[libbluray-devel] BDGraphics: implement fillPolygon()

[Ian Curtis]

libbluray | branch: master | Ian Curtis <i.curtis at gmail.com> | Tue Mar 25 13:26:34 2014 +0200| [d79c6c8eb37d15a40091e331e593db92642c0a58] | committer: hpi1

BDGraphics: implement fillPolygon()

> http://git.videolan.org/gitweb.cgi/libbluray.git/?a=commit;h=d79c6c8eb37d15a40091e331e593db92642c0a58
---

 .../bdj/java-j2se/java/awt/BDGraphics.java         |   66 +++++++++++++++++-
 src/libbluray/bdj/java/java/awt/PolyEdge.java      |   73 ++++++++++++++++++++
 2 files changed, 138 insertions(+), 1 deletion(-)

diff --git a/src/libbluray/bdj/java-j2se/java/awt/BDGraphics.java b/src/libbluray/bdj/java-j2se/java/awt/BDGraphics.java
index 49c274e..bc1016b 100644
--- a/src/libbluray/bdj/java-j2se/java/awt/BDGraphics.java
+++ b/src/libbluray/bdj/java-j2se/java/awt/BDGraphics.java
@@ -21,7 +21,10 @@ package java.awt;
 
 import java.lang.reflect.Field;
 import java.text.AttributedCharacterIterator;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
 import java.awt.image.AreaAveragingScaleFilter;
 import java.awt.image.BufferedImage;
 import java.awt.image.ImageConsumer;
@@ -643,7 +646,68 @@ class BDGraphics extends Graphics2D implements ConstrainableGraphics {
 
     /** Fills a polygon with the current fill mask */
     public void fillPolygon(int xPoints[], int yPoints[], int nPoints) {
-        logger.unimplemented("fillPolygon");
+
+        int minY = Integer.MAX_VALUE;
+        int maxY = Integer.MIN_VALUE;
+        int colour = foreground.getRGB();
+
+        if (nPoints < 3) {
+            return;
+        }
+
+        for (int i = 0; i < nPoints; i++) {
+            if (yPoints[i] > maxY) {
+                maxY = yPoints[i];
+            }
+            if (yPoints[i] < minY) {
+                minY = yPoints[i];
+            }
+        }
+
+        // check the last point to see if its the same as the first
+        if (xPoints[0] == xPoints[nPoints - 1] && yPoints[0] == yPoints[nPoints - 1]) {
+            nPoints--;
+        }
+
+        PolyEdge[] polyEdges = new PolyEdge[nPoints];
+
+        for (int i = 0; i < nPoints - 1; i++) {
+            polyEdges[i] = new PolyEdge(xPoints[i], yPoints[i], xPoints[i + 1], yPoints[i + 1]);
+        }
+
+        // add the last one
+        polyEdges[nPoints - 1] = new PolyEdge(xPoints[nPoints - 1], yPoints[nPoints - 1], xPoints[0], yPoints[0]);
+        ArrayList xList = new ArrayList();
+        for (int i = minY; i <= maxY; i++) {
+            for (int j = 0; j < nPoints; j++) {
+                if (polyEdges[j].intersects(i)) {
+                    int x = polyEdges[j].intersectionX(i);
+                    xList.add(new Integer(x));
+                }
+            }
+
+            // probably a better way of doing this (removing duplicates);
+            HashSet hs = new HashSet();
+            hs.addAll(xList);
+            xList.clear();
+            xList.addAll(hs);
+
+            if (xList.size() % 2 > 0) {
+                xList.clear();
+                continue;                       // this should be impossible unless the poly is open somewhere
+            }
+
+            Collections.sort(xList);
+
+            for (int j = 0; j < xList.size(); j +=2 ) {
+                int x1 = ((Integer)xList.get(j)).intValue();
+                int x2 = ((Integer)xList.get(j + 1)).intValue();
+
+                drawSpan(x1, i, x2 - x1, colour);
+            }
+
+            xList.clear();
+        }
     }
 
     /** Draws an oval to fit in the given rectangle */
diff --git a/src/libbluray/bdj/java/java/awt/PolyEdge.java b/src/libbluray/bdj/java/java/awt/PolyEdge.java
new file mode 100644
index 0000000..f83558d
--- /dev/null
+++ b/src/libbluray/bdj/java/java/awt/PolyEdge.java
@@ -0,0 +1,73 @@
+/*
+ * This file is part of libbluray
+ * Copyright (C) 2014  libbluray
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+package java.awt;
+
+class PolyEdge {
+
+    private int x1;
+    private int y1;
+    private int x2;
+    private int y2;
+    private float m;
+    private float c;
+    private boolean vertical;
+
+    PolyEdge(int x1, int y1, int x2, int y2) {
+
+        // sort lowest to highest
+        if (y2 < y1) {
+            int swap;
+            swap = x1; x1 = x2; x2 = swap;
+            swap = y1; y1 = y2; y2 = swap;
+        }
+
+        this.x1 = x1;
+        this.y1 = y1;
+        this.x2 = x2;
+        this.y2 = y2;
+
+        if (x1 == x2) {
+            vertical = true;
+            m = 0;
+        } else {
+            m = (float)(y2 - y1) / (float)(x2 - x1);
+            c = (-x1 * m) + y1;
+            vertical = false;
+        }
+    }
+
+    public boolean intersects(int y) {
+
+        if (y <= y2 && y >= y1 && y1 != y2) {
+            return true;
+        }
+
+        return false;
+    }
+
+    public int intersectionX(int y) {
+
+        if (vertical) {
+            return x1;
+        }
+
+        return (int)((y - c) / m);
+    }
+}