JP3146771B2 - Font rasterizing apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a font rasterizing apparatus and method for forming a raster character image of an arbitrary size from reference outline information.

[0002]

2. Description of the Related Art In recent years, in the field of desk publishing and the like, when a raster character image is output, instead of a dot font, several points indicated by coordinates and a contour line connecting them, that is, a shape of a character represented by an outline is used. The outline font, which is the font that defines, has been used.

In order to output a raster character image of a character using this outline font, coordinate position information of some dots serving as a base point is held as a part of the outline information. A line (outline) that follows the character and passes through the outline is calculated, the outline is filled, and the resulting raster character image is output.

In the background where the outline font has come to be used, since the outline font basically needs to hold only the coordinate data of the base point, a fine-grained font having a large number of dots is stored. In this case, the required storage capacity is significantly smaller than that of the dot font. Also, when outputting characters having different sizes, the basic outline font is enlarged / reduced by calculation, so that it is not necessary to have a font for each character size unlike a dot font. Further, in the outline font, characters can be deformed relatively freely. In other words, the use of outline character information in an outline font makes it possible to obtain characters of arbitrary size and deformed / modified characters with a low storage data amount and a high quality compared to the case of using raster character data in a dot font. Is obtained.

As a related technique for outputting high-quality characters using this outline information, Japanese Patent Application Laid-Open No.
There is a character processing device described in JP-A-006164.
This character processing apparatus is used when the width of each stroke represented by an outline, which is generated when performing enlargement / reduction processing using outline information, becomes uneven or the balance between strokes becomes poor. A correction technique is disclosed. As a result, it is possible to output a high-quality raster character image utilizing the characteristics of characters, for example, the characteristics unique to kanji characters.

Further, Japanese Patent Application No. 3-292407 discloses a drawing apparatus for efficiently developing a raster data when drawing characters from outline information. In this method, various processes on how to develop an outline on a bitmap plane are determined appropriately from the form of dot misalignment, and the appropriate process is selected and executed using the results. It is.

Further, Japanese Patent Application Laid-Open No. 2-219094 discloses that extra points (control points) are used when generating a raster character image using reduced outline character data (including vector font character data). In order to solve the problem of crushing of characters due to the occurrence of line width variation in characters and the processing time due to the large number of points, depending on the reduction ratio, point data to be deleted An identifier indicating the reduction ratio to be deleted is added in advance, and when generating the reduced character, the point data to be deleted is determined by the identifier of each point data according to the reduction ratio, and it is deleted. A vector font character reduction method for generating reduced characters based on the point data described above is described.

On the other hand, among raster character data in a dot font, raster characters having a size of 10 dots or 12 dots are applied to human illusion and strokes in the characters are intentionally omitted to improve readability. A better technique, the illusion technique, is used.

For example, FIG. 17 is a diagram showing "negative" raster character data of 10 dots.times.10 dots.
In 7, the central element of the character “negative” is “eye”
When expressed by a horizontal stroke of a book, the element "eyes" is crushed, and the readability of the character "negative" is deteriorated. It is expressed as By using such an illusion technique in which the element "eye" of the character "negative" is set to "day", the readability of the character "negative" can be improved even with a low-resolution output device.

[0010]

As described above, conventionally, when the resolution of one character such as 10 dots.times.10 dots is low, the readability of the character is improved by using an illusion technique. .

However, a font rasterizing apparatus using outline information that can obtain a character of any size or a deformed / modified character with a small amount of stored data and high quality can output a character using the illusion technique described above. I couldn't.

For this reason, even in a font rasterizing apparatus using outline information, if the resolution per character is low, the output character may be crushed, and a character with good readability may be output. could not.

Accordingly, the present invention has been made to solve the above-mentioned problem and to provide a font rasterizing apparatus and a method thereof capable of outputting a character with good readability as a character using an illusion technique when the resolution per character is low. The purpose is to provide.

