Abstract:
The present invention employs the notion of a Chinese writing brush moving a geometric figure to produce a style of calligraphy, and the area of the geometric figure is big or small, then the strokes of a character is also big or small. Hence the purpose that is the variance of the strokes of a character achieved using the present invention. The present invention only decides the moving path of the strokes of a character and the size of the geometric figure from the starting points and the end points, and then moves the geometric figure along the moving path, the area the geometric figure passing is the style of calligraphy.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a descriptive method of characters, and more particularly to a descriptive method of characters for displaying the thickness of strokes thereof.  
           [0003]    2. Description of the Prior Art  
           [0004]    In general, the fonts produced by descriptive methods of characters comprise three types: bitmap font, outline font, vector font, respectively. The three types of descriptive methods of characters will be described below.  
           [0005]    1. Bitmap Font: The descriptive method of bitmap font is displayed with pixels. As shown is FIG. 1A, the area  2  with oblique lines displayed in the area of the font and the white area  4  without oblique lines is displayed in the outer area of the font. Therefore, the bitmap font is an image of the font and displayed the form of a font accurately in the fixed size of the font. Furthermore, the bitmap font easily displays characters in a monitor. But, the disadvantage is that the data of the font is very large. Moreover, due to the bitmap font being an image and the size of the bitmap font being fixed, a resized font has a problem with distortion. Hence, the bitmap font is not fit for resizing and the resized font is not refined and beautiful.  
           [0006]    2. Outline Font: As shown in FIG. 2A and FIG. 2B, the outline font is described by means of curves and strokes controlled by control points  8 . The outline  10  of the font is described by the curves. The area surrounded by the curves is the form of the font, as shown in FIG. 1B. In general, the bend of the outline  10  thereof is displayed with a quadratic curve (two-order function) or a cubic Bézier curve (three-order function). Furthermore, the curves of the outline font are described by the stroke thickness of the font. Because the bend of the outline  10  and the thickness of strokes, the font can be described exquisitely with the starting and ending control point  6 , and control point  8 , the outline font is refined and beautiful. Moreover, compared with the bitmap font, the data of the font is less and the resized outline font is still refined and beautiful as well as the original outline font. Therefore, the outline font is a popularly font, e.g. TrueType Font PostScript. A general set of a Chinese, Japanese, or Korean (CJK) fonts is about 7,000˜18,000 characters and a set of these fonts are about 5˜12 Million bytes. Regarding a PDA (Personal Digital Assistant), Set-Top Box, and a cellular phone, the amount of the characters in these apparatuses is limited due to the limitation of memory.  
           [0007]    3. Vector Font: The vector font is described by the means of central curves and strokes controlled by control points  8 , as shown in FIG. 1C. Due to the lack of form, description and a thickness of strokes, the vector font limits the font to a lightface or boldface. Therefore, the appearance of the font is not refined and beautiful as the outline font. However, the data of the vector font is mainly the central curves of the strokes without describing the variant of the form of characters. Hence, the amount of the data thereof can be efficiently reduced. Compared with the bitmap font and the outline font, the amount of the data thereof is minimum. Moreover, the resized font can be performed without distortion.  
           [0008]    The current trend of development of Information Appliance is mobile and exquisite, however, the memory limitation in a device will result in a serious problem. Hence, it needs a new descriptive method of characters, not only saves more characters under the limitation of memory and the low-resolution of display screens, but also to transmit the characters through a limited bandwidth in a shorter time. The present invention can overcome the aforementioned disadvantages to describe refined characters and economize on memory.  
         SUMMARY OF THE INVENTION  
         [0009]    In the conventional arts, a larger number of data is needed to describe refined characters or it limits characters to a lightface or boldface with less data that cannot describe the variants in the thickness of characters. Based on the previous mentioned embodiments, it is an objective for the present invention to provide a descriptive method of characters for displaying the thickness of strokes thereof with less data.  
