JPH07140945A - Method and device for displaying gradation character - Google Patents

Abstract

PURPOSE:To improve the quality of a display character when a gradation character is displayed by preventing the thinning in a horizontal line part and showing so that a vertical line and a horizontal line are displayed with the thickness different from each other. CONSTITUTION:The character font data 101 are converted to the dot matrix data 102, and display pixels are decided for the dots of the data 102, and gradation levels are decided based on the number of dots corresponding to respective pixels of the whole one character, and the gradation level data 103 are generated. On the other hand, the horizontal line and the vertical line of the character font data 101 are cut out to be converted to the data 104, and the display pixels are decided for the data 104, and the gradation levels are decided based on the number of dots corresponding to respective pixels, and the gradation level data 105 are generated. The data 106 making the gradation of the horizontal line brighter are generated from the data 105. The brighter one between the gradation of the data 106 and the data 103 corresponding to respective pixels constituting the horizontal line and the vertical line are made the data 107 corresponding to respective pixels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high quality character display method and device in a matrix type display device such as a CRT display or a liquid crystal display.

[0002]

2. Description of the Related Art Conventionally, when a character is displayed on a display such as a CRT which forms an image with a set of points close to a circle, even if an oblique line or a curved line is displayed, it becomes a comparatively smooth line, and a contour portion (edge) is displayed. The change in the luminance is also gentle (see FIG. 2A).

However, if characters are displayed on a display that forms an image with square points instead of circular points, such as a liquid crystal display, jaggies (jagged edges) are conspicuous, and slanted lines and curved parts lose smoothness, and the outline parts are lost. The change in luminance was abrupt, resulting in a reduction in character quality (see FIG. 2 (b)).

With respect to such a problem, Japanese Patent Laid-Open No. 63-3
Japanese Laid-Open Patent No. 13191 discloses a character font creating apparatus which makes the jaggies inconspicuous by gradationally displaying the dots in at least three stages in accordance with the extent of the area ratio of the outline portion of the character in one dot. Is disclosed.

Further, in Japanese Patent Laid-Open No. 63-157192, the density difference of a character is expressed as a numerical value by obtaining the ratio of black dots and white dots of the character pattern, and the vertical or horizontal line of the character is expressed according to this numerical value. A technique for correcting the line width is disclosed.

Further, in Japanese Patent Laid-Open No. 5-53563, each horizontal position of each horizontal line portion is at the center of a mesh (display pixel) in each halftone font having each horizontal line portion. A technique for position correction is disclosed in.

[0007]

However, when a gradation character is displayed by the technique described in Japanese Patent Laid-Open No. 63-313191, the jaggies existing in the outline of the character become visually inconspicuous, but Chinese characters and the like. The dots in the horizontal line portion of the character included in many are also displayed in halftone, and as a result, the display color of the horizontal line portion appears lighter than the entire character. For this reason, there is a problem in that the horizon looks visually faint and a means for displaying the characters beautifully results in deterioration of the character quality.

Further, in the technique described in JP-A-63-157192, the line width of the vertical line or the horizontal line changes, and in the technique described in JP-A-5-53563, the position of the horizontal line is corrected. Must.

In the present invention, in consideration of the conventional problems, when a character is displayed in gradation, even if the width and position of the horizontal line are not corrected, the horizontal line does not appear visually faint and the jaggies are not noticeable. It is an object of the present invention to provide a gradation character display system and a device capable of displaying quality characters.

[0010]

In order to solve the above-mentioned problems, a character display device according to the present invention receives font data defining a contour line of a character, converts the font data into dot matrix data, and converts the dot data into dot matrix data. The matrix is divided into minute sections, one display pixel is defined for a plurality of dots included in each section, and based on the number of dots forming a character corresponding to the one display pixel,
In a character display device that generates gradation level data relating to the brightness of the display pixel and displays a character having gradation based on the gradation level data, a dot matrix corresponding to each pixel of the entire character. Based on the number of dots that make up the characters of the data, first set the gradation level
For a pixel in the horizontal portion of the one character, the means for obtaining the gradation level of the character is closer to the maximum gradation level of the character than the first gradation level defined for each pixel forming a horizontal line, Means for obtaining a predetermined gradation level as the second gradation level, and for each pixel forming the horizontal line, the maximum gradation level of the character among the first and second gradation levels. Means for providing a similar gray level as a gray level for the pixel.

