JPH06208370A - Method for character display by raster by coupling aliasing suppression to lattice adaptation - Google Patents

Abstract

PURPOSE: To generate a pixel image which is superior in terms of art and which is easily read on a method for making a character such as KANJI(Chinese character) into rasters. CONSTITUTION: The image is generated by connecting aliasing inhibiting technology and grid combination technology. The process contains various stages for obtaining ideal character display and a hint, converting hint information from the font unit of abstract coordinate space into a pixel unit, converting a control point into the pixel unit by using hint. information, generating a series of scaled segments and curves, sampling the points of prescribed intervals along the respective curves and segments, deciding fragmentary coloring values against respective pixels and processing the sampled points so that a sharp shift part is easily generated in a character point indicated to be important in terms of art. Thus, the clarity and the reading easiness of KANJI on Chinese and Japanese are improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to computer graphics, and more particularly to a method of displaying ideal characters using rasterization techniques for text rendering. More particularly, the present invention relates to a character rasterization method that employs lattice matching and antialiasing techniques.

[0002]

2. Description of the Related Art A font is rasterized to C
Numerous methods exist for producing pixel images that can be displayed on a display device such as an RT or that can be used for conventional laser printers and printing. A conventional method for generating a pixel image of a font is the scan conversion method. The scan conversion method converts an ideal description of a character, called a character description, into a pixel image. Figure 1A
Referring to FIG. 3, a character description of Kanji is illustrated. A character description usually consists of a series of curves and points, which define the ideal outline or contour of the area forming the character.
All existing methods for converting an ideal character description into a pixel image use generalization or roughening techniques, which introduce imperfections in the resulting pixel image. As shown in FIG. 1B, when the ideal character representation of FIG. 1A is converted to a 95 × 95 pixel matrix, the symbols remain well readable despite imperfections. However, these imperfections become increasingly problematic as the ideal character size is reduced. FIG. 1C shows an enlarged view of the character display of FIG. 1A converted to a 14 × 14 pixel matrix. As shown, the 14 pixel one is unreadable.

The display technology of common computers varies from 70 to 90 dots per inch. At these resolutions, text of relatively common size (10 to 20 typographic points) can be difficult to read and can be artistically inferior. One approach used in the prior art to solve this problem is the "two-color grid matching" method. This method produces pixel images using only white or black pixels. The grid fitting method is a technique for changing the ideal character shape to match the pixel grid in order to obtain a more artistically pleasing and readable result.
Referring to FIG. 2, the operation of the grid fitting method is illustrated. Parts AD of FIG. 2 are graphic representations of pixel grids, black and white pixels and characters. Figure 2
Part A and Part B of FIG. 6 show pixel conversion results for the Latin letter O using standard scan conversion techniques. As shown in part A of FIG. 2, the scan conversion method yields satisfactory results if the ideal contour happens to be in harmony with the pixel grid. However, FIG. 2B
If the ideal contours do not match the pixel grid, as shown in the section, the scan conversion method will result in undesirable artifacts such as the two additional pixels 10 shown in section B of FIG. The scan conversion shown in part B of FIG. 2 is mathematically correct, but it produces an artistically unpleasant offset between the left and right sides of the character. Traditional grid fitting methods attempt to overcome this problem by providing "hints" to specific parts of the character. These hints identify important parts of the character that should be fitted to the pixel grid to produce an artistically pleasing result. Parts C and D of FIG. 2 show the effects or consequences of grid fitting. The C portion of FIG. 2 illustrates the same characters as the B portion of FIG. Since the character parts with hints do not match the pixel grid, the grid fitting method
The hints are used to control the contour rounding and matching process to produce the distorted contour shown in part D of FIG. 2 where the character portions between the ends of the hints are aligned with the pixel grid. As seen in part D of FIG. 2, the right side of “Ο” is shifted to the left by half a pixel to avoid the unwanted artifacts 10 created in part B of FIG. The hinting method removes details from the shape of the ideal contour so as to depict different shapes. This shape is
It is less than ideal, but more pleasing than the previous one under quasi-fitting conditions where the number of pixels is too small to accurately represent the ideal contour. While the improvements provided by the grid fitting method are acceptable for Latin letters, the translated pixel image of Chinese or Japanese syllabaries is still unreadable on conventional computer displays. Even with the grid fitting method, the conventional technique is for small Kanji phonetic characters.
Results similar to FIG. 1C were produced. Thus, there is a need for a way to convert an ideal character representation into a high quality pixel image.

