JPH0683313A - Contour correcting mehtod - Google Patents

Abstract

PURPOSE:To effectively correct variance in the line width of a stem due to a magnification varying process and a rounding. CONSTITUTION:The attributes of dots of outline data are checked (step 104); and an (x)-axial and a (y) axial rounding process are performed (step 105) for dots having an attribute 0, an (x)-axial adapting process (one example of line width corrections) and a (y)-axial rounding process is performed (step 106) for dots having an attribute 1. For dots having an attribute 2, an (x)-axial rounding process and a (y)-axial adapting process are carried out (step 107). For dots having an attribute 3, an (x)-axial and a (y)-axial adapting process are carried out (step 108).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour line correction method in hinting an outline font.

[0002]

2. Description of the Related Art FIG. 8 is a processing configuration diagram of an outline font. The outline data read from the font file 1 is expanded as a contour line in the expansion unit 2, and then scaled to a size obtained by the scaling unit 3,
In the hinting processing unit 4, hinting such as line width correction is performed on the scaled outline data, and a rasterizer 5 performs a filling process to develop the inside of the contour into dot data 6.

Regarding the above-mentioned technology, NIKK
EI BYTE / JUNE 1992pp158-165
(Reference 1), same FEBRRUARY 1992 pp11
2-123 (reference 2).

[0004]

In the following description, it is assumed that the pixel is a unit square with the grid point at the lower left corner, and therefore the center of the pixel is (m + 0.5, n + 0.5) where m , N is an integer. Of course, the grid point may be assumed to be the pixel center.

The problem of the prior art will be described using an example in which a character "H" designed in a space of 256 × 256 pixels is reduced to 16 × 16 pixels. The outline data read from the font file 1 is developed as a contour line as shown in FIG. When the outline data is reduced to 16 × 16 pixels, the data shown in FIG. 10 is obtained.

Here, if a filling rule is adopted for the filling processing, that is, a pixel having a pixel center on or inside a contour line is inverted, the left vertical stem becomes 2 pixels and the right vertical stem. Becomes 1 pixel.

Further, when the x and y coordinates of each point are rounded off, FIG. 11 is obtained, and in this case as well, the thickness of the vertical stem is different. On the other hand, when rounding up or down is used instead of rounding, the stem on the right side becomes thicker and the stem on the left side becomes thinner. Such a problem that the line width varies is also pointed out on page 163 of the above-mentioned document 1. A technique for solving this is a technique called hinting.

An object of the present invention is to provide a contour line contour correction method for an outline font, which effectively corrects variations in stem line width caused by scaling processing and rounding.

[0009]

In order to achieve the above object, according to the invention of claim 1, in an outline font outline correction method, an outline corresponding to a first outline point forming an outline at design time. The distance to the line segment on the line is set in advance, the first contour point forming the outline after the scaling processing is obtained, the distance obtained by scaling the design distance to the current size is obtained, and the The first contour point is moved by the scaled distance, and the second
The hinting applied at the point is applied to the first contour point after the scaling and returned to the original position by the preset line width to maintain the line width identity before and after the scaling. Is characterized by.

According to the second aspect of the present invention, in the outline font outline correction method, the distance to the line segment on the outline corresponding to the first outline point forming the outline at the time of design is set in advance and the scaling is performed. The first coordinate value of the first contour point forming the outline after processing is determined, the distance obtained by scaling the design distance to the current size is determined, and the first contour point is first scaled. The scaled distance is added to the coordinate value of the, and the hinting applied at the second point, which is the added second coordinate value, is applied to the scaled first contour point, A fourth coordinate value obtained by subtracting a preset line width from the third coordinate value of the hinted first contour point is obtained, and the hinting is applied to the obtained fourth coordinate value. Move the 1st contour point with It is characterized in that the retaining identity.

According to a third aspect of the present invention, in the outline font outline correction method, the first outline point and the second outline point are used.
There is a third point that is a midpoint between the contour point and the contour point, and the distance to the line segment on the contour line corresponding to the first contour point at the time of design and the line width that the stem should have are set in advance, The second distance and the second line width obtained by halving the value of the distance and the line width obtained by scaling the distance and the line width at the time of designing are obtained, and the second distance and the second line width are calculated. The line width is used to perform hinting on the first contour point and the second contour point.

In the invention according to claim 4, when the line width takes an odd value, the hinting for the midpoint is to move to the pixel center, and when the line width takes an even value, the midpoint. Hinting for is characterized by a move to a pixel boundary.