[0014]

SUMMARY OF THE INVENTION The present invention relates to a font rasterizing apparatus for generating raster data of a character of an arbitrary size based on reference outline information, and relates to a stroke forming the character of an arbitrary size from the reference outline information. Calculating means for calculating stroke information; first determining means for determining whether each stroke of the stroke indicated by the calculated stroke information is a predetermined optional stroke in the reference outline information; Second determining means for determining whether or not each stroke line width of the stroke indicated by the calculated stroke information is equal to or less than a predetermined threshold value, and determining by the first determining means and the second determining means Referring to the result, it is possible to omit strokes that can be omitted and have a stroke line width equal to or less than a predetermined threshold. Characterized by comprising a drawing means for drawing the characters of any size having a stroke which is the calculated.

[0015]

According to the present invention, when generating raster data of a character of an arbitrary size based on reference outline information, a calculating means calculates stroke information on a stroke constituting the character of the arbitrary size from the reference outline information. The first determining means determines whether each of the strokes indicated by the calculated stroke information is a predetermined optional stroke in the reference outline information, and the second determining means It is determined whether or not each stroke line width of the stroke indicated by the calculated stroke information is equal to or smaller than a predetermined threshold value. An arbitrary size character having the calculated stroke is drawn, excluding the stroke that is equal to or smaller than the threshold value.

[0016] Therefore, even when characters are drawn on a bitmap having a low resolution due to reduction, it is possible to output characters with good readability.

[0017]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a font rasterizing apparatus according to one embodiment of the present invention.

In FIG. 1, the font rasterizing device includes outline character information 11b, vertical / horizontal stroke boundary position information 11a which has been manually or automatically extracted from the outline character information 11b, and this boundary position information 11a. Correspondingly, the external storage unit 11 storing outline information including a deleteable flag 11c indicating that this stroke can be deleted,
An extraction unit 12 for extracting boundary position information 11a, outline character information 11b, and a deletable flag 11c for an arbitrary character from the external storage unit 11, and a storage unit 13 for temporarily storing extracted or corrected outline information. The outline information stored in the storage unit 13 is enlarged / reduced to a designated arbitrary size,
Alternatively, a conversion unit 15 that performs conversion such as an arbitrary rotation process, a stroke correction unit 16 that corrects boundary position information among outline information converted by the conversion unit 15, and a boundary position information corrected by the stroke correction unit 16. An outline character information correcting unit 17 for correcting outline character information based on the original, a developing unit 14 for raster developing the corrected outline character information on a bitmap, and an extracting unit 12, a storage unit 13, a developing unit 14, Converter 15,
Stroke correction unit 16, outline character information correction unit 1
7 are connected to each other, and the control unit 18 controls each process.

Further, the stroke correction section 16 stores the storage section 1
3, the deletion flag detection unit 16a that detects whether the stroke can be deleted by referring to the deletion possible flag 11c stored in the storage unit 3 and the boundary position information converted by the conversion unit 15 to determine the stroke width. And a deletion determining unit 16b that determines whether or not is less than or equal to a predetermined threshold. When the stroke detected by the deletion flag detection unit 16a has a stroke width equal to or smaller than a predetermined threshold value by the deletion determination unit 16b, the stroke is deleted.

Here, the stroke is a stroke of a character determined by an outline generated by the outline character information, and the boundary position information is coordinate information indicating the boundary position of the stroke on the outline coordinates. . The stroke and the boundary position information will be described later in detail with reference to the drawings.

FIG. 2 is a diagram showing a functional configuration of a printer system incorporating the font rasterizing device of FIG.

In FIG. 2, a data input unit 21 receives input data 23 printed or displayed by an output device 22 such as a printer or a CRT, and supplies it as data 28 to a data interpretation execution control unit 27.

The font processing unit 26 manages and searches for font data. If there is raster character data 29 for the requested character, the raster character data 29 is supplied to the data interpretation execution control unit 27. When the data 29 specifies outline characters, the font processing unit 26 performs enlargement / reduction processing or transformation processing of outline information, and the like.
After performing the expansion processing, the data interpretation execution control unit 27
To supply. A font file 31 is connected to the font processing unit 26, and the font processing unit 26 extracts font data 32 from the font file 31. Here, the external storage unit 11 in FIG. 1 corresponds to the font file 31, and the other components in FIG. 1 correspond to the font processing unit 26.