Another method used in the prior art to improve the readability of complex characters such as Chinese characters is the antialiasing method. Antialiasing technology is mainly used in television and video production.
Used to improve pixel image quality. Various antialiasing techniques use pixels of medium density or color to create a high resolution illusion. When an intermediate color or grayscale value is used, details such as curvature and stroke thickness variation, which are lost in the two-color grid fitting method, are highly visible as shown in part A of FIG. Can be depicted with fidelity. However, FIG. 3B
As illustrated in the section, even with antialiasing techniques applied, the pixel image still has undesirable distortions and artifacts 12 due to the mismatch with the pixel grid. Therefore, none of the prior art approaches are effective at providing a pixel image of a complex phonetic character in a small size. Thus, it is possible to read phonetic characters,
There is a need for a method of producing high quality pixel images.

[0005]

SUMMARY OF THE INVENTION The present invention overcomes the limitations and drawbacks of the prior art and provides an improved method for producing an artistically pleasing and readable pixel image from an ideal character representation, even at small dimensions. Is to provide. The present invention preferably combines a two-color grid matching technique and an anti-aliasing technique to produce phonetic and Latin characters with uniformly pleasing artistic characteristics. The preferred embodiment of the present invention retrieves or retrieves the ideal character representations and hints from the font, fits the ideal character representations to a pixel grid using a grid matching technique, and uses the adapted character representations and hints. And then divide it into multiple non-overlapping bands, and apply the aliasing prevention technique to each band to generate the final grayscale bit-mapped bitmap without considering the pixel values outside the band. Includes processing steps.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 4, a preferred embodiment of the general method of the present invention will be described. The method of the present invention is
It is convenient to be able to generate a pixel image that is more artistically pleasing and readable for both Latin characters and Asian phonetic characters. The method of the present invention is preferably a computer that can be used by a conventional computer to display the characters on a conventional display device such as a monitor or CRT, or to print the characters on a conventional laser printer. It should be an implementation process.

FIG. 4 shows the outline of the preferred embodiment of the method of the present invention. The method begins at step 400. In step 401, a computer (not shown) retrieves or retrieves character information including ideal character display and hints (guidelines). Each character information is a large number of closed contours and hint data. Each contour preferably comprises a starting point and a number of connecting lines and curves identified by control points or reference points. This character information specifies the outline or contour of the area for the character, and is specified in font units in the abstract coordinate space. The hint data can be applied to all contours and control points of a character, or a subset of contours. Each hint identifies the portion of the character that should fit exactly on the pixel grid boundary. Then, in step 402, the hint portion of the textual information is converted from the font unit of the abstract coordinate space to the pixel unit. Pixel units are set according to the operational constraints of the printer or display device being used. The scaling factor is also determined by the global distance of the type surface and the desired pixel size. In step 402,
The hints are scaled using a particular grid fitting technique, as described below. However, it will be appreciated that one skilled in the art may utilize various prior art grid matching techniques. Once the hints have been transformed, the control points are transformed into pixels in step 403. The hint transformation effectively divides the image into a set of non-overlapping bands. In each band, the scaling factor is slightly different than in other bands,
This fits the hints to the grid. In step 403, the scaling information from the hint transformation step (step 402) transforms the control points of the contour into pixel space resulting in a series of scaled line segments and curves. Next, in step 404, fixedly spaced points along each curve and line segment are sampled. Then, in step 405, the sampled points are processed band by band to determine a fractional color value for each pixel and produce a grayscaled image. The process is complete and ends at step 406. The present invention utilizes this method to produce sharp transitions in a character at points determined to be of artistic importance. Conversely, adjacent features are prevented from affecting the character simply because they are near some important point.

