CN1021381C - raster scan display system - Google Patents

Abstract

The raster scanning display system provided by the present invention is used to compose multi-frame color images. The first frame buffer memory (5) and the second frame buffer memory (6), which respectively store the first and second frame color images, are accessed in a synchronous manner with the CRT. Next, the first and second color pixel data streams (8), (9) are respectively provided from the first and second frame buffer memory, subsequently, the first color pixel data stream is combined with the predetermined color (14 ) comparison, if pointing out that the two colors are different when comparing, then the first color pixel data flow is sent on the CRT; if pointing out that the two colors are the same, then the second color pixel data is sent on the CRT. Therefore, the first color image is superimposed on the second color image except for the portion with the predetermined color. In this way, the predetermined color portion in the first color image appears to be transparent.

Description

The present invention relates to a raster scan display system which reads display data from a memory in synchronization with raster scan and displays them on a CRT (cathode ray tube) or similar device. In particular, the invention relates to a raster scan display device capable of displaying in various ways.

The raster scan display system is used to store a frame of character or image data in a memory and display a piece of text or an image on a CRT or similar device by fetching data from the memory. Recently, it has been proposed to synthesize several images to form a variety of colorful image frames.

An example is set forth in Japanese Laid-Open Patent Application No. 185085/83, entitled "Image Display", in which display data output from an external memory, such as a floppy disk drive, is written into an image memory Before the device, it is stipulated that there are prohibited colors. In the storage units assigned to the prohibited colors, the original display data remains unchanged, while the display data from the floppy disk drive is rewritten in other storage units. In this way, multiple images can be synthesized to form a more varied picture. For example, there is a case where an image of a car shown in FIG. 5B is stored in an image memory, assuming that the vehicle body is red and the tires are black, these two colors are specified as prohibited colors. Then, the image data representing the scenery shown in Figure 5A is written into the above-mentioned memory from a disk drive, and this has just realized storing a frame of combined images (as shown in Figure 5C) in the image memory data. The combined image can be displayed on a CRT or similar device.

Difficulties arise if one intends to perform more complex image processing, such as animation, in this conventional manner. That is, if it is intended to display a moving car, say a car moving from left to right in Figure 5C, while the background scenery remains stationary, this requires continuous processing of the data representing the background image. This complicates the program and reduces the processing speed.

Other conventional examples related to the present invention are found in Japanese Laid-Open Patent Application No. 161839/79 entitled "Image Generator" and No. 167079/82 entitled "Control System for CRT Picture Overwriting Display" In the book, it is all described.

Japanese Patent Application No. 161839/79, entitled "Image Generator", describes a technique for generating a combined image by combining many basic geometric figures, in which those basic geometric figures are formed by different parameters, and provide a transparency feature for a given parameter, so that the background is exposed in the area related to the transparency feature of the given parameter, that is to say, make the background see through the corresponding one or several Basic geometry. Therefore, the movement of one or several basic geometric figures can make the corresponding background area appear, that is, without complicating the program or reducing the processing speed. But because this patent invention is to form the combination image with the combination of basic geometry figure, so its application is limited. It could not form the image shown in Fig.5.

Titled "Control System for CRT Picture Rewriting Display" Japanese Patent Application No. 167079/82. Its content describes a technology for displaying factory processes in pictures and changing process images from time to time. In this technique, the factory process is decomposed into process units like stack memories, and a frame memory is prepared for each of these units. In each frame memory, predetermined display data is written into the storage unit corresponding to the decomposed flow unit, while the other storage area is a data-free area. A priority order is specified for these frame memories, and the same memory location therein is repeatedly checked according to the given order. During detection, no data storage area is passed, and when the first display data is detected, it is transferred to a display device, such as a CRT. Of course, this detection and transfer of display data is done in all memory locations in a CRT-synchronized manner.

Such a system is convenient for moving and displaying each cell, because other cells (the background) do not have to be considered. Then it can be seen that when displaying is required at the same time, it is difficult for this method to display the words or images covered by each unit, and it is also difficult to make the image of each unit transparent, so its use is also limited to a certain extent.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a raster scan display device which can easily synthesize moving images and can change the manner of synthesis in various ways.

According to the present invention, a raster scan display system includes the following parts:

a plurality of storage devices for storing display data, each of which is capable of storing one of a plurality of frames of images in color;

memory access means for simultaneously retrieving a plurality of display data streams from said plurality of storage means;

means for setting one or more reference colors, wherein a portion of the color is displayed as transparent in at least one of the above-mentioned plurality of frames of color images;

means for comparing at least one of said plurality of display data streams with said one or more reference colors;

Means for selecting color data from the above plurality of display data streams based on the comparison and sending the selected data to a display.