It is also possible to provide an input unit for externally inputting the gradation type instructions of the first and second gradation levels.

Further, it is also possible to provide an input means for externally inputting an instruction of a correspondence relationship between a range of the number of dots forming the character and a kind of gradation level determined based on the range.

In the present invention, the maximum gradation level of a character refers to white when the background is black and the character is white. Further, for example, when the background is white and the characters are black, it indicates black.

[0014]

The character font data is converted into dot matrix data, display pixels are determined for the dots of the dot matrix data, and a gradation level is determined for each pixel of one character based on the number of corresponding black dots. Is determined to generate the first gradation level data. On the other hand, the horizontal and vertical lines of the character font data are cut out and converted into dot matrix data, and the gradation level is determined for each pixel of the dot matrix data by determining the gradation level based on the corresponding number of black dots. Generate level data. Gradation level data in which the gradation of the horizontal line is brighter than this gradation level data is generated and used as the second gradation level data. Of the gradations of the first and second gradation level data corresponding to each pixel, the brighter one is regarded as gradation level data (third gradation level data) corresponding to each pixel, and the third gradation The gradation character is displayed according to the gradation level data.

Thus, when displaying gradation characters, it is possible to prevent fading of characters, which is often seen in horizontal lines such as Chinese characters, and the vertical and horizontal lines are displayed with different thicknesses. Since it looks like, the quality of displayed characters can be improved.

Further, since the gradation correction display data is not prepared in advance for each character but is generated based on each font data, the gradation font data and a storage device such as a memory for storing the gradation font data are unnecessary in advance. Becomes

Further, by providing a means for setting the value of the gradation boundary value used in determining the gradation level when the gradation correction display data is generated, the user can freely set the gradation boundary value. It can be changed, and a gradation character that the user likes can be displayed.

Further, when the gradation correction display data is generated, the gradation level assigning means for allocating some numerical values in correspondence with the gradation level corresponds to the degree of gradation. Since the number of gradations can be changed, it is possible to display gradation characters corresponding to any number of gradations.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing a configuration example of a gradation character display device that realizes the gradation character display system of the present invention.

This gradation character display device has a font ROM 30 for storing font data of various formats.
1. A character generator 302 for reading outline font data from the font ROM 301 and converting it into character data represented in a raster format, an input device 303 for inputting characters and the like, document data and an operation program for this device. A central processing unit (hereinafter, referred to as a CPU) including a stored RAM 304 and a gradation character display unit of the present invention.
305, a memory 306 for storing output data to be sent to the display device, and a display device 307 for displaying the output data.

The font ROM 301 is a read-only memory (font ROM) for storing outline font data of various characters. In this embodiment, outline font data of 1024 × 1024 dots is stored in this font ROM 301. It has been done.

The character generator 302 includes a font ROM 3
The outline font data is read from 01, subjected to affine transformation such as enlargement / reduction, curve interpolation processing, line generation and filling processing, and converted into raster character data.

The RAM 304 stores document data to be displayed,
The operation program of this device is stored.

The CPU 305 includes the gradation character display section of the present invention and controls the gradation character display device and the like.

The memory 306 is composed of a page memory for storing output data sent to the display device, a dot memory for temporarily storing display data, a display memory, and the like. The display device 307 is, for example, a liquid crystal display having a dot matrix configuration in which the screen is composed of a plurality of display pixels.

A method of displaying a gradation character by using this gradation character display device will be described with reference to FIGS. 3 and 12.

