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add termination callback to DiscreteCurveEvolution
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@micycle1
micycle1 committed Jan 27, 2024
1 parent dea9514 commit bdfc00b
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92 changes: 28 additions & 64 deletions src/main/java/micycle/pgs/PGS_Morphology.java
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@
import micycle.pgs.commons.EllipticFourierDesc;
import micycle.pgs.commons.GaussianLineSmoothing;
import micycle.pgs.commons.ShapeInterpolation;
import micycle.pgs.commons.DiscreteCurveEvolution.DCETerminationCallback;
import processing.core.PConstants;
import processing.core.PShape;
import processing.core.PVector;
Expand Down Expand Up @@ -133,8 +134,8 @@ public static PShape variableBuffer(PShape shape, double startDistance, double e
* @param bufferCallback A callback function that receives the vertex coordinate
* and a double representing tractional distance (0...1)
* of the vertex along the shape's boundary. The function
* may use properties of the vertex, along with its
* position, to determine the buffer width at that point.
* may use properties of the vertex, or its position, to
* determine the buffer width at that point.
* @return A new shape representing the original shape buffered with variable
* widths as specified by the callback function. The width at each
* vertex is calculated independently.
Expand Down Expand Up @@ -250,34 +251,39 @@ public static PShape simplifyTopology(PShape shape, double distanceTolerance) {
/**
* Simplifies a shape via <i>Discrete Curve Evolution</i>.
* <p>
* Discrete curve evolution involves a stepwise elimination of kinks that are
* least relevant to the shape of the polygonal curve. The relevance of kinks is
* intended to reflect their contribution to the overall shape of the polygonal
* curve.
* This algorithm simplifies a shape by iteratively removing kinks from the
* shape, starting with those having the least shape-relevance.
* <p>
* The simplification process terminates according to a user-specified callback
* that decides whether the DCE algorithm should terminate based on the current
* kink (having a candidate vertex), using its coordinates, relevance score, and
* the number of vertices remaining in the simplified geometry. Implementations
* can use this method to provide custom termination logic which may depend on
* various factors, such as a threshold relevance score, a specific number of
* vertices to preserve, or other criteria.
*
* @param shape The input shape to be simplified, which can be a
* polygonal (inclusive of holes) or a lineal
* shape. Note that GROUP shapes are not supported
* by this method.
* @param vertexRemovalFraction The proportion of the least significant kinks or
* vertices to be removed from each ring in the
* shape. This value should be in the range of 0 to
* 1.
* @param shape The input shape to be simplified, which can be a
* polygonal (inclusive of holes) or a lineal shape.
* Note that GROUP shapes are not supported by this
* method.
* @param terminationCallback The callback used to determine when the
* simplification process should terminate.
* {@code true} if the DCE process should terminate;
* {@code false} otherwise.
* @return A new, simplified copy of the input shape, with the least significant
* kinks or vertices removed according to the provided fraction.
* @since 1.3.0
* @since 2.0
* @see PGS_Morphology#simplifyDCE(PShape, int)
*/
public static PShape simplifyDCE(PShape shape, double vertexRemovalFraction) {
vertexRemovalFraction = 1 - vertexRemovalFraction; // since dce class is preserve-based, not remove-based
public static PShape simplifyDCE(PShape shape, DCETerminationCallback terminationCallback) {
Geometry g = fromPShape(shape);
switch (g.getGeometryType()) {
case Geometry.TYPENAME_GEOMETRYCOLLECTION :
case Geometry.TYPENAME_MULTIPOLYGON :
case Geometry.TYPENAME_MULTILINESTRING :
PShape group = new PShape(GROUP);
for (int i = 0; i < g.getNumGeometries(); i++) {
group.addChild(simplifyDCE(toPShape(g.getGeometryN(i)), vertexRemovalFraction));
group.addChild(simplifyDCE(toPShape(g.getGeometryN(i)), terminationCallback));
}
return group;
case Geometry.TYPENAME_LINEARRING :
Expand All @@ -287,8 +293,8 @@ public static PShape simplifyDCE(PShape shape, double vertexRemovalFraction) {
LinearRing[] dceRings = new LinearRing[rings.length];
for (int i = 0; i < rings.length; i++) {
LinearRing ring = rings[i];
DiscreteCurveEvolution dce = new DiscreteCurveEvolution((int) Math.round(vertexRemovalFraction * ring.getNumPoints()));
dceRings[i] = PGS.GEOM_FACTORY.createLinearRing(dce.process(ring));
Coordinate[] dce = DiscreteCurveEvolution.process(ring, terminationCallback);
dceRings[i] = PGS.GEOM_FACTORY.createLinearRing(dce);
}
LinearRing[] holes = null;
if (dceRings.length > 1) {
Expand All @@ -297,56 +303,14 @@ public static PShape simplifyDCE(PShape shape, double vertexRemovalFraction) {
return toPShape(PGS.GEOM_FACTORY.createPolygon(dceRings[0], holes));
case Geometry.TYPENAME_LINESTRING :
LineString l = (LineString) g;
DiscreteCurveEvolution dce = new DiscreteCurveEvolution((int) Math.round(vertexRemovalFraction * l.getNumPoints()));
return toPShape(PGS.GEOM_FACTORY.createLineString(dce.process(l)));
Coordinate[] dce = DiscreteCurveEvolution.process(l, terminationCallback);
return toPShape(PGS.GEOM_FACTORY.createLineString(dce));
default :
System.err.println(g.getGeometryType() + " are not supported for the simplifyDCE() method."); // pointal geoms
return new PShape(); // return empty (so element is invisible if not processed)
}
}

/**
* Simplifies a shape via <i>Discrete Curve Evolution</i>.
* <p>
* Discrete curve evolution involves a stepwise elimination of kinks that are
* least relevant to the shape of the polygonal curve. The relevance of kinks is
* intended to reflect their contribution to the overall shape of the polygonal
* curve.
*
* @param shape a polygonal (can include holes) or lineal shape.
* GROUP shapes are not supported.
* @param targetNumVertices the number of vertices that should remain/be
* preserved in <b>each ring</b> of the input
* @return simplifed copy of the input shape
* @since 1.3.0
* @see #simplifyDCE(PShape, double)
*/
public static PShape simplifyDCE(PShape shape, int targetNumVertices) {
Geometry g = fromPShape(shape);
if (g instanceof Polygon) {
targetNumVertices += 1; // as to not count the closing vertex in the number
LinearRing[] rings = new LinearRingIterator(g).getLinearRings();
LinearRing[] dceRings = new LinearRing[rings.length];
for (int i = 0; i < rings.length; i++) {
LinearRing ring = rings[i];
DiscreteCurveEvolution dce = new DiscreteCurveEvolution(targetNumVertices);
dceRings[i] = PGS.GEOM_FACTORY.createLinearRing(dce.process(ring));
}
LinearRing[] holes = null;
if (dceRings.length > 1) {
holes = Arrays.copyOfRange(dceRings, 1, dceRings.length);
}
return toPShape(PGS.GEOM_FACTORY.createPolygon(dceRings[0], holes));
} else if (g instanceof LineString) {
LineString l = (LineString) g;
DiscreteCurveEvolution dce = new DiscreteCurveEvolution(targetNumVertices);
return toPShape(PGS.GEOM_FACTORY.createLineString(dce.process(l)));
} else {
System.err.println(g.getGeometryType() + " are not supported for the simplifyDCE() method (yet).");
return shape;
}
}

/**
* Creates a <a href="https://github.com/micycle1/Hobby-Curves"><i>Hobby
* Curve</i></a> from the vertices of the shape. This tends to simplify/round
Expand Down
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