifies the x, y coordinates (X, Y) of the position to be displayed on the display at a constant timing by x%, passes through the bus 13, the y coordinate path, and converts it into a bit map. Send to memories 20□ to 20a. The nth bitmap memo 1J20 shown in FIG.
n, the x and y coordinates are subtracted by subtractors 233 and 235.
and 232 and 234 of the same.

The subtracters 232 and 233 include a window register 21
The values Y1F Xt of the upper left y coordinate field 212 and upper left X coordinate field 213 of 0 are given, and
,.

The value of X-x is obtained on the relative y-coordinate bus 332 and the relative X-coordinate bus 333. These values are values obtained by converting the X, y coordinates sent out by the display controller 10 using the upper left corner ρX, y coordinates of the window of the bitmap memory 20n as a reference point. Similarly, the other input to the subtracters 234 and 235 is the value 3'z l
, X2-X are the output values of the subtracters 234 and 235. Here, the signs of the subtractors 232 to 235)
S, -s, are applied to the gate control circuit 340 via code lines 301 to 304, and sl・S,・s3・s4
When is 1, the page is transmitted to gate 206, and game 1-26
0 and the contents of the priority knife yield 211 of the window register 210' are transferred to the priority bus 23.
It is presented in ゜.

The above logical formula is (Ml <Y), (X+ <X), (Y< yt
)・(X<X2), which is equivalent to the condition that (X
, Y) are included within the window.

On the other hand, relative X coordinate bus 332, relative X coordinate bus 333
are input to one of the adders 241 and 242, respectively, and are added to the contents y on the X coordinate field 221 and the contents x3 on the X coordinate field 222 of the map register 220, respectively, and the results are added to the contents y and x
The data of the location n1 transmitted as coordinates is read out and placed on the data line 24n.

As a result of the above addition, the address given to the image memory 250 is ((X-XI)+X3, (Y-yt)+ys)
, and n correctly indicates the point 2002 shown in FIG.

Now, in the above, only one bitmap memo 1J20
．． Although the operation is shown only for the bitmap memories, similar operations occur in other bitmap memories, and data may be read from two or more bitmap memories at the same time. At this time, the priority selector 30 selects the data to be sent to the display.

That is, priority buses 231-23. Of these,
One of the data lines 241-248 corresponding to the one exhibiting the highest priority is selected and sent to the display via display data line 31. Such priority control mechanisms are known per se and will not be described further here.

Thus, to change the window position on the display and the vertical relationship of overlap, use window register 2.
The contents of 10 can also be seen through the window (
To change the range of the image memory (displayed), it is sufficient to simply change the contents of the map register 220, making it possible to effectively change the display without rewriting the image memory.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the entirety of the disaster side of the 96-page book, Fig. 2 is a block diagram showing details of the bitmap memory 20, and Fig. 3 is a diagram showing the correspondence between the display screen and image memory positions. be. . In the figure, 10 is a display controller, 12 is an X-coordinate bus, 13 is an X-coordinate bus, - 20 to 208 are bitmap memories, 23 to 238
is the priority bus, 24, ~U are the data lines, 30 is the priority selector, 31 is the display data line, 210 is the window register, 211 is the priority field, 212 is the upper left X coordinate field, 213 is the upper left X coordinate field, 214 is the 215 is the lower right X coordinate field; 220 is the map register; 221 is the y coordinate field; 222 is the X coordinate field; 232 to 235 are subtractors; 250 is an image memory, 260 is a gate, 301 to 304 are code lines, 332 is a relative X coordinate bus, 333 is a relative X coordinate bus, 340 is a gate control circuit, 1000 is a display screen, 1001 is a window on the display screen, ”002
is the point in the window, 2000 is the painting bath! Memory virtual display area, 2001
is the display range corresponding to the above 1001, and 2002 is the display range corresponding to the above 1
The point corresponding to 002 is shown. 1st drawing 2nd drawing

Claims (1)

[Claims] In a multi-window bitmap display device having a bitmap memory corresponding to each window, the size of the bitmap memory is larger than the size of the window, and the position of the corresponding window on the display (hereinafter referred to as A window register indicating the relationship between the relative position within the window and the position on the bitmap memory (hereinafter referred to as the memory position), and a map register indicating the relationship between the relative position within the window and the position on the bitmap memory (hereinafter referred to as the memory position). a display controller that generates coordinates indicating the display position of the point;
At each display timing, the bitmap memory corresponding to the window with the highest display priority is selected among the plurality of windows that include the display position of the display point, and the bitmap memory corresponding to the window with the highest display priority is selected. A multi-window bitmap display device characterized in that it is controlled to output bits corresponding to display points.