JP3203973B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for displaying an image reproduced from a CD (compact disk) -G (graphics) (including a CD-EG (CD-extended graphics)).

[0002]

2. Description of the Related Art CD graphics is an audio C
The image data is recorded in an area of subcodes R to W (6 bits), which is an unused area of D. This image data is completely independent of audio data. It can be displayed in synchronization with the playback audio. This CD graphics is currently used for karaoke and the like, and requires a dedicated hardware and a decoder using personal computer software. Technologies related to such CD graphics include:
For example, it is disclosed in JP-A-2-226296.

FIG. 12 shows a conventional CD graphics display device using dedicated hardware. When the subcode data (hereinafter, simply referred to as a subcode) read from the CD graphics by the CD drive device 1 is applied to the control module 2, the content of the subcode is analyzed, and the subcode data is a CD graphics command. Following this instruction, data necessary for display is read from the subcode recorded in a predetermined format, and the display V
(Video) The image is drawn on the RAM 3. The data drawn in the VRAM 3 is applied to the display circuit 4, converted into a video signal, and displayed on the screen of the display device 5.

FIG. 13 shows a conventional C which performs similar processing by a general-purpose computer instead of using dedicated hardware.
1 shows a D graphics display device. The difference is VR
Before drawing on AM3, once draw on the internal memory 6, VR
The reason for this is that the data is transferred to the AM3 because the VRAM3 cannot be directly accessed from the program unlike the dedicated hardware.

[0005] The control module 2 shown in FIG.
The D graphics instructions are analyzed and rendered in the internal memory 6, and then the data is converted again to transfer the data to the display circuit 4 on the computer system side, or necessary information is added and a predetermined procedure is performed. (Call the function of the computer system) to transfer the data to the display circuit 4.

[0006]

By the way, since the instructions of CD graphics are reproduced at a maximum of 1/300 seconds, if the dedicated hardware has a processing capacity of a certain level or more, the above-mentioned transfer rate is not satisfied. Can be processed without any problem. However, processing by hardware with low processing capability or software of a general-purpose computer has a problem that if processing of one instruction requires more than the above time, the processing cannot be performed in time.

If the processing of the CD graphics command cannot be made in time, the reproduction (display timing) of the image data recorded in synchronization with the audio data is originally delayed, resulting in a display state different from the original. . In particular, when used for purposes such as karaoke, the display of the performance and the lyrics are shifted, which is not practical.

Next, the case of processing various instructions read from CD graphics will be described. First, for a certain position (unit of 6 horizontal dots × 12 vertical dots), 16
To display color (4-bit) images, use Write Font
After two colors are drawn by the instruction, a process of replacing a predetermined pixel with a desired color number by an exclusive OR operation (EX-OR) for each two colors is performed by using an EX-OR Font instruction.

FIGS. 14A and 14B show 16 types of pixel values “0” (= 0000) to “15” (= 1111) for each 4 × 4 dot for simplicity of explanation. An example is shown. In this process, first, FIG.
As shown in (a), pixel values “0” and “1” (= 0001) are drawn in two areas by a Write Font command which is the first command.

Next, as shown in FIG. 15B, a pixel value "0" is obtained by an EX-OR Font command which is a second command.
By drawing “2” (= 0010) in two areas, “0” to “3” (= 0011) are drawn, and then, as shown in FIG. OR
Pixel value “0”, “4” (= 010)
By drawing “0” in two areas, “0” to “7” (= 0111) are drawn, and finally, FIG.
As shown in (b), the pixel values “0” and “8” (= 1000) are drawn in two areas by the fourth command, the EX-OR Font command, so that 16 × 4 dots are provided for each 4 × 4 dot. Different pixel values “0” to “15” can be drawn.

That is, in order to draw an image in a desired position at a certain position, a plurality of commands (Write Font command and EX-OR Font command) must be processed at the same position. Therefore, it is meaningless to display the processing state in the middle until drawing of one font is finally completed, and the method of drawing a color image using CD graphics has considerable redundancy.

