JPH09171379A - Method for generating character font from character, method for recording character font, and method for reconstructing character from character font - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a character font from which a character of high quality can be obtained by making font data compact. SOLUTION: The character (n) is divided into character elements 1 and 2, and the shape of the font is set on the basis of center lines 11 -13 and c1 of the character elements. Data on the respective character elements are stored in the form of coordinates (vertex coordinate) of end points of straight or curved lines and information (vertex information) regarding the character elements. As the vertex information control point coordinates determining center line attributes, stroke pressure, and the curved lines are used. To reconstruct the character on a character output device, the vertical coordinates, control point coordinates, and stroke pressure are calculated and the outline of the stem of a character element is generated from the stroke pressure at both end points.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for creating a character font, a method for recording a character font, and a method for reconstructing a character from a character font.

[0002]

2. Description of the Related Art An outline font is one of the character fonts for drawing high quality characters. A normal outline font forms a character by having vector data of the outline of the character. FIG. 12 shows the relationship between the character “n” and the coordinates s, p ₁ , p ₂ ... P ₉ used for font data, and FIG. 13 shows
Indicates the contents of the data. Outline font data is
As shown in FIG. 13, it has outline information of all characters.

[0003]

Since the above outline font data has contour information of all characters,
The size of the font data becomes large, and the capacity of the main storage memory or the external storage device is burdened. When an outline font is used and characters are output by the character output device, the stem width is adjusted for the same stem. At this time, when different outlines are given to the same stem, it may be determined that they are different stems even if they are the same stem, and the process of matching the stem widths cannot be performed. In this case, there is a problem that the quality of the output character is deteriorated.

For example, as shown in FIG. 14A, the stem adjustment with respect to the vertical stem can be easily performed. The figure shows one vertical stem 21 and 22 of the same width and another vertical stem 31 and 32 of the same width, and these stems 21 to 32 intersect with other stems not shown, Two
It shows that it is cut at 3,33. In this case, even if the outline information is separate outlines, in the case of the vertical stem as shown in the figure, 21 and 22 and 31 and 32 are used.
Can be determined to be the same stem. Therefore, the stem width (the number of dots) is adjusted so that the same stem appears as a continuous stem. This also applies to the horizontal stem.

On the other hand, in the case of outlines that form diagonal straight lines, curved lines, and stems of varying thickness, it is difficult to determine that they are the same stem. FIG.
(B) shows the case of an oblique straight line. As shown in the figure, when 41 and 42 are one stem and 51 and 52 are another stem, and cut in the range 43, 53,
There is no common point in the coordinates of each stem. Therefore, it is very difficult to determine which stem each stem 41 to 52 should be paired with. Therefore, consistent stem width adjustment cannot be performed for the same stem,
There is a problem that the quality of characters including these parts is deteriorated.

The present invention provides a method for creating a character font from characters, a method for recording a character font, and a method for reconstructing a character from a character font, which enables compact font data and obtains high-quality characters. It is intended to be provided.

[0007]

In order to achieve the above object, the present invention divides a character into elements representing the character and sets the font shape based on the center line of each character element. The center line is composed of a straight line or a curved vector. The data of each character element is stored by the coordinates (vertex coordinates) at the end points of a straight line or a curve and the information (vertex information) about the character element. As the vertex information, the centerline attribute and writing pressure are used when the centerline is a straight line, and the centerline attribute, writing pressure information, and control point coordinates are used when the centerline is a curve. Furthermore, the vertex information can include a connection flag and a contact shape flag.

Here, the center line attribute is information indicating whether the center line is a straight line or a curved line. The vertex coordinates represent the coordinates of the end point of the center line in absolute coordinates (the lower left of the character is the origin). The writing pressure is an image of the strength with which the writing instrument is pressed onto the paper on the center line. The actual stem width (stroke width) is
The width conversion curve is used to determine the writing pressure value. The control point coordinates are coordinates for expressing the curve as a Bezier curve (Bezier).