           [0010]    It is another objective for present invention to provide a descriptive method of characters for displaying the thickness of strokes thereof which reduces the amount of data. Therefore, more characters and types of characters can be saved under the memory limitation and the more complicated Chinese, Japanese, or Korean (CJK) fonts can be transmitted.  
           [0011]    It is a still another objective of the present invention to provide a descriptive method for displaying the stroke thickness of characters thereof to display the characters in a screen readily and refined.  
           [0012]    It is another objective of the present invention to provide a descriptive method for displaying the stroke thickness of characters thereof, so that a user can use exquisite and varied characters.  
           [0013]    As aforementioned, the present invention provides a descriptive method for displaying the stroke thickness of characters thereof. The descriptive method can decide at least one moving path of the character according to the characteristics of at least one stroke, decide upon the dimension of the geometric figure at a plurality of control point. This is achieved according to the characteristics and thickness of the at least one stroke, and the path of movement along the center of the geometric figure which varies the dimension of the geometric figure to form the character. The present invention also provides a method for composing font. The method forms a database comprising of at least one common basic stroke for at least one character. Wherein a descriptive method of the at least one common stroke for the at least one character of the database is comprised of the following. At least one moving path of the character must be decided according to the characteristics of the at least one common basic stroke of the at least one character of the database. Deciding upon a dimension of the geometric figure at a plurality of control points, according to the characteristics of the thickness of at least one basic stroke; and the movement at the center of the geometric figure along at least one moving path and the varying dimension of the geometric figure to form the character. The present invention further provides an apparatus for descriptive font. The apparatus comprises an assembly deciding at least one moving path of the character according to characteristics of the at least one stroke. An assembly deciding a dimension of the geometric figure at a plurality of control point according to characteristics of the thickness of the at least one stroke. And an assembly moving towards the center of the geometric figure along at least one moving path varying the dimension of the geometric figure to form the character is provided.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0015]    [0015]FIG. 1A to FIG. 1C is a diagram of the bitmap font, the outline font, and the vector font, respectively;  
         [0016]    [0016]FIG. 2A to FIG. 2B is a curve described by a quadratic equation and a cubic equation, respectively;  
         [0017]    [0017]FIG. 3 is a diagram of a circle moving along a moving path;  
         [0018]    [0018]FIG. 4A is a radius of a circle described by a cubic equation;  
         [0019]    [0019]FIG. 4B is a stroke described by a parameter of a radius of a circle;  
         [0020]    [0020]FIG. 4C is a diagram of a stroke passed by a circle;  
         [0021]    [0021]FIG. 4D is a diagram of a complicated stroke  
         [0022]    [0022]FIG. 5A to FIG. 5D is a character by means of the present invention;  
         [0023]    [0023]FIG. 6A to FIG. 6H is the comparison of the Chinese writing brush font, the outline font, and the vector font.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]    Some sample embodiments of the invention will now be described in greater detail. Nevertheless, it should be recognized that the present invention can be practiced in a wide range of other embodiments, besides those explicitly described, and the scope of the present invention is expressly not limited expect as specified in the accompanying claims.  
         [0025]    The concept of a Chinese writing brush is employed by the present invention, which a stroke becomes thicker as more force is applied and the stroke becomes thinner as the force on the Chinese writing brush is weakened. Therefore, the main concept of the present invention is to control the dimension of a geometric figure as well as the force of the Chinese writing brush to change the thickness of strokes. The area the geometric figure through is the strokes of a character. The geometric figure may be a circle, an oval-shaped, a rectangle, a square, or the other different form (e.g. irregular-shaped). Referring to FIG. 4A-FIG. 4C, one preferred embodiment of this invention employs a circle  28  to describe the thickness in strokes. In fact, the area of a character  30  should fill with colors, but the area of a character is replaced filling colors by oblique lines in the drawings. The step thereof comprises:  
         [0026]    1. In accordance with the characteristic of strokes of character  30 , the moving paths  26  in the center of circle  28  and coordinates of the starting control points  20 , control points  24 , and ending control points  22  are decided.  