The image processor 25 processes the data interpreted by the data interpretation processor 27 and develops the data on the image memory 33. The expanded data 34 is supplied to the data output unit 24 via the image processing unit 25 and the data interpretation execution processing unit 27, and is transmitted as output data 36 to the output device 22 connected to the data output unit 24. . In this case, what is stored in the image memory 33 includes, in addition to the image data expanded by the image processing unit 25, the character data expanded by the font processing 26.

FIG. 3 is a diagram showing a circuit configuration of the printer system of FIG. That is, FIG. 3 shows an actual hardware configuration.

In FIG. 3, the CPU 41 is connected to the following units via a bus 42.

(1) RAM 43: This is a random access memory, which is used as a memory area for temporarily storing character data, a work area for deforming and expanding character data of outline information, and a printer system. It is used to temporarily store a program for controlling the operation or temporarily store various data processed for execution of the program. Further, the RAM 43 has an image memory area and also plays a role as the image memory 33 shown in FIG.

(2) Magnetic disk device 44: This is an external storage device that stores a program for controlling the printer system, a font file, and stores data for storage as needed. .

(3) Communication control unit 45: This is connected via a cable 46 to an external telephone communication network, local area network, or the like. Then, data for printing is input from an information source such as a host computer connected thereto. This data is, for example, data described in a page description language or the like.

(4) Keyboard 47: This is a device to which a mouse 48 as a pointing device can be connected, and which inputs various data for operating the printer system. Data for printing can be directly input from the keyboard 47.

(5) CRT control unit 49: graphic
It is connected to a CRT 51 as a display, and performs control for visually displaying various data on the CRT 51.

(6) Printer control unit 52: functions as the data output unit 24 shown in FIG.

Next, an outline of the operation of the printer system including the font rasterizing apparatus will be described with reference to a flowchart.

FIG. 4 is an operation flowchart of the printer system.

In FIG. 4, first, input data for printing is read (step 101). The input data is in a command format, and the CPU 41 causes the data interpretation execution control unit 27 to interpret the command. As described above, this command is described in the page description language.

Then, it is determined whether or not this command is a command for font processing (step 10).
2) If the command is for font processing, font processing is performed by the font processing unit 26 (step 10).
3). Then, control goes to a step 107. On the other hand, if it is determined in step 102 that the command is not a command for font processing, it is further determined whether or not the command is a command for image processing (step 104). Image processing is performed in step 25 (step 105), and the process proceeds to step 107. If the command is not an image processing command in step 104, the data interpretation execution control unit 27 performs other command processing such as a language processing system in the data interpretation execution control unit 27 (step 106), and proceeds to step 107. I do.

In step 107, the data interpretation execution control section 27 determines whether or not the input data has been completed.
If not, the process moves to step 102 and the above-described processing is repeated. On the other hand, when the input data is completed, the image contents developed in the image memory area in the RAM 43 are transferred to the laser printer 53, and printing is performed by the laser printer 53.

Next, the font processing in step 103 will be described.

FIG. 5 is a diagram showing the structure of a font file required for font processing.

In FIG. 5, the font file is one font and one file, and the file is composed of a raster character information section 61 and an outline character information section 62.

The raster character information section 61 includes raster character information 63 and character width information 64.

The outline character information section 62 has outline character information 65, character width information 66, stroke boundary position information 67, and a stroke deletion possible flag 68.

Here, the input character information is defined for one or both of the raster character information part 61 and the outline character information part 62. The raster character information part 61 has a character size and a character code. The outline character information section 62 can search for characters of character information by character codes.

FIG. 6 is a flowchart showing a font processing procedure of the font processing unit 26.

In FIG. 6, first, a search is performed for the character size and character code of the character information requested by the raster character information section 61 in the font file (step 20).
1). Then, from the search result, the raster character information section 6
It is determined whether or not the character size and the character code of the requested character information are present in 1 (step 202). If the character information of the requested character size and character code exists in the raster character information section 61, all the requested information such as the raster character information 63 and the character width information 64 are transferred from the raster character information section 61 to the RAM 43. (Step 20)
3), end this processing.

On the other hand, if the requested character information does not exist in the raster character information section 61 in step 202, the character information of the requested character code is further searched in the outline character information section 62 (step 202). 20
4). If the character information requested from the search result does not exist, error processing is performed (step 20).
6), end this processing. On the other hand, if the requested character information exists in step 206, the process further proceeds to step 207.

