Draw and fill a polygon in

Arbitrary Polygon Filling Algorithm on J2EE

Http://www.docin.com/p-160437612.html

Jmicropolygon is a project to provide polygon drawing and filling facilities for j2's (MIDP 1.0 and 2.0) without relying on extension APIs.

Http://sourceforge.net/projects/jmicropolygon/

package com.cvte.game.game;import java.util.Stack;import javax.microedition.lcdui.Graphics;public class PolygonGraphics {public static void drawPolygon(Graphics g, int[] xPoints, int[] yPoints) {int max = xPoints.length - 1;for (int i = 0; i < max; ++i)g.drawLine(xPoints[i], yPoints[i], xPoints[(i + 1)], yPoints[(i + 1)]);g.drawLine(xPoints[max], yPoints[max], xPoints[0], yPoints[0]);}public static void fillPolygon(Graphics g, int[] xPoints, int[] yPoints) {Stack stack = new Stack();fillPolygon(g, xPoints, yPoints, stack);while (!(stack.isEmpty()))fillPolygon(g, (int[])stack.pop(), (int[])stack.pop(), stack);}private static void fillPolygon(Graphics g, int[] xPoints, int[] yPoints, Stack stack) {while (xPoints.length > 2) {int a = GeomUtils.indexOfLeast(xPoints);int b = (a + 1) % xPoints.length;int c = (a > 0) ? a - 1 : xPoints.length - 1;int leastInternalIndex = -1;boolean leastInternalSet = false;if (xPoints.length > 3) {for (int i = 0; i < xPoints.length; ++i) {if ((i != a) && (i != b) && (i != c)&& (GeomUtils.withinBounds(xPoints[i], yPoints[i], xPoints[a], yPoints[a], xPoints[b], yPoints[b], xPoints[c], yPoints[c]))&& (((!(leastInternalSet)) || (xPoints[i] < xPoints[leastInternalIndex])))) {leastInternalIndex = i;leastInternalSet = true;}}}if (!(leastInternalSet)) {g.fillTriangle(xPoints[a], yPoints[a], xPoints[b], yPoints[b], xPoints[c], yPoints[c]);int[][] trimmed = GeomUtils.trimEar(xPoints, yPoints, a);xPoints = trimmed[0];yPoints = trimmed[1];}else {int[][][] split = GeomUtils.split(xPoints, yPoints, a, leastInternalIndex);int[][] poly1 = split[0];int[][] poly2 = split[1];stack.push(poly2[1]);stack.push(poly2[0]);stack.push(poly1[1]);stack.push(poly1[0]);return;}}}}

package com.cvte.game.game;public abstract class GeomUtils {static boolean withinBounds(int px, int py, int ax, int ay, int bx, int by, int cx, int cy) {if ((px < min(ax, bx, cx)) || (px > max(ax, bx, cx)) || (py < min(ay, by, cy)) || (py > max(ay, by, cy)))return false;boolean sameabc = sameSide(px, py, ax, ay, bx, by, cx, cy);boolean samebac = sameSide(px, py, bx, by, ax, ay, cx, cy);boolean samecab = sameSide(px, py, cx, cy, ax, ay, bx, by);return ((sameabc) && (samebac) && (samecab));}static int[][][] split(int[] xPoints, int[] yPoints, int aIndex, int bIndex) {int firstLen;int index;if (bIndex < aIndex)firstLen = xPoints.length - aIndex + bIndex + 1;elsefirstLen = bIndex - aIndex + 1;int secondLen = xPoints.length - firstLen + 2;int[][] first = new int[2][firstLen];int[][] second = new int[2][secondLen];for (int i = 0; i < firstLen; ++i) {index = (aIndex + i) % xPoints.length;first[0][i] = xPoints[index];first[1][i] = yPoints[index];}for (int i = 0; i < secondLen; ++i) {index = (bIndex + i) % xPoints.length;second[0][i] = xPoints[index];second[1][i] = yPoints[index];}int[][][] result = new int[2][][];result[0] = first;result[1] = second;return result;}static int[][] trimEar(int[] xPoints, int[] yPoints, int earIndex) {int[] newXPoints = new int[xPoints.length - 1];int[] newYPoints = new int[yPoints.length - 1];int[][] newPoly = new int[2][];newPoly[0] = newXPoints;newPoly[1] = newYPoints;int p = 0;for (int i = 0; i < xPoints.length; ++i)if (i != earIndex) {newXPoints[p] = xPoints[i];newYPoints[p] = yPoints[i];++p;}return newPoly;}static int indexOfLeast(int[] elements) {int index = 0;int least = elements[0];for (int i = 1; i < elements.length; ++i)if (elements[i] < least) {index = i;least = elements[i];}return index;}private static boolean sameSide(int p1x, int p1y, int p2x, int p2y, int l1x, int l1y, int l2x, int l2y) {long lhs = (p1x - l1x) * (l2y - l1y) - (l2x - l1x) * (p1y - l1y);long rhs = (p2x - l1x) * (l2y - l1y) - (l2x - l1x) * (p2y - l1y);long product = lhs * rhs;boolean result = product >= 7930382294286598144L;return result;}private static int min(int a, int b, int c) {return Math.min(Math.min(a, b), c);}private static int max(int a, int b, int c) {return Math.max(Math.max(a, b), c);}}

Draw and fill a polygon in