KR100273334B1 - How to Implement Vector Fonts in CAD Systems - Google Patents

Abstract

The present invention relates to a vector font implementation method of the CAD system, conventionally, by applying a vector font that uses the coordinates as a reference to the current reference point resolution is reduced when the character is implemented in a single line, the price of the character implementation in double lines as well as fonts There was a disadvantage that was not beautiful. In view of the above, the present invention obtains and stores the data of the outline font when implementing a character, and then implements the data of the outline font as a vector font to improve the resolution of the character as well as to diversify the type of the font or printer or plotter. Can be used for

Description

How to Implement Vector Fonts in CAD Systems

1 is an explanatory diagram of a vector font implementation of a conventional CAD system.

Figure 2 is an explanatory diagram of the outline font of the CAD system according to the present invention.

Figure 3 is an explanatory diagram of implementing the outline font of the CAD system according to the present invention in a vector font.

Figure 4 is a signal flow diagram when implementing the font of the CAD system according to the present invention.

The present invention relates to a vector font implementation used in a CAD system, and more particularly, to a vector font implementation method of a CAD system for converting an outline font into a vector font to improve the resolution of the vector font.

In general, in order to display characters on the screen in a CAD system, it is possible to have a vector font of the character to be displayed, and a vector font must also exist when outputting and printing a character to a plotter or a laser printer emulating the plotter. It is possible.

In order to generate such a vector font, the coordinate values of the newly obtained point must be expressed in relative values based on the coordinate values of the current point, and the coordinate values must be moved.

The range of coordinate values used for vector fonts is -126 to +127.

A vector font implementation of a conventional CAD system is described with reference to FIG. 1 as follows.

First, in order to implement the vector font “A”, it is panned up based on the coordinate value (0.0) of the current point (S ₀ ), and then moves to a random point (S ₁ ), and the moving point (S ₁ ) at this time. Is corrected to the current point, pen down, and the coordinate value of the random point S ₂ is obtained.

At this time, after subtracting the coordinates of the current point (S ₁₎ in the coordinate value of the moving point (S ₂₎ moves by the difference value and correct the movement point (S ₂₎ to the current point any point (S ₃₎ Find the coordinate value of.

In this way, the mobile point (S ₃₎ and then by subtracting the coordinates of the current point (S ₂₎ in the moving coordinate value by the difference value to the moving point (S ₃₎ of the present point is corrected.

Thereafter, paeneop (Pen up) to obtain the coordinate value of the moving point (S ₄₎ in the coordinate value of the moving point (S ₄₎ at this time by subtracting the coordinates of the current point (S _3), move by the difference value The moving point S ₄ is set as the current point.

In other words, by repeatedly performing the above process to implement a single vector letter and to display the data structure according to it as follows.

Pen up

move (S ₁ -S ₀ )

Pen down

move (S ₂ -S ₁ )

move (S ₃ -S ₂ )

Pen up

ㆍ

ㆍ

ㆍ

However, the vector font implemented in the conventional CAD system is represented by a single line, so the resolution is reduced, and the vector font represented by the double line has a better resolution than the single line vector font but is more expensive and monotonous than the outline font, and the characters are not beautiful. There was a problem.

Accordingly, an object of the present invention is to create a vector font implementation method of a CAD system that improves the resolution by reading the data of the outline font and converting the data into a vector font.

Hereinafter, described in detail with reference to the accompanying drawings of the present invention.

To implement a vector font, as shown in FIG. 2, the absolute coordinate system of the font outline should be obtained.

The outline font is obtained from four commands and coordinates (x.y).

First, "moveto" is a command for moving a coordinate position by using a given coordinate point as the current point. When implemented with a vector font command, "moveto" is the same as the "move" operation.

Second, "lineto" is a command that draws a straight line from the current point to a given coordinate point and modifies the newly given coordinate point to the current point. If implemented with a vector font command, "lineto" is the same as "move".

Third, "curveto" is a command that implements a Bezier curve by obtaining five relative coordinate values from the current point and the newly given three coordinate points. do.

In other words, the straightening of the curve has four control points and repeats the task of finding the midpoint of each control point several times to find the new coordinate points, and then operates the "Pen down" and "move" operations using the start point and the end point of these and four initial control points. Repeat the process to find the Weser curve.

Fourth, "closepath" is a command that draws a straight line from the current point to the point used in "moveto". If it is implemented by a vector font command, it is the same as "move" after "Pen down".