In step 207, the outline character information 65, the character width information 66, the stroke boundary position information 67, the stroke deletion enable flag 68 and the like of the requested character information existing in the outline character information section 62 are set to R.
Transfer to AM43.

Then, the converting unit 15 performs enlargement / reduction processing to uniformly set the outline character information 65, character width information 66, and stroke boundary position information 67 temporarily stored in the RAM 43 to the required size (step 208). . Of course, not only the enlargement / reduction processing, but also processing such as deformation is performed.

Further, the stroke correcting section 16 performs a process of correcting the stroke boundary position information that has been enlarged / reduced in step 208 (step 209). This correction process is intended to correct the stroke information in the outline information uniformly converted by the conversion unit 15 and to correct the stroke boundary position information to a value suitable for bitmap development. to correct. That is,
Performs rounding processing by integer conversion. Then, the deletion flag detection unit 16a detects a stroke that can be deleted, and if the width of the detected stroke is equal to or smaller than a predetermined threshold, a correction process for deleting this stroke is performed.
Such a correction for deleting a stroke often occurs in the case of reduction conversion.

Next, when the stroke correction unit 16 completes the correction of the stroke boundary position information, based on the corrected stroke boundary position information, the outline character information correction unit 17 performs a final correction process of the outline character information. Is performed (step 210). This correction processing corrects positions other than the stroke boundary position to appropriate values based on the stroke boundary position information corrected in step 209. That is, based on the correction value of the stroke boundary position subjected to the priority processing and the value of the stroke boundary position before this correction, the continuous conversion relationship of other positions including this value is obtained, and based on this continuous conversion relationship, hand,
All outline character information is corrected. Thus, the corrected stroke maintains the corrected value, and the outline character information of the other portions is corrected to an appropriate value by the above-described continuous conversion relationship corresponding to the corrected stroke.

The outline character information thus corrected and temporarily stored in the RAM 43 is raster-expanded by the expansion unit 14 by a predetermined method to form raster characters (step 211). Thus, the font processing ends.

Next, the font processing in steps 208 to 211 will be described based on a specific example.

FIG. 7 is a diagram showing the structure of the reference outline character information section of the character of the "eye". FIG. 8 shows the outline of the reference outline information of the character of the "eye" on the outline drawing coordinates. FIG.

In FIG. 7, the reference outline information of the character “eye” is stored in the pointer storage area 71 as the first stage.
In the storage area 71, a pointer P1 indicating the storage address of the outline character information 74, a pointer P2 indicating the storage address of the vertical stroke boundary position information 75, and a horizontal stroke boundary position information 76 are sequentially stored from the head address A1. A pointer P3 indicating the storage address of the vertical stroke deletion enable flag 77, a pointer P5 indicating the storage address of the horizontal stroke deletion enable flag 78, and a pointer P6 indicating the storage address of the character width information 79. Is stored.

The outline character information 74 indicated by the pointer P1 stores outline line types 72 and control points 73 in pairs. And the outline line type "0"
Means a start point of an outline to be closed, and a control point corresponding thereto indicates coordinates on outline drawing coordinates. Further, the outline line type “1” means that the outline is a straight line, and indicates that the outline is a straight line up to a pair of coordinates. Although other outline line types such as circles and higher-order curves are prepared in advance, they are not used for the reference outline character information of the character of “eye”.

For example, the first of the outline character information 74
The second outline line type is "0", and the corresponding control point is (20, 57), which corresponds to the control point SP1 in FIG. The outline line type stored next second is “1”, and the corresponding control point is (20, 8), whereby the coordinates (20, 5) are obtained.
A straight line is drawn from 7) to coordinates (20, 8). That is, a part of the outline of the vertical stroke is drawn. Here, a straight line between the drawn control points is called a segment, and an outline to be closed is drawn as a set of the segments. Similarly, the next third outline line type stored is “1”, and the corresponding control point is (84, 8).
A straight line segment is drawn from the third control point coordinates (20, 8) to the third control point coordinates (84, 8). Similarly, a straight line segment is drawn from the coordinates (84, 8) to the coordinates (84, 57) by the outline character type "1" and the fourth outline character information of the control point coordinates (84, 57). Based on the outline line type “1” and the fifth outline character information of the control point coordinates (20, 57), the coordinates (84, 57) to the coordinates (20, 57)
A straight segment is drawn up to. Thus, the outline CL1 to be closed is drawn.

