PPW Curves

An example implementation for PPW Curves: A C^2 Interpolating Spline with Hyperbolic Blending of Rational Bézier Curves.

Requirements

• Unity 2021.3.3f1
  • It should work with some older/newer versions

Quick start

1. Clone this repository
2. Open the scene Assets/Scenes/Drawer.unity with Unity Editor
3. Play it and click the Game view to put control points

Control guide

Mouse/Keyboard inputs

In the following grid, the "@" and "/" represent "click a control point (CP)" and "click a path" respectively.

Control	Action
Esc	Open/Close help
Right Click and Drag	Move canvas
Wheel	Zoom in/out
Left Click	Create paths
Left DoubleClick	End path creation
Ctrl + @	Move CP
Ctrl + /	Add CP
Shift + @	Weight CP
Shift + /	Weight segment
Alt + @	Delete CP
Alt + /	Delete segment
Ctrl + Alt + @	Sharpen CP
Ctrl + Shift + @	Connect CP
Ctrl + Shift + /	Duplicate path
Shift + Alt + @,/	Move path
Ctrl + Shift + Alt + @,/	Delete path
Ctrl + Q	Quit app
F1	Export SVG
F2	Screenshot (Assets/Results/SS/...)
F3	FullScreen (standalone-only)
Shift + Z/Y	Undo/Redo (experimental, editor-only)
Ctrl + Z/Y	Undo/Redo (experimental, standalone-only)
0~9	Input preset shapes

GUI inputs

UI	Action
Input field and Save/Load buttons	Save/Load current paths as a json file to Assets/Results/JSON/<input>.json
Curvature Solver	This is for rational κ-Curves, so don't take care
Show Control points	Show/hide control points on paths
Show Control polygon	Show/hide control polygons (the paths before being blended)
Show Weight	Show/hide weight value of each control point
Show Curvature	Show/hide curvature-indicator for paths Zooming in/out canvas can redraw them

For code readers

The core implementation of PPW Curves is Assets/Plugins/RUtil/Scripts/Runtime/Curve/PPWCurve.cs. The drawer Assets/Scripts/PathDrawer/PPWCurveDrawer.cs constructs and inputs curve data into PPWCurve.CalcAll. Calculation results will be stored in the input PPWCurve.CurveData instance as Plots.