Restore PrecisionRectangle substitutability for Rectangle

Recent changes to PrecisionRectangle adapted how the integer-based
size values are calculated, which introduced inconsistencies with other
operations and data (such as the relation between bottom-right and
top-left corner of a rectangle) and which may also break existing
consumers due to the changed behavior of API methods.

This change reverts the changes to the necessary extent such that the
existing behavior is restored. It also adds tests for some of the
scenarios that broke with the changes.

Author: HeikoKlare

org.eclipse.draw2d.tests/src/org/eclipse/draw2d/test/PrecisionRectangleTest.java

@@ -119,7 +119,7 @@ public void testScale() {
 		assertEquals(91, r.preciseWidth(), 0);
 		assertEquals(91, r.preciseHeight(), 0);
 		// Different rounding behavior between Rectangle and PrecisionRectangle.
-		assertEquals(17, 17, 92, 92, r);
+		assertEquals(17, 17, 91, 91, r);
 	}
 
 	@SuppressWarnings("static-method")
@@ -147,6 +147,16 @@ public void testGetSize() {
 		assertEquals(r.height, r.getSize().height);
 	}
 
+	@SuppressWarnings("static-method")
+	@Test
+	public void testGetSize_Zero() {
+		PrecisionRectangle r = new PrecisionRectangle(0.5, 0.5, 0, 0);
+		assertEquals(r.width, r.getSize().width);
+		assertEquals(r.height, r.getSize().height);
+		assertEquals(0, r.getSize().width);
+		assertEquals(0, r.getSize().height);
+	}
+
 	@SuppressWarnings("static-method")
 	@Test
 	public void testGetLocation() {
@@ -155,4 +165,13 @@ public void testGetLocation() {
 		assertEquals(r.x, r.getLocation().x);
 		assertEquals(r.y, r.getLocation().y);
 	}
+
+	@SuppressWarnings("static-method")
+	@Test
+	public void testGetBottomRight() {
+		Rectangle rect = new PrecisionRectangle(100.5, 100.5, 250, 250);
+		assertEquals(rect.getBottomRight().x - rect.getTopLeft().x, rect.width);
+		assertEquals(rect.getBottomRight().y - rect.getTopLeft().y, rect.height);
+	}
+
 }

org.eclipse.draw2d.tests/src/org/eclipse/draw2d/test/PrecisionTests.java

@@ -69,7 +69,7 @@ public void testPreciseTranslateToAbsolute() {
 		Rectangle r2 = new PrecisionRectangle(13, 37, 163, 377);
 		fig.translateToAbsolute(r1);
 		fig.translateToAbsolute(r2);
-		assertEquals(493, 1404, 6187, 14309, r1);
+		assertEquals(493, 1404, 6186, 14307, r1);
 		assertEquals(r1.x, r2.x);
 		assertEquals(r1.y, r2.y);
 		assertEquals(r1.width, r2.width);
@@ -82,7 +82,7 @@ public void testPreciseTranslateToRelative() {
 		Rectangle r2 = new PrecisionRectangle(753, 891, 353, 564);
 		fig.translateToRelative(r1);
 		fig.translateToRelative(r2);
-		assertEquals(19, 23, 11, 16, r1);
+		assertEquals(19, 23, 9, 14, r1);
 		assertEquals(r1.x, r2.x);
 		assertEquals(r1.y, r2.y);
 		assertEquals(r1.width, r2.width);

org.eclipse.draw2d/src/org/eclipse/draw2d/geometry/PrecisionRectangle.java

@@ -952,12 +952,10 @@ private final void updateHeightInt() {
 	}
 
 	/**
-	 * Calculates the int-height of this rectangle using the same algorithm as used
-	 * by AWT in {@link java.awt.geom.RectangularShape#getBounds()
-	 * RectangularShape#getBounds()}
+	 * Calculates the int-height of this rectangle.
 	 */
 	private int getHeightInt() {
-		return PrecisionGeometry.doubleToInteger((Math.ceil(preciseY + preciseHeight) - Math.floor(preciseY)));
+		return PrecisionGeometry.doubleToInteger(preciseHeight);
 	}
 
 	/**
@@ -1025,12 +1023,10 @@ private final void updateWidthInt() {
 	}
 
 	/**
-	 * Calculates the int-height of this rectangle using the same algorithm as used
-	 * by AWT in {@link java.awt.geom.RectangularShape#getBounds()
-	 * RectangularShape#getBounds()}
+	 * Calculates the int-height of this rectangle.
 	 */
 	private int getWidthInt() {
-		return PrecisionGeometry.doubleToInteger(Math.ceil(preciseX + preciseWidth) - Math.floor(preciseX));
+		return PrecisionGeometry.doubleToInteger(preciseWidth);
 	}
 
 	/**