JPH01303491A - Image display device - Google Patents

Abstract

PURPOSE:To make superimposed character easily viewed by selecting an area on a graphic screen by surrounding the superimposed character, outputting an area specification signal when a scanned position on the screen is in said area and lowering the brightness of the graphic screen in said area. CONSTITUTION:The data on the position of the area selected by surrounding the part of the character on a character screen recorded in a display memory 1 is recorded in an area data storage circuit 6. When the scanned position on the screen is within said area, an area specification signal generation circuit 7 outputs the area specification signal showing that, so that an image data level lowering circuit 8 is driven in said area and the level of the image data read out from a display memory 2 is lowered in said area to accomplish a display where luminance is made lower. Thus, the character superimposed and displayed on said area can be easily viewed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image display device capable of superimposing and displaying the character "4" on a graph ink screen or the like.

[Conventional technology]

In conventional image display devices, the display memory for the graphic screen and the display memory for the character screen are independently set up, as described in Japanese Patent Laid-Open No. 62-194286 or No. 62-231984. The data is combined and superimposed display is performed.

[Problem to be solved by the invention]

The above-mentioned conventional technology simply relates to a technique for superimposing characters on a graphic screen, and no consideration is given to the visibility of the superimposed characters, and the difference between the characters and the background is not considered at all. There is a problem in that when the graphic screens have the same color or when the background graphic screen has a pattern with the same shape as the characters, the superimposed characters become very difficult to read.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image display device in which the next character is superimposed on a graphic screen or the like and is very easy to see.

[Means to solve the problem]

The present invention includes a first display memory for recording character information, etc.;
a second display memory for recording graphic information, etc.; means for reading image data from the first and second display memories for display; and means for reading image data read from the first and second display memories, respectively. Area data that stores data regarding the position of an area set within one screen in an image display device that is equipped with a signal synthesis means that synthesizes and displays a character screen and is capable of superimposing and displaying a character screen on a graphic screen. storage means, means for generating a signal specifying an area within the screen from data regarding the position of this area, and means for completely lowering the level of confidence data read from the second display memory and supplied to the @signal synthesis means. It is characterized by having the following.

[Effect]

