2014/10/15 下午 10:04:34

iphone Programming Glossary: bezierinterpolation

Find a point, a given distance, along a simple cubic bezier curve. (On an iPhone!)

http://stackoverflow.com/questions/4058979/find-a-point-a-given-distance-along-a-simple-cubic-bezier-curve-on-an-iphone

code so I wrote this sample UIView as it's probably the easiest way to get you started. #import MBBezierView.h CGFloat bezierInterpolation CGFloat t CGFloat a CGFloat b CGFloat c CGFloat d CGFloat t2 t t CGFloat t3 t2 t return a a 3 t 3 a a t t 3 b t 6 b b 3.. p3 bezierPath stroke UIColor brownColor setStroke for CGFloat t 0.0 t 1.00001 t 0.05 CGPoint point CGPointMake bezierInterpolation t p1.x p2.x p3.x p4.x bezierInterpolation t p1.y p2.y p3.y p4.y UIBezierPath pointPath UIBezierPath bezierPathWithArcCenter.. setStroke for CGFloat t 0.0 t 1.00001 t 0.05 CGPoint point CGPointMake bezierInterpolation t p1.x p2.x p3.x p4.x bezierInterpolation t p1.y p2.y p3.y p4.y UIBezierPath pointPath UIBezierPath bezierPathWithArcCenter point radius 5 startAngle 0 endAngle 2..

Find the tangent of a point on a cubic bezier curve (on an iPhone)

http://stackoverflow.com/questions/4089443/find-the-tangent-of-a-point-on-a-cubic-bezier-curve-on-an-iphone

complete answer in code which works and runs It draws approxidistant points along the curve and it draws the tangents. bezierInterpolation finds the points and bezierTangent finds the tangents There is also an alternate version of Michal's answer which is more.. finds the tangents There is also an alternate version of Michal's answer which is more explanatory . To repeat bezierInterpolation finds the points. The routine altBezierInterpolation finds exactly the same points using the same math. But it is written.. using the same math. But it is written in a simpler way which is easier to understand. You can use either routine bezierInterpolation or altBezierInterpolation for identical results. In both cases use bezierTangent to find the tangents. Finally at the bottom..