Next, a case where another instruction is processed will be described. With currently available CD graphics software, Preset Memor fills one screen with a specified color to prevent playback from the middle of the track due to skip processing, etc., and to prevent screen disturbance due to data loss due to errors.
Preset Bor that fills the border area with the specified color
der instruction, Load CL to change color scheme of color palette
In many cases, a UT (Color Look Up Table) instruction is recorded (multiplexed) more than necessary. Therefore, in the case of dedicated hardware or a high-speed playback device, there is no problem if such multiplexed instructions are sequentially executed, but in the case of slow processing hardware or the use of personal computer software. In the case of a decoder, a deviation from the sound occurs.

As another instruction, there are two designation methods in the CDG scroll processing. The first method is to specify the offset of the display start address of the current VRAM for graphic display.
And hardware such as an address counter, and specifically, 0 to 11 in the vertical direction.
A dot (PV) and an offset of 0 to 5 dots (PH) are specified in the horizontal direction. By specifying this offset, the position where the graphic image drawn on the VRAM is actually displayed on the display device can be changed. In this case, the processing of the image data drawn on the VRAM is performed in line. I can't. Hereinafter, this process is referred to as dot-based scrolling.

The second scroll designating method is a process of actually moving image data in units of 12 dots vertically and 6 dots horizontally. In this case, dedicated hardware also transfers image data on a VRAM by block transfer or the like. Moving.
Hereinafter, this processing is referred to as scrolling in character units.

By the way, in the case of the dot unit scroll processing, only the screen display start address of the VRAM is changed in the case of dedicated hardware, so that the entire screen is not transferred, but the software of the personal computer is used. In a decoder or the like, the VRAM cannot be operated at the hardware level, so that even in scrolling in units of dots, movement processing on the VRAM corresponding to the entire screen is required.

Here, in normal CDG data, these scroll instructions are reproduced at the maximum (1/30) second.
When scrolling one screen continuously in the horizontal direction, scrolling is performed 300 times continuously. Therefore, there is a problem that the processing of such data is delayed by hardware or software using a personal computer in a decoder or the like, and the screen display is delayed for each scroll instruction.

In view of the above-mentioned conventional problems, the present invention displays an image without problems even when the ability to process a command for CD graphics (including CD-G and CD-EG in the present invention) is low. It is an object of the present invention to provide an image display device capable of performing the following.

[0018]

According to the present invention, in order to achieve the above object, a command to be drawn and a subsequent command are provided with a Write Font command or an EX-OR command for the same position and the same channel.
In the case of the Font command, drawing is not performed in the VRAM. That is, according to the present invention, a first storage means for storing subcodes for a plurality of instructions read from CD graphics, and an image based on the instructions indicated by the subcodes stored in the first storage means. A second storage unit for expanding the data, a VRAM for storing, when the expanded image data is transferred to the second storage unit, the image data to be displayed on a screen, and the first storage unit The image data is expanded in the second storage means based on the instruction to be processed indicated by the sub-code stored in the sub-code.
Command or EX-OR Font command, the image data developed in the second storage means is not transferred to the VRAM, and in the case of another command, the image data developed in the second storage means is not transferred to the VRAM. An image display device having control means for transferring data to a VRAM is provided.

The present invention also provides a preset memory to be processed.
Instruction, Preset Border instruction, one of the LoadCLUT instruction
And so as not to process the instructions when color or is displayed in color and the current screen shown is the same. That is, according to the present invention, image data storage means for expanding image data based on a command indicated by a subcode read from CD graphics, and the image data expanded in the image data storage means are transferred. A VRAM for storing this on the screen, a color data storage means for storing the color data currently displayed on the screen, and an instruction indicated by the subcode read from the CD graphics. Memory instruction, Preset Border instruction, Load
Control means for comparing a color indicated by each instruction in any case of the CLUT instruction with a color stored in the color data storage means, and controlling not to process the instruction if they match. A display device is provided.

