JPH0455515B2 - - Google Patents

Description

[Detailed description of the invention]

OBJECT OF THE INVENTION INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a color display control method used in a teletext receiver. Conventional technology Teletext broadcasting transmits and receives large amounts of breaking information such as news, weather forecasts, and traffic information displayed in text and graphics in the form of packets during the vertical retrace period of a television video signal. The system extracts this image and displays it in place of the television image according to the recipient's request. For such teletext broadcasting, a pattern transmission method was initially considered in which character information was sent in patterns, but code transmission was adopted, taking into account the advantages of improved transmission efficiency and lower memory costs due to recent LSI technology. The method has been moved to In the code transmission method, character information is sent as a code, and the receiver side performs a decoding process in which the coded character information is converted into a bit pattern and written into a pattern memory for display. Conversion from this code to a bit pattern involves reading a specific location in a read-only memory called a character generator, which stores the shapes (fonts) of various characters in the form of bit patterns of "1" or "0". This is realized by Coloring information and display control information are added to the character information in units of one character or a group of consecutive characters. The coloring information consists of a foreground color in which the "1" portion indicates the color to be displayed and a background color in which the "0" portion indicates the color to be displayed when the aforementioned bit pattern is displayed on the screen. This coloring information is written into the color memory at the same time that the character code is converted into a bit pattern and written into the pattern memory. This color memory is provided corresponding to each character area of the pattern memory, and is a memory for coloring characters by being referenced during display. The foreground color and background color are each specified by a 5-bit entry number, and are associated with specific columns (entry addresses) in the 32 color lookup tables. This color lookup table contains 4 bits each for "R (red)", "G (green)", and "B (blue)" (total) for each entry address.
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It is a memory with a capacity of (bits). Each 4-bit information is represented by the three primary colors of light: "R", "G", and "B".
The brightness of each color is defined in 16 levels, and any of 4096 colors can be expressed by the combination of "R", "G", and "B", each of which is defined as one of the 16 levels of brightness. The display control information includes functions such as flashing, which causes a certain character or group of characters to blink at a predetermined period, and concealing, which displays hidden characters after waiting for a request from the recipient. This concealment function is used in quizzes, educational programs, etc., where answers are hidden until requested by the viewer. This display control information is written into the attribute memory at the same time as the character code is converted into a bit pattern and written into the pattern memory, as in the case of colored information. This attribute memory is provided corresponding to each character area of the pattern memory and is referenced during display to realize character display control. Normally, when a character converted into a bit pattern is displayed on the screen, the foreground color is always referred to for the "1" portion of the pattern memory. However, if flushing is specified for a certain character, the foreground color and background color are alternately referenced at a predetermined period for the "1" portion of the pattern memory. Additionally, if concealment is specified for a certain character, the background color is initially referred to for the "1" part of the pattern memory, and the original foreground color is changed at the request of the information person. Referenced. Therefore, a teletext receiver has a pattern memory for developing one screen's worth of shape information, a color memory for developing coloring information, and a color lookup table for determining actual display colors.
An attribute memory is required to expand the display control information. In teletext, a geometric figure function is defined as one of the figure display functions, as it is a desirable function for future development. In this geometric figure, points, straight lines, rectangles, polygons, and circles are drawn by specifying coordinates on the screen, and the figure is displayed by a combination of one or more codes that specify this drawing. It will be done. Coloring of geometric figures is achieved in 1×1 pixel units by a combination of a bitmap memory and a color lookup table. Bitmap memory is a display memory that has a depth of 5 bits for each pixel, and this 5-bit depth information allows it to be associated with a specific column (entry address) of the 32 color lookup tables. . In this way, pixels on the bitmap memory are displayed according to the contents of the associated color lookup table.
Colored and displayed in 16 out of 4096 colors. Therefore, a teletext receiver equipped with a geometry function requires one screen's worth of bitmap memory in addition to one screen's worth of pattern memory, color memory, color lookup table, and attribute memory. Problems to be Solved by the Invention The conventional teletext receiver equipped with the geometry function described above has a pattern memory for one screen,
