summaryrefslogtreecommitdiffstats
path: root/doc/canvas.n
diff options
context:
space:
mode:
Diffstat (limited to 'doc/canvas.n')
-rw-r--r--doc/canvas.n50
1 files changed, 36 insertions, 14 deletions
diff --git a/doc/canvas.n b/doc/canvas.n
index a9bee5f..7403907 100644
--- a/doc/canvas.n
+++ b/doc/canvas.n
@@ -6,7 +6,7 @@
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: canvas.n,v 1.15 2004/08/16 08:24:45 dkf Exp $
+'\" RCS: @(#) $Id: canvas.n,v 1.16 2004/08/19 14:41:52 dkf Exp $
'\"
.so man.macros
.TH canvas n 8.3 Tk "Tk Built-In Commands"
@@ -1396,20 +1396,29 @@ irrelevant.
.TP
\fB\-smooth \fIsmoothMethod\fR
\fIsmoothMethod\fR must have one of the forms accepted by
-\fBTk_GetBoolean\fR or a line smoothing method. Only \fBbezier\fR is
-supported in the core, but more can be added at runtime. If a boolean
+\fBTk_GetBoolean\fR or a line smoothing method. Only \fBtrue\fR and \fBraw\fR are
+supported in the core (with \fBbezier\fR being an alias for \fBtrue\fR), but more can be added at runtime. If a boolean
false value or empty string is given, no smoothing is applied. A boolean
-truth value assumes \fBbezier\fR smoothing.
-It indicates whether or not the line should be drawn as a curve.
-If so, the line is rendered as a set of parabolic splines: one spline
+truth value assumes \fBtrue\fR smoothing.
+If the smoothing method is \fBtrue\fR, this indicates that the line
+should be drawn as a curve, rendered as a set of quadratic splines: one spline
is drawn for the first and second line segments, one for the second
and third, and so on. Straight-line segments can be generated within
a curve by duplicating the end-points of the desired line segment.
+If the smoothing method is \fBraw\fR, this indicates that the line
+should also be drawn as a curve but where the list of coordinates is
+such that the first coordinate pair (and every third coordinate pair
+thereafter) is a knot point on a cubic Bezier curve, and the other
+coordinates are control points on the cubic Bezier curve. Straight
+line segments can be venerated within a curve by making control points
+equal to their neighbouring knot points. If the last point is a
+control point and not a knot point, the point is repeated (one or two
+times) so that it also becomes a knot point.
.TP
\fB\-splinesteps \fInumber\fR
Specifies the degree of smoothness desired for curves: each spline
will be approximated with \fInumber\fR line segments. This
-option is ignored unless the \fB\-smooth\fR option is true.
+option is ignored unless the \fB\-smooth\fR option is true or \fBraw\fR.
.SH "OVAL ITEMS"
.PP
Items of type \fBoval\fR appear as circular or oval regions on
@@ -1516,17 +1525,30 @@ If this option isn't specified then it defaults to \fBmiter\fR.
.TP
\fB\-smooth \fIboolean\fR
\fIBoolean\fR must have one of the forms accepted by \fBTk_GetBoolean\fR
-It indicates whether or not the polygon should be drawn with a
-curved perimeter.
-If so, the outline of the polygon becomes a set of parabolic splines,
-one spline for the first and second line segments, one for the second
-and third, and so on. Straight-line segments can be generated in a
-smoothed polygon by duplicating the end-points of the desired line segment.
+or a line smoothing method. Only \fBtrue\fR and \fBraw\fR are
+supported in the core (with \fBbezier\fR being an alias for \fBtrue\fR), but more can be added at runtime. If a boolean
+false value or empty string is given, no smoothing is applied. A boolean
+truth value assumes \fBtrue\fR smoothing.
+If the smoothing method is \fBtrue\fR, this indicates that the polygon
+should be drawn as a curve, rendered as a set of quadratic splines: one spline
+is drawn for the first and second line segments, one for the second
+and third, and so on. Straight-line segments can be generated within
+a curve by duplicating the end-points of the desired line segment.
+If the smoothing method is \fBraw\fR, this indicates that the polygon
+should also be drawn as a curve but where the list of coordinates is
+such that the first coordinate pair (and every third coordinate pair
+thereafter) is a knot point on a cubic Bezier curve, and the other
+coordinates are control points on the cubic Bezier curve. Straight
+line segments can be venerated within a curve by making control points
+equal to their neighbouring knot points. If the last point is not the
+second point of a pair of control points, the point is repeated (one or two
+times) so that it also becomes the second point of a pair of control
+points (the associated knot point will be the first control point).
.TP
\fB\-splinesteps \fInumber\fR
Specifies the degree of smoothness desired for curves: each spline
will be approximated with \fInumber\fR line segments. This
-option is ignored unless the \fB\-smooth\fR option is true.
+option is ignored unless the \fB\-smooth\fR option is true or \fBraw\fR.
.PP
Polygon items are different from other items such as rectangles, ovals
and arcs in that interior points are considered to be ``inside'' a