Make IFigure#translate...() results backward compatible for Rectangle

The wrapping of Rectangles into their precision representations when
calling IFigure#translate...() methods leads to results that are
incompatible with pre-existing behavior when only a single scaled layer
is involved. The reason is the different rounding applied in a basic
Rectangle compared to a PrecisionRectangle. Recent attempts to adapt the
PrecisionRectangle behavior failed because they broke backward
compatibility. But without streamlining the rounding of Rectangle and
PrecisionRectangle, the results of IFigure#translate...() become
incompatible.

For that reason, this change adapts the unwrapping of PrecisionRectangle
to Rectangle in IFigure#translate...() to use the same rounding as
applied in Rectangle to ensure backward compatibility of the method's
behavior.

Author: HeikoKlare

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

@@ -18,8 +18,8 @@
 import org.eclipse.draw2d.IFigure;
 import org.eclipse.draw2d.ScalableLayeredPane;
 import org.eclipse.draw2d.geometry.PointList;
+import org.eclipse.draw2d.geometry.PrecisionDimension;
 import org.eclipse.draw2d.geometry.PrecisionPointList;
-import org.eclipse.draw2d.geometry.PrecisionRectangle;
 import org.eclipse.draw2d.geometry.Rectangle;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -65,11 +65,13 @@ private static ScalableLayeredPane createLayer(double scale) {
 
 	@Test
 	public void testPreciseTranslateToAbsolute() {
+		PrecisionDimension scaleDimension = new PrecisionDimension(0, 1);
+		fig.translateToAbsolute(scaleDimension);
+		double fullScale = scaleDimension.preciseHeight();
 		Rectangle r1 = new Rectangle(13, 37, 163, 377);
-		Rectangle r2 = new PrecisionRectangle(13, 37, 163, 377);
 		fig.translateToAbsolute(r1);
-		fig.translateToAbsolute(r2);
-		assertEquals(493, 1404, 6186, 14307, r1);
+		Rectangle r2 = new Rectangle(13, 37, 163, 377).scale(fullScale);
+		assertEquals(493, 1404, 6187, 14309, r1);
 		assertEquals(r1.x, r2.x);
 		assertEquals(r1.y, r2.y);
 		assertEquals(r1.width, r2.width);
@@ -78,11 +80,13 @@ public void testPreciseTranslateToAbsolute() {
 
 	@Test
 	public void testPreciseTranslateToRelative() {
+		PrecisionDimension scaleDimension = new PrecisionDimension(0, 1);
+		fig.translateToAbsolute(scaleDimension);
+		double fullScale = scaleDimension.preciseHeight();
 		Rectangle r1 = new Rectangle(753, 891, 353, 564);
-		Rectangle r2 = new PrecisionRectangle(753, 891, 353, 564);
 		fig.translateToRelative(r1);
-		fig.translateToRelative(r2);
-		assertEquals(19, 23, 9, 14, r1);
+		Rectangle r2 = new Rectangle(753, 891, 353, 564).scale(1 / fullScale);
+		assertEquals(19, 23, 11, 16, r1);
 		assertEquals(r1.x, r2.x);
 		assertEquals(r1.y, r2.y);
 		assertEquals(r1.width, r2.width);
@@ -108,4 +112,26 @@ public void testPreciseTranslateToRelative_PointList() {
 		assertArrayEquals(p1.toIntArray(), new int[] { 13, 16, 18, 8 });
 		assertArrayEquals(p1.toIntArray(), p2.toIntArray());
 	}
+
+	// Ensure that results are compatible with pre-existing behavior for translating
+	// a rectangle when only a single scaled layer is present
+	@SuppressWarnings("static-method")
+	@Test
+	public void testPreciseTranslateToAbsolute_singleLayerCompatibility() {
+		Figure figure = new Figure();
+		ScalableLayeredPane layer = createLayer(1.4);
+		IFigure root = new Figure();
+		root.add(layer);
+		layer.add(figure);
+		Rectangle customRectangle = new Rectangle(13, 37, 13, 377) {
+		};
+		Rectangle plainRectangle = new Rectangle(customRectangle);
+
+		figure.translateToAbsolute(customRectangle);
+		figure.translateToAbsolute(plainRectangle);
+		assertEquals(customRectangle.x, plainRectangle.x);
+		assertEquals(customRectangle.y, plainRectangle.y);
+		assertEquals(customRectangle.width, plainRectangle.width);
+		assertEquals(customRectangle.height, plainRectangle.height);
+	}
 }

org.eclipse.draw2d/src/org/eclipse/draw2d/Figure.java

@@ -2128,7 +2128,9 @@ private void fromPreciseShape(Translatable source, Translatable target) {
 			} else if (source instanceof PrecisionDimension d1 && target instanceof Dimension d2) {
 				d2.setSize(d1.width, d1.height);
 			} else if (source instanceof PrecisionRectangle r1 && target instanceof Rectangle r2) {
-				r2.setBounds(r1.x, r1.y, r1.width, r1.height);
+				r2.setBounds(r1.x, r1.y,
+						(int) (Math.ceil(r1.preciseX() + r1.preciseWidth()) - Math.floor(r1.preciseX())),
+						(int) (Math.ceil(r1.preciseY() + r1.preciseHeight()) - Math.floor(r1.preciseY())));
 			} else if (source instanceof PrecisionPointList p1 && target instanceof PointList p2) {
 				System.arraycopy(p1.toIntArray(), 0, p2.toIntArray(), 0, p2.size() * 2);
 			}