[0013]

[Operation] The attribute of the point of the outline data is checked, and the attribute 0
Rounding is performed in the x-axis direction and the y-axis direction for points
For the attribute 1 point, the matching process is performed in the x-axis direction,
Rounding is performed in the y-axis direction. Regarding the point of attribute 2,
Rounding processing is performed in the x-axis direction, matching processing is performed in the y-axis direction, and for points of attribute 3, matching processing is performed in the x-axis direction and the y-axis direction. As a result, the line widths of the stems can be made uniform. Further, by moving the center of the stem (the midpoint between the first contour point and the second contour point) to the pixel boundary or the pixel center, it is possible to maintain the vertical and horizontal symmetry of the character.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. <Embodiment 1> FIG. 1 is a flowchart of the contour line correction processing of the present invention. For example, as described above, 256 × 25.
16x character "H" designed in 6 pixel space
Hinting processing of correction processing is performed when the reduction / magnification processing is performed to 16 pixels. This processing is executed by the hinting processing unit 4 shown in FIG.

In the outline data shown in FIG. 9,
Attribute 0 is given to points 2, 3, 6, 7, and 11, attribute 1 is given to points 0, 1, 4, 5, and 8, attribute 2 is given to point 10, and point 9 is given. Attribute 3 is given. Then, as shown in FIG. 2, for the attributes of each point at the time of designing, a line width table storing the distance to the line segment on the corresponding contour line and the line width that the stem should have is provided.

For example, regarding a point 1 having a point attribute of 1 in the table, a distance 24 is read, and this distance is the distance from the point 1 to the contour line formed by the corresponding points 2 and 3. It means that it is 24 dots, and that its line width is 24 dots.

When the scaling process is performed, the above-mentioned distance becomes a value after the scaling process, and the line width described above is
It is a value obtained by rounding the distance that has undergone scaling processing. There is no necessity for this rounding. In other words, as long as it provides the same line width for points having the same attribute, it is not necessary to round it, and it is also possible to use a completely different table.

The operation of this embodiment will be described. The number of outline data is set to numpoint (step 101), n is set to 0 (step 102), and n is set.
As long as does not exceed numpoint (step 10
3) The attributes of the points of the outline data are checked (step 104), and the points having the attribute 0 are rounded in the x-axis direction and the y-axis direction (step 105). For example, point 2
Has the attribute 0, the x-coordinate position of the point 2 after scaling is 2.
It becomes 75 (= 44/16) and becomes 3.0 when rounded.

With respect to the point having the attribute 1, a fitting process as described later is performed in the x-axis direction and a rounding process is performed in the y-axis direction (step 106). For points having the attribute 2, rounding processing is performed in the x-axis direction, and matching processing is performed in the y-axis direction (step 107). For the points having the attribute 3, the matching processing is performed in the x-axis direction and the y-axis direction (step 1
08). For other points, hinting is performed by another method (step 109). With n as the next point (step 110), the above processing is repeated to process all points of the outline data.

Here, the rounding processing refers to conversion such as rounding, rounding up, and rounding down to make a decimal number an integer. In the following description, rounding is used. The rounding process and the matching process are examples of hinting processes.

The fitting process described above, eg x for point 1.
A description will be given by taking an adaptation process in the axial direction (an example of line width correction) as an example. Since the character “H” designed in the space of 256 × 256 pixels is reduced to 16 × 16 pixels,
The distance 24 read from the line width table (FIG. 2) corresponding to the attribute 1 of the point 1 is 1.5 (= 24/16),
In addition, the line width is obtained by rounding off the distance of 1.5.

Point 1 having an x coordinate of 1.25 (= 20/16) is moved to the right by a distance of 1.5. This point is exactly where point 2 is (2.75).

Therefore, the distance is moved to the right by 1.5, and x
The rounding process (step 105) performed on the point 2 is performed on the point 1 whose coordinates are 2.75. That is, the point 1 having an x coordinate of 2.75 is the closest pixel boundary 3.
Move to 0.

Point 1 having an x coordinate of 3.0 is moved leftward by a line width of 2, and the x coordinate of point 1 is 1.0 and the x coordinate of point 2 is 3.
A stem subjected to hinting processing (line width correction) having 0 and a line width of 2 is obtained.

<Embodiment 2> In the above-mentioned embodiment, the point movement processing is performed three times (twice right and left one time), but in the second embodiment, the number of times of movement of the point is reduced. is there. That is, (1) The distance 1.5 and the line width 2 corresponding to the attribute 1 of the point 1 are obtained. (2) Obtain the x-coordinate of 1.25 for point 1 and add 1.5 to it.
Is added. This is exactly the x coordinate of point 2. (3) The obtained x coordinate 2.75 is rounded to obtain 3.0. (4) Subtract a line width of 2 from the obtained x coordinate of 3.0. (5) Move point 1 to the obtained position of x coordinate 1.0.

In this embodiment, the process of moving the point 1 only needs to be moved once to the left, so that the process is simplified. FIG. 3 shows outline data hinted by Examples 1 and 2.