Similarly, the outline CL2 is obtained from the sixth to tenth outline character information.
However, an outline CL3 is drawn by the eleventh to fifteenth outline character information, and an outline CL4 is drawn by the sixteenth to twentieth outline character information.

Next, the stroke boundary position information 75 and 76 indicated by the pointers P2 and P3 will be described. The stroke boundary position information indicates the stroke boundary position on the outline drawing coordinates for the stroke constituting the "eye". The boundary is indicated by a pair [outside, inside] of the outline drawing area.

For example, vertical stroke boundary position information 75
Is [20,28] by the first and second pairs and [84,76] by the third and fourth pairs. Will be shown. The horizontal stroke boundary position information 76 is [8, 1] based on the pair of the first and second strokes.
5], [22, 2] by the combination of the third and fourth
9], [43, 3] by the combination of the fifth and sixth
6], and the combination of the seventh and eighth [57,
50] indicates the boundary positions of the four strokes beside the character "eye" (see FIG. 8).

Next, the stroke deletion possible flags 77, 78 indicated by the pointers P4, P5 will be described.
Is the vertical and horizontal stroke boundary position information 7 described above.
When the flag is “1”, it indicates that the corresponding stroke can be deleted. When the flag is “0”, the corresponding stroke is stored. This indicates that it is not possible to delete the stroke that is performed. In this case, since the horizontal stroke deletion possible flag is “1”, it is indicated that the stroke indicated by the set [22, 29] of the horizontal stroke boundary position information 76 corresponding to this can be deleted. I have.

The character width information 79 indicated by the pointer P6
Indicates the size of the area where the character is drawn. In this case, the character width information 79 is “100”. Therefore, the outline drawing coordinate plane shown in FIG. 8 is a 100 × 100 drawing area in the first quadrant where both the X axis and the Y axis are positive.

Note that the control points (X1, Y1) at X1, Y
Numeral 1 indicates an X coordinate and a Y coordinate on the outline drawing coordinates, respectively. Further, it is needless to say that the outline drawing coordinate plane is a virtual one in the processing and is not actually drawn.

Next, the conversion unit 15 in step 208
Will be described. Here, a case where the reference outline information is reduced to 1/10 will be described.

FIG. 9 is a diagram showing the result of outline information that has been reduced to 1/10. In FIG. 9, the conversion unit 15 includes control point information 73 of outline character information 74, vertical and horizontal stroke boundary position information 75 and 76, and vertical and horizontal stroke deletion possible flags in the reference outline information shown in FIG. The control point information 73a of the outline character information 74a, the vertical and horizontal stroke boundary position information 75a and 76a, and the vertical and horizontal stroke elimination flags that uniformly set the values of 77, 78 and the character width information 79 to 1/10 77a, 78a, and character width information 7
9a.

Next, the correction processing of the stroke boundary position information reduced and converted by the conversion unit 15 will be described. This processing corresponds to step 209.

FIG. 10 is a diagram showing a process of correcting stroke boundary position information.

First, outer stroke boundary position information among the stroke boundary position information uniformly reduced and converted by the conversion unit 15 shown in FIG. That is, an integer conversion process is performed. As a result, the vertical and horizontal stroke boundary position information 75b, 76b shown in FIG.
Is corrected as follows. Next, the distance between the paired outer and inner stroke boundary positions is calculated, the calculated result is rounded, and the rounded value is added to the already rounded outer stroke boundary position value. Then, correction is performed using this value as the inner stroke boundary position information. The result is as shown in FIG.

That is, the inner stroke boundary position is calculated as shown in the following equation.

(Inner stroke boundary position) = (Integrated outer stroke boundary position) + FIX (Distance from outer stroke boundary position to inner stroke boundary position) Here, FIX () is an integer. The function to perform. Also,
The distance from the outer stroke boundary position to the inner stroke boundary position is substantially the line width of the stroke.

