diff options
author | Sven Gothel <[email protected]> | 2011-04-01 06:56:02 +0200 |
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committer | Sven Gothel <[email protected]> | 2011-04-01 06:56:02 +0200 |
commit | 7ff7e5dd2c4f863fd6fca4f79ab544275fdd424e (patch) | |
tree | 52cd37b0d7e4e94e083f543d5f8dc8b1cb8bb9c7 /turtle2d/src/jogamp/graph/math/plane/Crossing.java | |
parent | ecab143a041af5aa9cdd3972a980d628f540fe93 (diff) | |
parent | 4b8bd5ec58cb2edfb51bd9ee930beb9c539a8a0b (diff) |
Merge turtle2d in it's subdifrectory for later relocation
Diffstat (limited to 'turtle2d/src/jogamp/graph/math/plane/Crossing.java')
-rw-r--r-- | turtle2d/src/jogamp/graph/math/plane/Crossing.java | 897 |
1 files changed, 897 insertions, 0 deletions
diff --git a/turtle2d/src/jogamp/graph/math/plane/Crossing.java b/turtle2d/src/jogamp/graph/math/plane/Crossing.java new file mode 100644 index 000000000..8f8638632 --- /dev/null +++ b/turtle2d/src/jogamp/graph/math/plane/Crossing.java @@ -0,0 +1,897 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/** + * @author Denis M. Kishenko + */ +package jogamp.graph.math.plane; + +import jogamp.graph.geom.plane.Path2D; +import jogamp.graph.geom.plane.PathIterator; +import jogamp.graph.math.MathFloat; + + +public class Crossing { + + /** + * Allowable tolerance for bounds comparison + */ + static final float DELTA = (float) 1E-5; + + /** + * If roots have distance less then <code>ROOT_DELTA</code> they are double + */ + static final float ROOT_DELTA = (float) 1E-10; + + /** + * Rectangle cross segment + */ + public static final int CROSSING = 255; + + /** + * Unknown crossing result + */ + static final int UNKNOWN = 254; + + /** + * Solves quadratic equation + * @param eqn - the coefficients of the equation + * @param res - the roots of the equation + * @return a number of roots + */ + public static int solveQuad(float eqn[], float res[]) { + float a = eqn[2]; + float b = eqn[1]; + float c = eqn[0]; + int rc = 0; + if (a == 0.0) { + if (b == 0.0) { + return -1; + } + res[rc++] = -c / b; + } else { + float d = b * b - 4.0f * a * c; + // d < 0.0 + if (d < 0.0) { + return 0; + } + d = MathFloat.sqrt(d); + res[rc++] = (- b + d) / (a * 2.0f); + // d != 0.0 + if (d != 0.0) { + res[rc++] = (- b - d) / (a * 2.0f); + } + } + return fixRoots(res, rc); + } + + /** + * Solves cubic equation + * @param eqn - the coefficients of the equation + * @param res - the roots of the equation + * @return a number of roots + */ + public static int solveCubic(float eqn[], float res[]) { + float d = eqn[3]; + if (d == 0) { + return solveQuad(eqn, res); + } + float a = eqn[2] / d; + float b = eqn[1] / d; + float c = eqn[0] / d; + int rc = 0; + + float Q = (a * a - 3.0f * b) / 9.0f; + float R = (2.0f * a * a * a - 9.0f * a * b + 27.0f * c) / 54.0f; + float Q3 = Q * Q * Q; + float R2 = R * R; + float n = - a / 3.0f; + + if (R2 < Q3) { + float t = MathFloat.acos(R / MathFloat.sqrt(Q3)) / 3.0f; + float p = 2.0f * MathFloat.PI / 3.0f; + float m = -2.0f * MathFloat.sqrt(Q); + res[rc++] = m * MathFloat.cos(t) + n; + res[rc++] = m * MathFloat.cos(t + p) + n; + res[rc++] = m * MathFloat.cos(t - p) + n; + } else { +// Debug.println("R2 >= Q3 (" + R2 + "/" + Q3 + ")"); + float A = MathFloat.pow(MathFloat.abs(R) + MathFloat.sqrt(R2 - Q3), 1.0f / 3.0f); + if (R > 0.0) { + A = -A; + } +// if (A == 0.0) { + if (-ROOT_DELTA < A && A < ROOT_DELTA) { + res[rc++] = n; + } else { + float B = Q / A; + res[rc++] = A + B + n; +// if (R2 == Q3) { + float delta = R2 - Q3; + if (-ROOT_DELTA < delta && delta < ROOT_DELTA) { + res[rc++] = - (A + B) / 2.0f + n; + } + } + + } + return fixRoots(res, rc); + } + + /** + * Excludes float roots. Roots are float if they lies enough close with each other. + * @param res - the roots + * @param rc - the roots count + * @return new roots count + */ + static int fixRoots(float res[], int rc) { + int tc = 0; + for(int i = 0; i < rc; i++) { + out: { + for(int j = i + 1; j < rc; j++) { + if (isZero(res[i] - res[j])) { + break out; + } + } + res[tc++] = res[i]; + } + } + return tc; + } + + /** + * QuadCurve class provides basic functionality to find curve crossing and calculating bounds + */ + public static class QuadCurve { + + float ax, ay, bx, by; + float Ax, Ay, Bx, By; + + public QuadCurve(float x1, float y1, float cx, float cy, float x2, float y2) { + ax = x2 - x1; + ay = y2 - y1; + bx = cx - x1; + by = cy - y1; + + Bx = bx + bx; // Bx = 2.0 * bx + Ax = ax - Bx; // Ax = ax - 2.0 * bx + + By = by + by; // By = 2.0 * by + Ay = ay - By; // Ay = ay - 2.0 * by + } + + int cross(float res[], int rc, float py1, float py2) { + int cross = 0; + + for (int i = 0; i < rc; i++) { + float t = res[i]; + + // CURVE-OUTSIDE + if (t < -DELTA || t > 1 + DELTA) { + continue; + } + // CURVE-START + if (t < DELTA) { + if (py1 < 0.0 && (bx != 0.0 ? bx : ax - bx) < 0.0) { + cross--; + } + continue; + } + // CURVE-END + if (t > 1 - DELTA) { + if (py1 < ay && (ax != bx ? ax - bx : bx) > 0.0) { + cross++; + } + continue; + } + // CURVE-INSIDE + float ry = t * (t * Ay + By); + // ry = t * t * Ay + t * By + if (ry > py2) { + float rxt = t * Ax + bx; + // rxt = 2.0 * t * Ax + Bx = 2.0 * t * Ax + 2.0 * bx + if (rxt > -DELTA && rxt < DELTA) { + continue; + } + cross += rxt > 0.0 ? 1 : -1; + } + } // for + + return cross; + } + + int solvePoint(float res[], float px) { + float eqn[] = {-px, Bx, Ax}; + return solveQuad(eqn, res); + } + + int solveExtrem(float res[]) { + int rc = 0; + if (Ax != 0.0) { + res[rc++] = - Bx / (Ax + Ax); + } + if (Ay != 0.0) { + res[rc++] = - By / (Ay + Ay); + } + return rc; + } + + int addBound(float bound[], int bc, float res[], int rc, float minX, float maxX, boolean changeId, int id) { + for(int i = 0; i < rc; i++) { + float t = res[i]; + if (t > -DELTA && t < 1 + DELTA) { + float rx = t * (t * Ax + Bx); + if (minX <= rx && rx <= maxX) { + bound[bc++] = t; + bound[bc++] = rx; + bound[bc++] = t * (t * Ay + By); + bound[bc++] = id; + if (changeId) { + id++; + } + } + } + } + return