# US 5,353,396 A · System and method for generating complex calligraphic curves

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- Number: US 5,353,396 A
- Document ID: US5353396A
- Status: Granted
- Kind: A
- Application number: 07/894,272
- Filed: 1992-06-04
- Granted: 1994-10-04
- Earliest claimed: 1992-06-04
- Assignees: Altsys Corporation
- Inventors: John B. Ahlquist, Jr.; James R. Von Ehre, II; Samantha Seals-Mason
- Web page: https://patentgrep.com/patent/US5353396A

## CPC

- G06T 11/23: using straight lines or curves
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A system and method for generating complex calligraphic curves from an input source. The input can be a stylus and the angle of attack of the line with respect to a surface can be fixed or variable. The calligraphic curve can have a fixed or variable width which can be point-by-point edited to form a new calligraphic curve. The system has the ability to expand a calligraphic image with crossing strokes.

## Claims

### Claim 1

A method of creating a calligraphic image of a line, said method comprising the steps of:
accepting data representative of the width of the line to be created, and an input pen angle for said calligraphic image of a line;
accepting data representative of a direction of the line to be created;
constructing said calligraphic image of said line concurrently as said line direction is accepted, said constructed line moving at a constant constructed pen angle in accordance with said accepted input pen angle data; and
generating a spine of said direction data, said spine being the longitudinal center line of said constructed calligraphic image, said spine containing points there along, each said point having data associated therewith pertaining to said width and said pen angle for said calligraphic line image,
wherein said spine angle data is expressed in Cartesian coordinates representative of said angle at said point, said coordinates used in conjunction with said width data at said point to generate one point along a top peripheral outline of said direction and one point along the bottom peripheral outline of said direction, said peripheral points movable to modify said calligraphic image.

### Claim 2 (depends on 1)

The method of creating a calligraphic image in claim 1 further including the step of:
substituting an outline for said constructed calligraphic image immediately upon the cessation of said accepted line direction data.

### Claim 3 (depends on 1)

The method of creating a calligraphic image in claim 1 wherein said constructing step includes:
maintaining the pen angle at the start point of the image line and the pen angle at the end point of the image line equal to said accepting pen angle data.

### Claim 4 (depends on 1)

The method of claim 1 further including the steps of:
modifying said constructed calligraphic image of said line by changing said angle information while said direction data is being received.

### Claim 5 (depends on 1)

The method of claim 1 further including the steps of:
modifying said constructed calligraphic image of said line by changing said width information while said direction data is being received.

### Claim 6 (depends on 1)

The method set forth in claim 1 wherein said direction information accepting step includes the step of receiving data from a stylus moving with respect to a surface.

### Claim 7 (depends on 6)

The method set forth in claim 6 wherein said end of said stylus is a calligraphic pen tip and wherein said angle is controlled by the angle of said pen tip at any point along said pen tip's trajectory.

### Claim 8 (depends on 6)

The method set forth in claim 6 wherein said width data is provided by the pressure of said stylus against said surface.

### Claim 9 (depends on 1)

The method of creating a calligraphic image in claim 1 further including the steps of:
implementing a first expansion of said spine segment into said calligraphic image if the starting angle of direction of said segment and the ending angle of direction of said segment cross the pen angle for said calligraphic line.

### Claim 10 (depends on 9)

The method of creating a calligraphic image in claim 9 further including the step of:
implementing a second expansion at the intersection of said segment and a next segment if the angle of direction at the end of said segment and the angle of direction at the beginning of said next segment cross the pen angle of said calligraphic line.

### Claim 11 (depends on 10)

The method of creating a calligraphic image in claim 10 further including the step of:
expanding said line segment using calligraphic expansion if said first and second expansions have not occurred.

### Claim 12 (depends on 9)

The method of creating a calligraphic image in claim 9 wherein said first expansion step further includes:
prohibiting a crossover of the outlines of said image.

### Claim 13 (depends on 10)

The method of creating a calligraphic image in claim 10 wherein said second expansion step further includes:
generating points along a top peripheral outline of said segment and points along the bottom peripheral outline of said segment;
generating points along a top peripheral outline of said next segment and points along the bottom peripheral outline of said next segment; and
connecting the end points of said peripheral outlines of said segment to the beginning points of said peripheral outlines of said next segment wherein a crossover of said peripheral outlines is prohibited.