The connection flag indicates whether or not the center line is connected from the end point of the center line to the next end point. The contact point shape flag is information that determines the shape of the connection point between the center lines. In the font data format based on the above center line, only one vector is set at the center of the center line instead of the outline of the font vector. As a result, the font data can be made more compact than the outline font data format in which one stem requires two or more vectors.

When a character output device is used to reconstruct a character by using the above character font, for a straight center line, the vertex coordinates and pen pressure mapped on the character output device are calculated, and the pen pressure at both end points is calculated. Create a stem outline of a character element from. For the curve center line, the vertex coordinates and control point coordinates mapped on the character output device and the writing pressure are calculated, and the curve obtained by the end points and the control points is approximated to a straight line to obtain a divided line segment. Create the outline of the stem of the character element from the writing pressure at both end points of the minute.

As described above, since the outline of the character element is determined by one center line and its writing pressure, consistent stem width adjustment is performed for the same stem, and high quality character output is obtained. be able to. Furthermore, the quality of the output character can be further improved by creating the shape of the connection point between the character elements based on the contact shape flag.

The stroke width can be adjusted by using the width conversion curve coefficient, and the change in writing pressure when actually writing a character can be easily reproduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the relationship between characters and font data when the character “n” is taken as an example, and FIG. 2 shows the data format. The character “n” in FIG. 1 is divided into character elements 1 and 2. In the first character element 1, a straight center line l _{1 that} is completed by only _one is set. Second
In the character element 2 of, the curved center line c ₁ and the straight line center line l ₂ are continuously set.

Font data for the character "n" is shown in FIG.
Will be recorded. At the beginning of the data,
The width conversion curve coefficient 3 for determining the change, and the smoothness of the curve
The number of curve divisions, 4 which determines the size, is recorded. These width conversion songs
Details of the line coefficient 3 and the curve division number 4 will be described later. straight
Line Center line l₁As the data of,
Vertex coordinates (x ₁Coordinates, y₁Coordinate) and related to it
Vertex information and the vertex coordinates (x_Twoseat
Mark, y_TwoCoordinate) and associated vertex information is recorded
You. The vertex information includes centerline attributes, connection flags,
Includes contact shape flag and writing pressure.

The straight center line having the center line attribute at the first vertex coordinates (x ₁ coordinate, y ₁ coordinate) is
This indicates that the center line l ₁ is a straight line. The continuation in the connection flag means that the center line l ₁ continues from this end point to the next end point. No processing in the contact shape flag means that both ends of the center line l ₁ are cut as they are, and no special processing is performed. The stem width A ₁ is recorded as the writing pressure.

The vertex information at the second vertex coordinates (x ₂ coordinate, y ₂ coordinate) is almost the same as that at the first vertex coordinate (x ₁ coordinate, y ₁ coordinate), but the center line l ₁ is Since it ends at this point, the end is recorded in the connection flag. Also, A ₁ having the same width as the _{first one} is recorded as the writing pressure. Therefore, when the character is output, the character element 1 has the same width from the start point to the end point.

Next, the data of the curve center line c ₁ will be described. The curve in this example is given as a Betzel curve and control point coordinates are used to control the curve. Therefore, the curved center line c
The data of ₁ is the vertex coordinates (x
₃ coordinates, y ₃ coordinates), control point coordinates (x ₃ control points, y ₃ control points) and associated vertex information, vertex coordinates (x ₄ coordinates, y ₄ coordinates) and control point coordinates at the fourth end point. (X ₄
Control points, y ₄ control points) and associated vertex information are recorded.

