tracingBorders
作者：互联网
边界追踪。。
public static List<Border> tracingBorders(double[][] S0, double[] X, double[] Y, int[][] S1, double undefData) {
List<BorderLine> borderLines = new ArrayList();
int m = S0.length;
int n = S0[0].length;
int i;
int j;
for(i = 0; i < m; ++i) {
for(j = 0; j < n; ++j) {
if (doubleEquals(S0[i][j], undefData)) {
S1[i][j] = 0;
} else {
S1[i][j] = 1;
}
}
}
int l;
int r;
int b;
int t;
int lb;
int rb;
int lt;
int rt;
for(i = 1; i < m - 1; ++i) {
for(j = 1; j < n - 1; ++j) {
if (S1[i][j] == 1) {
l = S1[i][j - 1];
r = S1[i][j + 1];
b = S1[i - 1][j];
t = S1[i + 1][j];
lb = S1[i - 1][j - 1];
rb = S1[i - 1][j + 1];
lt = S1[i + 1][j - 1];
rt = S1[i + 1][j + 1];
if (l > 0 && r > 0 && b > 0 && t > 0 && lb > 0 && rb > 0 && lt > 0 && rt > 0) {
S1[i][j] = 2;
}
if (l + r + b + t + lb + rb + lt + rt <= 2) {
S1[i][j] = 0;
}
}
}
}
boolean isContinue;
do {
isContinue = false;
for(i = 1; i < m - 1; ++i) {
for(j = 1; j < n - 1; ++j) {
if (S1[i][j] == 1) {
l = S1[i][j - 1];
r = S1[i][j + 1];
b = S1[i - 1][j];
t = S1[i + 1][j];
lb = S1[i - 1][j - 1];
rb = S1[i - 1][j + 1];
lt = S1[i + 1][j - 1];
rt = S1[i + 1][j + 1];
if (l == 0 && r == 0 || b == 0 && t == 0) {
S1[i][j] = 0;
isContinue = true;
}
if (lt == 0 && r == 0 && b == 0 || rt == 0 && l == 0 && b == 0 || lb == 0 && r == 0 && t == 0 || rb == 0 && l == 0 && t == 0) {
S1[i][j] = 0;
isContinue = true;
}
}
}
}
} while(isContinue);
for(j = 0; j < n; ++j) {
if (S1[0][j] == 1) {
if (S1[1][j] == 0) {
S1[0][j] = 0;
} else if (j == 0) {
if (S1[0][j + 1] == 0) {
S1[0][j] = 0;
}
} else if (j == n - 1) {
if (S1[0][n - 2] == 0) {
S1[0][j] = 0;
}
} else if (S1[0][j - 1] == 0 && S1[0][j + 1] == 0) {
S1[0][j] = 0;
}
}
if (S1[m - 1][j] == 1) {
if (S1[m - 2][j] == 0) {
S1[m - 1][j] = 0;
} else if (j == 0) {
if (S1[m - 1][j + 1] == 0) {
S1[m - 1][j] = 0;
}
} else if (j == n - 1) {
if (S1[m - 1][n - 2] == 0) {
S1[m - 1][j] = 0;
}
} else if (S1[m - 1][j - 1] == 0 && S1[m - 1][j + 1] == 0) {
S1[m - 1][j] = 0;
}
}
}
for(i = 0; i < m; ++i) {
if (S1[i][0] == 1) {
if (S1[i][1] == 0) {
S1[i][0] = 0;
} else if (i == 0) {
if (S1[i + 1][0] == 0) {
S1[i][0] = 0;
}
} else if (i == m - 1) {
if (S1[m - 2][0] == 0) {
S1[i][0] = 0;
}
} else if (S1[i - 1][0] == 0 && S1[i + 1][0] == 0) {
S1[i][0] = 0;
}
}
if (S1[i][n - 1] == 1) {
if (S1[i][n - 2] == 0) {
S1[i][n - 1] = 0;
} else if (i == 0) {
if (S1[i + 1][n - 1] == 0) {
S1[i][n - 1] = 0;
}
} else if (i == m - 1) {
if (S1[m - 2][n - 1] == 0) {
S1[i][n - 1] = 0;
}
} else if (S1[i - 1][n - 1] == 0 && S1[i + 1][n - 1] == 0) {
S1[i][n - 1] = 0;
}
}
}
int[][] S2 = new int[m + 2][n + 2];
for(i = 0; i < m + 2; ++i) {
for(j = 0; j < n + 2; ++j) {
if (i != 0 && i != m + 1) {
if (j != 0 && j != n + 1) {
S2[i][j] = S1[i - 1][j - 1];
} else {
S2[i][j] = 0;
}
} else {
S2[i][j] = 0;
}
}
}
int[][] UNum = new int[m + 2][n + 2];
for(i = 0; i < m + 2; ++i) {
for(j = 0; j < n + 2; ++j) {
if (S2[i][j] != 1) {
UNum[i][j] = 0;
} else {
l = S2[i][j - 1];
r = S2[i][j + 1];
b = S2[i - 1][j];
t = S2[i + 1][j];
lb = S2[i - 1][j - 1];
rb = S2[i - 1][j + 1];
lt = S2[i + 1][j - 1];
rt = S2[i + 1][j + 1];
if (l != 1 || r != 1 || b != 1 || t != 1 || (lb != 0 || rt != 0) && (rb != 0 || lt != 0)) {