### Claim 14 (depends on 13)

The method of creating a calligraphic image in claim 13 wherein said connecting step connects said end point of said top peripheral outline of said segment to said beginning point of said bottom peripheral outline of said next segment and connects said end point of said bottom peripheral outline of said segment to said beginning point of said top peripheral outline of said next segment.

### Claim 15

A method of creating a calligraphic image of a line, said method comprising the steps of:
accepting data representative of the initial width of the line to be created, and an initial pen angle for said calligraphic line;
accepting data representative of a direction of the line to be created;
accepting data representative of any variations in said width data and said pen angle data of said line concurrently with the reception of said direction data; and
constructing said calligraphic image of said line concurrently as said line direction is accepted, incorporating said initial data and said variations in said width and said pen angle of said line.

### Claim 16 (depends on 15)

The method of creating a calligraphic image in claim 15 further including the step of:
substituting an outline for said constructed calligraphic image immediately upon the cessation of said accepted line direction data.

### Claim 17

A system for creating a calligraphic image of a line, said system comprising:
means for accepting data representative of the width of the line to be created, and an input pen angle for said calligraphic line;
means for accepting data representative of a direction of the line to be created;
means for constructing said calligraphic image of said line concurrently as said line direction is accepted, said constructed image line moving at a constant constructed pen angle in accordance with said accepted input pen angle data; and
means for generating a spine of said direction data, said spine being the longitudinal center line of said constructed calligraphic image, said spine containing points there along, each said point having data associated therewith pertaining to said width and said pen angle for said calligraphic line image,
wherein said spine angle data is expressed in Cartesian coordinates representative of said angle at said point, said coordinates used in conjunction with said width data at said point to generate one point along a top peripheral outline of said direction and one point along the bottom peripheral outline of said direction, said peripheral points movable to modify said calligraphic image.

### Claim 18 (depends on 17)

The system for creating a calligraphic image in claim 17 further including:
means for substituting an outline for said constructed calligraphic image immediately upon the cessation of said accepted line direction data.

### Claim 19 (depends on 17)

The system for creating a calligraphic image in claim 17 wherein said means for constructing includes:
means for maintaining the pen angle at the start point of the image line and the pen angle at the end point of the image line equal to said accepting pen angle data.

### Claim 20 (depends on 17)

The system of claim 17 further including:
means for modifying said constructed calligraphic image of said line by changing said pen angle information while said direction data is being received.

### Claim 21 (depends on 17)

The system of claim 17 further including:
means for modifying said constructed calligraphic image of said line by changing said width information while said direction data is being received.

### Claim 22 (depends on 17)

The system set forth in claim 17 wherein said means for accepting direction information includes means for receiving data from a stylus moving with respect to a surface.

### Claim 23 (depends on 22)

The system set forth in claim 22 wherein said end of said stylus is a calligraphic pen tip and wherein said angle is controlled by the angle of said pen tip at any point along said pen tip's trajectory.

### Claim 24 (depends on 22)

The system set forth in claim 22 wherein said width data is provided by the pressure of said stylus against said surface.

### Claim 25 (depends on 17)

The system for creating a calligraphic image set forth in claim 17 further including:
means for choosing a segment of said spine for expansion into a calligraphic image; and
means for implementing a first expansion of said spine segment into said calligraphic image if the starting angle of direction of said segment and the ending angle of direction of said segment cross the pen angle for said calligraphic line.

### Claim 26 (depends on 25)

The system for creating a calligraphic image set forth in claim 25 further including:
means for implementing a second expansion at the intersection of said segment and a next segment if the angle of direction at the end of said segment and the angle of direction at the beginning of said next segment cross the pen angle of said calligraphic line.

### Claim 27 (depends on 26)

The system for creating a calligraphic image set forth in claim 26 further including:
means for expanding said line segment using straightforward calligraphic expansion if said first and second expansions have not occurred.

### Claim 28 (depends on 25)

The system for creating a calligraphic image set forth in claim 25 wherein said first expansion further includes:
means for generating points along a top peripheral outline and points along the bottom peripheral outline of said segment, wherein a crossover of said top outline and said bottom outline is prohibited.