The present invention also relates to a Soft Scroll Sc to be processed.
reen with Preset instruction or Soft Scroll Screen with Co
If the difference between the number of dots indicated by the py instruction and the number of dots in the current scroll state is less than a predetermined number of dots, the instruction is not processed. That is, according to the present invention, image data storage means for expanding image data based on a command indicated by a subcode read from CD graphics, and the image data expanded in the image data storage means are transferred. When the VRAM is stored to display this on the screen, and the instruction indicated by the subcode read from the CD graphics is Soft S
croll Screen with Preset instruction or Soft Scroll Screen
In the case of the with Copy instruction, the number of dots indicated by the instruction and
Determining means for determining whether or not the difference from the number of dots in the current scroll state is less than a predetermined number of dots; and if the determining means determines that the number of dots is equal to or more than the predetermined number of dots, the instruction is issued. A control unit for processing the predetermined number of dots and controlling not to process the instruction when the determination unit determines that the number of dots is less than the predetermined number of dots.

[0021]

According to the present invention, the instruction to be processed and the following instruction are the Write Font instruction or EX for the same position and the same channel.
In the case of the -OR Font command, since the image is not drawn in the VRAM, an image can be displayed without any problem even when the processing capability is low.

In the present invention, the preset Mem
ory instructions, Preset Border instruction, Load CLUT instructions
In any case, if the color indicated by each instruction is the same as the color currently displayed on the screen, the instruction is not processed,
The multiple-written instruction is not processed, and therefore, even when the processing capability is low, an image can be displayed without any practical problem.

In the present invention, the Soft Scrol to be processed is
l Screen with Preset instruction or SoftScroll Screen with
If the difference between the number of dots indicated by the Copy instruction and the number of dots in the current scroll state is less than the predetermined number of dots, the instruction is not processed, so even if the processing capacity is low, there is no practical problem. Can be displayed.
Furthermore, in the present invention, since scroll processing is performed in units of characters without performing scroll processing in units of dots, an image can be displayed practically without problems even when the processing capacity is low.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the image display device according to the present invention, and the same components as those in the conventional example are denoted by the same reference numerals. 2 is a flowchart for explaining the operation of the image display device shown in FIG. 1, FIG. 3 is an explanatory diagram showing an example of a CDG instruction stored in the data storage buffer shown in FIG. 1, and FIG. 4 is a data diagram shown in FIG. FIG. 14 is an explanatory diagram showing another example of the CDG instruction stored in the storage buffer.

First, one pack of CD subcodes R to W (6 bits) is composed of 6 bits × 24 symbols.
Each symbol is the 0th symbol = mode (3 bits) + item (3 bits) 1st symbol = instruction (instruction) 2nd, 3rd symbol = parity 4th to 19th symbol = data field 20th to 23rd symbol = Parity.

In the case of CD graphics, the 0th symbol is a CDG instruction (command) (= 9) of “001” (mode) + “001” (item). In addition, the following are the first symbol instructions. “000001” (= 1): Preset Memory (Preset Memory) “000010” (= 2): Preset Border (Preset Border) “000110” (= 6): Write Font (010100) (= 20): Soft Scroll Screen wit
h Preset (soft scroll screen with
"Preset""011000" (= 24): Soft Scroll Screen wit
h Copy (soft scroll screen with copy) “011110” (= 30): Load CLUT
0 0-7 (color) “011111” (= 31): Load CLUT
18-15 (color) "100110" (= 38): EX-OR Font (exclusive or font) For details of the above instructions, refer to, for example, the so-called Red Book of Philips (issued in May 1991) or transistor technology ( (October 1992), pages 397 to 404, "Study on CD-G Standards and Image Reproduction".

