Edge identity #240
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Edge identity #240
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added 30 commits
March 30, 2022 23:45
# Conflicts: # src/properties/splineproperty.cpp # src/properties/splineproperty.h # src/serializers/abstractserializer.h # src/serializers/jsonserializer.cpp # src/serializers/jsonserializer.h
That requires some re-implementation of QPainterPath features, like `constains`. The usage of `QPainterPath::operator-` has been replaced by `Face::operator^` because it's easier to implement and gives the same result if one path contains the other.
# Conflicts: # src/path/face.cpp # src/path/face.h # src/properties/CMakeLists.txt # src/properties/splineproperty.cpp # src/propertytypeenum.h # src/renderers/offscreenrenderer.cpp # src/variant.h
improves error messages if it's used in the wrong way.
don't expect options parameter, options are the same for all tests.
Face operator^ is principally impossible to implement because edges don't have an identity (there might be multiple indistinguishable edges between two points). Therefore, PathVector::faces is simpler now. It's still not correct, but the (now removed) complicated implementation (employing operator^) wouldn't make it better. Simple and wrong is better than complicated and wrong. Fixing it properly probably requires a complete change of paradigms (i.e., identifiable edges)
added 29 commits
November 1, 2022 18:47
There is no straight forward way to compute similarity of two points wrt. their normals because points can have arbitrary number of tangents.
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Until now, edges did not have an identity but were defined to be the connection between two unique points (instances of
PathPoint).There was a class
Edge, but it was merely a descriptor of a connection of two points that could be copied around.Such an edge descriptor is unique because
PathPoints are unique perPathand because there could only be oneEdgebetween twoPathPoints within aPath.Things become tricky when introducing joined points (without which faces would be impossible).
When
PathPoints are joined, they act as the same point, i.e., they not only coincidentally have the same position, also their selection is synchronized and they are not distinguished by certain algorithms.In this graph, the points
0,2and3are joined and1and5are joined.Hence the graph exhibits two faces:
0--1--2and3--4--5--3.Note that the blue face only exists if the blue path is closed, i.e., if considering the joined points
0and2"the same".This is okay in the first place.
After all, joined points were introduced to close paths.
However, if we consider
0and2the same, then we cannot distinguish the two edges of the blue face anymore.We might apply some tricks considering direction, which becomes very cumbersome quickly.
This PR proposes a fundamentally different approach:
A
Pathdoes not own a sequence ofPathPoints but a sequence ofEdges.Those edges are not descriptors but they carry an identity.
Edges share ownership of twoPathPoints.That is, a
PathPointcan be owned by more than oneEdge, which makes the concept of joined points superfluous (implementing joined points makes a lot of noise in many places).Roadmap:
Edge, changePathand related classesPathPoints now).Ellipse,Rectangle, etc. toPathObject