### Claim 29 (depends on 26)

The system for creating a calligraphic image set forth in claim 26 wherein said second expansion further includes:
means for generating points along a top peripheral outline of said segment and points along the bottom peripheral outline of said segment;
means for generating points along a top peripheral outline of said next segment and points along the bottom peripheral outline of said next segment; and
means for connecting the end points of said peripheral outlines of said segment to the beginning points of said peripheral outlines of said next segment wherein a crossover of said peripheral outlines is prohibited.

### Claim 30 (depends on 29)

The system for creating a calligraphic image in claim 29 wherein said means for connecting connects said end point of said top peripheral outline of said segment to said beginning point of said bottom peripheral outline of said next segment and connects said end point of said bottom peripheral outline of said segment to said beginning point of said top peripheral outline of said next segment.

### Claim 31 (depends on 25)

The system for creating a calligraphic image in claim 25 wherein said first expansion further includes:
means for generating said points along said top peripheral outline until arriving at the crossing point along said spine segment where said starting angle of direction of said segment and the ending angle of direction of said segment cross said pen angle for said calligraphic line;
means for generating said points along said bottom peripheral outline after said crossing point;
means for connecting with a straight line the last point along said top peripheral outline before said crossing point and the beginning point along said bottom peripheral outline after said crossing point,
wherein a first side of said expanded spine segment includes said top peripheral outline before said crossing point and said bottom peripheral outline after said crossing point and said straight-line connection;
means for generating said points along said bottom peripheral outline before said crossing point;
means for generating said points along said top peripheral outline after said crossing point;
means for connecting with a straight line the last point along said bottom peripheral outline before said crossing point and said top peripheral outline after said crossing point,
wherein a second side of said expanded spine segment includes said bottom peripheral outline before said crossing point and said top peripheral outline after said crossing point and said straight line connection;
means for examining separately said first and second sides for points of intersection;
means for leaving either of said first or second sides intact if no points of intersection are found;
means for discarding said straight-line connection in said side if either side intersects said either side; and
means for discarding said points along said outlines from said ends of said straight-line connection to said intersection point.

### Claim 32

A system for creating a calligraphic image of a line, said system comprising:
means for accepting data representative of the initial width of the line to be created, and an initial pen angle for said calligraphic line;
means for accepting data representative of a direction of the line to be created;
means for accepting data representative of any variations in said width data and said pen angle data of said line concurrently with the reception of said direction data; and
means for constructing said calligraphic image of said line concurrently as said line direction is accepted, incorporating said initial data and said variations in said width and said pen angle of said line.

### Claim 33 (depends on 32)

The system for creating a calligraphic image in claim 32 further including:
means for substituting an outline for said constructed calligraphic image immediately upon the cessation of said accepted line direction data.

### Claim 34

A system for generating a font image having calligraphic characteristics, said system comprising:
means for accepting data representative of the width for each curve in said font image, and an input pen angle for each said curve;
means for accepting data representative of a direction of each desired curve in said font image;
means for constructing each said curve of said font image concurrently as said curve direction is accepted, said constructed font curve moving at a constant constructed pen angle in accordance with said accepted input pen angle data; and
means for generating a spine of said direction data, said spine being the longitudinal center line of said constructed calligraphic font image, said spine containing points there along, each said point having data associated therewith pertaining to said width and said pen angle for said calligraphic font image,
wherein said spine angle data is expressed in Cartesian coordinates representative of said angle at said point, said coordinates used in conjunction with said width data at said point to generate one point along a top peripheral outline of said direction and one point along the bottom peripheral outline of said direction, said peripheral points movable to modify said calligraphic font image.

### Claim 35 (depends on 34)

The system for generating a font as set forth in claim 34 wherein said accepting means is an object moving across a surface to define said desired position and direction characteristics.

### Claim 36 (depends on 35)

The system for generating a font as set forth in claim 35 wherein said object is a stylus having a point of contact with said surface.

### Claim 37 (depends on 35)

The system in claim 35 wherein said object is a mouse.

### Claim 38 (depends on 34)

The system for generating a font as set forth in claim 34 wherein said accepting means and said generating means are included within a computer system wherein said font is generated within said computer system for display by an output means.

### Claim 39 (depends on 38)

The system for generating a font as set forth in claim 38 wherein said output means is a video terminal.