In the present invention, the area data storage means stores data related to the position of the area, such as the coordinate value of the starting point of a rectangular area and the horizontal and vertical lengths, and the area designation signal generation means is stored in the area data storage means. The image data level lowering means lowers the level of the image data read out from the display memory. This image data level lowering means, which darkens the image, is driven by an area designation signal output from the area designation signal generation means. Therefore, if you select an area surrounding the character to be superimposed on the graphic screen and write data related to this position in the area data storage means, the area designation signal generating means will cause the area to overlap when the screen scanning position is exactly within this area. A designation signal is output, and this region designation signal drives the V image data level lowering means to reduce the brightness of the graphic screen within this region, surrounding the characters superimposed on the graphic screen. It is possible to cast a so-called shadow on the graphic screen, making it easier to see superimposed characters.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image display device according to an embodiment of the present invention, in which 1 and 2 are display memories for recording different image data, and 5 is a display memory 1 and a display memory for display. 2 is a memory readout circuit for reading out image data; 4 is a transparent color detection circuit for detecting transparent color data among the image data read out from the display memory 1; 5 is a transparent color detection circuit for detecting transparent color data by the transparent color detection circuit 4; a switching circuit that selects and displays image data in display memory 2 at times and selects and displays image data in display memory 1 at other times;
7 is an area data storage circuit that records data regarding the position of an area to be set within the screen, and 7 is an area designation number 1a that indicates from the data recorded in the area data storage circuit 6 that the scan position of the screen is exactly within that area. 8 is an image data level lowering circuit that lowers the level of image data read out from the display memory 2; other circuits not directly related to the description of the present invention are omitted. . In the image display device shown in FIG. 1, the display memory 1 mainly stores image data such as character screens, and the display memory 2 mainly stores image data such as graphic screens. In this case, by recording data representing a transparent color as character background data on the character screen recorded in the display memory 1, the transparent color detection circuit 4 will not detect the transparent color in the character part and switch. The circuit 5 selects and displays the image data in the display memory 1, but the transparent color detection circuit 5 detects a transparent color in the background part of the characters, and the switching circuit 5 selects the image data in the display memory 2 based on the detection output. The characters are superimposed on the graphic screen. According to the present invention, an area data storage circuit 6, an area designation signal generation circuit 7, and an image data level lowering circuit 8 are added to the image display device shown in FIG. Area data storage circuit 6
For example, if this area is limited to a rectangular area, the coordinates of the upper left corner of the rectangle and the width of the rectangle in the horizontal and vertical directions are recorded. The designation signal generation circuit 7 compares the data recorded in the area data storage circuit 6 with the readout address of the display memory output from the memory readout circuit 3, and designates the area to indicate that the screen scanning position is exactly within the area. The image data level lowering circuit 8 lowers the level of image data read out from the display memory 2 and darkens the brightness of the image. FIG. 2 shows a specific example of the configuration of this image data level lowering circuit 8, and it is assumed that the image data read out from the simple refined display memory 2 is expressed in v4 bits per pixel. The part surrounded by a broken line in FIG. 2 corresponds to the image data level lowering circuit 8 in FIG. (i-0 to 3) are the image data supplied to the switching circuit 5, and S is the area designation signal output from the area designation signal generation circuit 7. Note that image data D2
and d□, 1=5 is the most significant bit, i=
Let o indicate the least significant bit. The image data level lowering circuit shown in Figure 2 is composed of four switches that are switched by the area designation signal S. When the area designation signal S is not output, the switch is on the nine side, indicated by a solid line in the diagram. However, when the area designation signal S is output, the switch is connected to the side shown by the broken line in the figure. If the switch is connected to the side indicated by the solid line in the figure, the image data D,
(1=0-3) becomes dyu (i=0-3) and is output as is. On the other hand, when the switch is connected to the side indicated by the broken line in the figure, the data of d3 is zero as shown in the figure.
2 to 0) will be output, and in the end the image data will be 1.
The bits will be output shifted to the least significant bit side, which means that the level of the image data will be lowered to half (however, the decimal point will be discarded) without any correction. be. Returning to the explanation of the image display device shown in FIG. 1, the area data storage circuit 6 selects an area surrounding the character portion of the character screen recorded in the display memory 1, and stores data regarding the position of this area. Record it.

By doing so, the area designation signal generation circuit 7 outputs an area designation signal to notify when the screen scanning position is within this area, so the image data level reduction circuit 8 is driven within this area and the display memory 2 The level of the image data read out is lowered in this area, and a display with darker brightness is realized, making it easier to see the characters displayed superimposed on this area. In Fig. 1, it is assumed that the image data is recorded as it is in the display memory 1 or display memory 2, and the character screen is recorded in the display memory 1 in the form of a character code, and when it is displayed, the image data is transferred through the character generator. The data for the graphic screen may also be compressed and recorded in the display memory 2, and when displayed, the decompression circuit may output li! ! It is also possible to obtain l image data. Further, the superimposed display of the two screens is not limited to the selective switching display by the switching circuit 5, but may also be performed by addition processing of two image data or the like. Furthermore, the area data storage circuit 6 is not limited to the above-mentioned method of recording the starting point coordinate value and the length in the horizontal and vertical directions of a rectangular area, but also has a bitmap memory corresponding to the display memory 2, and records the pixel by pixel. It is also possible to record whether or not it corresponds to a desired area, and then read the data from this memory and use the data as it is as an area designation signal. Further, the image data level lowering circuit 8 shown in FIG. 2 lowers the level of image data by a method that subtracts a certain amount of data from image data or a method that converts data using a data conversion memory, not limited to the example sentence. You can.

〔Effect of the invention〕

Claims (1)

[Claims] 1. a first display memory for recording character information, etc.; a second display memory for recording graphic information, etc.; means for reading image data from the first and second display memories for display; and a signal synthesizing means for synthesizing and displaying the image data respectively read from the second display memory, and is capable of superimposing and displaying a character screen, etc. on a graphic screen, etc. an area data storage means for recording data regarding the position of an area to be set within the screen; and means for generating an area designation signal indicating that the scanning position of the screen is within the area from the data regarding the position of the area; comprising means for reducing the level of image data read from the second display memory and supplied to the signal synthesis means; What is claimed is: 1. An image display device characterized in that the image display device is configured to display images.