Therefore, if the area in the foreground picture that has the same color as the reference hue is replaced by the background picture, the image in Figure 5C can be easily synthesized, and there is no need to consider the background image, even during animation display. in this way.

In addition, when a character generation system instead of a bitmap system is used for image display, it is possible to display many articles in multiple screens according to the color of text chapters or the like.

Next, an embodiment in which the present invention is applied to a microcomputer system will be described with reference to the accompanying drawings.

With reference to Fig. 1, the first embodiment has been shown among the figure, a CPU (central processing unit), for example is an 8088 microprocessor, it passes the control bus not shown on the figure bus 2, address bus 3 and the figure, It is connected to various input/output devices not shown in the figure or a storage device. These input/output and storage devices are removed from the figure for ease of illustration.

Address control circuit 4 provides address and control signal by CPU ₁ and CRT control circuit 7 respectively, simultaneously image memory 54 and sub-memory 6 are addressed, so it can store images according to vertical and horizontal synchronization The device 5 and the secondary memory 6 are accessed.

The image memory 5 can be composed of a 64k byte RAM (random access memory) with 8 bits per byte, and the display data is written through the data bus 2. Display data is stored in the image memory in the form of a bit map, and for one pixel, for example, 4 bits can be allocated. Therefore, 16 (=2 ⁴ ) colors can be displayed. The data in the image memory 5, under the control of the address control circuit 4, is read out one by one by byte or by 8 bits, and sent to the parallel/serial conversion circuit 8 of the subsequent stage. As described above, one pixel is composed of 4 bits, and the data read out from the image memory 5 has 8 bits, or two pixels. Therefore, the parallel/serial conversion circuit reads out two pixels in parallel and sends them to the subsequent stage in series.

Sub-memory 6 has a structure similar to image memory 5 (for example, is 8 bits 32k bytes), although only one sub-memory 6 is shown in the figure, if adopting a plurality of sub-memory The device 6 is more suitable, and the output data of the secondary storage 6 is sent to another parallel/serial conversion circuit 9, which is the same as the parallel/serial conversion circuit 8.

Two pairs of 4-bit pixel data from the parallel/serial conversion circuits 8 and 9 are fed by the multiplexer 10 to the color correction circuit 11, where they are converted into image signals R, G, B, and I, which The signal is sent to the CRT through the buffer circuit 12. As for the toning circuit 11, it will be introduced later.

The switching action of the multiplexer 10 is controlled by the transparent color selection circuit 13 and the switch control circuit 14 . That is, the transparent color data P is received and registered by the transparent color selection circuit 13 through the data bus 2 . And send them to the switch control circuit 14. The transparent color selection circuit 13 obtains the PR signal (arbitration signal) and the EN signal (transparent color square) by decoding the data sent by the data bus. type permission signal), and feed them to the switch control circuit 14 of the subsequent stage. PR is a one-bit signal which indicates which pixel data from the image memory 5 or the sub-memory 6 should be processed with priority. For example, if the PR signal is "1", the pixel data in the image memory 5 is normally sent out from the multiplexer 10. On the contrary, if the PR signal is "0", usually the pixel data in the sub-memory 6 is sent first, and the EN signal transparent color mode can be enabled. Regarding the transparent color method, it will be described in detail later.

The switch control circuit 14 feeds the switch signal SW to the multiplexer 10 . For example, if the switch signal SW is "1", the pixel data in the image memory 5 is sent to the next stage, and if the signal is "0", the pixel data in the sub-memory 6 is sent to the next stage. to the next level. Switch control circuit 14 not only receives transparent color data P, PR signal and EN signal from transparent color selection circuit 13, but also inputs pixel data from image memory 5 and sub memory 6, respectively. It compares the two pairs of pixel data with the transparent color data, and then sends out the switch signal "1" or "0" as indicated in Table 1 and Table 2 according to the comparison result, PR signal and EN signal. In these two tables, Comparison output "1" represents that the comparison result is consistent, while "0" represents inconsistency, and Table 1 and Table 2 also indicate the category of the pixel data sent from multiplexer 10 (image memory=V, vice versa memory = S).

Table 1 (EN = "1"; transparent color mode)

Comparison output Switching signal SW

Image memory Sub-memory PR = "1" PR = "0"

0 0 1(V) 0(S)

0 1 0(S) 1(V)

1 0 1(V) 0(S)

1 0(S) 1(V)

Table 2 (EN = "0"; non-transparent color mode)

Comparison output Switching signal SW

Image memory Sub-memory PR = "1" PR = "0"

0 0 1(V) 0(S)

0 1 1(V) 0(S)

1 0 1(V) 0(S)

1 1 1(V) 0(S)

Hereinafter, an example of the configuration of the transparent color selection circuit in FIG. 1 will be described with reference to FIG. 2 .