### Claim 40 (depends on 38)

The system for generating a font as set forth in claim 38 wherein said output means is a printer.

### Claim 41 (depends on 9)

The method of creating a calligraphic image in claim 9 wherein said first expansion step further includes:
generating said points along said top peripheral outline until arriving at the crossing point along said spine segment where said starting angle of direction of said segment and the ending angle of direction of said segment cross said pen angle for said calligraphic line;
generating said points along said bottom peripheral outline after said crossing point;
connecting with a straight line the last point along said top peripheral outline before said crossing point and the beginning point along said bottom peripheral outline after said crossing point,
wherein a first side of said expanded spine segment includes said top peripheral outline before said crossing point and said bottom peripheral outline after said crossing point and said straight-line connection;
generating said points along said bottom peripheral outline before said crossing point;
generating said points along said top peripheral outline after said crossing point;
connecting with a straight line the last point along said bottom peripheral outline before said crossing point and said top peripheral outline after said crossing point,
wherein a second side of said expanded spine segment includes said bottom peripheral outline before said crossing point and said top peripheral outline after said crossing point and said straight line connection;
examining separately said first and second sides for points of intersection;
leaving either of said first or second sides intact if no points of intersection are found;
discarding said straight-line connection in said side if either side intersects said either side; and
discarding said points along said outlines from said ends of said straight-line connection to said intersection point.

### Claim 42

A method of creating a calligraphic image of a line, said method comprising the steps of:
accepting data representative of the width of the line to be created, and an input pen angle for said calligraphic line;
accepting data representative of a direction of the line to be created;
constructing said calligraphic image of said line concurrently as said line direction is accepted, said constructed image line moving at a constant constructed pen angle in accordance with said accepted input pen angle data;
generating a spine of said direction data, said spine being the longitudinal center line of said constructed calligraphic image, said spine containing points there along, each said point having data associated therewith pertaining to said width and said pen angle for said calligraphic line image;
choosing a segment of said spine for expansion into a calligraphic image; and
implementing a first expansion of said spine segment into said calligraphic image if a crossing point occurs in said spine segment wherein the starting angle of direction of said segment and the ending angle of direction of said segment cross the pen angle for said calligraphic line.

### Claim 43 (depends on 42)

The method of creating a calligraphic image in claim 42 wherein said first expansion step further includes the steps of:
generating points along a first side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the direction of said pen angle and continuing to generate points along said spine segment until arriving at said crossing point along said spine segment;
generating a first point along said first side at said crossing point utilizing said normal calligraphic expansion;
generating a second point along said first side at said crossing point by moving out from said spine segment one-half of said width in the opposite direction of said pen angle;
connecting with a straight line said first point and said second point at said crossing point; and
generating points along said first side of said spine segment after said crossing point by moving out from said spine segment one-half of said width in said opposite direction of said pen angle;
generating points along a second side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the opposite direction of said pen angle and continuing to generate points along said spine segment until arriving at said crossing point along said spine segment;
generating a first point along said second side at said crossing point utilizing said normal calligraphic expansion in said opposite direction of said pen angle;
generating a second point along said second side at said crossing point by moving out from said spine segment one-half of said width in said direction of said pen angle;
connecting with a straight line said first point and said second point along said second side at said crossing point;
generating points along said second side of said spine segment after said crossing point by moving out from said spine segment one-half of said width in said direction of said pen angle.

### Claim 44 (depends on 42)

The method of creating a calligraphic image in claim 42 further comprising the step of:
implementing a second expansion at the point of intersection of said spine segment and a next spine segment of said calligraphic line if the angle of direction at the end of said spine segment and the angle of direction at the beginning of said next spine segment cross the pen angle of said calligraphic line.

### Claim 45 (depends on 44)

The method of creating a calligraphic image in claim 44 wherein said second expansion step further includes the steps of:
generating points along a first side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the direction of said pen angle and continuing to generate points along said spine segment until arriving at said intersection point along said spine segment;
generating a first point along said first side at said intersection point utilizing said normal calligraphic expansion;
generating a second point along said first side at said intersection point by moving out from said spine segment one-half of said width in the opposite direction of said pen angle;
connecting with a straight line said first point and said second point at said intersection point;
generating points along said first side of said spine segment after said intersection point by moving out from said spine segment one-half of said width in said opposite direction of said pen angle;
generating points along a second side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the opposite direction of said pen angle and continuing to generate points along said spine segment until arriving at said intersection point along said spine segment;
generating a first point along said second side at said intersection point utilizing said normal calligraphic expansion in said opposite direction of said pen angle;
generating a second point along said second side at said intersection point by moving out from said spine segment one-half of said width in said direction of said pen angle;
connecting with a straight line said first point and said second point along said second side at said intersection point; and
generating points along said second side of said spine segment after said intersection point by moving out from said spine segment one-half of said width in said direction of said pen angle.