Next, the data fields of the fourth to nineteenth symbols of each instruction will be described. First, the data field of the Preset Memory command (= 1) is composed of the fourth symbol = 0,0 + color number (4 bits), the fifth symbol = 0,0 + (the above repetition), the sixth to nineteenth symbols = all 0, The data field of the Preset Border command (= 2) is composed of the fourth symbol = 0,0 + color number (4 bits), the fifth to nineteenth symbols = all zeros.

The data field of the Write Font command (= 6) and the data field of the EX-OR Font command (= 38) are both the fourth symbol = CH0 (2 bits) + color 0 (color number: 4).
Bit) 5th symbol = CH1 (2 bits) + color 1 (color number: 4
6th symbol = 0 + row address (5 bits) 7th symbol = column address (6 bits) 8th to 19th symbols = font data

[0029] Soft Scroll Screen with Preset instruction (=
The data field of 20) is: 4th symbol = 0,0 + color number (4 bits) 5th symbol = horizontal movement direction (2 bits) + 0 + horizontal shift pointer (3 bits) 6th symbol = vertical movement direction (2 bits) + Vertical shift pointer (4 bits) 7th to 19th symbols = all 0s The data field of the Soft Scroll Screen with Copy instruction (= 24) is as follows: 4th symbol = all 0s 5th to 19th symbols = Soft Scroll Screen with Pres
Consists of the same as the et instruction.

In the data field of the Load CLUT0 command (= 30), CLUT colors 0-7 are indicated,
The data field of the LUT1 instruction (= 31) is CLU
T colors 8-15 are shown. A total of 12 bits of 4 bits each of RGB of one color is recorded as two symbols.

Next, the configuration and operation of the first embodiment will be described with reference to FIGS. Subcodes for a plurality of instructions read from the CD graphics by the CD drive 1 are temporarily stored in the data storage buffer 7 via the control module 2 (step S1). The control module 2 analyzes the contents of the subcode stored in the data storage buffer 7 (step S2), and executes another subcode processing if the instruction is not a CD graphics instruction (CDG instruction) (step S3 → S
5) Return to step S2.

On the other hand, if the command is a CDG command in step S3, it is determined whether the command is a Write Font command or an EX-OR Font command (step S4), and if NO, another graphic corresponding to the command is determined. The process is executed (Step S10), and the process returns to Step S2. Then, step S3
In the case of the Write Font command or the EX-OR Font command, the data of the symbol following this command is read out, drawn as a graphic in the internal memory 6, and the display position is stored (step S6).

Next, the contents of the subcode of the next instruction stored in the data storage buffer 7 are analyzed (step S7), and the next instruction (or an instruction following in an arbitrary range) is sent to the same position and the same channel. Write Font instruction or
If the command is an EX-OR Font command (step S8), VRA
The process returns to step S2 without drawing on M3. In other cases, the data drawn in the internal memory 6 is converted to VR
Transfer to AM3 (step S9), and return to step S2. The data drawn in the VRAM 3 is applied to the display circuit 4 to be converted into a video signal and displayed on the screen of the display device 5.

A specific example will be described with reference to FIG.
In the example shown in FIG. 3, the address t of the data storage buffer 7 is
09: CDG instruction 06: Write Font instruction xx, xx: Parity R1: Row address C1: Column address ch1: Channel **, **, **,...: Data are stored.

For the next address t + 1, 09: CDG instruction 38: EX-OR Font instruction xx, xx: parity R1: row address C1: column address ch1: channel **, **, * *, ...: Data is stored.

In such a case, the buffer address t
Is a Write Font instruction, and at the buffer address t + 1, the same position (the same row address R
1, the same column address C1) and the same channel ch1
Therefore, the rendering process on the VRAM 3 in response to the Write Font instruction at the buffer address t is not performed. If the instruction at the buffer address t + 1 is an instruction other than the Write Font instruction or the EX-OR Font instruction, or is located at another position or another channel, the instruction is transferred to the VRAM 3 by processing at the buffer address t.

