An app to create and and edit circle packings in openFrameworks with C++. The app allows for manipulation of a graph which is a triangulation of a closed topological disc and computing its circle packing with given boundary conditions.
There are two modes in computing the packing, the first fixes the labels (radii) of the boundary vertices (circles) while the second fixes the 'angle sums' of the boundary vertices. The angle sum of a vertex is the sum of the angles it make with the center of each mutually adjacent pair of its petals (neighbours), see ([^1]) for more information.
The main algorithm used to compute the circle packing is based on an implementation of a paper by Collins and Stephenson[^1].
[^1] = https://doi.org/10.1016/S0925-7721(02)00099-8
Select a vertex and delete it. If the selected vertex is an interior vertex, fill the void it creates by connecting its petals in a zig-zag fashion. If deleting a vertex leaves a neighbour with only two petals remaining, it is also removed (this might also lead to subsequent deletions).
Select two vertices, with at least one being interior, then they have two mutual petals. This function disconnects the two selected vertices and connects their two mutual petals.
Select two vertices. This function disconnects them and adds a new vertex, this vertex is connected both selected vertices and any mutual petals of the selected vertices.
Select two vertices. These two vertices have two mutual petals (one if they're both boundaries) that makes a face (triangle). This function adds a new vertex connected to the three vertices of the chosen face.
| Input | Description |
|---|---|
| BACKSPACE | Undo graph edit |
| RETURN | Toggle mode |
| T | Toggle theme |
| V | Reset view |
| P | Print graph info to console |
| Input | Description |
|---|---|
| LEFT CLICK | Select first vertex |
| RIGHT CLICK | Select second vertex |
| R | Remove vertex |
| DOWN | Flip edge |
| UP | Replace edge with new vertex |
| LEFT/RIGHT | Add new vertex in a face |
| Input | Description |
|---|---|
| LEFT CLICK | Select vertex |
| UP/DOWN | Increase/decrease boundary angle |
| LEFT/RIGHT | Navigate boundary vertices |
| 0-9 | Set boundary targets to n-gon |
You need to have openFrameworks installed to compile this project. Find setup guides for openFrameworks projects here: https://openframeworks.cc/download/
To compile and run:
make -j6 && make run
or, for console and text output:
make -j6 && make run | tee output.txt
To enable running the program by double-clicking the exe file, copy the required DLLs:
make copy_dlls