JPH0361995A - Plural picture superposing type color display device - Google Patents

Abstract

PURPOSE:To utilize a screen effectively by providing an image memory writing means and a color conversion table setting means and displaying plural pictures preferentially one over another. CONSTITUTION:The color display device is provided with, specially, the image memory writing part 5 with a mask function and the color conversion table setting part 6. The image memory writing part 5 with the mask function divides an image memory 2 into plural blocks in the depth direction and writes mutually different data selectively in block units. Further, the color conversion table setting part 6 sets which picture is given priority according to the data array in a color conversion table 3. Therefore, plural pictures can be displayed preferentially one over another. Consequently, the screen can be utilized effectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color display device equipped with an image memory and a color conversion table, and in particular to a color display device that is capable of giving priority to a plurality of screens and displaying them by overlapping each other. The present invention relates to a residual color display device that allows multiple screens to be superimposed.

[Conventional technology]

A conventional example of a color display device is shown in FIG. 7, and its details are shown in FIG.

As shown in FIG. 7, the conventional color display device includes, for example, an image memory writing section 11, an image memory 21, a color conversion table 3, a color conversion table control section 4, and the like.

The image memory writing section 1 writes a plurality of bits (for example, 8 bits) of data to the image memory 2 for each pixel. The image memory 2 has a depth corresponding to the number of bits of write data, and is read out by a data reading section (not shown). The read data is given to the color conversion table 3,
Color conversion tables 31 (R: red), 32 (G: green), 33
(B: blue) is converted into a predetermined color (brightness) and becomes display data. The color conversion table control unit 4 controls writing and reading of data to and from the color conversion table 3.

[Problem to be solved by the invention]

However, in the above-mentioned devices, since multiple bits of data are associated with each pixel, it is possible to display multiple gradations, but it is not possible to display overlapping screens (also called split screens). The problem is that it can't be done.

[Means to solve the problem]

For a color display device that reads data from an image memory in which color information for each pixel is written in the depth direction, refers to a color conversion table using this data, and converts it to a predetermined color for display, the depth of the image memory A writing means for dividing the direction into a plurality of blocks and selectively writing mutually different data for each block, and a setting means for setting which of the plurality of screens is given priority based on the data arrangement in the color conversion table. , multiple screens are given priority and displayed on top of each other.

[Operation] By providing the writing means and the setting means as described above, a plurality of screens can be given priority and displayed on top of each other, thereby making effective use of the screens.

〔Example〕

FIG. 1 is a schematic block diagram showing an embodiment of the present invention, and FIG.
The figure is a block diagram showing FIG. 1 in more detail.

As is clear from FIG. 1, this embodiment is different from the one shown in FIG. 7 in that an image memory writing section 5 with a mask function and a color conversion table setting section 6 are provided. In other words, in order to enable screen division, the image memory 2
Divide the depth direction of the color into multiple blocks. for example,
The 8-bit data read from image memory 2 is divided into the upper 5 bits and lower 3 bits, and the lower 3 bits are displayed on screen 1.
Then, the upper 5 bits are assigned to screen 2, respectively.

This allocation is performed by an image memory writing section 5 with a masking function, and when data is written to one screen, data is selectively written by masking data from other screens. Note that the number of bits into which the data read from the image memory 2 is divided can be selected as appropriate.

Here, it is assumed that a triangle is drawn on the screen 1 and a circle is drawn on the screen 2 by the image memory writing section 5 with a masking function, as shown in FIG. 3, for example. In this state R, G
, B are set by the color conversion table setting unit 6 as shown in FIG. Priority control as shown in FIG. 3(c) is performed. That is, in FIG. 4, display colors (data) At to A7 on screen l are converted to addresses 0 to 7 in color conversion table 3.
By allocating display colors (data) B1 to B31 of screen 2 to addresses 8 to 255 of color conversion table 3, respectively, the data of screen 2 is present (any of the 3rd to 7th bits of the read data 1" is set), no matter how much data there is on screen 1, address 8 and later in color conversion table 3 will be specified, and as a result, data on screen 2 will be given priority. That's why. In other words, screen division with the relationship of screen 2>screen 1 becomes possible. Note that for display colors (data) Al to A7, different data is stored for each address;
For the display colors (data) B1-B31, exactly the same data is stored in each 8 addresses.

Based on the same concept, FIG. 5 allows screen division with the relationship of screen 1>screen 2.

That is, in the figure, the upper 5 bits of data (B1 to B51) are valid only when the lower 3 bits are all "0", so the screen 1 has priority. As a result, if each data on screen 1.2 is as shown in FIGS. 3(a) and 3(b), the display screen in this case becomes as shown in FIG. 3(d).

Incidentally, if the above-described priority control is not performed, the color of the portion of the screen where the triangle and the circle overlap shown in FIGS. 3(c) and 3(d) will be an indeterminate color that is a mixture of both.

Note that as the setting data in each of the above cases, similar data as shown in FIG. 6 is used in both cases. Further, each reference numeral in the figure is the same as above, and AO and BO are transparent (no data).

〔Effect of the invention〕

According to this invention, since the conventional color display device is provided with a writing means and a setting means, it is possible to display a plurality of screens by overlapping each other and giving priority to the screens. , it becomes possible to use the screen effectively.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention, and FIG.
The figure is a detailed block diagram showing the details, Figure 3 is an explanatory diagram to explain the relationship between screen data and display screens, and Figure 4 is an explanatory diagram to explain the data setting method when giving priority to screen 2. 5 is an explanatory diagram for explaining the data setting method when giving priority to screen 1, FIG. 6 is an explanatory diagram for explaining an example of data set in the color conversion table, and FIG.
The figure is a schematic block diagram showing a conventional example of a color display device, and FIG. 8 is a detailed block diagram showing its details. Code explanation 1... Image memory writing section, 2... Image memory, 3.
...color conversion table, 4...color conversion table control unit,
5... Image memory writing section with mask function, 6... Color conversion table setting section.

Claims (1)

[Claims] 1) A color display device that reads data from an image memory in which color information for each pixel is written in the depth direction, refers to a color conversion table using this data, and converts the data into a predetermined color for display. In contrast, dividing the image memory in the depth direction into multiple blocks,
A writing means for selectively writing data that is different from each other in block units; and a setting means for setting which of the plurality of screens should be given priority based on the data arrangement in the color conversion table, A multi-screen overlapping type color display device characterized by displaying multiple screens superimposed on each other.