For example, taking the third and fourth stroke boundary position information 76a in FIG. 10A as an example,
The third value is the outer stroke boundary position information “2.
In “2”, the fourth value is the inner stroke boundary position information “2.9”. First, the outer stroke boundary position information “2.2” is integer-corrected, as shown in FIG. 10B. Becomes “2.0”. Next, the outer stroke boundary position information “2.2” and the inner stroke boundary position information “2.
9 is calculated, and the distance “0.7” is calculated.
"7" is converted to an integer and becomes a distance "1.0". Then, the corrected distance “1.0” is added to the outer stroke boundary position information “2.0” already corrected to the integer, and as shown in FIG. The position information “3.0” is obtained.

Next, the deletion flag detection section 16a searches the stroke deletion enable flags 77 and 78 and detects a stroke whose flag is "1". In this case, it is detected that the second flag of the horizontal stroke deletion enable flag 78 is "1". Further, the deletion determining unit 16b
Determines whether the stroke width corresponding to the stroke whose flag is "1" is equal to or smaller than a predetermined threshold "1", and if the stroke width is equal to or smaller than "1", The correction unit 16 sets the stroke boundary position information inside the stroke corresponding to the flag to the same value as the stroke boundary position information outside. Therefore, the fourth value of the horizontal stroke boundary position information is corrected to the same value “2.0” as the third value “2.0”, as shown in FIG. As a result, when the stroke deletion possible flag is “1” and the stroke width is equal to or smaller than the threshold value “1”, the stroke width indicated by the stroke boundary position information becomes “0”. Will be deleted.

FIG. 11 is a diagram showing an outline imaged by correcting stroke boundary position information. FIG. 11A shows an outline imaged from the stroke boundary position information of FIG. 10A, and shows a state where the reference outline information is uniformly reduced. On the other hand, FIG.
(D) shows an outline imaged from the stroke boundary position information, which indicates that one horizontal stroke has been deleted. FIG. 11 is only an image diagram. This is because the outline character information has not yet been corrected, and is merely a correction of the stroke boundary position information for correcting the outline character information.

Returning to FIG. 10, in FIG. 10 (e), the stroke correction unit 16 sorts vertical and horizontal stroke boundary position information. In this sorting process, the values of the stroke boundary position information are rearranged in ascending order. This sorting is performed to obtain the above-described continuous conversion relationship. The result of this sorting process is as shown in FIG. 10E, and the values are rearranged in ascending order.

Next, the stroke correction unit 16 performs a process for obtaining a continuous conversion relationship based on the sorted boundary position information 75f, 76f. That is, based on the stroke boundary position information before and after the correction, the following values are obtained for each of the stroke boundary position information by the following equations. That is, (increment of broken line) = (change amount of stroke boundary position after correction) / (change amount of stroke boundary position before correction) (Y intercept) = (stroke boundary position after correction) − (stroke before correction) Boundary position) × (increment of polygonal line)

FIG. 12 is a diagram showing the results of the increment of the polygonal line and the Y intercept for obtaining the continuous conversion relationship. In FIG. 12, for example, the first value of the polygonal line increment 75g and the Y intercept 75h is obtained as follows. First, the increment of the polygonal line is (increment of the polygonal line) = (3.0−2.0) / (2.8−2.0) = 1.25, and the Y intercept is (Y intercept) = 2.0−1.0 × 1.25 = −0.5. In this way, all line segment increments and Y
Obtain the section. However, when the next information does not exist, for example, the fourth increment of the polygonal line and the Y intercept in the vertical stroke boundary position information are set such that the increment of the polygonal line is “1” and the increment of the polygonal line is “1” to Y. Obtain the section. That is, (increment of the polygonal line) = 1.0 (Y intercept) = 8.0−8.4 × 1.0 = −0.4. The increment 76g of the polygonal line of the horizontal stroke boundary position information and the Y intercept 76h are similarly obtained.

The meaning of the obtained increment of the polygonal line and the Y intercept will be described.

FIG. 13 is a diagram showing a continuous conversion relationship before and after correction of a control point. In FIG. 13, FIG.
FIG. 13B shows a continuous conversion relationship before and after the correction of the X coordinate value of the control point, and FIG. 13B shows a continuous conversion relationship before and after the correction of the Y coordinate value of the control point.

