Only use double-precision translation when HighDPI scaling is enabled

When the "draw2d.enableAutoscale" system property is enabled, additional
(scalable) layers are injected into the IFigure hierarchy to take the
monitor zoom into consideration.

As a result of this, translating geometric shapes may cause additional
rounding errors, which are the result of translating integer-values with
an additional, fractional zoom level.

To work around this problem, the "useDoublePrecision()" method was added
with 5cfe5b7, which converts the
geometric shapes to their precise variants. This conversion is generally
not backwards compatible.

To make sure clients can fully opt-out of this new behavior, this
conversion should only be done when the "draw2d.enableAutoscale" is set
to true, meaning only when these new layers are added, that require this
extended translation logic.

Author: ptziegler

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

@@ -13,6 +13,8 @@
 
 package org.eclipse.draw2d.test;
 
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
 import org.eclipse.draw2d.Figure;
 import org.eclipse.draw2d.FigureUtilities;
 import org.eclipse.draw2d.IFigure;
@@ -21,6 +23,7 @@
 import org.eclipse.draw2d.geometry.PrecisionPointList;
 import org.eclipse.draw2d.geometry.PrecisionRectangle;
 import org.eclipse.draw2d.geometry.Rectangle;
+import org.eclipse.draw2d.internal.InternalDraw2dUtils;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -65,6 +68,7 @@ private static ScalableLayeredPane createLayer(double scale) {
 
 	@Test
 	public void testPreciseTranslateToAbsolute() {
+		assumeTrue(InternalDraw2dUtils.isAutoScaleEnabled());
 		Rectangle r1 = new Rectangle(13, 37, 163, 377);
 		Rectangle r2 = new PrecisionRectangle(13, 37, 163, 377);
 		fig.translateToAbsolute(r1);
@@ -78,6 +82,7 @@ public void testPreciseTranslateToAbsolute() {
 
 	@Test
 	public void testPreciseTranslateToRelative() {
+		assumeTrue(InternalDraw2dUtils.isAutoScaleEnabled());
 		Rectangle r1 = new Rectangle(753, 891, 353, 564);
 		Rectangle r2 = new PrecisionRectangle(753, 891, 353, 564);
 		fig.translateToRelative(r1);
@@ -91,6 +96,7 @@ public void testPreciseTranslateToRelative() {
 
 	@Test
 	public void testPreciseTranslateToAbsolute_PointList() {
+		assumeTrue(InternalDraw2dUtils.isAutoScaleEnabled());
 		PointList p1 = new PointList(new int[] { 13, 29, 32, 5 });
 		PointList p2 = new PrecisionPointList(new int[] { 13, 29, 32, 5 });
 		fig.translateToAbsolute(p1);
@@ -101,6 +107,7 @@ public void testPreciseTranslateToAbsolute_PointList() {
 
 	@Test
 	public void testPreciseTranslateToRelative_PointList() {
+		assumeTrue(InternalDraw2dUtils.isAutoScaleEnabled());
 		PointList p1 = new PointList(new int[] { 518, 628, 715, 313 });
 		PointList p2 = new PrecisionPointList(new int[] { 518, 628, 715, 313 });
 		fig.translateToRelative(p1);

org.eclipse.draw2d/src/org/eclipse/draw2d/ScalableFreeformLayeredPane.java

@@ -14,6 +14,7 @@
 
 import org.eclipse.draw2d.geometry.Rectangle;
 import org.eclipse.draw2d.geometry.Translatable;
+import org.eclipse.draw2d.internal.InternalDraw2dUtils;
 
 /**
  * @author hudsonr
@@ -120,6 +121,6 @@ public void translateFromParent(Translatable t) {
 	 */
 	@Override
 	protected boolean useDoublePrecision() {
-		return true;
+		return InternalDraw2dUtils.isAutoScaleEnabled();
 	}
 }

org.eclipse.draw2d/src/org/eclipse/draw2d/ScalableLayeredPane.java

@@ -15,6 +15,7 @@
 import org.eclipse.draw2d.geometry.Dimension;
 import org.eclipse.draw2d.geometry.Rectangle;
 import org.eclipse.draw2d.geometry.Translatable;
+import org.eclipse.draw2d.internal.InternalDraw2dUtils;
 
 /**
  * A non-freeform, scalable layered pane.
@@ -133,7 +134,7 @@ public boolean isCoordinateSystem() {
 	 */
 	@Override
 	protected boolean useDoublePrecision() {
-		return true;
+		return InternalDraw2dUtils.isAutoScaleEnabled();
 	}
 
 }