In addition to the color memory, color lookup table, and attribute memory, a bitmap memory for one screen is required, so there is a problem that the display memory capacity becomes excessive. An object of the present invention is to reduce the display memory capacity of a teletext receiver equipped with a geometry function, so that the display memory can be reduced to just one screen's worth of bitmap memory and color lookup table. , conventional pattern memory,
The object of the present invention is to provide a method for realizing coloring and display control functions, which were realized by color memory, color lookup table, and attribute memory, by using bitmap memory and color lookup table. Means for Solving the Problems of the Structure of the Invention The coloring display control method of the present invention, which solves the problems of the prior art described above, uses color look-up and The color is registered in a predetermined entry in the first area of the table, and for a broad color consisting of a color value and an attribute, it is registered in the color display management table, and the color value is stored in the second area of the color lookup table. A coloring control process is performed in which entries are registered in empty entries. Independently of this coloring control processing, the coloring values registered in each entry in the second area of the color lookup table are changed according to the coloring change attribute of the broad color registered in the coloring display management table. Display control processing to change the display is executed. As a result, the large-capacity attribute memory is replaced with a small-capacity coloring display management table, and the memory capacity for coloring and display control is significantly reduced. Note that the terms "color in a narrow sense" and "color in a broad sense" are used here for convenience of explanation. "Color in a broad sense" used here refers to the color expressed on the screen, such as "full brightness yellow for positive phase flashing" and "full brightness red for concealing", as well as the coloring change attributes of flashing and concealing. We have decided to treat the combination of these specifications as a color in a broad sense, and call it a ``color in a broad sense,'' except in cases where there is no coloring change attribute, such as ``full brightness yellow that is neither flushed nor concealed.'' . Furthermore, in contrast to "colors in a broad sense," colors without coloring change attributes are particularly referred to as "colors in a narrow sense."
In the following explanation, the words "color in a broad sense" and "color in a narrow sense" will be used for convenience of explanation. Hereinafter, the operation of the present invention will be explained in detail together with examples. Embodiment FIG. 1 shows a teletext receiver to which a color display control method according to an embodiment of the present invention is applied.
FIG. 2 is a block diagram showing the configuration of the minimum necessary parts for explaining this embodiment. This receiver includes a central processing unit (CPU) 1, a work RAM 2, a display bitmap memory 3,
Color lookup table 4, system
It includes a bus 5, a character generator 6, a CRT controller 7, a program ROM 8, a data extraction circuit 9, a line buffer 10, and a D/A converter 11. The data extraction circuit 9 extracts character information appearing within the vertical retrace period of the television signal supplied from the receiver side, performs error correction, and clock reproduction. The extracted character information is line buffer 1
0 and the system bus 5 to the central processing unit 1. When the central processing unit 1 receives the coded character information, it converts it into a corresponding pattern using the character generator 6, and stores the foreground color and background color of the pattern in the pattern writing position in the display bitmap memory 3. Write. These foreground and background colors are represented by predetermined entry numbers in the first area of the color lookup table 4 in the narrow sense of colors consisting only of coloring values. On the other hand, the foreground color and background color, which are colors in a broad sense consisting of coloring values and attributes, are expressed by entry numbers in the second area of the color lookup table 4. For colors in a narrow sense consisting only of coloring values, the central processing unit 1 registers the necessary coloring values in a predetermined entry in the first area of the color lookup table 4 as before. On the other hand, the central processing unit 1 selects a color that is not registered in the coloring display management table created in the work RAM 2 out of the broadly defined colors consisting of coloring values and attributes every time it is necessary to use the color. It is registered in the free space of the coloring display management table in work RAM 2, and
Color Lookup Table 4
It is registered in a free entry in the second area within. Figure 2 shows color lookup table 4.
FIG. 2 is a conceptual diagram showing the configuration of. In this color lookup table, the color is specified by a 6-bit entry number.
A 12-bit coloring value is registered in each of the 64 entries. The entry number is the top 2
It consists of the bit palette number (P.NO.) and the lower 4 bits of the color map row address (CMLA). The 12-bit coloring value is composed of 4-bit R, G, and B tone signals.

The first palette numbered [0] and [1]
In the area, as in the past, coloring values of colors in a narrow sense consisting only of coloring values are registered. The relationship between each coloring value and registered entry is fixed. For example, full brightness red is the palette number

CMLA of [0]
In [2], the total brightness yellow is the palette number

[0] of
CMLA [3], and half-bright green is the palette number

It is fixed to CMLA [A] of [0]. The same applies to each entry of palette number [1]. Palette number

In CMLA [8] and [F] of [0], transparent color of all “0” and half-brightness white (gray) are registered, respectively. Transparent color is a color specific to teletext broadcasting, etc., and characters specified to be displayed in this color are displayed with the same foreground and background colors as the raster color, which can be called the background color of the entire character screen. . Half-bright white is also a color specific to teletext broadcasting, and when half-bright white is specified as the background color under super display mode in which the text screen is displayed superimposed on the television screen, this Half-bright white serves to reduce the brightness of the television screen around the characters displayed by the foreground color. Note that all "0" registered in the entry of palette number [1] means black. Therefore, for colors in a narrow sense consisting only of coloring values registered in the first area of the color lookup table 4, not only the coloring values but also the registered entries have meaning. On the other hand, the second areas of palette numbers [2] and [3] are used to register coloring values of colors in a broad sense including attributes. In this second area, unlike the first area, the entry number and coloring value are not fixed on a one-to-one basis, and each time it is necessary to register a color in a broad sense as the coloring state progresses, The coloring values are dynamically registered in vacant entries in increasing order starting from the smallest entry number. FIG. 3 is a conceptual diagram showing the structure of a colored display management table formed in the work RAM 2. As shown in FIG. Every time the central processing unit 1 starts receiving character information for one screen, it clears each column of this coloring display management table, and then clears the attributes from the top row to the bottom row in the order in which the need for registration occurs. Register colors in a broad sense including . The first column of each row displays the presence/absence of registration.
A bit flag is prepared. In the next column, 1-bit flags indicating the presence/absence of flushing are prepared separately for the case of normal phase flushing and the case of reverse phase flushing. The phases of blinking are shifted by 180 degrees between the normal phase and the reverse phase.
A 1-bit flag indicating presence/absence of concealment is provided in the next column. In the next two columns, the foreground color and background color are written as 5-bit entry numbers. These entry numbers are conventional color lookup table entry numbers specified in the received signal from the center station;
In this example, the palette number of color lookup table 4 is