         [0027]    2. In accordance with the thickness of a starting point and a ending point of the strokes, dimensions of the circle  28  for starting control points  20 , control points  24 , and ending control points  22  are decided.  
         [0028]    3. A center of circle  28  moves along the moving path  26  and the dimensions of circle  28  is changed with a function. The function is decided according to the variant of thickness in the strokes.  
         [0029]    4. Character  30  is the area the circle  28  moves through.  
         [0030]    Step 1: Referring to FIG. 3, in accordance with the characteristics of the strokes in the character, the moving path  26  of circle  28  and the coordinates of the starting control points  20 , control points  24 , and ending control points  22  are decided. The moving path  26  is described by, one order function, two order function, three order function or other order functions that can best describe the moving path  26 . One order function needs the coordinates of one starting control point  20  and one ending control point  22 . Two-order function needs coordinates of one starting control point  20 , one ending control point  22 , and one control point  24 . Three order function needs coordinates of one starting control point  20 , one ending control point  22 , and two control points  24 , and so on. For example, a moving path  26  is described by a three-order function, as shown in FIG. 4A: 
           x ( t )= a   3   t   3   +a   2   t   2   +a   1   t   1   +x   0   (1) 
           y ( t )= b   3   t   3   +b   2   t   2   +b   1   t   1   +y   0   tε[ 0,1]  (2) 
         [0031]    where a 1 =3(x 1 −x 0 )  
         [0032]    a 2 =3(x 2 −x 1 )−a 1    
         [0033]    a 3 =x 3 −x 0 −a 2 −a 1    
         [0034]    b 1 =3(y 1 −y 0 )  
         [0035]    b 2 =3(y 2 −y 1 )−b 1    
         [0036]    b 3 =y 3 −y 0 −b 2 −b 1    
         [0037]    Due to the function being a three order function, it needs the coordinates of four points: (x 0 , y 0 )˜(x 1 , y 1 )˜(x 2 , y 2 )˜(x 3 , y 3 ), wherein (x 0 , y 0 ) the coordinate of the starting control point  20  of the moving path  26 ; (x 3 , y 3 ) is the coordinate of the ending control point  24  of the moving path  26 ; (x 1 , y 1 ) and (x 2 , y 2 ) are the coordinates of control points  22  of the moving path  26 . Moreover, the control points  24  are not necessarily on the moving path  26 . When t is the parameter for controlling the moving path  26 , its range is 0 to 1. If t is 0, x(0)=x 0 , y(0)=y 0 , i.e. the coordinate of the starting control point  20 , and t is 1, x(1)=x 3 , y(1)=y 3 , i.e. the coordinate of the ending control point  24 . Therefore, the path of the coordinate (x(t), y(t)) during t being 0 to 1 is the moving path  26 . The variants or bends of the moving path  26  can be controlled by changing the coordinate (x 0 , y 0 ), (x 1 , y 1 ), (x 2 , y 2 ), and (x 3 , y 3 ) the starting control point  20 , control points  24 , and ending control point  22 . Then, the moving path  26  can be described by Eq. (1) and (2).  
         [0038]    Step 2: In accordance with the thickness of a starting point and an ending point of strokes, the dimensions of the starting control points  20 , control points  24 , and ending control points  22  are decided. When a stroke is thick, the circle  28  is bigger, and when a stroke is thin, the circle  28  is smaller. The radiuses, that are ro of circle  28  of the starting control point  20 , r 1  and r 2  of the circle  28  of the control point  24 , and r 3  of the circle  28  of ending control point  22 , are decided according to the stroke characteristic.  