In the above embodiment, the instruction to be processed and the following 1
Although it is configured to determine whether or not to perform processing with only one instruction, it may be configured to determine whether or not to perform processing with an instruction to be processed and a plurality of subsequent instructions. FIG.
Shows an example in which the determination is made based on the instruction to be processed and the following three instructions. The buffer address t is: 09: CDG instruction 06: Write Font instruction xx, xx: Parity R1: Row address C1: Column address ch1: Channel ** , **, **, ...: Data is stored.

Here, 09: CDG instruction 06: Write Font instruction xx, xx: Parity R1: Row address C1: Column address ch2: Channel **, **, **,. If stored, it is a Write Font instruction for the same position (R1, C1), but the channel ch1, ch
Ignore because 2 is different.

When the buffer address t + 2 contains 09: CDG instruction 02: Preset Border instruction **, **, **,...
Although it is not a Font command, it is ignored because it does not affect the drawing state at the buffer address t.

Further, 09: CDG instruction 38: EX-OR Font instruction xx, xx: Parity R1: Row address C1: Column address ch1: Channel **, **, **, ...: Data at buffer address t + 3 Is stored, the instruction at the buffer address t is a Write Font instruction, and at the buffer address t + 3, the EX to the same position (the same row address R1, the same column address C1) and the same channel ch1 is written.
-OR Font instruction, so the buffer address t
The processing for the Write Font command is not transferred to the VRAM3.

That is, buffer addresses t + 1 to t + 1
At +3, the transfer to the VRAM 3 is not performed only when a Write Font instruction and an EX-OR Font instruction to the same position and the same channel as the instruction at the buffer address t are found. Furthermore, even if a Write Font command or EX-OR Font command to the same location and the same channel is found, a Preset Memory command and Soft Scroll Screen with Pr
When an eset / Copy (scroll screen) command is found, the transfer to the VRAM 3 is forcibly performed so that the drawing state at the buffer address t does not change.

Here, the above processing is summarized as follows. (1) Write Font command to the same location, same channel, EX
-OR Font command → Do not transfer to VRAM3. (2) Write Font command to other than same channel, same channel, EX-OR Font command → ignore (analyze next command) (3) Preset Memory command → transfer to VRAM3. (4) Preset Border instruction → ignore (analyze next instruction) (5) Load CLUT 0-7 instruction → ignore (analyze next instruction) (6) Load CLUT 8-15 instruction → ignore (analyze next instruction) (7) Soft Scroll Screen with Preset instruction → VRAM
Transfer to 3. (8) Soft Scroll Screen with Copy instruction → VRAM3
Transfer to

Next, a second embodiment will be described with reference to FIGS. FIG. 5 is a block diagram showing the image display device of the second embodiment, FIG. 6 is a flowchart for explaining the operation of the image display device shown in FIG. 5, and FIG. 7 is a CDG read in the second embodiment. FIG. 9 is an explanatory diagram illustrating an example of an instruction. In this embodiment, as shown in FIG. 5, a color information memory 8 is used in place of the data storage buffer 6 shown in FIG. 1, and the color information memory 8 stores the last processed Pr.
The drawing color of the eset Memory command, the drawing color of the Preset Border command, and the CLUT value of the Load CLUT command, that is, the currently displayed color data, are stored.

The configuration and operation of this embodiment will be described with reference to FIGS. The subcode is read from the CD graphics by the CD drive 1 (step S
11), analyzed by the control module 2 (step S12). If the subcode is not a CDG instruction, the control module 2 executes another subcode process (step S13 → S14), and returns to step S12.

On the other hand, if the command is a CDG command in step S13, the command is a Preset Memory command, a Preset Bor
It is determined whether the instruction is a der instruction or a Load CLUT instruction (step S15). If NO, another graphic processing corresponding to the instruction is executed (step S16), and step S16 is executed.
Return to 12.