Referring to FIG. 2 , the transparent color selection circuit 13 has a transparent color register 15 and a decoder 16 , for example, the selection circuit 13 can receive transparent color selection data through the data bus 2 by executing a program. The transparent color data P in the transparent color selection data, for example 4 bits, is prepared to be sent to the transparent color register 15 . On the other hand, the decoder 16 detects the transmission of the transparent color selection data. And send a write signal WE to the register 15 to store the transparent color data P.

Decoder 16 receives the display mode switching data sent by data bus 2, the information in these data includes, which one has priority in image memory 5 or secondary memory 6, and whether to adopt transparent color mode , and then, the decoder 16 sends PR and EN signals.

With reference to Fig. 3, switch control circuit 14 in Fig. 1 is described, as shown in Fig. 3, switch control circuit 14 is made up of two comparator circuits 17 and 18, a latch 19 and a switch signal generating circuit 20 . Each of the comparator circuits 17 and 18 has an input terminal fed with transparent color data P from the transparent color register in the transparent color selection circuit 13 (see Fig. 2). The parallel/serial conversion circuit 8 supplies the pixel data in the image memory 5 to the other input terminal of the comparator circuit 17 through the latch 21 . Similarly, the pixel data in the sub-memory 6 is supplied to another input terminal of another comparator 18 through a latch 22 from another parallel/serial conversion circuit 9 . The comparison output signals "1" or "0" from the comparator circuits 17 and 18 are fed to the switching signal generating circuit 20 through the latch 19 .

At the same time, the PR and EN signals from the decoder 16 in the transparent color selection circuit 13 are also fed to the switch signal generation circuit 20, and the switch signal is fed to the multiplexer 10 according to the above-mentioned Table 1 and Table 2, and multiple The way the converter switches according to the switching signal has been indicated in Table 1 and Table 2.

Latches 21, 22, 23 and 24 are omitted from FIG. 1 .

Referring to FIG. 4 , the toning circuit 11 in FIG. 1 will be described. Referring to FIG. 4 , the toning circuit 11 is composed of a decoder 25 , toning registers 26 ₁ -26 _n , gate circuits 27 ₁ -27 _n and an OR circuit 28 . From the pixel data of multiplexer 10, once locked by latch 29, promptly send to decoder 25, decoder 25 has several output lines, for example output lines 25 ₁ -25 _n can be 16 lines, And generate output according to 4-bit pixel data, which is output from one output terminal in turn. The output line 25 ₁ of the decoder is connected to a write signal input end of the color palette register 26 ₁ and a gate signal input end of the gate circuit 27 ₁ , while other output lines 25 ₂ -25 _n are similarly connected to corresponding Toning registers 26 ₂ -26 _n and gate circuits 27 ₂ -27 _n , and toning registers 26 ₁ -26 _n input toning data through data bus 2 .

The content of palette register 26 _{1-26 n} is placed like this, input comes from multiplexer 10, predetermined pixel data, and this pixel triggers one output line corresponding to it in 25 _{1-25 n} , then will come from Data from data bus 2 is stored in a corresponding register in 26 ₁ - 26 _n . For example, the transmitted toning data is stored in the register ₂₆₁ via the trigger output line ₂₅₁ . After thus writing the data into the color palette registers 26 ₁ - 26 _n , if the pixel data is provided to the decoder 25 through the multiplexer 10 again. Then a corresponding one of the gate circuits 27 ₁ - 27 _n is strobed, and the corresponding toning data is provided to the CRT through the OR circuit 28 .

Because during the registration of the toning data, one of the gate circuits 27 ₁ - 27 _n corresponding to a pre-set register in 26 ₁ - 26 _n is also strobed. This has the potential to transfer the toning data to the CRT, resulting in a bad display. Therefore, the registration of the toning data is performed during the rescan of the CRT. The palette registers 26 ₁ - 26 _n may be 5 bits or longer. Of course, the grading data is also 5 bits or longer. In this case, 32 (=2 ⁵ ) or more colors can be set. 16 of these colors can be displayed simultaneously.

Now, the operation of this embodiment will be described with reference to the images in Fig. 5C or 5D. Typically, this work is performed by an application program.