As the vertex information at the third end point of the curved center line c ₁ , the curved center line as the center line attribute, continuation as the connection flag, no processing as the contact shape flag, and B ₁ as the writing pressure. Will be recorded. Regarding the vertex information at the fourth end point of the curved center line c ₁ , the curved center line is recorded as the center line attribute. As the connection flag, the continuation is recorded because it continues to the next straight center line l ₂ . A circle is recorded as the contact point shape flag in order to smooth the connection shape between the curved center line c ₁ and the straight center line l ₂ . This will be described later. As the writing pressure, B ₂ having a value different from that of the third end point is recorded. This point will also be described later.

The contact shape flag will be described with reference to FIG. The figure shows the shape of contacts when connecting two character elements 5 and 6. (A) of the figure shows a case where the contact shape flag is not processed. In this case, since the end points of the character elements 5 and 6 are not processed at all, the quality when the character is output deteriorates. (B) shows a case where a square is designated as the contact shape flag, (c) shows a case where a circle is designated, and (d) shows a case where a sharp point is designated. These are specified when creating the character font. In the example of FIG. 1, the contact point shape flag of the curve c ₁ and the straight line l ₂ is circular so that the joint is not noticeable.

Next, the writing pressure will be described with reference to FIG. When the stem width of the character element changes as indicated by reference numeral 7 in (a) of the figure, different values A ₁ and A ₂ are set as the writing pressure at both ends. Further, the manner of changing the stroke width is adjusted by using a width conversion curve as shown in (b). The straight line 7 in (b) shows the case where the stroke width changes linearly, the curve 7-1 shows the case where the stroke width changes rapidly in the first half, and the curve 7-2
Indicates a case where the change is abrupt in the latter half.

The width conversion curve is, for example, y = a
Each variable a, b, c, d can be recorded in the width conversion curve coefficient 3 in FIG. 2 by expressing it by a cubic expression of x ³ + bx ² + cx + d. Note that the width conversion curve coefficient 3 in FIG. 2 is set for each character, but it can be set for each character element. Next, regarding the curve division number 4 in FIG.
This will be described with reference to FIG.

[0022] When the character font is output as a character by the character output device, the curve centerline c shown in (a), (b), the straight centerline l ₁₁ ~
is transformed into a set of l ₁₆ . The greater the number of divisions, the higher the quality of characters. In this example, the division number can be set for each character, but the division number can be set not for each character but for each character element.

Returning to FIG. 1, a straight centerline l ₂ is recorded following the curved centerline c ₁ . This straight line l ₂ is almost the same as the straight line center line l ₁ described above, and therefore a duplicated description will be omitted. In the example of the drawing, the straight line center line l ₂ continues from the end point of the curved center line c ₁ , so the coordinates of the start point and the vertex information are omitted.

As is clear from the above description, in the font data format based on the center line, only one vector is set at the center of the center line, not at the contour of the font vector. This allows 2 stems
Font data is made more compact than the outline font data format that requires more than one vector. Next, about how to reconstruct a character from a character font,
This will be described with reference to the drawings.

First, the schematic flow of the reconstruction process will be described with reference to FIG. In step S1, it is determined whether the center line is a straight center line based on the center line attribute of the character element. If it is a straight center line, the process proceeds to step S2, and if it is a curved center line, the process proceeds to step S5. If it is a straight center line, in step S2, the vertex coordinates and writing pressure mapped onto the character output device are calculated. Then, an outline of the character element is created from the writing pressure at both end points. At this time, if necessary, the stem width and contact shape are adjusted. Then, in step S4, if there is no next character element, the process ends, and if there is, the process returns to step S1.

If it is a curved center line, step S
In step 5, the coordinates of the end points, the coordinates of the control points, and the writing pressure that are mapped onto the character output device are calculated. In step S6, polygonal line approximation of the Betzel curve is performed from the coordinates of the end points and the coordinates of the control points. In step S7, the writing pressure at both end points of each line segment of the approximated polygonal line is calculated. In step S8, an outline of the stem is created from the writing pressure at both end points of each line segment. In addition,
At this time, the stem width and contact shape are adjusted if necessary. Then, the process proceeds to step S4.