By executing such a command, the data structure of implementing the outline font of "a" in FIG. 2 is as follows.

t ₁ moveto

t ₂ lineto

t ₃ , t ₄ , t ₅ curveto

t ₆ lineto

t ₇ , t ₈ , t ₉ curveto

t ₁₀ lineto

closepath

Therefore, in the present invention, a process as shown in FIG. 4 is performed to implement the outline font as a vector font as shown in FIG. 3.

First, check whether there is outline font data to implement vector font.

At this time, if the outline font data is present, the coordinate value of the arbitrary point of the outline font data and the attribute of the point are read, and then it is determined whether the attribute of the read point is the end of the character.

Therefore, if the attribute value of the read point is determined as the end of the character, the implementation of the Hangul character is completed. The origin of the next character is obtained by adding the width of the vector font, which is the width of the character, to the origin of the vector font, which is the origin of the current character. Checks whether the data of the outline font exists.

If the attribute value of the read point is not the end of the character, it is compared and determined whether the attribute value is "moveto".

Accordingly, in the case of "moveto", after "Penup", the value of the new coordinate point is obtained as the absolute value and the relative value. The absolute value is the data of the outline font and the relative value is the data of the vector font. In the case of "closepath", the current point is moved after saving the relative value in vector font data as well as saving for regression.

It also determines whether the attribute value is "lineto" or not "moveto".

Accordingly, when it is determined as "lineto", "Pen down" is performed, and the relative value of the new point and the current point is stored in the vector font data, the current point is moved to the new point, and the data of the next outline font is checked. Perform the action.

If the attribute value is neither the end of the character nor "moveto" or "lineto", the attribute value is "curveto".

Therefore, when the attribute value is determined as "curveto", the vector font commands "Pen down" and "move" are repeated to straighten the curve by repeatedly calculating the midpoints of the control points with the control points of the Bezier curve. Repeat this, "Pen down" and then read two more values of the new point to get five new relative coordinates with the current point and three new points, save them in vector font data, and then use the "move" command to select the current point. Specify a new one.

On the other hand, if the attribute value is not the end of the character and is not "moveto" or "lineto" or "curveto", the attribute value is determined as "closepath" and the "Pen down" is stored as the absolute coordinate point stored when the current point and the attribute value are "moveto". And get the new current point and move the coordinate point with "move" command.

In this way, after one letter is implemented according to the attribute value, it checks whether the data of the next outline font exists.

Therefore, if there is the next outline font data, the above operation is repeated. On the contrary, if there is no outline font data, the character implementation is terminated.

Accordingly, the vector font implementation of the outline font as shown in FIG. 3 is completed, and the data structure at this time is as follows.

Pen up

move (S ₁ -S ₀ )

Pen down

move (S ₂ -S ₁ )

move (S ₃ -S ₂ )

move (S ₄ -S ₃ )

.

.

.

As another embodiment of the present invention, when straightening a Bezier curve to implement a curve, a vector font is obtained by arcing by performing the operation of finding the midpoint of the midpoints several times in finding a new midpoint with each control point. It can be formed according to the method.

As described in detail above, the vector font implementation method of the CAD system of the present invention is not only applicable to a plotter or a laser printer emulating a plotter function by implementing a vector font using data of an outline font, but also has a high font resolution and a type of font. There is an effect that can be diversified.

Claims (1)

When there is data of outline font to convert to vector font, after reading the coordinate value and attribute value of one point data of the outline font, whether the attribute value is the end of character or one of "moveto", "lineto", "curveto" A first step of discriminating; and a second step of obtaining the origin of the next letter by adding the width of the character to the origin of the current character when the attribute value is determined as the end of the character; and a new coordinate when the attribute value is determined as "moveto". A third step of obtaining and storing the point value as an absolute value and a relative value, and moving the current point; and when the attribute value is determined as "lineto", the relative value of the new point and the current point is obtained to convert the current point to the new point. A fourth step of replacing and a fifth step of implementing a bezier curve according to the straightening of the curve by obtaining five relative coordinate values using the current point and three new points when the attribute value is determined as "curveto"; Genus from above If the value is not the end of the character, or "moveto" or "lineto" or "curveto" or "closepath" is determined by the sixth step to obtain a new point with the absolute value in the third step to move the current point How to implement vector fonts in CAD systems.