First, the CPU 305 sets information such as a display character size in the character generator 302 according to the document data stored in the RAM 304 and activates it. Further, the CPU 305 sets the outline font data corresponding to the character code of the input character data to the font RO.
It is read from M301 and transferred to the character generator 302 (1201). The character generator 302 converts the outline font data into character data represented in a raster format based on various data instructed by the CPU 305 (1202). The CPU 305 converts the character data represented in the raster format into gradation correction display data and transfers it to the memory 306 (1203). After repeating the above processing for all characters, the CPU 305
The gradation correction display data stored in the memory 306 is transferred to the display device 307 and displayed (1204).

First, the outline font data is read from the font ROM 301, and the character generator 30 is read.
The process of expanding the character data in 2 and storing the character data represented in the raster format in the dot memory in the memory 306 (1201, 1202) will be described with reference to FIG.

Outline font data is read from the font ROM 301 and transferred to the character generator 302 (401). The character generator 302 performs affine transformation to reduce the displayed character size to n times the vertical and horizontal sizes (402). For example, to display and output a character of 18 × 18 dots, if n = 8,
The outline font data corresponding to 1024 × 1024 dots may be reduced to the outline font data corresponding to 18n × 18n = 144 × 144 dots. Next, curve interpolation processing such as cubic Bezier curve interpolation and cubic spline curve interpolation is performed (403), and line generation / filling processing is performed (404). Then, the character data represented in the raster format is converted into the dot memory 1 in the memory 306.
(405). Also, similarly, font R
The outline font data is read from the OM 301 (406), and only the horizontal and vertical line portions of the characters in the read outline font data are extracted (40).
7), reduction processing is performed by affine transformation (408),
Line generation / filling processing is performed (409), and character data of the horizontal / vertical line portion represented in the raster format is stored in the dot memory 2 in the memory 306 (410).

In this embodiment, specifically, FIG.
As shown in (a), a direction attribute flag 1101 is attached to each coordinate of the font data to form one coordinate 3 words. The direction attribute flag is added to the start point of the horizontal / vertical line or the slanted line / curve as shown in FIG. 11C, and is 0 for the slanted line / curve as shown in FIG. A direction attribute of 2 is added to the start point of the line. Then, the point where the direction attribute flag is other than 0 and the point next to the point other than 0 are detected,
The coordinate points of only the horizontal and vertical line parts are taken out and converted into character data represented in raster format.

Next, the character data represented in the raster format is read from the dot memories 1 and 2 and converted into gradation character display data, and the gradation correction method of the present invention is used from this gradation character display data. To convert the gradation correction display data to display gradation characters on the display device 307 (12 in FIG. 12).
03, 1204) will be described with reference to the flowcharts of FIGS.

In this embodiment, the value of n set by affine transformation is n = 16. Therefore, when it is desired to display a gradation character of 16 × 16 dots, the dot memory 1 and the dot memory 2 have 25 characters as shown in FIGS.
This means that the dot data “娃” of 6 × 256 dots is stored. Further, FIG. 7C is an enlarged view of the outline of the hatched portion of the character in FIG. 7A. FIG. 7D is the same as FIG.
It is a data block diagram in the actual dot memory of data like (c).

The flowchart of FIG. 5 shows the dot memory 1
This is a representation of a method of converting the dot data stored in (4) to gradation character display data. First, dot font data is read word by word from the dot memory 1 (501) and the number of character areas in 16 × 16 dots is calculated. In this case, the data shown in FIG. 7C is actually stored in the dot memory 1 as shown in FIG.
Since the data structure is as shown in (d), the number of dots in one word can be calculated by counting the number of bits for which "1" is set (502). Similarly, the dot font data is sequentially read word by word, and the number of bits for which "1" is set is counted and added each time (503). In this way, all the data for 32 words are read, and the total number m of dots in the character area in the 16 × 16 square data is calculated (50
4). Next, the gradation level is determined according to the value of the total number of dots m (505) and stored in the display memory 1 (50
6).

