这是我和我的同事想出来的一个解决方案。希望它能帮助其他人。
public class PolygonHelper {
public Polygon makePolygon(List<Rectangle> rectangles){
List<Point> points = calcPoints(rectangles);
return new Polygon(points);
}
private List<Point> calcPoints(List<Rectangle> rectangles) {
List<Point> ret = new ArrayList<>();
List<Float> yCoords = new ArrayList<>(getAllYCoords(rectangles));
yCoords.sort(Comparator.naturalOrder());
float previousLeftCoord = 0;
float previousRightCoord = 0;
for(float yCoord : yCoords) {
System.out.println("Considering yCoords "+ yCoord);
float minimumXLeftCoord = minXLeftCoord(yCoord, rectangles);
float maximumXRightCoord = maxXRightCoord(yCoord, rectangles);
System.out.println("min X: "+minimumXLeftCoord);
System.out.println("max X: "+maximumXRightCoord);
if(yCoord == yCoords.get(0)) {
ret.add(new Point(minimumXLeftCoord, yCoord));
ret.add(new Point(maximumXRightCoord, yCoord));
} else {
if(minimumXLeftCoord!=previousLeftCoord) {
ret.add(0, new Point(previousLeftCoord, yCoord));
ret.add(0, new Point(minimumXLeftCoord, yCoord));
} else {
ret.add(0, new Point(minimumXLeftCoord, yCoord));
}
if(maximumXRightCoord!=previousRightCoord) {
ret.add(new Point(previousRightCoord, yCoord));
ret.add(new Point(maximumXRightCoord, yCoord));
} else {
ret.add(new Point(maximumXRightCoord, yCoord));
}
}
previousLeftCoord = minimumXLeftCoord;
previousRightCoord = maximumXRightCoord;
System.out.println(ret);
}
return ret;
}
private Set<Float> getAllYCoords(List<Rectangle> rectangles) {
List<Float> allBottomYCoords = rectangles.stream().map(rectangle -> rectangle.getBottom().getY()).collect(Collectors.toList());
List<Float> allTopYCoords = rectangles.stream().map(rectangle -> rectangle.getTop().getY()).collect(Collectors.toList());
Set<Float> allCoords = new HashSet<>();
allCoords.addAll(allTopYCoords);
allCoords.addAll(allBottomYCoords);
return allCoords;
}
private float minXLeftCoord(Float y, List<Rectangle> rectangles) {
return rectanglesAtY(y, rectangles).stream().map(rect -> rect.getLeft().getX()).min(Comparator.naturalOrder()).get();
}
private float maxXRightCoord(Float y, List<Rectangle> rectangles) {
return rectanglesAtY(y, rectangles).stream().map(rect -> rect.getRight().getX()).max(Comparator.naturalOrder()).get();
}
private List<Rectangle> rectanglesAtY(Float y, List<Rectangle> rectangles) {
List<Rectangle> rectsAtYExcBottomLines = rectsAtYExcBottomLines(y, rectangles);
if(rectsAtYExcBottomLines.size()>0) {
return rectsAtYExcBottomLines;
} else {
return rectsAtYIncBottomLines(y, rectangles);
}
}
private List<Rectangle> rectsAtYExcBottomLines(Float y, List<Rectangle> rectangles) {
return rectangles.stream()
.filter(rect -> rect.getTop().getY()<=y && rect.getBottom().getY()>y).collect(Collectors.toList());
}
private List<Rectangle> rectsAtYIncBottomLines(Float y, List<Rectangle> rectangles) {
return rectangles.stream()
.filter(rect -> rect.getTop().getY()<=y && rect.getBottom().getY()==y).collect(Collectors.toList());
}
}
Area
将形状组合在一起。假设你正在使用类似java.awt.Rectangle
的东西,那么你可以将其包装在一个Area
中,并将其添加到另一个代表最终状态的Area
中。你也可以查看java.awt.Rectangle
,因为它有许多add
方法。 - MadProgrammer