This corresponds to the entry number in the first area that has [0] and [1]. The last two columns are filled with 12-bit foreground and background color values, respectively. This 12-bit foreground and background color is
Each is displayed as a combination of bit R, G, and B gradation signals. The central processing unit 1 registers the broad color that has become necessary for coloring in an empty row of the coloring display management table, and also stores the coloring value of this broad color in an empty entry in the second area of the color lookup table. A coloring control process to register and a display control process to change the coloring value of the broad color registered in this coloring display management table on the second area of the color lookup table 4 according to its coloring change attribute. Run independently. FIG. 4 is an example of a display screen for explaining the content of the coloring control process by the central processing unit 1 and the display control process based on the timer interrupt and concealment cancellation interrupt. In this display screen, "This is" is displayed in a "yellow" coloring value, followed by "TV teletext" which is also flashing in a "yellow" coloring value, and then "TV teletext" is also flashed in a "yellow" coloring value. This is followed by "This is an experimental broadcast." displayed as a value. Furthermore, in the following example, "this" is displayed with a "red" coloring value, "new" is concealed with a "red" coloring value, and "broadcast..." is displayed with a "red" coloring value. . FIG. 5 shows the arrangement of control codes and character codes that the central processing unit 1 should receive when displaying the display screen of FIG. 4. For convenience of illustration, both the above-mentioned "yellow" and "red" are assumed to be at full brightness, and the modifier "full brightness" is omitted in FIG. When the central processing unit 1 receives a foreground color specification code that specifies the foreground color as "full brightness yellow" at the start of the screen, it causes the built-in foreground color holding register to hold the corresponding entry number "03". . This entry number "03" is the conventional entry number when the coloring value and its storage entry are fixed, and for convenience of explanation, it is to be distinguished from the actual entry number in the color lookup table 4. , the former is expressed in brackets "", and the latter is expressed in brackets [ ]. Prior to this, the central processing unit 1 selects a predetermined background color value (in this example, "half-brightness green") that is to be selected if no background color value is specified.
The entry number ``0A'' is held in the built-in background color holding register. When the central processing unit 1 subsequently receives the character code for the hiragana "ko", it determines whether the coloring value of the entry number "03" held in the background color holding register is to be used as a color in a narrow sense or a color in a broad sense. It is determined by checking the flags in the built-in flushing flag register and concealment flag register. In this example,
Since neither flushing nor concealment is specified, each of the above flags is "0". Therefore, the central processing unit 1 determines that "Full brightness yellow" with entry number "03" held in the foreground color holding register is to be used as a color in the narrow sense, and changes it to the color in the broad sense on the color display management table. Immediately generates a corresponding character pattern in the character generator 6 without searching or registering the color, and retains the foreground color at each dot position and background position of the character pattern in the display bitmap memory 3. The contents of the register "03" and the contents of the background color holding register "0A" are written, and the coloring control process for the hiragana "ko" is completed. When the central processing unit 1 receives the subsequent hiragana ``re'', it stores the corresponding dots generated by the character generator 6 in the display bitmap memory 3 in exactly the same way as in the case of ``ko'' above.
For each position of the pattern and each of its background positions,
The contents ``03'' of the foreground color holding register and the contents ``0A'' of the background color holding register are written, and the coloring control processing for the hiragana ``re'' is completed. The central processing unit 1 performs the same coloring control process for the subsequent hiragana "ha" as the coloring control processing for the hiragana "re". When the central processing unit 1 next decodes the control code for starting positive phase flushing, it sets "1" in the built-in positive phase flushing flag register. When the central processing unit 1 receives the katakana "te", it searches for the content "1" in the positive phase flushing flag register and sets the "total brightness" of the entry number "03" held in the foreground color holding register. A search is made to see if "yellow" is registered on the coloring display management table as a color in a broad sense that includes the attribute of positive phase flushing. In this example, "full brightness yellow" in the broad sense, which includes the attribute of positive phase flushing, has not yet been registered on the colored display management table, so the central processing unit 1 is in the first empty row of the colored display management table [00] Write the foreground color entry number "03" held in the foreground color holding register and the background color entry number "0A" held in the background color holding register in the line. Subsequently, the central processing unit 1 reads out the foreground color value "full brightness yellow" and the background color value "half brightness green" from the corresponding entries in the first area of the color lookup table 4, and reads them out from the corresponding entries in the color display management table. Write on the line. Subsequently, the central processing unit 1 sets a flag indicating presence/absence of positive phase flushing and a flag indicating presence/absence of registration to "1" in the corresponding row of the colored display management table. When the registration of the broad color in the coloring control management table is completed in this way, the central processing unit 1 stores the corresponding foreground color value "full brightness yellow" in the first area of the second area of the color lookup table 4. Register in vacant entry [20]. When this registration is completed, the central processing unit 1 causes the character generator 6 to generate the katakana ``te'', and instructs the display bitmap memory 3 to color each dot position of this character pattern and its background position.・Luckup Table 4
Write the entry number [20] and [0A]. When the central processing unit 1 receives the subsequent katakana ``re'', the ``full brightness yellow'' held in the foreground color holding register is registered on the coloring display management table as a color in a broad sense that includes the attribute of positive phase flushing. Search to see if it is. In this example, such a broad color "full brightness yellow" has already been registered in the [00] row of the color display management table, so the central processing unit 1