bc; + } + + } + + /** + * CubicCurve class provides basic functionality to find curve crossing and calculating bounds + */ + public static class CubicCurve { + + float ax, ay, bx, by, cx, cy; + float Ax, Ay, Bx, By, Cx, Cy; + float Ax3, Bx2; + + public CubicCurve(float x1, float y1, float cx1, float cy1, float cx2, float cy2, float x2, float y2) { + ax = x2 - x1; + ay = y2 - y1; + bx = cx1 - x1; + by = cy1 - y1; + cx = cx2 - x1; + cy = cy2 - y1; + + Cx = bx + bx + bx; // Cx = 3.0 * bx + Bx = cx + cx + cx - Cx - Cx; // Bx = 3.0 * cx - 6.0 * bx + Ax = ax - Bx - Cx; // Ax = ax - 3.0 * cx + 3.0 * bx + + Cy = by + by + by; // Cy = 3.0 * by + By = cy + cy + cy - Cy - Cy; // By = 3.0 * cy - 6.0 * by + Ay = ay - By - Cy; // Ay = ay - 3.0 * cy + 3.0 * by + + Ax3 = Ax + Ax + Ax; + Bx2 = Bx + Bx; + } + + int cross(float res[], int rc, float py1, float py2) { + int cross = 0; + for (int i = 0; i < rc; i++) { + float t = res[i]; + + // CURVE-OUTSIDE + if (t < -DELTA || t > 1 + DELTA) { + continue; + } + // CURVE-START + if (t < DELTA) { + if (py1 < 0.0 && (bx != 0.0 ? bx : (cx != bx ? cx - bx : ax - cx)) < 0.0) { + cross--; + } + continue; + } + // CURVE-END + if (t > 1 - DELTA) { + if (py1 < ay && (ax != cx ? ax - cx : (cx != bx ? cx - bx : bx)) > 0.0) { + cross++; + } + continue; + } + // CURVE-INSIDE + float ry = t * (t * (t * Ay + By) + Cy); + // ry = t * t * t * Ay + t * t * By + t * Cy + if (ry > py2) { + float rxt = t * (t * Ax3 + Bx2) + Cx; + // rxt = 3.0 * t * t * Ax + 2.0 * t * Bx + Cx + if (rxt > -DELTA && rxt < DELTA) { + rxt = t * (Ax3 + Ax3) + Bx2; + // rxt = 6.0 * t * Ax + 2.0 * Bx + if (rxt < -DELTA || rxt > DELTA) { + // Inflection point + continue; + } + rxt = ax; + } + cross += rxt > 0.0 ? 1 : -1; + } + } //for + + return cross; + } + + int solvePoint(float res[], float px) { + float eqn[] = {-px, Cx, Bx, Ax}; + return solveCubic(eqn, res); + } + + int solveExtremX(float res[]) { + float eqn[] = {Cx, Bx2, Ax3}; + return solveQuad(eqn, res); + } + + int solveExtremY(float res[]) { + float eqn[] = {Cy, By + By, Ay + Ay + Ay}; + return solveQuad(eqn, res); + } + + int addBound(float bound[], int bc, float res[], int rc, float minX, float maxX, boolean changeId, int id) { + for(int i = 0; i < rc; i++) { + float t = res[i]; + if (t > -DELTA && t < 1 + DELTA) { + float rx = t * (t * (t * Ax + Bx) + Cx); + if (minX <= rx && rx <= maxX) { + bound[bc++] = t; + bound[bc++] = rx; + bound[bc++] = t * (t * (t * Ay + By) + Cy); + bound[bc++] = id; + if (changeId) { + id++; + } + } + } + } + return bc; + } + + } + + /** + * Returns how many times ray from point (x,y) cross line. + */ + public static int crossLine(float x1, float y1, float x2, float y2, float x, float y) { + + // LEFT/RIGHT/UP/EMPTY + if ((x < x1 && x < x2) || + (x > x1 && x > x2) || + (y > y1 && y > y2) || + (x1 == x2)) + { + return 0; + } + + // DOWN + if (y < y1 && y < y2) { + } else { + // INSIDE + if ((y2 - y1) * (x - x1) / (x2 - x1) <= y - y1) { + // INSIDE-UP + return 0; + } + } + + // START + if (x == x1) { + return x1 < x2 ? 