### Claim 46

A system for creating a calligraphic image of a line, said system comprising:
means for accepting data representative of the width of the line to be created, and a pen angle for said calligraphic line;
means for accepting data representative of a direction of the line to be created;
means for constructing said calligraphic image of said line concurrently as said line direction is accepted, said image line moving at a constant pen angle in accordance with said accepted pen angle data;
means for generating a spine of said direction data, said spine being the longitudinal center line of said constructed calligraphic image, said spine containing points there along, each said point having data associated therewith pertaining to said width and said pen angle for said calligraphic line image;
means for choosing a segment of said spine for expansion into a calligraphic image; and
means for implementing a first expansion of said spine segment into said calligraphic image if a crossing point occurs in said spine segment wherein the starting angle of direction of said segment and the ending angle of direction of said segment cross the pen angle for said calligraphic line.

### Claim 47 (depends on 46)

The system for creating a calligraphic image in claim 46 wherein said first expansion further includes:
means for generating points along a first side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the direction of said pen angle and continuing to generate points along said spine segment until arriving at said crossing point along said spine segment;
means for generating a first point along said first side at said crossing point utilizing said normal calligraphic expansion;
means for generating a second point along said first side at said crossing point by moving out from said spine segment one-half of said width in the opposite direction of said pen angle;
means for connecting with a straight line said first point and said second point at said crossing point;
means for generating points along said first side of said spine segment after said crossing point by moving out from said spine segment one-half of said width in said opposite direction of said pen angle;
means for generating points along a second side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the opposite direction of said pen angle and continuing to generate points along said spine segment until arriving at said crossing point along said spine segment;
means for generating a first point along said second side at said crossing point utilizing said normal calligraphic expansion in said opposite direction of said pen angle;
means for generating a second point along said second side at said crossing point by moving out from said spine segment one-half of said width in said direction of said pen angle;
means for connecting with a straight line said first point and said second point along said second side at said crossing point; and
means for generating points along said second side of said spine segment after said crossing point by moving out from said spine segment one-half of said width in said direction of said pen angle.

### Claim 48 (depends on 46)

The system for creating a calligraphic image in claim 46 further comprising:
means for implementing a second expansion at the point of intersection of said spine segment and a next spine segment of said calligraphic line if the angle of direction at the end of said spine segment and the angle of direction at the beginning of said next spine segment cross the pen angle of said calligraphic line.

### Claim 49 (depends on 48)

The system for creating a calligraphic image in claim 48 wherein said second expansion further includes:
means for generating points along a first side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the direction of said pen angle and continuing to generate points along said spine segment until arriving at said intersection point along said spine segment;
means for generating a first point along said first side at said intersection point utilizing said normal calligraphic expansion;
means for generating a second point along said first side at said intersection point by moving out from said spine segment one-half of said width in the opposite direction of said pen angle;
means for connecting with a straight line said first point and said second point at said intersection point;
means for generating points along said first side of said spine segment after said intersection point by moving out from said spine segment one-half of said width in said opposite direction of said pen angle;
means for generating points along a second side of said spine segment utilizing a normal calligraphic expansion wherein said points are generated by moving out from said spine segment one-half of said width in the opposite direction of said pen angle and continuing to generate points along said spine segment until arriving at said intersection point along said spine segment;
means for generating a first point along said second side at said intersection point utilizing said normal calligraphic expansion in said opposite direction of said pen angle;
means for generating a second point along said second side at said intersection point by moving out from said spine segment one-half of said width in said direction of said pen angle;
means for connecting with a straight line said first point and said second point along said second side at said intersection point; and
means for generating points along said second side of said spine segment after said intersection point by moving out from said spine segment one-half of said width in said direction of said pen angle.