diff options
Diffstat (limited to 'doc/canvas.n')
| -rw-r--r-- | doc/canvas.n | 50 |
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 |