UNum[i][j] = 1;
} else {
UNum[i][j] = 2;
}
}
}
}
int i3 = 0;
int j3 = 0;
PointD aPoint;
for(i = 1; i < m + 1; ++i) {
for(j = 1; j < n + 1; ++j) {
if (S2[i][j] == 1) {
List<PointD> pointList = new ArrayList();
List<IJPoint> ijPList = new ArrayList();
aPoint = new PointD();
aPoint.X = X[j - 1];
aPoint.Y = Y[i - 1];
IJPoint aijPoint = new IJPoint();
aijPoint.I = i - 1;
aijPoint.J = j - 1;
pointList.add(aPoint);
ijPList.add(aijPoint);
int sI = i;
int sJ = j;
int i2 = i;
int j2 = j;
int i1 = i;
int j1 = -1;
do {
int[] ij3 = new int[]{i3, j3};
if (!traceBorder(S2, i1, i2, j1, j2, ij3)) {
break;
}
i3 = ij3[0];
j3 = ij3[1];
i1 = i2;
j1 = j2;
i2 = i3;
j2 = j3;
--UNum[i3][j3];
if (UNum[i3][j3] == 0) {
S2[i3][j3] = 3;
}
aPoint = new PointD();
aPoint.X = X[j3 - 1];
aPoint.Y = Y[i3 - 1];
aijPoint = new IJPoint();
aijPoint.I = i3 - 1;
aijPoint.J = j3 - 1;
pointList.add(aPoint);
ijPList.add(aijPoint);
} while(i3 != sI || j3 != sJ);
--UNum[i][j];
if (UNum[i][j] == 0) {
S2[i][j] = 3;
}
if (pointList.size() > 1) {
BorderLine aBLine = new BorderLine();
aBLine.area = getExtentAndArea(pointList, aBLine.extent);
aBLine.isOutLine = true;
aBLine.isClockwise = true;
aBLine.pointList = pointList;
aBLine.ijPointList = ijPList;
borderLines.add(aBLine);
}
}
}
}
List<Border> borders = new ArrayList();
BorderLine aLine;
BorderLine bLine;
for(i = 1; i < borderLines.size(); ++i) {
aLine = (BorderLine)borderLines.get(i);
for(j = 0; j < i; ++j) {
bLine = (BorderLine)borderLines.get(j);
if (aLine.area > bLine.area) {
borderLines.remove(i);
borderLines.add(j, aLine);
break;
}
}
}
Border aBorder;
ArrayList lineList;
if (borderLines.size() == 1) {
aLine = (BorderLine)borderLines.get(0);
if (!isClockwise(aLine.pointList)) {
Collections.reverse(aLine.pointList);
Collections.reverse(aLine.ijPointList);
}
aLine.isClockwise = true;
lineList = new ArrayList();
lineList.add(aLine);
aBorder = new Border();
aBorder.LineList = lineList;
borders.add(aBorder);
} else {
for(i = 0; i < borderLines.size() && i != borderLines.size(); ++i) {
aLine = (BorderLine)borderLines.get(i);
if (!isClockwise(aLine.pointList)) {
Collections.reverse(aLine.pointList);
Collections.reverse(aLine.ijPointList);
}
aLine.isClockwise = true;
lineList = new ArrayList();
lineList.add(aLine);
for(j = i + 1; j < borderLines.size() && j != borderLines.size(); ++j) {
bLine = (BorderLine)borderLines.get(j);
if (bLine.extent.xMin > aLine.extent.xMin && bLine.extent.xMax < aLine.extent.xMax && bLine.extent.yMin > aLine.extent.yMin && bLine.extent.yMax < aLine.extent.yMax) {
aPoint = (PointD)bLine.pointList.get(0);
if (pointInPolygon(aLine.pointList, aPoint)) {
bLine.isOutLine = false;
if (isClockwise(bLine.pointList)) {
Collections.reverse(bLine.pointList);
Collections.reverse(bLine.ijPointList);
}
bLine.isClockwise = false;
lineList.add(bLine);
borderLines.remove(j);
--j;
}
}
}
aBorder = new Border();
aBorder.LineList = lineList;
borders.add(aBorder);
}
}
return borders;
}
参考：https://blog.csdn.net/weixin_39633134/article/details/116031614
标签：bLine,aLine,int,new,borderLines,tracingBorders,pointList 来源： https://www.cnblogs.com/2008nmj/p/15846004.html