Referring now to FIG. 5, a preferred method for performing grid fitting (steps 402, 403) according to the present invention will be described in more detail. The hint data structure and characters, once retrieved (step 401), are processed to convert the hints from font space to pixel space (step 402). Each hint should include a start point (s) and an end point (e), designated as "snap points". The hint also includes a norm or constraint width (c) for the spacing between snap points. The constrained width dictates the preferred distance between snap points at low resolution. The hint conversion process also uses two comprehensive metrics for type faces. That is, the standard horizontal and vertical stroke widths (W), which indicate the major stroke widths in each dimension. The preferred method begins with step 501 of FIG. 5A, where the starting point (s) is scaled to a fractional value or fragment value s'.
In step 502, the regulation width (c) is scaled to the fractional value c '. In step 503, the actual stroke width, that is, the absolute value of (se) is scaled to the fractional value w ', and in step 504, the standard stroke width
(W) is scaled to the fractional value W '. Next, in step 505, the fractional values for the regulation width, the actual width and the standard stroke width are compared. The actual stroke width fraction W'and the regulated stroke width fraction c'are 0 pixels.
If different by 5 or more, w'is used as the desired width. Otherwise, c'is used as the desired width and w'is set equal to c '. Further, if the fractional value W'of the standard stroke width differs from the fractional value of the actual stroke width w'by less than 0.5 pixel, then w'is set equal to W'and this is used as the desired stroke width. Unless the standard or regulated stroke width differs from the actual stroke width by more than 0.5 pixels, these are set as the desired stroke width in this step. In such a case, the actual stroke width is used as the desired stroke width. In step 506, the process determines if w'is wider than one pixel. If w'is wider than one pixel, the process continues at step 507, where the starting point s' and the fractional value w'of the actual stroke width are rounded to the nearest integer. Then, in step 508, the fractional value w'of the actual stroke width is added to or subtracted from the fractional value s'of the starting point depending on whether s> e to produce a transformed value of e. The hint conversion is complete and the process ends at step 514. On the other hand, in step 56, if the fraction value w ′ of the actual stroke width is not wider than 1 pixel, the process proceeds to step 509. In step 509, the fractional value w'of the actual stroke width is set to its actual value and 0.25 pixels, whichever is greater. A minimum value of 0.25 is enforced on w'to ensure that the area of the symbol does not disappear. Then, in step 510, the fractional value e'of the actual stroke width is added to or subtracted from the fractional value of the starting point s ', depending on whether s> e, to produce a fractional value for the end point e'. Now that the fractional values, s'and e ', have been determined, the process moves to the process of fitting these points to the pixel grid. In step 511, s'
The values of and e'are compared to the pixel boundaries. Since it was previously determined in step 506 that w'is less than one pixel wide, the distance spanned by s'and e'is at most 1.
Cross at pixel boundaries. In step 512, the process determines if s'and e'are in the same pixel. If they are contained within the same pixel, the stroke is contained within a single pixel,
The values for s'and e'remain unchanged. At this time, the process ends at step 514. On the other hand, if the pixel boundary is spanned by the region between s'and e ', the values of s'and e'are adjusted in step 513, and s'and e'
Shift the stroke in the direction of the smaller error to force e'to be in the same pixel. The situation of stroke shift in step 503 is shown in FIG. 7A.
Best understood by reference to ~ C. Then,
This figure shows three possible cases when s'and e'are compared to a pixel grid. As shown in FIG. 7A, no stroke adjustment is required when s'and e'are enclosed within a single pixel. Referring to FIG. 7B, the process of the present invention shifts the stroke of FIG. 7B left by subtracting s ′ and e ′ by the same value, forcing e ′ to align with the nearest pixel boundary. Similar adjustments in the opposite direction are shown in Figure 6C. Also, the process of the present invention shifts the stroke of FIG. 6C to the right by increasing s'and e'by the same value, forcing s'to align with the nearest pixel boundary. Therefore, the method of the present invention is advantageous with the benefit of stroke shifting, such as removing unwanted artifacts from the image that are caused when the ideal character representation does not correspond exactly to the pixel grid.
The removal of such artifacts results in a very sharp image.