First, the image data representing the car in FIG. 5B is written into the image memory 5 in FIG. 1. FIG. These data are input from an external memory such as a floppy disk drive. In Figure 5, the color of the background and car windows is blue, while the car body and car tires are red and black, respectively. Then, the landscape image data in FIG. 5A is written into the sub memory 6 in FIG. 1. FIG. The sub memory 6 is similar to the image memory 5 . Thereafter, transparent color data P is set. The transparent color data P is assumed to be blue. Under the control of the address control circuit 4, the image memory 5 and the secondary memory 6 are fetched, thereby obtaining the pixel data corresponding to Fig. 5B and 5A by each storage unit, and sending it to the switch control circuit 14. If the PR signal is "1" and the EN signal is also "1", in this case, when the storage unit corresponding to the background and the window in the image memory 5 is fetched, then from the image memory The pixel data of 5 coincides with the transparent color data P, so that the switch control circuit 14 generates an output signal of "0". Therefore, the pixel data in the sub-memory 6 is sent to the color correction circuit 11 of the subsequent stage to display the corresponding image. For this, please refer to Table 1 above. Since the pixel data from other storage units of the image memory 5 is inconsistent with the transparent color data, the switching signal is "1", and these pixel data in the image memory 5 are sent to the color correction circuit 11, Therefore, the data displayed on the CRT is the image in Fig. 5C.

If the transparent color data is changed, for example, to red, the image in Fig. 5D will be displayed. It is believed that no further elaboration is required on this point.

If the "PR" signal is "0", the car image in Fig. 5B becomes the background, and the landscape in Fig. 5A becomes the foreground. If the green color of the trees in the landscape is specified as a transparent color, it will show the car seen through the trees. If the EN signal becomes "0", only a picture with a high priority or a foreground picture is displayed. In other words, the transparent color method is no longer used.

The above-mentioned work process has only expressed an example, certainly can display for the image of various types.

Now, a second embodiment of the present invention will be described with reference to FIG. 6. FIG. In FIG. 6, the same numerals indicate the same components as those in FIG. 1, and these components will not be described in detail here.

The way that this embodiment is taken is in an "or" circuit 30, "and" circuit 31 and "exclusive OR" circuit 32, for the picture elements from the picture memory 5 and the secondary memory 6 The data is processed and the outputs of these circuits and the output from the multiplexer 10 are fed to another multiplexer 33 and displayed alternately under predetermined control. By doing so, a more varied display can be further performed.

The present invention is not limited to those embodiments described above, and it can appear in various ways.

For example, it can apply a character generation system or a bitmap/character generation combination system. In addition, the transparent color area can be specified by setting numbers of many transparent colors at the same time.

As described above, in the present invention, by selecting a transparent color, it is possible to define a predetermined area in one image as a transparent color area, and to perform various displays. For example, a changing combined image can be formed by synthesizing images, and dynamic motion added to the image can also be easily represented. It can be applied to a multi-picture screen to centrally display various text and pictures.

Brief description of the drawings:

Fig. 1 shows a schematic block diagram of the first embodiment of the present invention.

FIG. 2 is a schematic block diagram of the structure of the transparent color selection circuit in FIG. 1 .

FIG. 3 is a schematic block diagram of the structure of the switch control circuit in FIG. 1 .

FIG. 4 is a schematic block diagram of the structure of the toning circuit in FIG. 1 .

Fig. 5 is a schematic diagram of a display mode on a display device.

Fig. 6 is a schematic block diagram of a second embodiment of the present invention.

4...address control circuit; 5...image memory; 6...secondary memory; 10...multiplexer; 13...transparent color selection circuit; 14...switch control circuit; 17, 18 ...the comparator circuit.

Claims (3)

1. A plurality of stored images are formed into a frame image, and the raster scanning display system for displaying this frame image on a display device is characterized in that: first and second storage means for storing display data, each of which is capable of storing one of a plurality of color images, accessing means for simultaneously reading data from said first and second storage means to provide respectively streams of pixel data sets for display on a raster scan display means, A switch control device, which is connected to the above-mentioned two memory stores, thereby receiving the above-mentioned data stream; the device is also connected to a data processing device, so as to receive a value representing a selected element from the data processing device and has an output data set bearing a signal indicating whether each pixel set in a selected said data stream is equal or not equal to said selected pixel value data, and A first multiplexer, which receives the above-mentioned data streams and has a control input, corresponding to the above-mentioned output terminals, for each pair of corresponding pixels in each data stream according to the corresponding indication signal One or another data group is selected from the group, and the selected data group is sent to the above-mentioned raster scan display device through the above-mentioned first multiplexer. 2. The raster scanning system of claim 1, further comprising: A means for selecting one or more data streams from the plurality of display data streams for comparison with the reference color in the comparison means. 3. The raster scanning system according to claim 1, wherein each color data is represented by a predetermined number of bits in said storage device, and said color data is sent from said storage device to said In the process of displaying the device, it is converted into a set of corresponding color component signals by the color map device.

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