JPH02176825A - Display device for picture information - Google Patents

Abstract

PURPOSE:To attain the multi-window display by assigning the windows to an optional area of a frame memory and reading only the window display data having the highest priority rank out of the frame memory to display it in the case the windows overlap with each other. CONSTITUTION:A window WD priority selection part 3 is set or reset when a boundary detecting part 2 decides the least of the WD start and end points via the intra-WD deciding parts 31 - 34. The WD number of the highest priority rank is obtained via the decoders 35 - 38 and a priority encoder 39 with the outputs of the parts 31 - 34 used as the gate signals. A position memory part 55 of a segment generating part 5 obtains the address of the display data based on the stored preceding switch position and the WD number via an address calculating part 57. A size calculating part 56 calculates a size from the difference between the present and preceding positions and generates plural segment. A display control part 6 reads successively the display data out of a frame memory 7 and displays them based on the address and the size of the display data obtained via the part 5.

Description

Detailed Description of the Invention <Field of Industrial Application> The present invention relates to a raster-type image information display device that displays multi-windows, and in particular, allocates each window to an arbitrary area on one frame memory, and This invention relates to a multi-window display device in which, if there is overlap, only the display data of the window with the highest priority is read out from the frame memory and displayed.

<Prior Art> Multi-windows have been attracting attention as one of the man-machine interfaces used in recent personal computers and workstations.

Methods for realizing multi-windows are roughly divided into those with refresh memory that stores the same data as 5 display screens and those without refresh memory. There are two methods: a method that prepares one frame memory common to all windows.

A method that has a refresh memory requires extra memory, and a method that prepares a frame memory for each window has the disadvantage that memory usage becomes inefficient.

The method of preparing one frame memory common to all windows is superior in these respects, but the frame memory is not read-only, and it is necessary to reserve time for writing. Because it is necessary to switch the address from which the data is read, fairly high-speed processing is required. Therefore, in the past, an address generator was prepared for each window, and for each point or several consecutive points on a scanning line, such as 8 dots or 16 dots, the window with the highest priority among the windows containing that point was selected. The display data is read out from the address output by the address generator of that window and displayed.

<Problems to be Solved by the Invention> However, in this conventional method, as the screen size increases, the time allowed for processing one dot becomes shorter, so it is difficult to determine which window to process each dot or every few dots. There was a problem in that checking whether the window was inside the window or which window had the highest priority would not be enough to display the window in time.

The present invention was invented to solve the above-mentioned problems, and an object of the present invention is to provide a new image information display device.

Means for Solving the Problems> In order to achieve the above object, the present invention provides a raster-type image information display device that sequentially reads image information stored in a memory and displays it in a multi-window on a display unit. storage means for storing image information of a plurality of windows to be displayed on a screen of the display section; and for each scanning line on the screen of the display section, it is determined based on the data stored in the storage means whether or not the window exists on the scanning line. A first determination means for determining.

a calculation means for calculating a starting point and an end point on the scanning line of the window determined to be on the scanning line based on the output of the first determining means; a second calculating means for determining the display priority of the plurality of windows; and generating means for generating a plurality of line segments to be displayed on the scanning line based on the outputs of the calculation means and the second determination means. The above objective can be achieved.

Since the image information display device configured as described above generates a plurality of line segments to be displayed on the scanning line of the display section, the corresponding display data is generated for each line segment. Since the addresses are continuous in the frame memory, multi-windows can be displayed by sequentially reading them out and outputting them in synchronization with the scanning timing.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment according to the present invention,
This image information display device includes a scanning line window presence/absence check section 1. Boundary detection unit 2. Window priority selection section 3.
Switching determination section 4. Line segment generation section 5, display control section 6. It is roughly constituted by a frame memory 7.

In this embodiment, a window A as shown in FIG.

A certain scanning line 2 of a screen where B, C, and D are overlapped
Consider the case where 0 is displayed. In Figure 1, Xx-XV are the horizontal start and end points of window A, and Yl + Yl
' indicates the start point and end point in the vertical direction, and PRI indicates the display priority of window A. Similarly, window BK has X21X2'Yz, Y2', PR2, and window C has Xi+X3', Y3, Y3', P
R'a is X4, X4', Y4 in window D
-Y4' and PR4 correspond to each other.

In FIG.
is a scanning line number counter 11 and a ratio scaler 12 according to the number of windows. +3.14.15. The scanning line number counter 11 is cleared by the vertical synchronization signal (VSYNC) and incremented every horizontal synchronization signal (H8YNC). Comparators 12.18 and 14.15 compare whether there is a value in scanning line number counter 11 between the vertical start point and end point of each window, and output the result. Second
In the illustrated case, windows A, B, and C are included in the scan line 20.

The boundary detection unit 2 includes an input selector 2 according to the number of windows.
1, 22, 23, 24 and a minimum value selection section 25. The input selectors 21, 22, 23, and 24 output the horizontal start point or end point of the window, or an invalid value (a very large value) to the minimum value selection section 25.

Each input selector 2+, 22, 23.24 has a window presence/absence check section l on the scanning line for each comparison gt2. ],
a, +4. .

]5, a control signal is fed back from the minimum value selection unit 25 and inputted, and if the on-scanning line window presence/absence check unit 1 determines that a certain window is not on the scanning line, an invalid value is input. , if it is determined that there is, the value of the starting point of that window is output, and if the value of that starting point is once selected as the minimum value by the minimum value selection unit 25, the value of the ending point of that window is output,
Furthermore, if this value is also selected as the minimum value, an invalid value is output. In this way, the operation is repeated for each scanning line until the outputs of all the input selectors 21, 22, 23, 24 become invalid values, and each time the output of the minimum value selection section 25 is transmitted to the next stage. In the example of Figure 2, a+ t)v Cv
Each point of d+e+f is sequentially output.

The window priority selection unit 3 is the minimum value selection unit 25 in the previous stage.
Window determining units 81, 82, 38, 34 check whether each window includes the minimum value outputted by the point, and decoders 35, 36, 87, 34, 34, 34, 38, 34, 38, 34, 38, 34, 34, 34, 34, 38, 34, 34, 34, 34, 34, 38, 34, 34, 34, 34, 34, 34, 38, 34, 34, 34, 38, 34, 38, 34, 34, 38, 34, 34, 38, 34, 38, 34, 34, 34, 38, 34, 34, 38, 34, 38, 34, 38, 34, 38, 34, and 35, 36, 87. 88 and a priority encoder 39.

The within-window determination section 31.32.88.34 is set when the boundary detection section 2 determines the starting point of the window as the minimum value, and is reset when the boundary detection section 2 determines the end point of the window as the minimum value.

Further, the window number having the highest priority can be obtained from the decoders 35, 36, 37.degree. 38 and the priority encoder 39 using the outputs of the within-window determining sections 31, 32, 33, and 34 as gate signals. Considering the case where point b in FIG. 2 is to be processed, there are two windows, A and B, that include the b character. In this case, window A has a higher priority, so window A is selected.

The switching determination section 4 includes a window number storage section 41 and a comparator 4.
2, the window number storage unit 41 stores the window number when switching was performed last time,
Compare this output with the output of the window priority selection unit 3.
'ji 42 to compare and pass it on to the next stage. Again, considering point b in FIG. 2, the window that has the priority that includes point a at point Iia that was processed last time is window A, so it is the same as window A that was selected this time. therefore.

At point b, there is no need to switch windows. Next, if we consider point C, we can see that it has a priority that includes point C.
window is window B, which was previously processed b
Since window A is selected at the point, switching is required.

The line segment generation unit 5 includes line start address generation units 51, 52, 5.
8.54 and position storage section 55. and size calculation section 56.
It is composed of an address calculation section 57. The line start address generators 51, 52, 53, 54 obtain the access address of the display data at the beginning of the scanning line, and the 1 position storage unit 55 stores the position when switching was performed last time. The address of the display data can be obtained by the address calculation section 57 from the position and the window number, and the size can be obtained by the size calculation section 56 from the difference between the current position and the previous position. Taking point C in FIG. 2 as an example, the previous point where it was determined that switching was necessary was a, and a
Since the window with the priority that includes the point is window A, window A ID a is the window A from point a to point C based on the address on the frame memory 7 of the display data of point a and the difference between the positions of point a and point C. You can get the amount of data you need to display the data. Therefore, on the scanning line 20, from point 8 to point a is the base screen, from point a to point 0 is the window Ara to point e is the window Be.
A plurality of line segments are generated such that the window from point e to point f is C1, and the base screen is from point f to point E.

The display control unit 6 sequentially reads data from the frame memory 7 storing the display data based on the address and size of the display data obtained from the line segment generation unit 5.
Perform display.

<Effects of the Invention> Since the present invention is configured as described above, the need for address switching when accessing display data is not performed at each point on the scanning line, but the number of windows is at most twice the number of windows. Since it is only necessary to check the points, it is possible to improve the processing speed for display.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing the relationship between the screen configuration and the present invention. 1: Window presence/absence check unit on scanning line 2: Boundary detection unit, 3: Window priority selection unit, 4: Switching determination unit,
5: line segment generation section, 6: display control section. 7: Preme memory.

Claims (1)

[Claims] 1. In a raster-type image information display device that sequentially reads out image information stored in a memory and displays it in multiple windows on a display unit, the image information of a plurality of windows to be displayed on the display unit is stored. storage means; first determination means for determining whether or not the window exists on each scanning line on the screen of the display unit based on data stored in the storage means; calculation means for calculating the start and end points on the scanning line of the window determined to be on the scanning line based on the output of the second determination means for determining the display priority of the plurality of windows; An image information display apparatus, comprising: means for determining a plurality of line segments, and generating means for generating a plurality of line segments to be displayed on the scanning line based on the output of the second determining means.