<Embodiment 3> By the processing of Embodiments 1 and 2 described above, it becomes possible to keep the line width of stems designed to have the same line width the same even after scaling. However, in the above-described method, the position of the vertical stem is determined with the right end of the contour line as a reference, so that the overall balance may be lost in a small size. The third embodiment retains the character symmetry and produces a clean and well-balanced character.

FIG. 4 is a flow chart of the contour line correcting process of the third embodiment, which is 256 × 2 as in the above-mentioned embodiment.
16 letters "H" designed in a 56-pixel space
Hinting, which is a correction process, is performed when the reduction / magnification process is performed to × 16 pixels.

Further, in the outline data shown in FIG. 9, an attribute 10 is given to points 0, 1, 5, and 8,
Attribute 11 is given to point 4, attribute 12 is given to point 9, attribute 20 is given to points 2, 6, 7, and 11, attribute 21 is given to point 3, and point 10 is given. It is assumed that the attribute 22 is given. Of these 2-digit attributes,
The upper digit represents the attribute in the x-axis direction, and the lower digit represents the attribute in the y-axis direction.

Then, as shown in FIG. 5, with respect to the attributes of each point at the time of designing, a line width table storing the distance to the line segment on the corresponding contour line and the line width that the stem should have is provided. When the scaling process is performed, the distance and the line width described above are at the same time as the scaled values.

To explain the operation of this embodiment, the score of the outline data is set to numpoint (step 201), n is set to 0 (step 202), and n is set.
As long as does not exceed numpoint (step 20
3) Check the point attribute of the outline data (step 204), if the attribute in the x-axis direction is 0, rounding is performed in the x-axis direction (steps 205, 206, 207), and if the attribute in the x-axis direction is 1. If the left edge is adapted (step 2
08, 209, 210), and if the attribute in the x-axis direction is 2, the right end matching process is performed (steps 211, 212, 21).
3).

If the attribute in the y-axis direction is 0, rounding processing is performed in the y-axis direction (steps 205, 208, 211), and if the attribute in the y-axis direction is 1, upper end matching processing is performed (steps 206, 209). 212), if the attribute in the y-axis direction is 2, the lower end matching process is performed (steps 207, 210, 21).
3). For other points, hinting is performed by another method (step 214). The next point is set to n (step 215), and the above processing is repeated to process all points of the outline data.

Here, the rounding processing means conversion such as rounding, rounding up, and rounding down to make a decimal number an integer, as described above. In the following description, rounding is used.

The matching process described above, for example point 1 (attribute 1
The left edge matching process for 0) will be described as an example. 256
Since the character "H" designed in the space of x256 pixels is reduced to 16x16 pixels, the distance read from the line width table of Fig. 5 corresponding to the attribute 1 of the point 1 in the x-axis direction. 24 becomes 1.5 (= 24/16),
The line width is 1.5 (= 24/16).

By halving these, a distance of 0.75 and a line width of 0.75 are obtained. x coordinate is 1.25 (= 20/16)
The point 1 which is a point is moved to the right by a distance of 0.75. This point is exactly the midpoint between point 1 and point 2. x coordinate is 2.0
Move point 1 to be the closest pixel boundary 2.0. Point 1 whose x coordinate is 2.0 is moved to the left by a line width of 0.75. The fitting process at the right end for the point 2 is performed completely symmetrically to the fitting process for the point 1 described above. As a result, as shown in FIG. 6, a stem subjected to the hinting processing is obtained by performing line width correction so that the center line of the stem subjected to the scaling processing becomes the pixel boundary.

<Fourth Embodiment> In the above-described third embodiment, the point movement processing is performed three times (twice right, left one time), but in the fourth embodiment, the number of point movements is reduced. Is. In this embodiment, it is assumed that the value of the line width table in FIG. 5 is 1/2. Therefore, set the value in the line width table to 1
The operation of setting to / 2 is omitted.

(1) The distance 0.75 and the line width 0.75 corresponding to the attribute 1 of the point 1 in the x-axis direction are obtained. (2) Obtain the x-coordinate of 1.25 for point 1 and add 0.7 to it.
Add 5 This is just the x coordinate of the midpoint of points 1 and 2. (3) The obtained x coordinate 2.0 is rounded to obtain 2.0. (4) A line width of 0.75 is subtracted from the obtained x coordinate of 2.0. (5) Move point 1 to the obtained position of x coordinate 1.25.

In the fourth embodiment, the moving process of the point 1 is moved to the left only once, so that the process becomes simpler than that of the third embodiment. The result of this processing is the outline data that has been hinting processed as shown in FIG.

