Mac OS X
Components Crossplatform Mac & Win Server Client Old Guides Examples
New in version: 7.0 7.1 7.2 7.3 7.4 7.5 8.0 8.1 8.2 8.3 Statistic
Draws a bezier path.
|Component||Version||macOS||Windows||Server||FileMaker Cloud||FileMaker iOS SDK|
|The PDF reference returned from DynaPDF.New.|
|x1||X-Coordinate of the first control point P1||$x1|
|y1||Y-Coordinate of the first control point P1||$y1|
|x2||X-Coordinate of the second control point P2||$x2|
|y2||Y-Coordinate of the second control point P2||$y2|
|x3||X-Coordinate of the end point P3||$x3|
|y3||Y-Coordinate of the end point P3||$y3|
Returns OK or error.
DescriptionDraws a bezier path.
Curved path segments are specified as cubic Bézier curves. Such curves are defined by four points: the two endpoints (the current point P0 and the final point P3) and two control points P1 and P2. Given the coordinates of the four points, the curve is generated by varying the parameter t from 0.0 to 1.0 in the following equation:
R(t)=(1-t)3P0 +3t(1-t)2P1+3t2(1-t)P2 +t3P3
When t = 0.0, the value of the function R(t) coincides with the current point P0; when t = 1.0, R(t) coincides with the final point P3. Intermediate values of t generate intermediate points along the curve. The curve does not, in general, pass through the two control points P1 and P2. Cubic Bézier curves have two desirable properties:
- The curve can be very quickly split into smaller pieces for rapid rendering.
- The curve is contained within the convex hull of the four points defining the curve, most easily visualized as the polygon obtained by stretching a rubber band around the outside of the four points. This property allows rapid testing of whether the curve lies completely outside the visible region, and hence does not have to be rendered.
As mentioned earlier the function requires a start point that must be set with DynaPDF.MoveTo or another painting operator beforehand. Once the start point was set, multiple curve segments can be drawn to build circles, ellipses or other curved paths. The DynaPDF functions DynaPDF.DrawArc, DynaPDF.DrawCircle, DynaPDF.Ellipse and so on use all DynaPDF.Bezier123 to construct the path.
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