is immediately added to the character generator 6 without making any new registration in the second area of the color display management table and color lookup table 4.
The katakana ``re'' is generated in the display bitmap memory 3, and the entry number [02] of the color lookup table 4 is assigned to each dot position of this character pattern and its background position.
and write [0A]. The central processing unit 1 also converts the subsequent katakana “bi” into kanji “bun”,
The same coloring control process as in the case of the above-mentioned "R" is also performed for "character", "multi", "heavy", "ho", and "feed". When the central processing unit 1 next decodes the positive phase flushing end code, it returns "0" to the built-in positive phase flushing flag register. After that, when the central processing unit 1 receives the hiragana "no",
Since the contents of the flushing flag register and the conceal flag register are both "0", "full brightness yellow" of entry number "03" held in the foreground color holding register is used as the color in the narrow sense. Immediately, the contents of the foreground color holding register ``03'' and the background are stored in the display bitmap memory 3 at each dot position and the background position of the corresponding character pattern generated by the character generator 6. Write the contents of the color holding register “0A”. The central processing unit 1 processes the following kanji ``jitsu'', ``ken'',
``Ho'', ``Shoku'', hiragana ``de'', ``su'', and comma ``.''
Also, the same coloring control process as in the case of the hiragana "no" is performed. Next, when the central processing unit 1 decodes the foreground color specification code that specifies the foreground color as "full brightness red,"
Rewrite the contents of the foreground color holding register to the corresponding entry number "02". When the central processing unit 1 subsequently receives the hiragana ``ko'', since both the contents of the flushing flag register and the conceal flag register are ``0'', the central processing unit 1 changes the entry number ``02'' held in the foreground color holding register. ” coloring value is determined to be used as a color in a narrow sense. In this case, the central processing unit 1 immediately generates a corresponding character pattern in the character generator 6 and stores it in the display bitmap memory 3 without searching or registering the color in a broad sense on the coloring display management table. The content ``02'' of the foreground color holding register and the content ``0A'' of the background color holding register are written to each dot position and background position, respectively, and the coloring control process for the hiragana ``ko'' is completed. Regarding the subsequent hiragana ``no'', the central processing unit 1 inputs the character of the hiragana ``no'' generated by the character generator 6 into the display bitmap memory 3 in exactly the same way as in the case of the hiragana ``ko'' described above. Write entry numbers [03] and [0A] in the foreground color holding register and background color holding register to each dot position of the pattern and its background position, respectively. When the central processing unit 1 next decodes the conceal start control code, it sets "1" in the built-in conceal flag register. After that, when the central processing unit 1 receives the kanji ``new'', based on the content ``1'' of the conceal flag register, the ``total brightness red'' held in the foreground color holding register is changed to a broad meaning including the attribute of conceal. Search to see if it is registered as a color on the colored display management table. In this example, "full brightness red" in the broad sense, which includes the conceal attribute, is not registered in the coloring display management table, so the central processing unit 1 writes Background color entry number “0A” and foreground color entry number “02”
Write. Continuing, the central processing unit 1
The foreground color value "full brightness red" and the background color value "half brightness green" are read from the corresponding entries in the first area of the lookup table 4 and written to the corresponding rows in the colored display management table. Continuing with central processing unit 1
sets the flag indicating presence/absence of concealment and the flag indicating presence/absence of registration to "1" in the corresponding row of the colored display management table. When the registration of the broad color in the coloring control management table is completed in this way, the central processing unit 1 transfers the background color value "half-brightness green" to the next free space in the second area of the color lookup table 4. Register for entry [21]. When this registration is completed, the central processing unit 1 causes the character generator 6 to generate the kanji ``Shin'', and in the display bitmap memory 3, colors are added to each dot position of this character pattern and its background position.・Write the entry number [21] and [0A] of Lookup Table 4. When the central processing unit 1 receives the subsequent hiragana "shi", it checks whether "full brightness red" held in the foreground color holding register is registered on the coloring display management table as a color in a broad sense that includes the attribute of concealment. Search for whether or not. In this example, such a broad color "full brightness red" has already been registered in the [01] row of the color display management table, so the central processing unit 1 registers the color display management table and the color lookup table 4. Immediately generate the hiragana ``shi'' in the character generator 6 without making any new registration in the second area, and write each dot position of this character pattern and its background position to the display bitmap memory 3. In the color lookup table 4, entry numbers [21] and [0A]
Write. The central processing unit 1 performs the same coloring control process for the subsequent katakana ``i'' as in the case of the hiragana ``shi''. When the central processing unit 1 next decodes the concealment end code, it returns the built-in concealment flag register to "0". When the central processing unit 1 continues to receive the kanji character "ho", since the contents of the flushing flag register and the conceal flag register are "0", It is determined that "luminance red" is used as a color in the narrow sense, and the corresponding character pattern "radiance" generated by the character generator 6 is immediately stored in the display bitmap memory 3.
The entry numbers "02" and "0A" held in the foreground color holding register and background color holding register are written to each dot position and its background position, respectively. The central processing unit 1 performs subsequent "transmission", "de",
The same coloring control process as in the case of the above-mentioned "ha" is performed for "wa".... Therefore, each row of the color display management table and each entry of the second area of the color lookup table 4 has a one-to-one correspondence, and the required number of rows of the color display management table is equal to the number of rows of the color lookup table 4. There will be 32 lines, which is the same number of entries in area 2. The combination of attributes is ``with positive phase flushing specified,''