0 : -1; + } + + // END + if (x == x2) { + return x1 < x2 ? 1 : 0; + } + + // INSIDE-DOWN + return x1 < x2 ? 1 : -1; + } + + /** + * Returns how many times ray from point (x,y) cross quard curve + */ + public static int crossQuad(float x1, float y1, float cx, float cy, float x2, float y2, float x, float y) { + + // LEFT/RIGHT/UP/EMPTY + if ((x < x1 && x < cx && x < x2) || + (x > x1 && x > cx && x > x2) || + (y > y1 && y > cy && y > y2) || + (x1 == cx && cx == x2)) + { + return 0; + } + + // DOWN + if (y < y1 && y < cy && y < y2 && x != x1 && x != x2) { + if (x1 < x2) { + return x1 < x && x < x2 ? 1 : 0; + } + return x2 < x && x < x1 ? -1 : 0; + } + + // INSIDE + QuadCurve c = new QuadCurve(x1, y1, cx, cy, x2, y2); + float px = x - x1; + float py = y - y1; + float res[] = new float[3]; + int rc = c.solvePoint(res, px); + + return c.cross(res, rc, py, py); + } + + /** + * Returns how many times ray from point (x,y) cross cubic curve + */ + public static int crossCubic(float x1, float y1, float cx1, float cy1, float cx2, float cy2, float x2, float y2, float x, float y) { + + // LEFT/RIGHT/UP/EMPTY + if ((x < x1 && x < cx1 && x < cx2 && x < x2) || + (x > x1 && x > cx1 && x > cx2 && x > x2) || + (y > y1 && y > cy1 && y > cy2 && y > y2) || + (x1 == cx1 && cx1 == cx2 && cx2 == x2)) + { + return 0; + } + + // DOWN + if (y < y1 && y < cy1 && y < cy2 && y < y2 && x != x1 && x != x2) { + if (x1 < x2) { + return x1 < x && x < x2 ? 1 : 0; + } + return x2 < x && x < x1 ? -1 : 0; + } + + // INSIDE + CubicCurve c = new CubicCurve(x1, y1, cx1, cy1, cx2, cy2, x2, y2); + float px = x - x1; + float py = y - y1; + float res[] = new float[3]; + int rc = c.solvePoint(res, px); + return c.cross(res, rc, py, py); + } + + /** + * Returns how many times ray from point (x,y) cross path + */ + public static int crossPath(PathIterator p, float x, float y) { + int cross = 0; + float mx, my, cx, cy; + mx = my = cx = cy = 0.0f; + float coords[] = new float[6]; + + while (!p.isDone()) { + switch (p.currentSegment(coords)) { + case PathIterator.SEG_MOVETO: + if (cx != mx || cy != my) { + cross += crossLine(cx, cy, mx, my, x, y); + } + mx = cx = coords[0]; + my = cy = coords[1]; + break; + case PathIterator.SEG_LINETO: + cross += crossLine(cx, cy, cx = coords[0], cy = coords[1], x, y); + break; + case PathIterator.SEG_QUADTO: + cross += crossQuad(cx, cy, coords[0], coords[1], cx = coords[2], cy = coords[3], x, y); + break; + case PathIterator.SEG_CUBICTO: + cross += crossCubic(cx, cy, coords[0], coords[1], coords[2], coords[3], cx = coords[4], cy = coords[5], x, y); + break; + case PathIterator.SEG_CLOSE: + if (cy != my || cx != mx) { + cross += crossLine(cx, cy, cx = mx, cy = my, x, y); + } + break; + } + + // checks if the point (x,y) is the vertex of shape with PathIterator p + if (x == cx && y == cy) { + cross = 0; + cy = my; + break; + } + p.next(); + } + if (cy != my) { + cross += crossLine(cx, cy, mx, my, x, y); + } + return cross; + } + + /** + * Returns how many times