Next, referring to FIG. 8, the control points are converted from font units to pixel units (step 40 in FIG. 4).
A preferred method for 3) will be described. As mentioned above, the hint transformation process divided the pixel space into multiple non-overlapping bands or regions. The hint conversion is shown in FIGS.
And 7A-E are used to guide the conversion of control points by using the information obtained from the hint conversion process described with reference to FIGS. The preferred process begins at step 700. In step 701, the process tests whether there are control points left in the character that need to be converted from font units to pixels. If there are no control points to convert, the conversion process is complete and ends at step 706. Otherwise, the preferred process is until each control point is transformed,
It cycles through steps 702-705. Step 702
At, the control points to be converted are retrieved. Then, in step 703, hint information is searched. In particular, the process retrieves the information, if any, needed to determine the boundaries for each region defined by the transformation of hints in step 402. In this step, the scaling factor for each region is also determined. Then, in step 704, the converted control point value is compared with the hint information retrieved in step 703 to determine which band or region contains the control point, and thus the control point from the front unit to the pixel. A scaling factor for converting to units is determined. The control points are then scaled pixel-wise in step 705 using the scaling function associated with that region or band. Once the control points have been scaled, the process cycles to step 701 and repeats the process until all control points have been scaled. Those familiar with the art will recognize that there may be many control points in both the X and Y directions, and there may be several hints that affect the scaling of the control points in both the vertical and horizontal directions.

Referring now to FIG. 13, FIGS. 5, 6 and 8
And an example of the control point conversion process. FIG. 13 is a plot of pixel units along the Y-axis, font units along the X-axis, and the ideal transform (ie, linear scaling without hints) in dashed lines. Without hints, the control point values would simply be multiplied by the scaling factor and rounded. The introduction of hints distorts the transform space into a discontinuous but piecewise linear space. The boundary interval on the X-axis is [0,500] and the triple hint is (200, 275, 7
5) And consider an example of a contour with a standard width of 150.
The contour shall be scaled by 0.012. The contouring interval is scaled to 0.6. Using the steps described with reference to FIGS. 5 and 6, s'
= 200 × 0.012 = 2.4. The standard width is scaled to 150 x 0.012 = 1.8 and the actual and regulated width is scaled to 0.012 x 75 = 0.9. Since the standard width and the actual width do not differ by more than 0.5 pixels, the stroke width is chosen to have a constrained width of 0.9 and thus the endpoint coordinates are scaled to s '+ w' = 3.3. Using the stroke shift technique of step 513, s '= 2.1 and e' = 3.0. therefore,
The hint of the triplet divides the font unit of the interval [0,500] into three areas or bands as shown in FIG. The three bands are 0 to 200, 200 to 275 and
It is in the range of 275 to 500. Each band provides its own scaling function. In FIG. 13, the three scaling functions are represented by three solid line segments. X
Given the coordinates of, or control points in font units, the process determines which of the three ranges contains that value and applies a scaling function associated with that range or interval. The three scaling functions generated by the example hints are:

[Equation 1] It should be understood that there are two sets of hints associated with each depiction, one for the Y dimension and one for the Y dimension. Thus, a similar transformation would be needed for each point in the Y dimension.

Once the control points are determined, the method of the present invention performs anti-airing to obtain a sharper image. Antialiasing techniques involve fitting the character to a larger source pixel grid that is actually desired. Each pixel in the source grid is either black (off) or white (on) and is mathematically represented as a minimum (0) or maximum (1). On the other hand, the destination pixel grid allows pixel values to range between 0 and 1. When the source grid is actually reduced to the desired size, there will be several pixels (called samples) in the source grid that correspond to a single pixel on the destination grid. These values are 0
Either one or one, averaged and the result is a single final value in the range 0 to 1.

The present invention applies an aliasing prevention step to the characters on a band-by-band basis. As shown in FIG. 9, the hinting process divides the letter ("O") into a series of bands defined by the beginning and end points of the hint. Each band defines a pixel image portion that is predominantly black or white, and the edges of the band probably mark areas in the pixel grid where there are significant color transitions. The present invention is
It is convenient to use the band information created by the lattice match (ie hint) to act on the aliasing stop averaging process. As shown in FIG. 9, when averaging pixels within a band, pixels within adjacent bands are not considered, even if considered using the conventional antialiasing method. This conveniently creates sharper transitions between regions within the character identified as artistically important. Conversely, adjacent features are prevented from dominating part of the character because they are nearby. Hints are preferably used to divide a character into several non-overlapping areas. In the example of FIG. 9, the character is divided into three vertical bands (A, B and C) by two horizontal hints. One of ordinary skill in the art will appreciate that multiple vertical and horizontal hints may be used to divide a character into several non-overlapping bands in both the vertical and horizontal directions.