         [0039]    Setp3: The center of the circle  28  moves along the moving path  26  and the radius of the circle  28  changes with a function. The function is decided according to the variant of thickness in the strokes. In accordance with the characteristic of the thickness of different strokes, the variant of strokes can be described with different functions. For example, a function of the radius of the circle  28  is described below: 
           r ( t )=( r   3   −r   0 ) t+r   0 ε[0,1]  (3) 
         [0040]    where r 1  and r 3  are the radius of the circle  28  at starting control point  20  and ending control point  22 . The t is a parameter and its range is 0 to 1. When t is 0, r(0)=r 0 , i.e. the radius of the circle  28  at starting control point  20 , and t is 1, r(1)=r 3 , i.e. the radius of the circle  28  at ending control point  22 . Therefore, the radius r(t) during t being 0 to 1 is the radius of the circle at the coordinate (x(t), y(t)). The Eq. (3) describes that a stroke gradually becomes thick or thin.  
         [0041]    The other function is described below: 
           r ( t )= c   3   t   3   +c   2   t   2   +c   1   t+c   0   tε[ 0,1]  (4) 
         [0042]    wherein c 1 =3(r 1 −r 0 )  
         [0043]    c 2 =3(r 2 −r 1 )−c 1    
         [0044]    c 3 =r 3 −r 0 −c 2 −c 1    
         [0045]    The r 0 , r 1 , r 2 , and r 3  are the radiuses of circle  28 , respectively. The radiuses of r 1  and r 2  depend on the coordinate (x 1 , y 1 ) and (x 2 , y 2 ) of the control points  24  and are decided according to the thickness of the strokes. The t is a controlling parameter and its range is 0 to 1. When t is 0, the r(0)=r 0 , i.e. the radius of circle  28  at the starting control point  20 , and t is 1, the r(1)=r 3 , i.e. the radius of circle  28  at the ending control point  22 . The radius r(t) is the radius of circle  28  at the coordinate (x(t),y(t)) of moving path  26  during which t being 0 to 1. Eq. (4) describes a stroke with three transitions of thickness at most.  
         [0046]    Referring to FIG. 4B, when the center of the circle  28  moves along the moving path  26 , the variant of the radius of circle  28  is decided by substituting t of the radius r(t) for the coordinate (x(t),(y)t).  
         [0047]    Setp4: Referring to FIG. 4B, the character  30  is the area which circle  28  moves through.  
         [0048]    The moving path  26  can be separated by a plurality of moving path  26  if the moving path  26  has complicated transitions, especially at the starting or ending portions of a stroke. Then starting control points  20 , control points  22 , and ending control point  24  of the moving paths  26  are decided. The moving paths  26  may be not connected with each other, i.e. starting control point  20  of one of the moving paths  26  may be not ending control point  22  of the other moving path thereof. Referring to FIG. 4D, the stroke is accomplished refined and beautifully according to steps 1 to 4.  
         [0049]    Referring to FIG. 5A, a character  30  is separated several moving paths  26  and the complicated sections can be separated several extra moving paths  26  in accordance with steps 1 to 4. The circle  28  moves along the moving paths  26  and is changed the radius of the circle  28 . The character  30  is the area the circle  28  through. The accomplished characters  30  are as shown in FIGS. 5B, 5C, and  5 D.  
         [0050]    In the present invention, due to the Chinese writing brush font data, the coordinates of the starting control point  20 , control point  24 , and ending control point  22  of each moving path  26  and the parameters from the radius r(t) of circle  28 . The amount of data in the present invention is less than the amount of data of the outlined font and close to or slightly more than the amount of data of the vector font. For example, referring to FIG. 6A, is a stroke of “         ”. This stroke needs 45 points of starting control points, control points, and ending control points by means of the outline font. Referring to FIG. 6B, the stroke is separated by four moving paths  26 , of the Chinese writing brush font of the said present invention, wherein starting control points  20  of three moving paths  26  are ending control points  22  of the other moving path  26 , respectively. Therefore, the stroke has eight points consisting of, starting control points  20 , control points  24 , and ending control points  22 . Referring to FIG. 6C, the stroke further needs eight radiuses of r 0 , r 1 , r 2 , and r 3  for description. According to one datum is 8 bits, a coordinate (x,y) needs two data, i.e. 16 bits, and one radius needs one datum, i.e. 8 bits. Hence, in the example, it needs totally 45×16 bits=720 bits by means of the outline font, and the present invention needs 8×16 bits+8×8 bits=192 bits, so that the needed data of the present invention is one of fourth of the data of the outline font.  