ray from point (x,y) cross shape + */ + public static int crossShape(Path2D s, float x, float y) { + if (!s.getBounds2D().contains(x, y)) { + return 0; + } + return crossPath(s.iterator(null), x, y); + } + + /** + * Returns true if value enough small + */ + public static boolean isZero(float val) { + return -DELTA < val && val < DELTA; + } + + /** + * Sort bound array + */ + static void sortBound(float bound[], int bc) { + for(int i = 0; i < bc - 4; i += 4) { + int k = i; + for(int j = i + 4; j < bc; j += 4) { + if (bound[k] > bound[j]) { + k = j; + } + } + if (k != i) { + float tmp = bound[i]; + bound[i] = bound[k]; + bound[k] = tmp; + tmp = bound[i + 1]; + bound[i + 1] = bound[k + 1]; + bound[k + 1] = tmp; + tmp = bound[i + 2]; + bound[i + 2] = bound[k + 2]; + bound[k + 2] = tmp; + tmp = bound[i + 3]; + bound[i + 3] = bound[k + 3]; + bound[k + 3] = tmp; + } + } + } + + /** + * Returns are bounds intersect or not intersect rectangle + */ + static int crossBound(float bound[], int bc, float py1, float py2) { + + // LEFT/RIGHT + if (bc == 0) { + return 0; + } + + // Check Y coordinate + int up = 0; + int down = 0; + for(int i = 2; i < bc; i += 4) { + if (bound[i] < py1) { + up++; + continue; + } + if (bound[i] > py2) { + down++; + continue; + } + return CROSSING; + } + + // UP + if (down == 0) { + return 0; + } + + if (up != 0) { + // bc >= 2 + sortBound(bound, bc); + boolean sign = bound[2] > py2; + for(int i = 6; i < bc; i += 4) { + boolean sign2 = bound[i] > py2; + if (sign != sign2 && bound[i + 1] != bound[i - 3]) { + return CROSSING; + } + sign = sign2; + } + } + return UNKNOWN; + } + + /** + * Returns how many times rectangle stripe cross line or the are intersect + */ + public static int intersectLine(float x1, float y1, float x2, float y2, float rx1, float ry1, float rx2, float ry2) { + + // LEFT/RIGHT/UP + if ((rx2 < x1 && rx2 < x2) || + (rx1 > x1 && rx1 > x2) || + (ry1 > y1 && ry1 > y2)) + { + return 0; + } + + // DOWN + if (ry2 < y1 && ry2 < y2) { + } else { + + // INSIDE + if (x1 == x2) { + return CROSSING; + } + + // Build bound + float bx1, bx2; + if (x1 < x2) { + bx1 = x1 < rx1 ? rx1 : x1; + bx2 = x2 < rx2 ? x2 : rx2; + } else { + bx1 = x2 < rx1 ? rx1 : x2; + bx2 = x1 < rx2 ? x1 : rx2; + } + float k = (y2 - y1) / (x2 - x1); + float by1 = k * (bx1 - x1) + y1; + float by2 = k * (bx2 - x1) + y1; + + // BOUND-UP + if (by1 < ry1 && by2 < ry1) { + return 0; + } + + // BOUND-DOWN + if (by1 > ry2 && by2 > ry2) { + } else { + return CROSSING; + } + } + + // EMPTY + if (x1 == x2) { + return 0; + } + + // CURVE-START + if (rx1 == x1) { + return x1 < x2 ? 0 : -1; + } + + // CURVE-END + if (rx1 == x2) { + return x1 < x2 ? 1 : 0; + } + + if (x1 < x2) { + return x1 < rx1 && rx1 < x2 ? 