The FOLD API consists of several modules under the FOLD namespace:
FOLD.viewer: Visualize FOLD format in browser in SVGFOLD.filter: Select existing parts of, or compute new features of,
a given FOLD object.FOLD.convert: Augment an existing FOLD object with additional fields,
and convert between FOLD and other file formats.FOLD.file: Load/save/convert files on file system (Node only, not browser)FOLD.geom: Basic geometry tools (manipulation of vectors, angles,
lines, segments, etc.). Basically whatever we needed to implement other
features, but which you might find helpful too.See source code for details.
These operations all modify a FOLD object in-place. See source code for details.
FOLD.filter.subdivideCrossingEdges_vertices(fold, epsilon):
Given a FOLD object with 2D vertices_coords and edges_vertices,
subdivides all crossing/touching edges to form a planar graph.
All duplicate and loop edges are also removed.FOLD.filter.maybeAddVertex(fold, coords, epsilon):
Given a FOLD object with vertices_coords, adds a new vertex with
coordinates coords and returns its (last) index, unless there is already
such a vertex within distance epsilon, in which case return the closest
such vertex’s index. The new vertex has no new properties except
vertex_coords.FOLD.filter.addVertexAndSubdivide(fold, coords, epsilon):
Given a FOLD object with 2D vertices_coords and edges_vertices,
maybe adds a new vertex like FOLD.filter.maybeAddVertex, and then
subdivides if necessary (via an efficient use of
FOLD.filter.subdivideCrossingEdges_vertices).FOLD.filter.addVertexLike(fold, oldVertexIndex):
Given a FOLD object, adds a new vertex and copy all vertex_... attributes
to be like the existing vertex oldVertexIndex.
Returns the new vertex index.FOLD.filter.addEdgeLike(fold, oldEdgeIndex, [v1, v2]):
Given a FOLD object with edges_vertices, adds a new edge connecting
vertices v1 and v2, and copy all other edges_... attributes to be like
the existing edge oldEdgeIndex. Returns the new edge index.
If v1 and/or v2 are unspecified, the new edge inherits the same vertex
connections as the old edge.FOLD.filter.addEdgeAndSubdivide(fold, v1, v2, epsilon):
Given a FOLD object with 2D vertices_coords and edges_vertices,
adds an edge between vertex indices or points v1 and v2
(calling FOLD.filter.addVertexAndSubdivide when they are points),
subdividing if necessary (via an efficient use of
FOLD.filter.subdivideCrossingEdges_vertices).
Returns two arrays: one with the indices of all the subdivided parts of the
added edge, and the other with the indices of all other changed edges.
The new edge(s) have no properties except edges_vertices, so the first
array tells you which edges to set the properties of.
If the edge is a loop, the returned arrays are empty.
If the edge is a duplicate, the first array has the old edge index and the
second array is empty.FOLD.filter.splitCuts(fold, [es]):
Given a FOLD object with edges_vertices, edges_assignment, and
counterclockwise-sorted vertices_edges
(see FOLD.convert.edges_vertices_to_vertices_edges_sorted),
cuts apart (“unwelds”) all edges in es into pairs of boundary edges.
When an endpoint of a cut edge ends up on n boundaries,
it splits into n vertices.
Preserves above-mentioned properties (so you can then compute faces via
FOLD.convert.edges_vertices_to_faces_vertices_edges),
and recomputes vertices_vertices if present,
but ignores face properties.
If es is unspecified, cuts all edges with an assignment of "C",
effectively switching from FOLD 1.2’s "C" assignments to
FOLD 1.1’s "B" assignments.FOLD.filter.transform(fold, matrix):
Transforms a FOLD object by a given transformation matrix (generated by
FOLD.geom.matrix...), in particular transforming vertices_coords
(and any fields ending in _coords) and faces_flatFoldTransform
(and any fields ending in FoldTransform).See source code for details.
FOLD.convert.edges_vertices_to_vertices_vertices_unsorted(fold):
Given a FOLD object with edges_vertices property (defining edge
endpoints), automatically computes the vertices_vertices property.