In FIG. 13A, the horizontal axis indicates the X coordinate position data of the control point before correction, and the vertical axis indicates the X coordinate value position data of the control point after correction. FIG. 13 (a)
Are the conversion points before and after the correction of the stroke boundary position information, and the above-described increment of the broken line and the Y intercept are obtained because the straight line passing through the conversion points P1 to P4 is determined. It is. For example, the straight line between the conversion points P1 and P2 is represented by a polygonal line increment 75g and Y
The increment of the first polygonal line in the section 75h is "1.2
5 "and a Y intercept" -0.5 ". Therefore, by obtaining such a continuous conversion relationship, the control point information existing between the conversion points is also arranged at an appropriate position in relation to the stroke boundary position. For example, when the X coordinate of the control point is “5.2” before correction, the X coordinate after correction is “5.0” due to the linear relationship between the conversion points P2 and P3.

This is because the increment of the polygonal line is “0.83”, and
Since the Y intercept is “0.68”, the corrected X coordinate is determined as 0.83 × 5.2 + 0.68 = 5.0.

The conversion relationship between the conversion point P1 and the origin is indicated by a straight line connecting the conversion point P1 and the origin.
As described above, the continuous conversion relationship is represented by a straight line that passes through the conversion point P4 and sets the increment of the polygonal line to “1”. Of course, a straight line connecting the point (10, 10) and the point P4 may be formed.

It is to be noted that a continuous conversion relationship may be used in which a characteristic curve such as a higher-order curve passing through each conversion point is used instead of a straight line between the conversion points.

FIG. 13B shows the Y coordinate position data of the control point before correction on the horizontal axis, and the Y coordinate position data of the control point after correction on the vertical axis. As in the case of (a), the continuous conversion relationship by the polygonal line increment 76g and the Y-intercept 76h obtained based on the relationship before and after the correction of the horizontal stroke boundary position information is shown. Thereby, the value of the Y coordinate data of the control point is appropriately converted, and a non-natural outline is drawn.

FIG. 14 is a diagram showing final correction data of outline character information.

In step 210, the final outline character information correction data is corrected by the outline character information correction section 17 to control point information 73b. In this correction process, the outline character information converted by the conversion unit 15 is corrected and converted based on the continuous conversion relationship between the X coordinate and the Y coordinate of the control point shown in FIG.

In the case of FIG. 14, there are only control points related to stroke boundary position information. However, when there is a control point unrelated to stroke boundary position information, the X of the control point is determined based on the aforementioned continuous conversion relationship. The coordinate value and the Y coordinate value are converted and corrected.

This is for correcting the partial outline information such as “@” added to “large” of the character “dog” and the position of the control point existing between the boundary positions to an appropriate position.

As a result, the outline on the outline drawing coordinates of the outline information finally corrected is as shown in FIG. As shown in FIG. 15, a predetermined horizontal stroke of the character "eye" is deleted for reduction, so that a character with good readability can be generated.

The setting of the threshold value of the stroke width in the deletion determination section 16b can be arbitrarily changed.

Finally, in step 211, a raster character is generated based on the corrected outline character information.

The processing for developing outline character information into raster characters is performed by using a scan conversion algorithm such as an edge flag algorithm that does not paint a portion having a width of “0”.

FIG. 16 is a diagram showing an example of processing for developing outline character information into raster characters. FIG.
In (a), the outline drawing coordinates and the bitmap drawing coordinates are superimposed, and a bit is drawn at each intersection of the bitmap, for example, at the intersection PB. Here, “1 dot” of the bitmap drawing coordinates corresponds to “1” of the outline drawing coordinates. Then, as shown in FIG. 16A, a horizontal stroke segment is extracted based on the outline character information, and dots are arranged in the horizontal segment. Further, the bit is scanned from the bottom in the vertical direction, the bits arranged in the X-axis direction are taken out, the exclusive OR with the bit immediately above is taken, and the dot is written again, thereby painting out. As a result, a raster character as shown in FIG. 16B is generated.

In this embodiment, the extraction unit 12 extracts predetermined basic stroke boundary position information 11a and calculates corrected outline character information of an arbitrary size based on the stroke boundary position information. However, stroke boundary position information is automatically extracted from only the outline character information 11b itself, and corrected outline character information of an arbitrary size is calculated based on the automatically extracted stroke boundary position information. Good.
In this case, although a calculation time for automatic extraction is required, the storage capacity can be reduced because it is not necessary to store the stroke boundary position information 11a in the external storage unit 11.