1 : 0; + } + return x2 < rx1 && rx1 < x1 ? -1 : 0; + + } + + /** + * Returns how many times rectangle stripe cross quad curve or the are intersect + */ + public static int intersectQuad(float x1, float y1, float cx, float cy, float x2, float y2, float rx1, float ry1, float rx2, float ry2) { + + // LEFT/RIGHT/UP ------------------------------------------------------ + if ((rx2 < x1 && rx2 < cx && rx2 < x2) || + (rx1 > x1 && rx1 > cx && rx1 > x2) || + (ry1 > y1 && ry1 > cy && ry1 > y2)) + { + return 0; + } + + // DOWN --------------------------------------------------------------- + if (ry2 < y1 && ry2 < cy && ry2 < y2 && rx1 != x1 && rx1 != x2) { + if (x1 < x2) { + return x1 < rx1 && rx1 < x2 ? 1 : 0; + } + return x2 < rx1 && rx1 < x1 ? -1 : 0; + } + + // INSIDE ------------------------------------------------------------- + QuadCurve c = new QuadCurve(x1, y1, cx, cy, x2, y2); + float px1 = rx1 - x1; + float py1 = ry1 - y1; + float px2 = rx2 - x1; + float py2 = ry2 - y1; + + float res1[] = new float[3]; + float res2[] = new float[3]; + int rc1 = c.solvePoint(res1, px1); + int rc2 = c.solvePoint(res2, px2); + + // INSIDE-LEFT/RIGHT + if (rc1 == 0 && rc2 == 0) { + return 0; + } + + // Build bound -------------------------------------------------------- + float minX = px1 - DELTA; + float maxX = px2 + DELTA; + float bound[] = new float[28]; + int bc = 0; + // Add roots + bc = c.addBound(bound, bc, res1, rc1, minX, maxX, false, 0); + bc = c.addBound(bound, bc, res2, rc2, minX, maxX, false, 1); + // Add extremal points` + rc2 = c.solveExtrem(res2); + bc = c.addBound(bound, bc, res2, rc2, minX, maxX, true, 2); + // Add start and end + if (rx1 < x1 && x1 < rx2) { + bound[bc++] = 0.0f; + bound[bc++] = 0.0f; + bound[bc++] = 0.0f; + bound[bc++] = 4; + } + if (rx1 < x2 && x2 < rx2) { + bound[bc++] = 1.0f; + bound[bc++] = c.ax; + bound[bc++] = c.ay; + bound[bc++] = 5; + } + // End build bound ---------------------------------------------------- + + int cross = crossBound(bound, bc, py1, py2); + if (cross != UNKNOWN) { + return cross; + } + return c.cross(res1, rc1, py1, py2); + } + + /** + * Returns how many times rectangle stripe cross cubic curve or the are intersect + */ + public static int intersectCubic(float x1, float y1, float cx1, float cy1, float cx2, float cy2, float x2, float y2, float rx1, float ry1, float rx2, float ry2) { + + // LEFT/RIGHT/UP + if ((rx2 < x1 && rx2 < cx1 && rx2 < cx2 && rx2 < x2) || + (rx1 > x1 && rx1 > cx1 && rx1 > cx2 && rx1 > x2) || + (ry1 > y1 && ry1 > cy1 && ry1 > cy2 && ry1 > y2)) + { + return 0; + } + + // DOWN + if (ry2 < y1 && ry2 < cy1 && ry2 < cy2 && ry2 < y2 && rx1 != x1 && rx1 != x2) { + if (x1 < x2) { + return x1 < rx1 && rx1 < x2 ? 1 : 0; + } + return x2 < rx1 && rx1 < x1 ? -1 : 0; + } + + // INSIDE + CubicCurve c = new CubicCurve(x1, y1, cx1, cy1, cx2, cy2, x2, y2); + float px1 = rx1 - x1; + float py1 = ry1 - y1; + float px2 = rx2 - x1; + float py2 = ry2 - y1; + + float res1[] = new float[3]; + float res2[] = new float[3]; + int rc1 = c.solvePoint(res1, px1); + int rc2 = c.solvePoint(res2, px2); + + // LEFT/RIGHT + if (rc1 == 0 && rc2 == 0) { + return 0; + } + + float minX = px1 - DELTA; + float maxX = px2 + DELTA; + + // Build bound -------------------------------------------------------- + float