A preferred method for performing sampling and image generation according to the present invention will now be described with reference to FIGS. The method begins at step 900.
In step 901, the curve forming the character is decomposed into line segments (if any). Thus, step 90
After 1, the letters will be displayed only by line segments.
Next, in step 902, one of the character line segments is retrieved. In step 903, points are sampled on the line segment at 0.25 pixel cell spacing in the Y dimension. If familiar with the art, the value for the sampling interval can be selected according to the level of gray scale allowed by the display or printing device. In this example, 0.25 was selected for the 16 shades of gray. For example, according to step 903
Singing a line segment from (0.7,0.7) to (1.7,1.7) would require that the value of Y be chosen such as 0.75, 1.0, 1.25 and 1.5. Then, in step 904,
The corresponding X coordinate for each sampled value of Y is calculated. For the line segment from (0.7,0.7) to (1.7,1.7),
This process is (0.75,0.75), (1.0,1.0), (1.25,1.25)
And give (1.5,1.5). Then, step 905
At, the process determines if there are more line segments left to sample. The process preferably traverses each line of the contour until all the line segments of the contour have been sampled. If the character has more line segments to sample, the process returns to step 902, else step 907 continues. Step 90
In 7, to determine the area of each piecewise contribution,
A polygon filling algorithm is used. If you're familiar with the world, JD Foley and A. Van Dam, "Fundame
It will be appreciated that various polygon filling algorithms such as those described in "ntals of Interactive Computer Graphics" can be used for this determination. The algorithm is
Preferably, the fractional contribution is determined by identifying the start and end points (or a plurality thereof) on each scan line that have a region between the points on and off. Each point pair in the scan line represents an interval that contributes to the fractional coloring of the pixels it covers. Then, in step 910, the contribution to the fractional coloration is determined by measuring the area of each pixel covered by the spacing.
After the contributions for each pixel have been determined, they are aggregated in step 911 to yield a fragmented color value.

For example, (x ₀ , y) and (x ₁ , y), where x ₁ ≧
Let x ₀ be one such interval. When it is completely "turned off" (ie the outline of the character does not intersect pixel p at all), 0 is the C of pixel p.
(p) value. Similarly, when it is completely "turned on" (ie when p is completely covered by the drawn character and outline), 1 is the value C of the pixel.
(p). here,

[Equation 2] Compute the fractional color contribution of this interval for pixels spanning. here,

[Equation 3] Are the minimum and maximum integers of v, respectively. Assuming the initial value of each pixel is 0, the value for the pixel can be calculated according to the following equation:

[0015]

[Equation 4]

Once the fractional coloring for each pixel interval has been tabulated, the total is multiplied by 0.25. This is because each point was sampled at 0.25 pixel intervals in the Y dimension. The final sum of each C (p) represents the fractional coloring for each pixel, and this is step 9
It is used to generate an image at 12. Assuming that for a particular rendering, the background of the screen is color b (background) and it is desired to draw letters in color f (foreground), the final color of each pixel is rf = (1- r) b. Where r is the sum of each pixel calculated above.

Referring now to FIG. 12, the grayscale contribution to the example contour is shown. In particular, the contribution to the interval y = 0 is shown. The result for each pixel is calculated for each increment in the y dimension. Here, the integer value of y is = 0 (that is,
0.0, 0.25, 0.5 and 0.75). For each increment, the spacing is aggregated pixel by pixel according to the above equation,
2. Generate the values for each row of the table. Once the four rows for each pixel are determined, these are tabulated to determine the grayscale color value for each pixel.

Although the present invention has been described in terms of a preferred embodiment, it will be appreciated that various modifications can be made by those skilled in the art. For example, different algorithms could be used to implement the lattice matching and antialiasing of the present invention.

[Brief description of drawings]

FIG. 1A is a diagram showing a conventional character displayed in an ideal contour or outline, and FIG. 1B is a conventional character shown in A.
FIG. 6 is a diagram illustrating conventional pixel conversion to a matrix of 95 × 95 pixels; C is a diagram illustrating conventional pixel conversion of A conventional characters to a 14 × 14 matrix.

FIG. 2 is a graphic representation of a grid representing conventional pixel conversion results, characters and pixels.

FIG. 3 is a graphic representation of a pixel image enhanced using antialiasing techniques and pixel grids.

