Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
1998-07-27
2001-02-27
Powell, Mark R. (Department: 2779)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
C345S469000
Reexamination Certificate
active
06195100
ABSTRACT:
This invention relates to a method and system for rendering brush strokes on electrical documents, and more particularly, to a method and system for rendering brush strokes using multiple nibs to provide unique paint effects.
BACKGROUND OF THE INVENTION
There are many paint systems or applications which can render brush strokes on electrical documents in computer graphics systems. Brush strokes are drawn as a cursor is moved by a cursor moving device such as a mouse or a pen drawn over a pen tablet.
In many systems, a brush dab is comprised with a single nib. The size and shape of the brush nib may be changed by a user to render different brush strokes. However, in many systems, once a particular size and shape of the brush nib are selected, they are unchanged along a brush stroke.
In some systems, a nib shape is varied during a brush stroke. U.S. Pat. No. 5,155,813 issued on Oct. 13, 1992 to Donoghue et al discloses a computer apparatus for brush styled writing. A pen tablet is sampled to generate smooth brush strokes in real time to facilitate accurate calligraphy. U.S. Pat. No. 5,239,292 issued on Aug. 24, 1993 to Willan discloses how positional input from a graphics tablet is used to determine the position and some characteristics including nib shapes. However, those systems render only a single nib for a brush stroke.
Other paint systems can draw multiple nibs while a mouse is being moved. However, the positions of the multiple nibs are either fixed or simulated random. In impressionist clone systems, multiple nibs are provided at fixed positions. U.S. Pat. No. 5,347,620 issued on Sep. 13, 1994 to Zimmer refers to multiple dabs being rendered for each brush position. The position of the extra strokes is randomly generated to achieve the effect of a bristled brush.
There are many systems to simulate calligraphy, but no system has been proposed to render a brush stroke having a unique painting effect using multiple nibs.
It is therefore desirable to provide a paint system which can render a brush stroke with multiple nibs whose movement is controllable to provide unique painting effects.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and system for rendering a brush stroke with multiple nibs whose movement is controllable to provide unique painting effects.
To this end, the present invention provides multiple nibs in addition to a centre point indicated by a cursor, and controls the position and movement of each nib based on variables which can be set by a user. As the centre point is moved, the variables are incremented, and a dab is rendered at a new position of each nib determined by the incremented variables. Thus, the present invention provides brush strokes that are significantly different from traditional brush strokes.
In accordance with an aspect of the present invention, there is provided a method for rendering a brush stroke on an electrical document. The method is started by setting a number of nibs to be rendered in the brush stroke, setting initial position values determining an initial position of each nib relative to a centre point, and setting movement variables representative of movement of each nib relative to the centre point. Then, a current position of the centre point is determined relative to the document. A new position for each nib is calculated, relative to the current position of the centre point, based on the initial position values and the movement variables. A dab is rendered at the new position of each nib. By repeating the steps of determining a current position, calculating a new position and rendering a dab while the centre point is being moved, a brush stroke is rendered.
In accordance with another aspect of the present invention, there is provided a brush stroke rendering system for rendering a brush stroke on an electrical document. The system comprises an initial setting unit, a centre point position determining unit, a nib position calculating unit and a display controller. The initial setting unit allows setting of a number of nibs to be rendered in the brush stroke, initial position values determining an initial position of each nib relative to a centre point, and movement variables representative of movement of each nib relative to the centre point. The centre point position determining unit determines a current position of the centre point relative to the document. The nib position calculating unit calculates each nib position based on the initial position values and the movement variables, relative to the current position of the centre point determined by the centre point position determining unit. Then, the display controller renders a dab at each nib position calculated by the nib position calculating unit.
REFERENCES:
patent: 5155813 (1992-10-01), Donoghue et al.
patent: 5182548 (1993-01-01), Haeberli
patent: 5239292 (1993-08-01), Willan
patent: 5347620 (1994-09-01), Zimmer
patent: 5432896 (1995-07-01), Hwong et al.
patent: 5534893 (1996-07-01), Hansen, Jr. et al.
patent: 5687304 (1997-11-01), Kiss
patent: 5847712 (1998-12-01), Salesin et al.
patent: 2169627 (1995-05-01), None
“Non Interactive Graphics” John Lewell; 1985 Software Patent Institute Database of Software Technologies; pp. 1-3.
Corel Corporation
Good-Johnson Motilewa
Hayes, Soloway, Hennessey Grossman & Hage, P.C.
Powell Mark R.
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