Mercurial > dive4elements > gnv-client
view gnv-artifacts/src/main/java/de/intevation/gnv/raster/Vectorizer.java @ 518:464e03bf786b
Try to cull points from set of input points when generating "Profilschnitte".
gnv-artifacts/trunk@612 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
---|---|
date | Sat, 23 Jan 2010 18:10:34 +0000 |
parents | 92b7ccbf6163 |
children | 9a828e5a2390 |
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package de.intevation.gnv.raster; import java.util.BitSet; import java.util.List; import java.util.ArrayList; import gnu.trove.TIntStack; import gnu.trove.TIntObjectHashMap; import org.apache.log4j.Logger; /** * @author Sascha L. Teichmann (sascha.teichmann@intevation.de) */ public class Vectorizer { private static Logger log = Logger.getLogger(Vectorizer.class); public interface RingsHandler { void handleRings( List<Edge> rings, int value, int width, int height); } // interface RingsHandler public static final class Edge { public Edge prev; public Edge next; public int a; public int b; public Edge() { } public Edge(int a, int b) { this.a = a; this.b = b; } public Edge(Edge other) { a = other.a; b = other.b; } public void chain(Edge other, int found) { if (found == a) { other.next = this; prev = other; return; } if (found == b) { next = other; other.prev = this; return; } throw new IllegalStateException("cannot chain"); } public boolean isComplete() { Edge current = this; do { if (current.prev == null || current.next == null) { return false; } current = current.next; } while (current != this); return true; } public int length() { int length = 0; Edge current = this; do { ++length; } while ((current = current.next) != null && current != this); return length; } public Edge head() { Edge current = this; while (current.prev != null) { current = current.prev; } return current; } public int hashCode() { return (a << 16) | b; } public boolean equals(Object other) { Edge e = (Edge)other; return a == e.a && b == e.b; } } // class Edge protected static Edge simplify(Edge edge, int width) { Edge e1 = edge, start = edge; int length = edge.length(); if (length < 2) { return e1; } Edge e2 = edge.next; int count = 0; do { int e1x = e1.a % width; int e1y = e1.a / width; int e2x = e1.b % width; int e2y = e1.b / width; int e3x = e2.b % width; int e3y = e2.b / width; if ((e1x == e2x && e2x == e3x && e1x == e3x) || (e1y == e2y && e2y == e3y && e1y == e3y)) { e1.b = e2.b; Edge removed = e1.next; e1.next = e2.next; if (e1.next != null) { e1.next.prev = e1; } e2 = e1.next; count = 0; --length; if (removed == start) { start = e1; } } else { e1 = e1.next; e2 = e2.next; ++count; } } while (length > 1 && e2 != null && count < length + 2); return start; } protected int [] raster; protected int width; protected TIntObjectHashMap openEdges; protected List<Edge> rings; protected boolean simplify; public Vectorizer() { this(true); } public Vectorizer(boolean simplify) { openEdges = new TIntObjectHashMap(); rings = new ArrayList<Edge>(); this.simplify = simplify; } public Vectorizer(int [] raster, int width) { this(true, raster, width); } public Vectorizer(boolean simplify, int [] raster, int width) { this(simplify); this.raster = raster; this.width = width; } public static final int tl(int i, int w) { int x = i % w; int y = i / w; return x + (w + 1)*y; } public static final int tr(int i, int w) { return tl(i, w) + 1; } public static final int bl(int i, int w) { return tl(i, w) + w + 1; } public static final int br(int i, int w) { return bl(i, w) + 1; } protected void resetRegion() { openEdges.clear(); rings.clear(); } protected void emit(Edge edge) { Edge otherA = (Edge)openEdges.remove(edge.a); if (otherA != null) { otherA.chain(edge, edge.a); } Edge otherB = (Edge)openEdges.remove(edge.b); if (otherB != null) { otherB.chain(edge, edge.b); } if (edge.isComplete()) { rings.add(simplify ? simplify(edge, width + 1) : edge); } else { if (otherA == null) { openEdges.put(edge.a, edge); } if (otherB == null) { openEdges.put(edge.b, edge); } } } public int process(RingsHandler handler) { BitSet visited = new BitSet(raster.length); TIntStack stack = new TIntStack(); int regions = 0; int height = raster.length / width; for (int i = 0; i < raster.length; ++i) { if (visited.get(i)) { continue; } ++regions; int currentValue = raster[i]; visited.set(i); int current = i; visited.set(current); for (;;) { int tl = tl(current, width); int tr = tr(current, width); int bl = bl(current, width); int br = br(current, width); int t = current - width; if (t < 0) { emit(new Edge(tr, tl)); } else { if (raster[t] != currentValue) { emit(new Edge(tr, tl)); } else { if (!visited.get(t)) { visited.set(t); stack.push(t); } } } int b = current + width; if (b >= raster.length) { emit(new Edge(bl, br)); } else { if (raster[b] != currentValue) { emit(new Edge(bl, br)); } else { if (!visited.get(b)) { visited.set(b); stack.push(b); } } } int x = current % width; if (x == 0) { emit(new Edge(tl, bl)); } else { int l = current - 1; if (raster[l] != currentValue) { emit(new Edge(tl, bl)); } else { if (!visited.get(l)) { visited.set(l); stack.push(l); } } } if (x == width - 1) { emit(new Edge(br, tr)); } else { int r = current + 1; if (raster[r] != currentValue) { emit(new Edge(br, tr)); } else { if (!visited.get(r)) { visited.set(r); stack.push(r); } } } if (stack.size() == 0) { break; } current = stack.pop(); } handler.handleRings( rings, currentValue, width + 1, height + 1); resetRegion(); } return regions; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: