2006-07-27 Francis Kung <fkung@redhat.com>classpath-0_92-branch-point

	* gnu/java/awt/java2d/CubicSegment.java: Added import.
	(cp1): Renamed from first().
	(c2): Renamed from last().
	(first): Renamed to cp1().
	(getDisplacedSegments): Implemented.
	(last): Renamed to cp2().
	* gnu/java/awt/java2d/LineSegment.java
	(cp1): Renamed from first().
	(c2): Renamed from last().
	(first): Renamed to cp1().
	(last): Renamed to cp2().
	* gnu/java/awt/java2d/QuadSegment.java
	(cp1): Renamed from first().
	(c2): Renamed from last().
	(first): Renamed to cp1().
	(last): Renamed to cp2().
	* gnu/java/awt/java2d/Segment.java: Added comments.
	(first): New field.
	(Segment): Keep track of first element in list.
	(add): Update first & last element variables.
	(cp1): Renamed from first().
	(c2): Renamed from last().
	(first()): Renamed to cp1() to reduce ambiguity.
	(last()): Renamed to cp2() to reduce ambiguity.
	(reverseAll): Update first element variable..
	* gnu/java/awt/peer/gtk/CairoGraphics2D.java
	(draw): Remove flattening path iterator.
	* java/awt/BasicStroke.java: Clarified comments.
	(addSegments): Refactored some code into joinSegments and
	joinInnerSegments.
	(capEnd): Rename of Segment.first() and Segment.end().
	(joinInnerSegments): New method.
	(joinOuterSegments): New method.
	(joinSegments): Refactored some code into joinOuterSegments.
	(solidStroke): Connect segments together properly.

4 files changed, 95 insertions, 28 deletions

diff --git a/gnu/java/awt/java2d/CubicSegment.java b/gnu/java/awt/java2d/CubicSegment.java
index 7d169b78e..bf66be870 100644
--- a/gnu/java/awt/java2d/CubicSegment.java
+++ b/gnu/java/awt/java2d/CubicSegment.java
@@ -39,6 +39,7 @@ exception statement from your version. */
 package gnu.java.awt.java2d;
 
 
+import java.awt.geom.CubicCurve2D;
 import java.awt.geom.Point2D;
 
 /**
@@ -100,28 +101,67 @@ public class CubicSegment extends Segment
   }
 
   /**
-   * Get the "top" and "bottom" segments of this segment.
-   * First array element is p0 + normal, second is p0 - normal.
+   * Get the "top" and "bottom" segments of this segment. First array element is
+   * p0 + normal, second is p0 - normal.
    */
   public Segment[] getDisplacedSegments(double radius)
   {
+    // It is, apparently, impossible to derive a curve parallel to a bezier
+    // curve (unless it's a straight line), so we have no choice but to
+    // approximate the displaced segments. Similar to FlattenPathIterator.
+
+    Segment segmentTop = null;
+    Segment segmentBottom = null;
     this.radius = radius;
-    double x0 = P1.getX();
-    double y0 = P1.getY();
-    double x1 = cp1.getX();
-    double y1 = cp1.getY();
-    double x2 = cp2.getX();
-    double y2 = cp2.getY();
-    double x3 = P2.getX();
-    double y3 = P2.getY();
-    double[] p1 = normal(x0, y0, x1, y1);
-    double[] p2 = normal(x2, y2, x3, y3);
-
-    // FIXME: Doesn't compile.
-    // return new Segment[]{s1, s2};
-    return new Segment[0];
-  }
 
+    CubicCurve2D[] curves = new CubicCurve2D[10];
+    curves[0] = new CubicCurve2D.Double(P1.getX(), P1.getY(), cp1.getX(),
+                                        cp1.getY(), cp2.getX(), cp2.getY(),
+                                        P2.getX(), P2.getY());
+    int numCurves = 1;
+
+    // Hard-coded a recursion limit of 10 and flatness of 1... should we make
+    // this an option somewhere?
+    while (numCurves > 0)
+      {
+        // The curve is flat enough, or we've reached our recursion limit,
+        // so take the current start/end points and add it as a line segment
+        // to our final approximated curves
+        if (curves[numCurves - 1].getFlatnessSq() <= (radius / 3) || numCurves == 10)
+          {
+            Segment[] displaced = new LineSegment(
+                                                  curves[numCurves - 1].getP1(),
+                                                  curves[numCurves - 1].getP2()).getDisplacedSegments(radius);
+            if (segmentTop == null)
+              {
+                segmentTop = displaced[0];
+                segmentBottom = displaced[1];
+              }
+            else
+              {
+                segmentTop.add(displaced[0]);
+                segmentBottom.add(displaced[1]);
+              }
+            numCurves--;
+          }
+
+        // Otherwise, subdivide again and continue
+        else
+          {
+            CubicCurve2D left = new CubicCurve2D.Double();
+            CubicCurve2D right = new CubicCurve2D.Double();
+            curves[numCurves - 1].subdivide(left, right);
+            curves[numCurves - 1] = right;
+            curves[numCurves] = left;
+            curves[numCurves - 1] = right;
+            curves[numCurves] = left;
+            numCurves++;
+          }
+      }
+
+    return new Segment[] { segmentTop, segmentBottom };
+  }
+  
   public void reverse()
   {
     Point2D temp = P1;
@@ -132,12 +172,12 @@ public class CubicSegment extends Segment
     cp2 = temp;
   }
 
-  public double[] first()
+  public double[] cp1()
   {
     return new double[]{cp1.getX(), cp1.getY()}; 
   }
 
-  public double[] last()
+  public double[] cp2()
   {
     return new double[]{cp2.getX(), cp2.getY()}; 
   }
diff --git a/gnu/java/awt/java2d/LineSegment.java b/gnu/java/awt/java2d/LineSegment.java
index 4a34aa563..0395fd0af 100644
--- a/gnu/java/awt/java2d/LineSegment.java
+++ b/gnu/java/awt/java2d/LineSegment.java
@@ -106,12 +106,12 @@ public class LineSegment extends Segment
     P2 = p;
   }
 
-  public double[] first()
+  public double[] cp1()
   {
     return new double[]{P2.getX(), P2.getY()}; 
   }
 
-  public double[] last()
+  public double[] cp2()
   {
     return new double[]{P1.getX(), P1.getY()}; 
   }
diff --git a/gnu/java/awt/java2d/QuadSegment.java b/gnu/java/awt/java2d/QuadSegment.java
index c76804840..5e15fe881 100644
--- a/gnu/java/awt/java2d/QuadSegment.java
+++ b/gnu/java/awt/java2d/QuadSegment.java
@@ -217,12 +217,12 @@ public class QuadSegment extends Segment
     P2 = p;
   }
 
-  public double[] first()
+  public double[] cp1()
   {
     return new double[]{cp.getX(), cp.getY()}; 
   }
 
-  public double[] last()
+  public double[] cp2()
   {
     return new double[]{cp.getX(), cp.getY()}; 
   }
diff --git a/gnu/java/awt/java2d/Segment.java b/gnu/java/awt/java2d/Segment.java
index 9a985f696..df1f67605 100644
--- a/gnu/java/awt/java2d/Segment.java
+++ b/gnu/java/awt/java2d/Segment.java
@@ -42,24 +42,38 @@ import java.awt.geom.Point2D;
 
 public abstract class Segment implements Cloneable
 {
-  // segment type, PathIterator segment types are used.
+  // Start and end points of THIS segment
   public Point2D P1;
   public Point2D P2;
+  
+  // Segments can be linked together internally as a linked list
+  public Segment first;
   public Segment next;
   public Segment last;
+  
+  // Half the stroke width
   protected double radius;
 
+  /**
+   * Create a new, empty segment
+   */
   public Segment()
   {
     P1 = P2 = null;
+    first = this;
     next = null;
     last = this;
   }
 
+  /**
+   * Add a segment to the polygon
+   * @param newsegment segment to add
+   */
   public void add(Segment newsegment)
   {
+    newsegment.first = first;
     last.next = newsegment;
-    last = last.next;
+    last = last.next.last;
   }
 
   /**
@@ -68,6 +82,7 @@ public abstract class Segment implements Cloneable
   public void reverseAll()
   {
     reverse();
+    first = last;
     Segment v = next;
     Segment former = this;
     next = null;
@@ -91,7 +106,7 @@ public abstract class Segment implements Cloneable
 
   /**
    * Get the normal vector to the slope of the line.
-   * Returns: 0.5*width*(norm of derivative of the (x0,y0)-(x1,y1) vector)
+   * @return vector of length radius, normal to the (x0,y0)-(x1,y1) vector)
    */
   protected double[] normal(double x0, double y0, double x1, double y1)
   {
@@ -117,6 +132,9 @@ public abstract class Segment implements Cloneable
     return new double[]{ dx, dy };
   }
 
+  /**
+   * Reverse the current segment
+   */
   public abstract void reverse();
 
   /**
@@ -125,7 +143,16 @@ public abstract class Segment implements Cloneable
    */
   public abstract Segment[] getDisplacedSegments(double radius);
 
-  public abstract double[] first();
-  public abstract double[] last();
+  /**
+   * Returns the coordinates of the first control point, or the start point
+   * for a line segment.
+   */
+  public abstract double[] cp1();
+  
+  /**
+   * Returns the coordinates of the second control point, or the end point
+   * for a line segment.
+   */
+  public abstract double[] cp2();
 
 }