However, note that the vertices_vertices arrays will not be sorted
in counterclockwise order.FOLD.convert.edges_vertices_to_vertices_edges_unsorted(fold):
Given a FOLD object with edges_vertices property (defining edge
endpoints), automatically computes the inverse vertices_edges property.
However, note that the vertices_edges arrays will not be sorted
in counterclockwise order.FOLD.convert.edges_vertices_to_vertices_vertices_sorted(fold):
Given a FOLD object with 2D vertices_coords and edges_vertices property
(defining edge endpoints), automatically computes the vertices_vertices
property and sorts them counterclockwise by angle in the plane.FOLD.convert.edges_vertices_to_vertices_edges_sorted(fold):
Given a FOLD object with 2D vertices_coords and edges_vertices property
(defining edge endpoints), automatically computes the vertices_edges
and vertices_vertices property and sorts them counterclockwise by angle
in the plane.FOLD.convert.sort_vertices_vertices(fold):
Given a FOLD object with 2D vertices_coords and vertices_vertices
properties, sorts each vertices_vertices array in counterclockwise
order around the vertex in the plane.FOLD.convert.vertices_vertices_to_faces_vertices(fold):
Given a FOLD object with counterclockwise-sorted vertices_vertices
property, constructs the implicitly defined faces, setting faces_vertices
property.FOLD.convert.vertices_edges_to_faces_vertices_edges(fold):
Given a FOLD object with counterclockwise-sorted vertices_edges property,
constructs the implicitly defined faces, setting both faces_vertices
and faces_edges properties. Handles multiple edges to the same vertex
(unlike FOLD.convert.vertices_vertices_to_faces_vertices).FOLD.convert.edges_vertices_to_faces_vertices(fold):
Given a FOLD object with 2D vertices_coords and edges_vertices,
computes a counterclockwise-sorted vertices_vertices property and
constructs the implicitly defined faces, setting faces_vertices property.FOLD.convert.edges_vertices_to_faces_vertices_edges(fold):
Given a FOLD object with 2D vertices_coords and edges_vertices,
computes counterclockwise-sorted vertices_vertices and vertices_edges
properties and constructs the implicitly defined faces, setting
both faces_vertices and faces_edges property.FOLD.convert.vertices_vertices_to_vertices_edges(fold):
Given a FOLD object with vertices_vertices and edges_vertices,
fills in the corresponding vertices_edges property (preserving order).FOLD.convert.faces_vertices_to_faces_edges(fold):
Given a FOLD object with faces_vertices and edges_vertices,
fills in the corresponding faces_edges property (preserving order).FOLD.convert.faces_vertices_to_edges(fold):
Given a FOLD object with just faces_vertices, automatically fills in
edges_vertices, edges_faces, faces_edges, and edges_assignment.Basic fold/JSON conversion:
FOLD.convert.toJSON(fold):
Given a FOLD object, convert into a nicely formatted JSON string.FOLD.convert.deepCopy(fold):
Given a FOLD object, make a copy that shares no pointers with the original.File format conversion (supported formats are "fold" and "opx"):
FOLD.convert.convertFromTo(data, fromFormat, toFormat): Convert the
specified data from one format to another.FOLD.convert.convertFrom(data, fromFormat): Convert the specified data
from one format to FOLD.FOLD.convert.convertTo(data, toFormat): Convert the specified data
from FOLD to another format.FOLD.convert.oripa submodule implements the conversion between FOLD and
ORIPA .opx format. See
source code
for details.See source code for details.
The following functions are available in Node only, not in the browser (where filenames don’t really make sense).
FOLD.file.toFile(fold, filename): Save FOLD object to specified
filename, which can end in a supported extension (.fold or .opx).FOLD.file.fileToFile(inFilename, outFilename): Convert one filename
to another, using extensions to determine format.
Alternatively, outFilename can be just an extension, in which case
it will be combined with inFilename to form a full filename.See source code for details.
See source code for details.