A method of determining the gradation level will be described. First, make the gradation level correspond to the degree of gradation,
Numerical values “0” to “7” are assigned (see FIG. 8).
(A)). Next, the gradation level is determined for each dot to be displayed according to the value of the total number m of dots. The relationship between the total number of dots m and the gradation level in this embodiment is shown in FIG. In this embodiment, gradation characters are displayed with four gradations. For example, the calculated total number of dots m is m = 2
If it is 00, the displayed gradation level is white of "7", and if m = 164, the gradation level is a light gray of "5". In this way, the gradation level of one dot is determined, repeated for the number of dots of the character size at the time of output, and sequentially stored in the display memory 1.

The flowchart of FIG. 6 shows a method of converting the dot data of only the horizontal / vertical line portions stored in the dot memory 2 into the gradation character display data of the present invention. Also in this case, first, the same processing as when converting from the dot memory 1 to the gradation character display data is performed. First, one-word dot font data is read from the dot memory 2 (601), and the number of "1" bits in one word is counted (602). Similarly, the dot font data is sequentially read word by word, and the number of bits for which "1" is set is counted and added each time (603). In this way, all the data for 32 words are read, and the total dot number m of the character portion in the 16 × 16 square data is calculated (604). Next, the gradation level is determined according to the value of the total number of dots m (60
5), the gradation level is stored in the display memory 2 (60
6). This is repeated for the number of dots of the character size at the time of output and stored in the display memory 2 in order. Then, when conversion to the gradation level has been completed for all the dots (607),
Next, the gradation level stored in the display memory 2 is read again (608), and it is determined whether the read gradation level is "0" (609). Then, all the gradation level values other than “0” are extracted, and the highest gradation level value among the extracted gradation level values is 1
Or 2 to 2 lower gradation levels and stored again in the display memory 2 (610).

The reason for this will be described. The horizontal line portion in the Kanji outline font data etc. is designed to be thinner than the vertical line portion. If this is reduced and converted into dot font data, the dot widths of the horizontal line portion and the vertical line portion may become equal. When removing the blurring of the horizontal line portion by increasing the gradation level of the horizontal line portion, if the gray level of the horizontal line portion and the vertical line portion become equal, the horizontal line portion is visually thicker than the vertical line portion. There is a danger of it being visible. Therefore, in order to lower the gradation level of the horizontal line portion, the value of the highest gradation level is converted to the gradation level lower by 1 or 2 gradations. That is, the gradation level of the horizontal line converted by the method of FIG. 6 is a considerably high level. This is converted from a value of the highest gradation level to a level which is lower by 1 or 2 gradations to obtain a lower gradation. The difference in gradation level between the horizontal line portion and the vertical line portion may be changed in accordance with the total number of gradations.

Next, the gradation correction display method of the present invention is used to display one character of gradation characters on the display screen (see FIG. 1).
2 1204) method will be described with reference to the flowchart of FIG. First, the display memory 1 and the display memory 2 in which the gradation levels are stored are read out, and the gradation levels of the corresponding dots are compared (901). Then, the data with the larger gradation level is set as a new gradation level (90
3, 904) and store it in the page memory (905). 1
When the processing for the number of dots for the character is completed (906), the page memory is read and converted into gradation correction display data which is display data (907). For example, as shown in FIG. 8A, when the gradation level is “0”, the gradation correction display data is “0” for both RGB, and when the gradation level is “5”, the gradation correction display data is The data becomes data of "5" for both RGB, the gradation correction display data is transferred to the display device, and the gradation-corrected gradation characters are displayed in monochrome on the display screen (908).