"No concealment specified", "Reverse phase flushing specified, concealment specified", "Flushing not specified, concealment specified", "Normal phase flushing specified, concealment specified" and "Reverse phase flushing specified, concealed specified" Since there are five colors, there can be 32 x 5 = 160 colors in a broad sense. However, since the number of broadly defined colors used on one screen is about 32 at most, in this embodiment, the number of rows in the color display management table that is dynamically updated on a per screen basis and the color lookup
As mentioned above, the number of entries in the second area of Table 4 is sufficient to be 32 each. In parallel with the coloring control process, the central processing unit 1 includes registering a broad color in the coloring display management table in the work RAM 2 and registering a coloring value in the second area of the color lookup table 4. , executes the following display control processing. The central processing unit 1 starts a flashing display control process based on a timer interrupt of a predetermined period determined for flashing, and sets a flag indicating presence/absence of positive phase flashing to "1" from the colored display management table. The content of the entry in the second area of the color lookup table 4 having the entry number corresponding to the row number is changed from the foreground color to the background color. In addition, the central processing unit 1 searches the coloring display management table for a color in a broad sense for which a flag indicating the presence/absence of reverse phase flushing is set to "1", and determines the entry number corresponding to the row number. Color lookup table 4 with
Change the contents of the entry in the area from the background color to the foreground color. In the next flashing display control process based on a timer interrupt, the central processing unit 1 changes the corresponding entry contents in the second area of the color lookup table 4 from the background color to the foreground color for colors in a broad sense related to positive-phase flashing. For colors in a broad sense related to reverse phase flushing, the content of the corresponding entry in the second area of the color lookup table 4 is changed from the foreground color to the background color. In this way, by the flashing display control process based on the timer interrupt, the foreground color and the background color are alternated at the flashing period, and the corresponding character or character group is flashed at a predetermined period (1 second in teletext). In addition, when the central processing unit 1 receives a concealment cancellation command issued by the viewer of the screen via the keyboard or remote control pad, the central processing unit 1 starts concealment cancellation interrupt processing and displays the presence/absence of concealment from the colored display management table. Search for a broad color whose flag is set to "1" and convert the contents of the entry in the second area of the color lookup table 4 whose entry number corresponds to that row number from the background color value to the foreground color. Change to value. As a result, characters or character groups that were hidden in the background color appear on the display screen in the foreground color. Although the configuration in which the central processing unit 1 performs the coloring control process and the display control process has been exemplified above, the CRT controller 7 may share the display control process. In addition, although the central processing unit 1 has exemplified the configuration in which the coloring value to be registered in the coloring display management table or the second area of the color lookup table 4 is read out from the first area of the color lookup table 4, Instead of reading from the color lookup table 4, a correspondence table between the entry numbers of the first area and the coloring values is stored in the work RAM 2.
It may be configured such that the information is registered within the server and read from there. In addition, such a correspondence table can be stored in work RAM 2.
Multiple registers are registered in the internal memory, and one of them is selected based on the selection command from the center to perform the color adjustment.
It is also possible to adopt a configuration in which the coloring value of each entry in the first area of the lookup table 4 is changed. Effects of the Invention As explained in detail above, the coloring display control method of the present invention can perform coloring and coloring control functions that were conventionally realized by pattern memory, color memory, color lookup table, and attribute memory. The display memory of a teletext receiver equipped with a geometry function is realized by a bitmap memory and a color lookup table, including special display functions.
Since it can be configured with only a bitmap memory for a screen and a color lookup table, the required display memory capacity can be greatly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the minimum necessary parts for explaining this embodiment of a teletext receiver to which a color display control method according to an embodiment of the present invention is applied, and FIG. 1 is a conceptual diagram showing the configuration of the color lookup table 4, FIG. 3 is a conceptual diagram showing the configuration of the coloring display management table created in the work RAM 2 of FIG. 1, and FIGS.
The figure is a conceptual diagram showing an example of a display screen, reception control, and a character code string for explaining the coloring and display control processing by the central processing unit 1 of FIG. 1. 1...Central processing unit, 2...Work RAM, 3...Bitmap memory for display, 4...Color lookup table, 6...Character generator, 7...CRT controller.

Claims (1)

[Scope of Claims] 1. A coloring display management table that registers a color in a broad sense consisting of a coloring value of at least one of a foreground color and a background color of a displayed character, and a color change attribute of flashing, concealing, or similar coloring of this displayed character. ,
A color lookup area consisting of a first area in which a coloring value of a color in a narrow sense consisting only of coloring values is registered at a predetermined position, and a second area in which the color in a broad sense is registered.
A coloring control method for a teletext receiver comprising a table and a bitmap memory for storing an entry address of a coloring value in the color lookup table for each pixel, the method comprising: changing the color in a broad sense to the color; - Coloring control processing that registers the coloring value of this broad color in the lookup table and registers it in any free entry address in the second area of the color lookup table, and registers it in the coloring display management table. a display control process of changing the coloring value in the color lookup table according to the coloring value and coloring change attribute of the color in the broad sense that has been set. . 2. The teletext receiver according to claim 1, wherein the coloring values of the entries in the second area of the coloring display management table and the color lookup table are updated for each screen. Colored display control method.