Hereinafter, the character "t" will be described with reference to FIGS.
An example of drawing will be described. 7 and 8 show the font data, and FIG. 9 shows the drawn character "t".
In the font data of FIGS. 7 and 8, a predetermined value is set for the width conversion curve coefficient 3 and a numerical value of 5 is set for the curve division number 4.
Is set. First, the processing of the center line will be described.

Center line l following the number of curve divisions 2
_{For 1} , the straight center line is set as the center line attribute and the continuation is set as the connection flag. Also, since the connection flag at the end point is the end, as shown in FIG. 10, the first end point p ₁ (x ₁ , y ₁ ) to the second end point p
_A straight centerline l ₁ is drawn up to ₂ (x ₂ , y ₂ ).

Similarly to the first straight center line l ₁ , the second center line l ₂ also has a third end point p ₃ (x ₃ , y ₃ ) to a fourth end point p ₄ (as shown in FIG. x ₄ , y
_A straight center line l ₂ is drawn until ₄ ). The continuation of the second straight center line l ₂ is set in the connection flag at the end point, so that the next center line is configured to continue.

Third center line c₁Then the center
The line attribute is the curve center line, and the end point is the start point.
Coordinates (x_FourCoordinates, y_FourCoordinates) and control points to represent a curve
Coordinates (x_FourControl point, y_FourControl point) exists and the end point is the end point
Coordinates (x_FiveCoordinates, y_FiveCoordinate) and control to represent the curve
Point coordinates (x_FiveControl point, y_FiveControl points) exist. But
Thus, as shown in FIG. 10, the fourth end point p_Four(X_Four, Y
_Four) To the fifth end point p _Five(X_Five, Y_Five) Up to each coordinate
A Bethel curve is constructed.

Since the continuation of the connection flag at the end point of the third curve center line c ₁ is also set, the next center line is constructed as a continuation. The fourth center line l ₃ is similar to the _first straight center line l ₁ described above from the fifth end point p ₅ (x ₅ , y ₅ ) to the sixth end point p ₆ (x ₆ , y ₆ ). A straight center line is drawn up to. Since the connection flag at the sixth endpoint p ₆ has ended, the center line ends here.

Next, the polygonal line approximation on the curved center line c ₁ (step S6 in FIG. 6) will be described. Since the number of curve divisions of the curve c ₁ is 5, as shown in FIG. 11, a plurality of line segments l ₁₁ , l ₁₂ , l ₁₃ , l ₁₄ and l _{15 are included.}
Will be expanded to. The contact point shape flags at the end points of the line segments l _{11 to} l ₁₅ are rounded so that the line segments are smoothly continuous.

Regarding the writing pressure, the straight center line l ₁
Have the same writing pressure A _{1, that} is, the same stem width. Similarly, the straight line center line l ₂ has the same writing pressure B _1, and the straight line center line l ₃ has the same writing pressure B ₂ . The writing pressure of the curve center line c ₁ changes the stroke width according to the set width conversion curve coefficient.
Stroke width is determined for each line segment l ₁₁ to l _15. Therefore, the curve center line c ₁₁ has the outlines 8 and 9 shown in FIG. 9 created by the above processing in which the stroke width continuously changes from the writing pressure B ₁ to the writing pressure B _2, and is output as the character “t”. It

By thus setting the width conversion curve coefficient, the stroke width can be changed without changing the coordinate parameter of the center line or the writing pressure. Therefore, a variety of characters can be output with the same font data.

[0035]

According to the present invention, font data can be made compact and high-quality characters can be obtained. A method for creating a character font from characters, a method for recording a character font, and a method for reproducing characters from a character font are provided. You can get a way to build.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a relationship between characters and font data according to the present invention.

FIG. 2 is a diagram showing font data of the characters shown in FIG.

FIG. 3 is a diagram illustrating a contact shape of a character element according to the present invention.

FIG. 4 is a diagram illustrating adjustment of writing pressure and stroke width according to the present invention.

FIG. 5 is a diagram illustrating a relationship between a curve and a line segment obtained by dividing the curve in the present invention.

FIG. 6 is a flowchart showing a process of reconstructing a character from a character font according to the present invention.

FIG. 7 is a diagram (part 1) showing font data of a character t in the present invention.

FIG. 8 is a view showing font data of a character t according to the present invention (No. 2).

FIG. 9 is a diagram showing characters drawn from the font data shown in FIGS.

FIG. 10 is a diagram showing a character center line calculated from the data of FIG. 9;

FIG. 11 is a diagram showing a state where the curved center line of FIG. 10 is converted into a line segment.

FIG. 12 is a diagram showing a relationship between characters and font data of a conventional outline font.

13 is a diagram showing outline font data of the characters shown in FIG.

FIG. 14 is a diagram for explaining adjustment of stroke width of the same stem in a conventional outline font.

[Explanation of symbols]

 1, 2, 5, 6, 7, 8, 9 ... Character element 3 ... Width conversion curve coefficient recording location 4 ... Curve division number recording location A, B ... Writing pressure c ... Curve center line l ... Straight center line p ... End point

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06F 3/12 B41J 3/12 G

Claims (6)

[Claims] 1. A method of creating a character font from a character, wherein the character is divided into elements representing the character, a center line of each character element is set, and the data of each character element is a straight line of the center line. And a centerline attribute that is information indicating whether it is a curve, vertex coordinates that indicate the coordinates of the start point and the end point of the centerline when the centerline is a straight line, and the centerline attribute when the centerline is a curve. Character-to-character font characterized by being represented by vertex coordinates that represent the coordinates of the start point and the end point, control point coordinates that represent the shape of the curve by coordinates, and pen pressure information that represents the pen pressure at the start and end points of each centerline. How to create. 2. The data of each character element further includes a connection flag in which the vertex coordinates indicate either continuation or end, and a contact shape flag that determines the shape of the connection location of each character element. A method for creating a character font from characters according to claim 1. 3. A centerline attribute, which is information indicating whether the centerline of the character element is a straight line or a curved line, and a centerline attribute of the centerline when the centerline is a straight line. Vertex coordinates that represent the coordinates of the start and end points, vertex coordinates that represent the coordinates of the start and end points of the centerline when the centerline is a curve, control point coordinates that represent the shape of the curve by coordinates, and the start point of each centerline And a method of recording a character font by using the writing pressure information indicating the writing pressure at the end point. 4. The character font is recorded by further using a connection flag in which the vertex coordinates indicate either continuation or end, and a contact shape flag that determines the shape of the connection location of each character element. How to record a character font. 5. A method for reconstructing a character by a character output device using the character font recorded by the method according to claim 3, wherein a straight center line is mapped on the character output device. Calculate vertex coordinates and writing pressure,
The outline of the stem of the character element is created from the writing pressure at both end points of the center line, and for the curved center line, the vertex coordinates and control point coordinates and the writing pressure that are mapped on the character output device are calculated, and the end point and control point are calculated. A method of reconstructing a character from a character font, characterized in that the curve obtained by is approximated to a straight line is divided into line segments, and the outline of the stem of the character element is created from the writing pressure at the end points of each line segment. 6. A method of reconstructing a character by a character output device using the character font recorded by the method according to claim 4, wherein a straight center line is mapped on the character output device. Calculate vertex coordinates and writing pressure,
An outline of the stem of the character element is created from the writing pressure at both end points of the center line, and for the curved center line, the vertex coordinates and control point coordinates mapped on the character output device and the writing pressure are calculated, and the end point and the control point are calculated. Obtain a line segment obtained by approximating the curve obtained by to a straight line, create an outline of the stem of the character element from the writing pressure at the end points of each line segment, and set the shape of the connection point between the character elements to the contact shape flag. A method of reconstructing characters from a character font characterized by creating based on.