Then, in step S15, Preset M
emory instruction or Preset Border instruction, if any of the Load CLUT instructions, drawing color of Preset Memory instructions stored in color information memory 8, Preset Border
The drawing color of the command is compared with the value of the CLUT of the Load CLUT command (step S17). If they match, the process returns to step S12 without performing the processing of the command. On the other hand,
If they do not match, the contents of the color information memory 8 are updated (step S18), and the graphics data is drawn in the internal memory 6 based on the symbol data following this command, and the drawing data is transferred to the VRAM 3 (step S1).
9) Return to step S12.

FIG. 6 shows an example of the subcode read from the CDG. First, the contents of the color information memory 8 are initialized as follows. Preset Memory command drawing color = 0 Preset Border command drawing color = 0 CLUT0 content = all 0 CLUT1 content = all 0

As shown in FIG. 6, when the sub-code is read out at t1 to t14, the instruction is executed as follows at t1 to t4 since the color information memory 8 has been initialized. . t1: Load CLUT0 instruction t2: Load CLUT1 instruction t3: Preset Memory instruction t4: Preset Border instruction

The color information memory 8 stores t1:
Load CLUT0 instruction contents (00, 00, 00, 0
1, 01, 01) and t2: Load CLUT1 instruction contents (08, 08, 08, 09, 09, 09) and t3:
Drawing color (01) of Preset Memory command and t4: Preset
The drawing color (01) of the Border command is stored.

Next, t5: the drawing color (01) of the Preset Border command is ignored because the drawing color (01) of the Preset Memory command is the same and has the same CLUT contents, and t6: the drawing color (01) of the Preset Border command.
Are the same and have the same CLUT content and are ignored. Continued t
7: Since the drawing color (02) of the Preset Memory command is different, the processing is executed to store the color information memory 8 in this drawing color (0
Since the drawing color (02) of the subsequent t8: Preset Border command is different, the process is executed to update the color information memory 8 to this drawing color (02).

Next, the contents (00, 00, 00, 01, 01, 01) of the t9: Load CLUT0 instruction are the same, so they are ignored, and the contents of the t10: Load CLUT1 instruction (08, 08, 08, 09) are ignored. , 09, 09) are the same and are ignored. Subsequent t11: Since the contents of the Load CLUT0 instruction are different, the processing is executed and the color information memory 8 is executed.
And the following t12: Load CLUT1
Since the contents of the instruction are different, the processing is executed to update the contents of the color information memory 8. Next, t13: Preset Memor
The processing is executed because the drawing color (02) of the y instruction is the same but the contents of the CLUT are different, and t14: Preset Bor
The processing is executed because the drawing color (02) of the der instruction is the same but the contents of the CLUT are different.

Therefore, according to the second embodiment, C
Preset Memory instruction overwritten in DG, Preset
Since the processing of either the Border command or the Load CLUT command is appropriately omitted, an image can be displayed without any problem even when the processing capability is low.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram showing the image display device of the third embodiment, FIG. 9 is a flowchart for explaining the operation of the image display device shown in FIG. 8, and FIG. FIG. 11 is an explanatory diagram showing an example in which scroll processing is performed in dot units, and FIG. 11 is an explanatory diagram showing an example in which only scroll processing in character units is performed without performing scroll processing in dot units in the third embodiment.

In this embodiment, as shown in FIG. 8, a scroll processing determination module 9 is provided in place of the data storage buffer 6 shown in FIG. 1, and the scroll processing determination module 9 is used when the control module 2 processes a scroll command. It is determined whether scroll processing with an arbitrary number of dots or less is ignored or scrolling in dot units is ignored and only scrolling in character units is supported.

8 and 9, the subcode is read from the CD graphics by the CD drive 1 (step S21) and analyzed by the control module 2 (step S22). If the subcode is not a CDG instruction, the control module 2 executes another subcode process (step S23 → S24), and returns to step S22.