FIG. 4 is a flow chart illustrating a general method of the present invention for performing character rasterization.

FIG. 5 is a flowchart showing a preferred hint conversion method.

FIG. 6 is a flowchart showing a preferred hint conversion method.

7A, B and C are graphic representations of part of a stroke and pixel boundaries.

FIG. 8 is a flowchart showing a preferred control point conversion method.

FIG. 9 is a graphic representation showing a preferred method of applying an antialiasing step to characters band by band.

FIG. 10 is a flow chart showing a preferred method for sampling for scan conversion and processing the sampled points.

FIG. 11 is a flow chart showing a preferred method for sampling for scan conversion and processing the sampled points.

FIG. 12 is a graphical representation showing a table of contour lines, pixel boundaries, sample spacing and fractional pixel contributions.

FIG. 13 is a graph showing conversion from font units to pixel units.

[Explanation of symbols]

10 Pixels 12 Artifacts 400-913 Flowchart Block or Step References

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[Procedure amendment]

[Submission date] February 22, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

3. The hint information includes at least one hint, each hint includes a start point (s), an end point (e) and a preferred width (c), and the hint information conversion step includes On the other hand, the following steps are included, that is, the start point is scaled to a fractional value (s '), the regulation width is scaled to a fractional value (c'), the actual width (W) is calculated, and the actual width is set to a font. From the unit,
Scaling to fractional values (W ') in pixels, standard width (W) to fractional values (W'), comparing fractional values against actual width, standard width and regulation width,
Select one as the desired width, compare the desired width with the pixel width, and if the desired width is wider than one pixel value, round the start and desired width fractions to the nearest integer and convert to the converted end point. And calculating a fractional value of the end point and applying a stroke shift value such that the fractional values of the start point and the end point are within the same pixel if the desired width is not greater than a pixel. Rasterization method.

Wherein the step of comparing the end value is, the end value of the regulating range is selected as desired width, if the difference if the actual fraction values of fractional values and regulatory width of 0.5 pixels or higher Setting the desired value equal to the fractional value of the actual width, and setting the desired width equal to the fractional value of the standard width if the desired width and the fractional value of the standard width differ by 0.5 pixels or less. 3. The rasterization method described in 3.

Wherein the step of calculating the fractional values of the endpoints, set the desired width larger of 0.25 pixel and its value, the desired sign of scaling values, thus according to whether the starting point is greater than the end point Sum the width and the fractional value of the start point,
4. The rasterization method according to claim 3, including generating a fractional value of the end point.

Wherein the step of applying the stroke shift, fractional values of the start point and the end point compared with pixel boundaries, to determine the fraction value of the starting point and termination whether in the same pixel, if the starting point and 4. Comprising shifting the start and end fractions to a lesser error if the end fractions are not within the same pixel to produce a transformed start and end value within the same pixel. The described rasterization method.

7. A step of treating the point which is the sample, performs a gray-scaling, rasterization method according to claim 1 comprising causing colored for each pixel by using the points that are a plurality of samples .

8. processing the points is the sample, using a polygon filling algorithm to determine the region of the fractional contribution to character display, to determine the fractional contribution for each pixel, Claiming Aggregating Fragmental Contributions for Each Pixel to Determine Fragmental Coloring Values for Pixels and Generating a Pixel Image with a Grayscale Technique Using the Fragmentary Coloring Values Generated for Each Pixel The rasterization method according to Item 1.

9. A method of generating a pixel image from the character display, searching ideal character display and at least one tip, using grid fitting techniques to fit the ideal character displayed on the pixel grid, hint Use to split the adapted character representation into multiple non-overlapping bands and apply antialiasing techniques to each band without regard to pixel values outside the band, resulting in a final grayscaled bitmap A method for generating a pixel image, the method including: processing a band.