<Embodiment 5> In the above-described embodiment, the process for the middle point between point 1 and point 2 is to move (round off) to the pixel boundary. However, since the middle point is moved to a pixel boundary and the middle point is moved vertically or horizontally symmetrically, the number of pixels that appears is always an even number. The vertical stem in FIG. 6 has 2 pixels. Therefore, when the midpoint is moved to the pixel boundary, the number of pixels is 2 pixels, 4 pixels, 6 pixels. ． ．
Since the value of is taken, the width of the stem suddenly becomes thick and it is not possible to compose beautiful characters.

Even if the midpoint is moved to the pixel center,
The number of pixels is 1 pixel (horizontal stem in FIG. 6), 3 pixels, 5 pixels. ． ． Just like an odd number, the width of the stem suddenly becomes thick, and similarly beautiful characters cannot be constructed.

Therefore, in the present embodiment, when the line width held in the line width table is an odd number, hinting for the middle point is moved to the pixel center, and when the line width is an even number, it is moved to the pixel boundary. It is what That is, (1) A line width of 1.5 corresponding to the attribute 1 of the point 1 in the x-axis direction is obtained. (2) The line width of 1.5 is rounded to obtain 2. (3) Since 2 is an even number, the movement of the midpoint uses the movement to the pixel boundary. If it is an odd number, move to the pixel center.

The rounding is an example, and any method of converting a decimal value into an integer may be used. In addition to the rounding process described above, as shown in FIG. 7, an odd / even table may be provided for determining whether to use the pixel boundary or the pixel center according to the line width.

[0043]

As described above, according to the invention described in claims 1 and 2, the distance to the line segment on the preset contour line corresponding to a specific contour point and the line width of the stem are used. Since the matching process for the specific contour point is performed, the line widths of the stems can be made uniform even after scaling, and a well-balanced and high-quality character is output.

According to the third aspect of the present invention, since the center line of the scaled stem is moved to the pixel boundary or the pixel center, the left-right symmetry and the vertical symmetry of the stem can be maintained. In addition to being able to, it is possible to prevent the shape of the character from being spoiled.

According to the fourth aspect of the present invention, since the processing is performed in consideration of the odd and even stem line widths, it is possible to form beautiful characters.

[Brief description of drawings]

FIG. 1 is a flowchart of a contour line correction process of the present invention.

FIG. 2 is a diagram showing a line width table.

FIG. 3 is outline data hinted according to the present invention.

FIG. 4 is a flowchart of contour line correction processing according to another embodiment of the present invention.

FIG. 5 is a diagram showing a line width table of another embodiment.

FIG. 6 is outline data hinted according to the present invention.

FIG. 7 is a diagram showing an even-odd table.

FIG. 8 is a processing configuration diagram of an outline font.

FIG. 9 is expanded outline data.

FIG. 10 is scaled outline data.

FIG. 11 is rounded-out outline data.

[Explanation of symbols]

 1 Font file 2 Expansion unit 3 Magnification processing unit 4 Hinting processing unit 5 Rasterizer 6 Dot data

Claims (4)

[Claims] 1. An outline font contour correction method, wherein a distance to a line segment on the contour line corresponding to a first contour point forming the outline at the time of design is set in advance, and the outline after scaling processing is formed. First to do
Of the contour points, the distance at the time of the design is scaled to the current size is obtained, the first contour point after the scaling is moved by the scaled distance, and at the moved second point. The hinting to be applied is applied to the first contour point after the scaling and returned to the original position by a preset line width to maintain the same line width before and after the scaling. How to correct the contour line. 2. An outline font contour correction method, wherein a distance to a line segment on the contour line corresponding to a first contour point constituting the outline at the time of designing is preset, and the outline after scaling processing is constructed. First to do
The first coordinate value of the contour point is calculated, the distance obtained by scaling the design distance to the current size is calculated, and the scaled distance is changed to the first coordinate value of the scaled first contour point. Is added, and the hinting applied at the second point, which is the added second coordinate value, is applied to the scaled first contour point,
A fourth coordinate value obtained by subtracting a preset line width from the third coordinate value of the hinted first contour point is obtained, and the obtained fourth coordinate value is set to the hint coordinate. A contour line correction method, which comprises moving a first contoured point to maintain the same line width before and after scaling. 3. An outline font contour line correction method, wherein a third point, which is a midpoint between the first contour point and the second contour point, is present and corresponds to the first contour point at the time of designing. The distance to the line segment on the contour line and the line width that the stem should have are set in advance, and the distance and line width values obtained by scaling the distance and line width at the time of designing to the current size are halved. A second distance and a second line width are obtained, and hinting is performed on the first contour point and the second contour point using the second distance and the second line width. And the contour correction method. 4. When the line width has an odd value, hinting for the midpoint is a movement to a pixel center,
The contour line correction method according to claim 3, wherein when the line width has an even value, the hinting for the midpoint is movement to a pixel boundary.