As described above, in this embodiment, even when the resolution is low due to the reduction processing, a high-quality character with good readability can be output by deleting a predetermined stroke.

[0095]

As described above in detail, according to the present invention, when raster data of a character of an arbitrary size is generated based on the reference outline information, a stroke constituting the character of the arbitrary size is generated from the reference outline information. And calculating whether each stroke of the stroke indicated by the calculated stroke information is a predetermined optional stroke in the reference outline information, and determining the stroke indicated by the calculated stroke information. It is determined whether or not each stroke line width is equal to or less than a predetermined threshold, and as a result of the determination, it is possible to omit and exclude strokes in which the stroke line width is equal to or less than a predetermined threshold. An arbitrary size character having the calculated stroke is drawn.

For this reason, even when a character is drawn on a bitmap having a low resolution due to reduction, the outline character information is corrected so that the stroke width of the character is faithfully reproduced and a predetermined stroke is deleted. This has the advantage that high-quality characters with good readability can be output.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a font rasterizing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a functional configuration of a printer system incorporating the font rasterizing device of FIG. 1;

FIG. 3 is a diagram illustrating a circuit configuration of the printer system of FIG. 2;

FIG. 4 is an operation flowchart of the printer system.

FIG. 5 is a diagram showing a configuration of a font file required for font processing.

FIG. 6 is a flowchart showing a font processing procedure of a font processing unit 26;

FIG. 7 is a diagram illustrating a configuration of a reference outline character information portion of a character of “eye”.

FIG. 8 is a diagram showing an outline of reference outline information of a character “eye” on outline drawing coordinates.

FIG. 9 is a diagram showing a result of outline information reduced and converted to 1/10.

FIG. 10 is a diagram showing a process of correcting stroke boundary position information.

FIG. 11 is a diagram showing an outline imaged by correcting stroke boundary position information.

FIG. 12 is a diagram showing a result of a line segment increment and a Y intercept for obtaining a continuous conversion relationship.

FIG. 13 is a diagram illustrating a continuous conversion relationship before and after correction of a control point.

FIG. 14 is a diagram showing final correction data of outline character information.

FIG. 15 is a diagram illustrating an outline on outline drawing coordinates based on outline information that has been finally corrected.

FIG. 16 is a diagram showing an example of a process of developing outline character information into raster characters.

FIG. 17 is a diagram showing 10-dot × 10-dot “negative” raster character data using an illusion technique;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 External storage device 11a Boundary position information 11b Outline character information 11c Deletable flag 12 Extraction unit 13 Storage unit 14 Expansion unit 15 Conversion unit 16 Stroke correction unit 16a Delete flag detection unit 16b Deletion determination unit 17 Outline character information correction unit 18 Control unit

Claims (2)

(57) [Claims] 1. A font rasterizing apparatus for generating raster data of a character of an arbitrary size based on reference outline information, comprising: calculating means for calculating stroke information on a stroke constituting the character of an arbitrary size from the reference outline information; First determining means for determining whether each of the strokes indicated by the calculated stroke information is a predetermined optional stroke in the reference outline information, and a stroke indicated by the calculated stroke information A second determining means for determining whether or not each stroke line width is equal to or smaller than a predetermined threshold value; and a determination result obtained by referring to the determination results by the first determining means and the second determining means. Strokes that are possible and whose stroke line width is equal to or less than a predetermined threshold are excluded. Font rasterization apparatus being characterized in that; and a drawing means for drawing any size of a character having a stroke. 2. A font rasterizing method for generating raster data of a character of an arbitrary size based on reference outline information, comprising: calculating stroke information on a stroke constituting the character of the arbitrary size from the reference outline information; It is determined whether each of the strokes indicated by the obtained stroke information is a predetermined optional stroke in the reference outline information, and the stroke width of each of the strokes indicated by the calculated stroke information is set to a predetermined value. It is determined whether or not the stroke is equal to or less than a threshold value. As a result of the determination, an arbitrary size having the calculated stroke excluding a stroke that can be omitted and whose stroke line width is equal to or less than a predetermined threshold value A font rasterizing method characterized by drawing a character.