Find the tangent of a point on a cubic bezier curve

by

The tangent of a curve is simply its derivative. The parametric equation that Michal uses:

P(t) = (1 - t)^3 * P0 + 3t(1-t)^2 * P1 + 3t^2 (1-t) * P2 + t^3 * P3

should have a derivative of 

dP(t) / dt =  -3(1-t)^2 * P0 + 3(1-t)^2 * P1 - 6t(1-t) * P1 - 3t^2 * P2 + 6t(1-t) * P2 + 3t^2 * P3

Which, by the way, appears to be wrong in your earlier question. I believe you’re using the slope for a quadratic Bezier curve there, not cubic.

From there, it should be trivial to implement a C function that performs this calculation, like Michal has already provided for the curve itself.

More Related Contents:

  1. Cant seem to get past this line of code [duplicate]
  2. How to input currency format on a text field (from right to left) using Swift?
  3. libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)
  4. How to scroll List programmatically in SwiftUI?
  5. How to use Facebook iOS SDK on iOS 10
  6. How can I convert from degrees to radians?
  7. When and why should you use NSUserDefaults’s synchronize() method?
  8. Method ‘application:openURL:options:’ is not called
  9. FCM background notifications not working in iOS
  10. Unique values of array in swift [duplicate]
  11. How to calculate UILabel width based on text length?
  12. In Swift, Array [String] slicing return type doesn’t seem to be [String]
  13. How to find file UTI for file, withouth pathExtension, in a path in Swift
  14. iOS UINavigationBar button remains faded after segue back
  15. How to throttle search (based on typing speed) in iOS UISearchBar?
  16. How do you update a CoreData entry that has already been saved in Swift?
  17. UICollectionView header dynamic height using Auto Layout
  18. Code sign error : bundle format unrecognized, invalid, or unsuitable
  19. Does Swift support implicit conversion?
  20. Swift doesn’t convert Objective-C NSError** to throws
  21. Trouble running async functions in background threads (concurrency)
  22. performSegueWithIdentifier very slow when segue is modal
  23. Return value from completion handler – Swift
  24. Xcode Version 6.1 (6A1030) – Apple Mach O-Linker Error – Building
  25. Swift: Testing optionals for nil
  26. How to remove special characters from string in Swift 2?
  27. Disable zoom in WKWebView?
  28. Swift – How to record video in MP4 format with UIImagePickerController?
  29. What’s the state of developing iOS apps in Linux? [closed]
  30. Xcode 7 Swift 2 impossible to instantiate UIViewController subclass of generic UITableViewController

Leave a Comment