As shown in FIG. 1, as an example of character display, when n = 16, the background color is "black", and the display character color is "white", a floor of 16 * 16 dots "娃" The process of displaying keystrokes will be described. At this time, first, the dot data of 256 × 256 dots is generated from the outline font data “娃” (101) of 1024 × 1024 dots (102). And 1 at the time of output
The total number of dots in the character area in the 16 × 16 dot data corresponding to a pixel is calculated, and the gradation level to be displayed in the corresponding dot is determined from FIG. The key level is output to the display memory 1 (103). Similarly, the outline font data of 1024 x 1024 dots "娃" (101) to 25
Dot data for only horizontal and vertical line portions of a 6 × 256 dot character is generated (104). And 1 at the time of output
The total number of dots in the character area in the 16 × 16 dot data corresponding to a pixel is calculated, and the gradation level displayed in the corresponding dot is determined from FIG. 8B according to the value of the total number of dots. Then, the gradation level is output to the display memory 2 (105). Next, the gradation level output to the display memory 2 is read again, all the gradation levels other than "0" are extracted, and the highest gradation level "out of the extracted gradation level values" All the gradation levels corresponding to the gradation level "5" which is lower by 2 gradations from 7 "are converted and stored again in the display memory 2 (106). Corresponding dots are compared with the gradation levels respectively output to the display memories 1 and 2, and the data with the larger gradation level is set as a new gradation level to be gradation correction display data. as a result,
A gradation character as indicated by 107 is displayed on the display screen.

In the present embodiment, gradation characters are displayed with 4 gradations, but by setting the value of n set by affine transformation to 16, it is possible to support up to 16 × 16 = 256 gradations. it can.

When determining the gradation level from the number of dots in the character area, the user may set the gradation boundary value as a fixed value in advance, or by using a register or a table. The user may be allowed to freely set the numerical value of the gradation boundary value. For example, as shown in FIG. 10A, in the present embodiment, the number m of character area dots in 16 × 16 dots corresponding to one pixel at the time of output is 4
Although the value of the boundary value of the gradation is assigned evenly, the white ratio of the gradation display color is changed as shown in FIG. 10B by changing the boundary value of the gradation with a register or the like. The brightness can be increased by increasing the number.

Further, although the gradation characters are displayed in the 4-gradation display in this embodiment, the number of gradations can be freely changed by using a register or a table.

According to the above-described embodiment, the jaggies (jagged edges) of the character outline portion are visually inconspicuous and the slanted line portion looks smooth even in a display device having a sharp pixel boundary such as a liquid crystal display having a dot matrix structure. In addition, the horizontal / vertical line portion makes use of the characteristics of the display device and is subjected to display correction, so that the entire character does not appear blurred and a very easy-to-see display screen can be obtained.

Further, even in a display device having a low resolution,
Since the number of gradations can be freely changed, high quality characters can be displayed.

[0044]

According to the present invention, when displaying gradation characters, it is possible to perform good gradation character display without the characters appearing to be faint.

Further, the present invention can be applied to any type of font such as dot font and outline font. Further, since the user can freely change the gradation boundary value, it is possible to perform display according to the user's eyes.

[0046]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing internal data of a memory from outline font data to gradation correction display data generation.

FIG. 2 is a schematic diagram of display characters on a CRT display and a liquid crystal display.

FIG. 3 is a configuration diagram of a gradation character display device of the present invention.

FIG. 4 is a schematic diagram of generating dot data from outline font data.

FIG. 5 is a flowchart (1) illustrating a method of determining gradation character display data from dot data.

FIG. 6 is a flowchart (2) illustrating a method of determining gradation character display data from dot data.

FIG. 7 is an enlarged view of enlarged dot fonts stored in dot memories 1 and 2, a display pixel of the enlarged dot font, and an internal configuration diagram of the dot memory.

FIG. 8 is a diagram showing a relationship between a gradation level and gradation display data and a relationship between a total number of dots and a gradation level.

FIG. 9 is a flowchart illustrating a method of displaying gradation characters.

FIG. 10 is a diagram illustrating a change in gradation boundary value.

FIG. 11 shows the structure of font data in this embodiment.

FIG. 12 is a schematic flowchart of a character display procedure.

