Computer graphics processing and selective visual display system – Computer graphics processing – Shape generating
Reexamination Certificate
1998-12-30
2001-03-13
Brier, Jeffery (Department: 2779)
Computer graphics processing and selective visual display system
Computer graphics processing
Shape generating
C345S442000, C345S156000, C345S156000
Reexamination Certificate
active
06201549
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to digital drawing and painting and, more particularly, relates to a system and method for drawing and painting with bitmap brushes.
BACKGROUND OF THE INVENTION
Since the first incarnation of digital paint systems, there has been a lot of work done to make synthesized paint strokes look like those created using traditional paint and drawing tools, for example, watercolor brushes, chalk strokes, etc. In particular, two known commercial products, “PAINTER” and “EXPRESSION” sold by MetaCreations, provide tools for use in creating “natural media” digital painting and drawing. “PAINTER” is raster based and uses procedural algorithms to generate paint strokes that give the appearance that they have been created by their real world counterpart. “EXPRESSION” is vector based and uses “skeletal strokes” technology.
Skeletal strokes, described in S. C. Hsu and I. H. H. Lee, “
Drawing and Animation Using Skeletal Strokes,
” SIGGRAPH '94 Conference Proceedings, Jul. 1994 and S. C. Hsu, I. H. H. Lee, and N. E. Wiseman, “
Skeletal Strokes,
” UIST '93 Proceedings of the ACM SIGGRAPH and SIGCHI Symposium on User Interface Software Technology, Nov. 1993, utilizes a vector graphics realization of the brush and stroke metaphor using arbitrary pictures as “ink.” Generally, defining a skeletal stroke requires drawing an instance of the flesh, which could be any arbitrary picture, around a reference line with a right-angle bend. The reference line provides a reference x-axis for the points specifying the position of the flesh; a reference thickness provides a scale to specify the lateral distance of the these points from the reference line. A picture so anchored to a single reference line defines a skeletal stroke. Once a skeletal stroke is defined, it can be applied along any arbitrary path by simply drawing the path and aligning the reference line of the skeletal stroke with the given path. In this manner, the flesh is distorted (stretched, compressed, bent and/or sheared) to generally follow the path.
While these tools generally work for their intended purpose, both applications tend to fall a bit short in terms of the realism of the paint stroke synthesized. In particular, because of the procedural nature of “PAINTER” and the vector nature of “EXPRESSION”, the paint strokes produced lack the subtle flaws and detail of real brush strokes or real objects. Accordingly, a need exists for an apparatus and method for digitally producing brush strokes that appear to be hand drawn and painted.
SUMMARY OF THE INVENTION
In accordance with this need, the subject invention generally allows a user to paint and draw with a scanned bitmap brush that is warped along the path of a previously defined guide line. The bitmap brush may be an “artistic brush” in which case the brush
2
0
is a scanned bitmap of an actual artistic stroke created in a variety of styles including watercolor, oil, chalk, crayon, ink, etc. Additionally, the bitmap brush may be a “photo brush” in which case the brush is a scanned photo of an object such as a rope, wire, chain, etc. The bitmap brush is warped along the defined guide line thus producing a highly realistic artistic or photo stroke. In this manner, the approach taken by the subject invention allows a user to paint along any path and stay completely within the electronic domain. Furthermore, the subject invention has the advantage of allowing a user to paint and draw with a wide variety of strokes, instead on ones that merely consist of a solid color, while yielding realistic and visually pleasing results.
More particularly, the invention may be described as a method for drawing a paint stroke with a bitmap brush having pixels located at locations definable in a Cartesian coordinate system. The paint stroke is created by defining a path of a guide line, the path having an arc-length and the guide line having a thickness, and scaling the bitmap brush as a function of the arc-length of the path and the thickness of the guide line. The bitmap brush is then warped to the guide line by transforming the x-axis and the y-axis of the bitmap brush. In particular, the x-axis of the bitmap brush is transformed so that it generally aligns with the path and the y-axis of the bitmap brush is transformed so it generally aligns with an instantaneous normal to the path.
REFERENCES:
patent: 4774516 (1988-09-01), Henri et al.
patent: 4897638 (1990-01-01), Kokunishi et al.
patent: 4952051 (1990-08-01), Lovell et al.
patent: 5155813 (1992-10-01), Donoghue et al.
patent: 5216755 (1993-06-01), Walker et al.
patent: 5276787 (1994-01-01), Searby
patent: 5361333 (1994-11-01), Ahlquist, Jr. et al.
patent: 5432896 (1995-07-01), Hwong et al.
patent: 5488204 (1996-01-01), Mead et al.
patent: 5506603 (1996-04-01), Kawano et al.
patent: 5548706 (1996-08-01), Koizumi et al.
patent: 5615321 (1997-03-01), Corn
patent: 5717845 (1998-02-01), Patrick et al.
patent: 5767860 (1998-06-01), Zimmer et al.
patent: 5847712 (1998-12-01), Salesin et al.
patent: 6064388 (2000-05-01), Reyzin
Hsu, Siu Chi et al. “Drawing and Animation Using Skeletal Strokes”, Computer Graphics Proceedings, Annual Conference Series, 1994, ACM, Jul. 1994, pp. 109-118.
Hsu, Siu Chi et al., “Skeletal Strokes”, UIST'93 Proceedings of the ACG Siggraph and Sigchi Symposium on User Interface Software and Technology, ACM, Nov. 1993.
Foley J. et al.Computer Graphics Principles and Practice2ndEdition, Chapter 11.2 “Parametric Cubic Curves”, Addison-Wesley, 1990, pp. 478-491.
Schneider, Philip J., “Solving the Nearest-Point-on-Curve Problem” inGraphics Gems(A. Glassner ed.), Academic Press, Inc., 1990.
Rosenfeld A., et al.Digital Picture Processing, vol. 2, Chapter 9.3 “Geographic Transformation”, Academic Press, 1982, pp. 31-36.
Schmacher, D., “General Filtered Image Rescaling”, inGraphics Gems III(D. Kirk ed.), Academic Press Inc., 1992, pp. 8-16, 414-424.
Farin, G.,Curves and Surfaces for CAGD—A Practical Guide, 4thEdition, Academic Press, 1992.
Porter T., et al. “Compositing Digital Images”,Computer Graphics, vol. 18, No. 3, Jul. 1984, pp. 49-55.
Brier Jeffery
Hawan Thu-Thao
Leydig , Voit & Mayer, Ltd.
Microsoft Corporation
LandOfFree
System and method for drawing and painting with bitmap brushes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for drawing and painting with bitmap brushes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for drawing and painting with bitmap brushes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2470801