         [0051]    Referring to FIG. 6D, a whole character, “         ”, needs totally 70 points of starting control points  20 , control points  24 , and ending control points  22 . Due to too the fact that many points will cause a complicated figure, it omits control points  24 . Referring to FIG. 6E, the Chinese writing brush font of the present invention needs 15 points (comprising of a starting control points, control points, and ending control points). Referring to FIG. 6F, it needs 9 points (comprising of starting control points, control points, and ending control points), by means of the vector font. Therefore, the font data of the present invention is greatly less than the outline font data and slightly more than the vector font. Moreover, the Chinese writing brush font only needs extra data in the radius, i.e. the radiuses r 0 , r 1 , r 2 , and r 3  the starting control points, control points, and ending control points data, a total of 15, to describe the variant of thickness of the character. Referring to FIGS. 6G and 6H, the vector font is only decided a lightface or boldface and can not describe the variant of the thickness of strokes.  
         [0052]    Table. 1 shows the amount of data for the outline font, the vector font, and the Chinese writing brush font of the present invention. In general, the amount of data in the outline font is about 5 to 12 million bytes and the amount of data for the vector font is about 0.2 to 12 million bytes. Hence, the ratio for the amount of data for the vector font and the outline font is about one fourth to one twentieth.  
                                 TABLE 1                           The amount of data (Million Bytes)                Outline   Chinese Writing   Vector Font       Font   Font   Brush Font   (Stroke-based font)               Data   5-12   0.5-3     0.2-1.2       Ratio (Compared       1/4-1/20   1/10-1/50       with outline font)                  
 
         [0053]    Therefore, the amount of data for the Chinese writing brush font is similar to the amount of the data for the vector font and less than the amount of the data of the outline font. Moreover, the character described with the Chinese writing brush font is refined and beautifully similar to the outline font.  
         [0054]    The character displayed in different sizes can be described by modulating the coordinates of the starting control points  20 , the control points  24 , and the ending control points  22  of the moving path  26  with a ratio of equality. The radiuses r i  (i=0, 1, 2, . . . ) of the circle  28  may be modulated with the ratio of equality or a different ratio.  
         [0055]    Furthermore, the present invention may be employed with the composing font, i.e. a character  30  formed by composing the basic strokes of the character. The character is composed with the data of the needed basic strokes and positions of the strokes. In accordance with strokes of the character stored in a database and the positions of the strokes, the character is composed by modulating the size of the strokes according to the size of the character. Hence, the data of the composing font are only the same strokes of the characters  30  described by means of the Chinese writing brush font and the relative position of strokes in the characters. The amount of the data of the composing font is less than the amount of the data comprising total characters. The character composed by the basic strokes of the composing font can be described by modulating the coordinates of the starting control points  20 , the control points  24 , and the ending control points  22  of the basic strokes with a ratio of equality. The radiuses r 1  (i=0, 1, 2, . . . ) of the circle  28  may be modulated with the ratio of equality or a different ratio.  
         [0056]    According to the preferred embodiments, this invention discloses descriptive method of characters for displaying the thickness of strokes thereof. According to descriptive method of characters of the present invention, the amount of data is less than the amount of data for the bitmap font and the outline font and is close the amount of data for the vector font. Furthermore, it can describe the character as the outline font and does not have the disadvantages of the vector font that can not describe the character in a refined and beautiful manner. Moreover, it avoids the disadvantages of distortion of the resized characters and can keep the refined form from modulating the size of the characters easily.  
         [0057]    Although specific embodiments have been illustrated and described, it will be obvious to those conventional art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.