Claims (17)

[Claims] 1. A method of rasterizing hint information and an ideal character display to generate a pixel image, wherein the ideal character display and the hint information are obtained, and the hint information is obtained from a font unit in an abstract coordinate space. Converting to pixel units and defining multiple bands, using the converted hint information to convert the character representation from a font unit of the abstract coordinate space to a pixel unit, and converting the character representation to a plurality of line segments. And sample points at predetermined intervals along each line segment of the plurality of line segments and process the sampled points to determine a fractional coloration value for each pixel to produce the pixel image. A rasterization method comprising the steps of: 2. The rasterization method according to claim 1, wherein the hint information converting step includes applying a grid fitting technique to convert the hint information pixel by pixel. 3. The rasterization method according to claim 1, wherein the hint information converting step includes scaling the hint information from a font unit to a pixel unit. 4. The hint information includes at least one hint, each hint includes a start point (s), an end point (e) and a preferred width (c), and the hint information conversion step includes On the other hand, it includes the following steps, that is, the starting point is scaled to the fractional value (s '), the regulation width is scaled to the fractional value (c'), the actual width (W) is calculated, and the actual width is set to the font. From the unit, scale to the fractional value (W ') in pixels, scale the standard width (W) to the fractional value (W'), compare the fractional values against the actual width, standard width and regulation width,
Select one as the desired width, compare the desired width with the pixel width, and if the desired width is wider than one pixel value, round the start and desired width fractions to the nearest integer and convert to the converted end point. And calculating a fractional value of the end point and applying a stroke shift value such that the fractional values of the start point and the end point are within the same pixel if the desired width is not greater than a pixel. Rasterization method. 5. The step of calculating the actual width comprises calculating the absolute value of the difference between the start and end points.
The described rasterization method. 6. The step of comparing the fractional values includes selecting the fractional value of the regulation width as the desired width, and if the fractional value of the actual width and the fractional value of the regulation width differ by 0.5 pixels or more, the desired value is obtained. The raster of claim 4 including setting the value equal to the fraction of the actual width, and setting the desired width equal to the fraction of the standard width if the desired width and the fraction of the standard width differ by less than 0.5 pixels. Method. 7. The rounded value of the desired width and the rounded fractional value of the starting point according to the sign of the scaling value, and thus whether the starting point is greater than the ending point, the means for calculating the transformed ending point. 5. The method according to claim 4, including adding up and.
The described rasterization method. 8. The step of calculating the fractional value of the ending point sets the desired width to 0.25 pixels and the larger of the values, and sets the desired width according to the sign of the scaling value, and thus whether the starting point is greater than the ending point. Add up the fractional value of the starting point,
The rasterization method according to claim 4, which includes generating a fractional value of an end point. 9. The step of applying a stroke shift compares the starting and ending fractional values with a pixel boundary to determine whether the starting and ending fractional values are within the same pixel, and 5. The method includes shifting the start point and end point fractional values in the direction of smaller error to generate a transformed value of the start point and end point that are within the same pixel if the end point fractional values are not within the same pixel. The described rasterization method. 10. The method of claim 2 wherein the step of converting the character representation comprises converting the character representation pixel by pixel using the results of a grid fitting technique. 11. The character display includes a plurality of control points and curves, and the step of converting the character display includes: searching control points, searching hint information, and controlling which band using the hint information. Determining whether to include a point and scaling the control point using a scaling function associated with a band containing the control point.
The described rasterization method. 12. The rasterization method of claim 11, wherein the step of converting the text representation comprises repeating the steps of searching, determining and scaling for each control point of the text representation. 13. The method of claim 1 including searching for the line segment, sampling points along the line segment at predetermined intervals in the Y dimension, and computing the corresponding X coordinate for each sample point. Rasterization method. 14. The rasterization method of claim 13, wherein the step of sampling the points is performed at 0.25 pixel intervals. 15. The rasterization method of claim 1, wherein the step of processing the sampled points comprises performing gray scaling and using a plurality of sampled points to produce a tint for each pixel. . 16. The step of processing the sampled points determines a region of fractional contribution to the character representation using a polygon filling algorithm to determine a fractional contribution for each pixel, Claiming Aggregating Fragmental Contributions for Each Pixel to Determine Fragmental Coloring Values for Pixels and Generating a Pixel Image with a Grayscale Technique Using the Fragmentary Coloring Values Generated for Each Pixel The rasterization method according to Item 1. 17. A method of generating a pixel image from a text representation, searching for an ideal text representation and at least one hint, and using a grid matching technique to fit the ideal text display to a pixel grid and to provide the hint. Use to split the adapted character representation into multiple non-overlapping bands and apply antialiasing techniques to each band without regard to pixel values outside the band, resulting in a final grayscaled bitmap A method for generating a pixel, comprising: processing a band.