[Explanation of symbols]

101 ... 1024 × 1024 dot outline font data “娃” 102… 256 × 256 dot dot data “Ide” 103… 16 × 16 pixel gradation character display data “Ide” 104… 256 × 256 dot dot data “Ide” "
(Horizontal line / vertical line part only) 105 ... 16x16 pixel gradation character display data "娃" (horizontal line / vertical line part only) 106 ... 16x16 pixel gradation character display data "scroll" (horizontal line)・ Vertical line portion only) 107 ... Synthesized 16 × 16 pixel gradation correction display data "娃" 301 ... Font ROM 302 ... Character generator 303 ... Input device 304 ... RAM 305 ... CPU 306 ... Memory 307 ... Display device 401 ... 1024 × 1024 dot outline font data “P” 402 ... 144 × 144 dot outline font data “P” after affine transformation 403… Curve-interpolated 144 × 144 dot outline font data “P” 404 ... Dot font data "P" 405 ... Mori 1 406 ... 1024 × 1024 dot outline font data “P” (horizontal line / vertical line part only) 407… Affine-converted 144 × 144 dot outline font data “P” (horizontal line / vertical line part only) 408 ... Curve Interpolated 144 × 144-dot outline font data “P” (horizontal line / vertical line portion only) 409 ... Filled dot font data “P” (horizontal line / vertical line portion only) 410 ... Dot memory 2 (Horizontal and vertical lines only)

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G09G 5/24 9471-5G // G06T 5/00 (72) Inventor Wakisaka Shinji Yoshida Totsuka-ku, Yokohama-shi, Kanagawa 292, Machi Incorporated Hitachi, Ltd. Microelectronics Device Development Laboratory (72) Inventor Hiroshi Wada 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Incorporated Hitachi, Ltd. Microelectronics Device Development Laboratory (72) Invention Norio Tanaka, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Ltd. Inside the Microelectronics Equipment Development Laboratory, Hitachi, Ltd. (72) Inventor Tetsuya Suzuki, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Within

Claims (4)

[Claims] 1. A font data for defining a contour line of a character is received, the font data is converted into dot matrix data, the dot matrix is divided into minute sections, and a plurality of dots included in each section are divided. One display pixel is defined as a display pixel, grayscale level data relating to the brightness of the display pixel is generated based on the number of dots forming a character corresponding to the one display pixel, and based on the grayscale level data. In the character display method of displaying a character having gradation by using the number of dots forming the character of the corresponding dot matrix data for each pixel of the entire character, the gradation level is set as the first gradation level. For the pixels of the horizontal portion of the one character, from the first gradation level determined for each pixel forming the horizontal line, Close to the maximum gray level of characters, it obtains the gradation level which is predetermined as the second gray level for each pixel constituting the horizontal line, the first
And a gradation character display method, wherein a gradation close to the maximum gradation level of the character among the second gradation levels is given as the gradation level for the pixel. 2. A font data defining a contour line of a character is received, the font data is converted into dot matrix data, the dot matrix is divided into minute sections, and a plurality of dots included in each section are divided. One display pixel is defined as a display pixel, grayscale level data relating to the brightness of the display pixel is generated based on the number of dots forming a character corresponding to the one display pixel, and based on the grayscale level data. In a character display device that displays a character having gradation, the gradation level is set to a first gradation level for each pixel of the entire character based on the number of dots forming the character of the corresponding dot matrix data. The means for obtaining, and for the pixels of the horizontal portion of the one character, the first gradation level determined for each pixel forming the horizontal line. Close to the maximum gray level of characters than Le, means for determining a gradation level which is predetermined as the second gray level for each pixel constituting the horizontal line, the first
And a means for giving a gradation close to the maximum gradation level of the character among the second gradation levels as a gradation level for the pixel, a gradation character display device. 3. The character display device according to claim 2, further comprising input means for externally inputting a gradation type instruction of the first and second gradation levels. 4. The input device according to claim 2, further comprising an input unit for externally inputting an instruction of a correspondence relationship between a range of the number of dots forming the character and a kind of gradation level determined based on the range. A character display device characterized by the above.