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Rendering Wide Lines in a Fast And Efficient Manner

IP.com Disclosure Number: IPCOM000119601D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 95K

Publishing Venue

IBM

Related People

Kariolis, SJ: AUTHOR

Abstract

The rendering of wide lines is a very important and integral part of a graphics adapter. It is used extensively in a large number of applications in an interactive type of environment. To guarantee a user-friendly environment, it is of utmost importance that the adapter algorithms for drawing wide lines are providing "good" performance and "good" wide lines. The rendering of wide lines in essence involves the filling of polygons. Filling polygons is a time-consuming task that provides for poor performance in most applications. This characteristic, together with the fact that in many applications a large number of wide lines is displayed simultaneously, warrants the need for methods to speed up the rendering of wide lines by the adapter. Wide Line Specification

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Rendering Wide Lines in a Fast And Efficient Manner

      The rendering of wide lines is a very important and
integral part of a graphics adapter.  It is used extensively in a
large number of applications in an interactive type of environment.
To guarantee a user-friendly environment, it is of utmost importance
that the adapter algorithms for drawing wide lines are providing
"good" performance and "good" wide lines.  The rendering of wide
lines in essence involves the filling of polygons.  Filling polygons
is a time-consuming task that provides for poor performance in most
applications.  This characteristic, together with the fact that in
many applications a large number of wide lines is displayed
simultaneously, warrants the need for methods to speed up the
rendering of wide lines by the adapter. Wide Line Specification

      At the application level a series of wide lines may be
specified as a list of points that are to be interconnected. Each
pair of these points represents a line.  The rendering of the lines
is accomplished according to their properties and characteristics
that are specified to the adapter as a list of attributes.  Some of
these attributes are:
-    Width (an integer specifying how wide the line is)
-    Geometric (whether the width is transformable or not)
-    End Type (whether the end of wide line is round, flat, or
square)
-    Color (what color is the interior of the wide line)
-    Line Style (is the interior solid or some form of pattern)

      The above list is not complete.  As far as performance is
concerned the width and the end type are the critical parameters in
dictating how fast the wide line is drawn.

      The applications pass the list of points to the graphics
adapter with the list of attributes.  The adapter takes a pair of
points in sequence and draws a wide line for each pair of points with
characteristics conforming to the list of attributes.

      Background The commonly used procedure for drawing the wide
line computes the points that make up the rectan...