bound[] = new float[40]; + int bc = 0; + // Add roots + bc = c.addBound(bound, bc, res1, rc1, minX, maxX, false, 0); + bc = c.addBound(bound, bc, res2, rc2, minX, maxX, false, 1); + // Add extrimal points + rc2 = c.solveExtremX(res2); + bc = c.addBound(bound, bc, res2, rc2, minX, maxX, true, 2); + rc2 = c.solveExtremY(res2); + bc = c.addBound(bound, bc, res2, rc2, minX, maxX, true, 4); + // Add start and end + if (rx1 < x1 && x1 < rx2) { + bound[bc++] = 0.0f; + bound[bc++] = 0.0f; + bound[bc++] = 0.0f; + bound[bc++] = 6; + } + if (rx1 < x2 && x2 < rx2) { + bound[bc++] = 1.0f; + bound[bc++] = c.ax; + bound[bc++] = c.ay; + bound[bc++] = 7; + } + // End build bound ---------------------------------------------------- + + int cross = crossBound(bound, bc, py1, py2); + if (cross != UNKNOWN) { + return cross; + } + return c.cross(res1, rc1, py1, py2); + } + + /** + * Returns how many times rectangle stripe cross path or the are intersect + */ + public static int intersectPath(PathIterator p, float x, float y, float w, float h) { + + int cross = 0; + int count; + float mx, my, cx, cy; + mx = my = cx = cy = 0.0f; + float coords[] = new float[6]; + + float rx1 = x; + float ry1 = y; + float rx2 = x + w; + float ry2 = y + h; + + while (!p.isDone()) { + count = 0; + switch (p.currentSegment(coords)) { + case PathIterator.SEG_MOVETO: + if (cx != mx || cy != my) { + count = intersectLine(cx, cy, mx, my, rx1, ry1, rx2, ry2); + } + mx = cx = coords[0]; + my = cy = coords[1]; + break; + case PathIterator.SEG_LINETO: + count = intersectLine(cx, cy, cx = coords[0], cy = coords[1], rx1, ry1, rx2, ry2); + break; + case PathIterator.SEG_QUADTO: + count = intersectQuad(cx, cy, coords[0], coords[1], cx = coords[2], cy = coords[3], rx1, ry1, rx2, ry2); + break; + case PathIterator.SEG_CUBICTO: + count = intersectCubic(cx, cy, coords[0], coords[1], coords[2], coords[3], cx = coords[4], cy = coords[5], rx1, ry1, rx2, ry2); + break; + case PathIterator.SEG_CLOSE: + if (cy != my || cx != mx) { + count = intersectLine(cx, cy, mx, my, rx1, ry1, rx2, ry2); + } + cx = mx; + cy = my; + break; + } + if (count == CROSSING) { + return CROSSING; + } + cross += count; + p.next(); + } + if (cy != my) { + count = intersectLine(cx, cy, mx, my, rx1, ry1, rx2, ry2); + if (count == CROSSING) { + return CROSSING; + } + cross += count; + } + return cross; + } + + /** + * Returns how many times rectangle stripe cross shape or the are intersect + */ + public static int intersectShape(Path2D s, float x, float y, float w, float h) { + if (!s.getBounds2D().intersects(x, y, w, h)) { + return 0; + } + return intersectPath(s.iterator(null), x, y, w, h); + } + + /** + * Returns true if cross count correspond inside location for non zero path rule + */ + public static boolean isInsideNonZero(int cross) { + return cross != 0; + } + + /** + * Returns true if cross count correspond inside location for even-odd path rule + */ + public static boolean isInsideEvenOdd(int cross) { + return (cross & 1) != 0; + } +} |