On the other hand, if the command is a CDG command in step S23, this command is used as the Soft Scroll Screen with Preset.
It is determined whether the received command is a command or a Soft Scroll Screen with Copy command (step S25). If NO, another graphic process corresponding to the command is executed (step S2).
6) Return to step S22. Then, step S25
In Soft Scroll Screen with Preset instruction or Soft
In the case of the Scroll Screen with Copy command, data related to scrolling in units of dots and data related to scrolling in units of characters are read out from data following the command and passed to the scroll processing determination module 9.

The scroll processing determination module 9 determines the scroll information in character units and the scroll size in dot units from the data relating to the scroll. If the scroll in character units is not detected and the scroll is in dot units only, The scroll state is compared with the current dot state scroll state (the initial state is the scroll dot number 0 in both the vertical and horizontal directions), and if it is determined that the scroll is more than the predetermined number of dots, it is determined that the scroll processing is to be performed. If it is determined that the number of dots is less than the determined number of dots, it is determined that scroll processing is not performed (steps S27 and S28).

When scrolling in character units is included, the scroll state in dot units is first initialized, and it is calculated whether or not scrolling is performed for a predetermined number of dots or more. Is determined, the amount of scrolling in character units and the amount of movement obtained by adding or subtracting are determined, and a determination that scroll processing is performed by that amount is returned to the control module 2.

The control module 2 performs drawing processing by selecting whether or not to perform scroll processing based on the determination result returned from the scroll processing determination module 9 (step S30). When the scroll processing has been performed, the scroll processing determination module 9 stores the number of dots corresponding to the scroll processing performed as a determination criterion at the time of processing the next scrollway instruction (step S29). .

FIG. 10 shows an example of this, and for simplicity of description, of the scroll commands, only movement in character units and movement in dot units in the horizontal direction are shown.
In the case of one dot unit (conventional example), one dot is moved, but in the present invention, it is moved in two dot units or three dot units. Therefore, scrolling cannot be performed more smoothly than in the case of one dot unit. However, even if the processing time for one scroll command is delayed, there is no accumulation, so that no delay occurs on the display screen. Note that, as indicated by an asterisk (*) in FIG. 10, the shift direction differs from that in the case of one dot unit depending on the scroll direction. Therefore, when PH = 0, the movement is forcibly performed.

Here, in the above-described embodiment, a method of coping with only a change of a certain number of dots or more has been described.
In most cases, the process is not completed by scrolling only in units of dots. When scrolling is performed, scrolling is always used together with scrolling in units of characters, and final scrolling is created based on scrolling in units of characters.

The reason is that the screen display itself is scrolled by the dot unit scroll, but the vertical display is 11 dots.
This is because only five horizontal dots can be scrolled, and after all, one screen of character unit scroll is performed to scroll the entire screen. That is, in the normal scrolling, even if the scrolling in units of dots is ignored, the scrolling is not performed smoothly, and the scrolling process itself is completed for one screen. FIG.
Reference numeral 1 denotes an example in which scrolling in units of dots is completely ignored (no processing is performed) and only scrolling in units of characters is processed.

[0063]

As described above, according to the present invention, if the instruction to be processed and the subsequent instruction are the Write Font instruction or EX-OR Font instruction for the same position and the same channel, no drawing is performed in the VRAM. Even when the processing capacity is low, an image can be displayed practically without any problem.

In the present invention, the preset Mem
ory instructions, Preset Border instruction, Load CLUT instructions
If the color indicated by any of them is the same as the color currently displayed on the screen, the instruction is not processed, so that the instruction written multiplely is not processed, and therefore, even if the processing capacity is low, it is practically used. Images can be displayed without any problems.

In the present invention, the Soft Scrol to be processed is
l Screen with Preset instruction or SoftScroll Screen with
If the difference between the number of dots indicated by the Copy instruction and the number of dots in the current scroll state is less than the predetermined number of dots, the instruction is not processed, so even if the processing capacity is low, there is no practical problem. Can be displayed.
Furthermore, in the present invention, since scroll processing is performed in units of characters without performing scroll processing in units of dots, an image can be displayed practically without problems even when the processing capacity is low.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an image display device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the image display device shown in FIG.

FIG. 3 shows C stored in a data storage buffer shown in FIG. 1;
FIG. 4 is an explanatory diagram illustrating an example of a DG instruction.

FIG. 4 shows C stored in a data storage buffer shown in FIG.
FIG. 9 is an explanatory diagram showing another example of the DG instruction.

FIG. 5 is a block diagram illustrating an image display device according to a second embodiment of the present invention.

6 is a flowchart for explaining the operation of the image display device shown in FIG.

FIG. 7 is an explanatory diagram showing an example of a CDG instruction read in the second embodiment.

FIG. 8 is a block diagram showing an image display device according to a third embodiment of the present invention.

9 is a flowchart for explaining the operation of the image display device shown in FIG.

FIG. 10 is an explanatory diagram showing an example in which scroll processing is performed in units of two dots and three dots in the third embodiment.

FIG. 11 is an explanatory diagram showing an example in which only scroll processing in character units is performed without performing scroll processing in dot units in the third embodiment.

FIG. 12 is a block diagram showing a conventional image display device.

FIG. 13 is a block diagram showing another conventional image display device.

FIG. 14 is an explanatory diagram showing an example of developing a color number.

FIG. 15 is an explanatory diagram showing an example of developing a color number.

FIG. 16 is an explanatory diagram showing an example of developing a color number.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 CD drive device 2 control module (control means) 3 VRAM 6 internal memory (second storage means) 7 data storage buffer (first storage means) 8 color information memory (storage means) 9 scroll processing determination module (determination means) )

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI G09G 5/34 G09G 5/34 W 5/393 5/36 530E (56) References JP-A-5-108043 (JP, A) JP-A-6-162741 (JP, A) JP-A-63-198095 (JP, A) JP-A-58-182691 (JP, A) JP-A-2-226296 (JP, A) JP-A-5-14862 (JP, A) JP-A-6-162661 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G09G 5/00-5/40 G11B 20/10-20/16 G11B 27 / 10-27/34

Claims (3)

(57) [Claims] A first storage unit for storing sub-codes for a plurality of instructions read from the CD graphics; and image data based on the instructions indicated by the sub-codes stored in the first storage unit. A second storage unit for developing, and a VRAM for storing, when the developed image data is transferred to the second storage unit, displaying the image data on a screen
Image data is developed in the second storage means based on the instruction to be processed indicated by the subcode stored in the first storage means, and the instruction to be processed and the subsequent instruction are located at the same position and in the same channel. Does not transfer the image data expanded in the second storage means to the VRAM in the case of a Write Font instruction or an EX-OR Font instruction for
Control means for transferring the image data developed in the storage means to the VRAM. 2. An image data storage unit for expanding image data based on a command indicated by a subcode read from CD graphics, and when the expanded image data is transferred to the image data storage unit. VR that stores this for display on the screen
AM, color data storage means for storing the color data currently displayed on the screen, and instructions indicated by the subcode read from the CD graphics are Preset Memory instruction, Preset Border instruction, L
In the case of any of the oad CLUT instructions, the color indicated by each instruction is compared with the color stored in the color data storage means,
And control means for controlling not to process the command when they match. 3. An image data storage unit for expanding image data based on a command indicated by a subcode read from CD graphics, and when the expanded image data is transferred to the image data storage unit. VR that stores this for display on the screen
AM, the instruction indicated by the subcode read from the CD graphics is a Soft Scroll Screen with Preset instruction or So
In the case of the ft Scroll Screen with Copy instruction, determining means for determining whether or not the difference between the number of dots indicated by the instruction and the number of dots in the current scroll state is less than a predetermined number of dots; and When it is determined that the number of dots is equal to or more than the predetermined number of dots, the command is processed by the predetermined number of dots, and when the determination unit determines that the number is less than the predetermined number of dots, the command is processed. Control means for controlling not to perform the image display.