Add float precision to MonitorAwarePoint and MonitorAwareRectangle

Author: fedejeanne

bundles/org.eclipse.swt/Eclipse SWT Tests/win32/org/eclipse/swt/widgets/ControlWin32Tests.java

@@ -100,11 +100,11 @@ public void testCorrectScaleUpUsingDifferentSetBoundsMethod() {
 
 		button.setBounds(new Rectangle(0, 47, 200, 47));
 		assertEquals("Control::setBounds(Rectangle) doesn't scale up correctly",
-				new Rectangle(0, 82, 350, 83), button.getBoundsInPixels());
+				new Rectangle(0, 82, 350, 82), button.getBoundsInPixels());
 
 		button.setBounds(0, 47, 200, 47);
 		assertEquals("Control::setBounds(int, int, int, int) doesn't scale up correctly",
-				new Rectangle(0, 82, 350, 83), button.getBoundsInPixels());
+				new Rectangle(0, 82, 350, 82), button.getBoundsInPixels());
 	}
 
 	record FontComparison(int originalFontHeight, int currentFontHeight) {

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/MonitorAwarePoint.java

@@ -26,10 +26,24 @@
  */
 public final class MonitorAwarePoint extends Point {
 
-	private static final long serialVersionUID = 6077427420686999194L;
+	private static final long serialVersionUID = 7516155847004716654L;
+
+	public float residualX, residualY;
 
 	private final Monitor monitor;
 
+	public MonitorAwarePoint(int x, int y) {
+		this(x, y, null);
+	}
+
+	public MonitorAwarePoint(float x, float y, Monitor monitor) {
+		super(Math.round(x), Math.round(y));
+		this.residualX = x - this.x;
+		this.residualY = y - this.y;
+		this.monitor = monitor;
+	}
+
+
 	/**
 	 * Constructs a new MonitorAwarePoint
 	 *
@@ -58,5 +72,22 @@ public boolean equals(Object object) {
 	public int hashCode() {
 		return super.hashCode();
 	}
+	
+	public float getX() {
+		return x + residualX;
+	}
+
+	public float getY() {
+		return y + residualY;
+	}
 
-}
+	public void setX(float x) {
+		this.x = Math.round(x);
+		this.residualX = x - this.x;
+	}
+
+	public void setY(float y) {
+		this.y = Math.round(y);
+		this.residualY = y - this.y;
+	}
+}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/MonitorAwareRectangle.java

@@ -26,24 +26,34 @@
  */
 public final class MonitorAwareRectangle extends Rectangle {
 
-	private static final long serialVersionUID = 5041911840525116925L;
+	private static final long serialVersionUID = -54807918875027527L;
+
+	private float residualX, residualY, residualWidth, residualHeight;
 
 	private final Monitor monitor;
 
-	/**
-	 * Constructs a new MonitorAwareRectangle
-	 *
-	 * @param x the x coordinate of the top left corner of the rectangle
-	 * @param y the y coordinate of the top left corner of the rectangle
-	 * @param width the width of the rectangle
-	 * @param height the height of the rectangle
-	 * @param monitor the monitor with whose context the rectangle is created
-	 */
+	public MonitorAwareRectangle(int x, int y, int width, int height) {
+		this(x, y, width, height, null);
+	}
+
+	public MonitorAwareRectangle(float x, float y, float width, float height) {
+		this(x, y, width, height, null);
+	}
+
 	public MonitorAwareRectangle(int x, int y, int width, int height, Monitor monitor) {
 		super(x, y, width, height);
 		this.monitor = monitor;
 	}
 
+	MonitorAwareRectangle(float x, float y, float width, float height, Monitor monitor) {
+		super(Math.round(x), Math.round(y), Math.round(width), Math.round(height));
+		this.residualX = x - this.x;
+		this.residualY = y - this.y;
+		this.residualWidth = width - this.width;
+		this.residualHeight = height - this.height;
+		this.monitor = monitor;
+	}
+
 	/**
 	 * {@return the monitor with whose context the instance is created}
 	 */
@@ -60,10 +70,46 @@ public boolean equals(Object object) {
 	public int hashCode() {
 		return super.hashCode();
 	}
-
+	
 	@Override
 	public MonitorAwareRectangle clone() {
-		return new MonitorAwareRectangle(x, y, width, height, monitor);
+		return new MonitorAwareRectangle(getX(), getY(), getWidth(), getHeight(), monitor);
+	}
+
+	public float getX() {
+		return x + residualX;
+	}
+
+	public float getY() {
+		return y + residualY;
+	}
+
+	public float getWidth() {
+		return width + residualWidth;
+	}
+
+	public float getHeight() {
+		return height + residualHeight;
+	}
+
+	public void setX(float x) {
+		this.x = Math.round(x);
+		this.residualX = x - this.x;
+	}
+
+	public void setY(float y) {
+		this.y = Math.round(y);
+		this.residualY = y - this.y;
+	}
+
+	public void setWidth(float width) {
+		this.width = Math.round(width);
+		this.residualWidth = width - this.width;
+	}
+
+	public void setHeight(float height) {
+		this.height = Math.round(height);
+		this.residualHeight = height - this.height;
 	}
 
-}
+}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/Rectangle.java

@@ -374,7 +374,7 @@ public Rectangle union (Rectangle rect) {
  */
 public static Rectangle of(Point topLeft, int width, int height) {
 	if (topLeft instanceof MonitorAwarePoint monitorAwareTopLeft) {
-		return new MonitorAwareRectangle(topLeft.x, topLeft.y, width, height, monitorAwareTopLeft.getMonitor());
+		return new MonitorAwareRectangle(monitorAwareTopLeft.getX(), monitorAwareTopLeft.getY(), width, height, monitorAwareTopLeft.getMonitor());
 	}
 	return new Rectangle(topLeft.x, topLeft.y, width, height);
 }

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java

@@ -228,11 +228,11 @@ public static Point autoScaleDown(Point point) {
 
 public static Point scaleDown(Point point, int zoom) {
 	if (zoom == 100 || point == null) return point;
+	MonitorAwarePoint fPoint = FloatAwareGeometryFactory.createFrom(point);
 	float scaleFactor = getScalingFactor(zoom);
-	Point scaledPoint = new Point (0,0);
-	scaledPoint.x = Math.round (point.x / scaleFactor);
-	scaledPoint.y = Math.round (point.y / scaleFactor);
-	return scaledPoint;
+	float scaledX = fPoint.getX() / scaleFactor;
+	float scaledY = fPoint.getY() / scaleFactor;
+	return new MonitorAwarePoint(scaledX, scaledY, fPoint.getMonitor());
 }
 
 /**
@@ -255,16 +255,7 @@ public static Rectangle autoScaleDown(Rectangle rect) {
 }
 
 public static Rectangle scaleDown(Rectangle rect, int zoom) {
-	if (zoom == 100 || rect == null) return rect;
-	Rectangle scaledRect = new Rectangle (0,0,0,0);
-	Point scaledTopLeft = scaleDown(new Point (rect.x, rect.y), zoom);
-	Point scaledBottomRight = scaleDown(new Point (rect.x + rect.width, rect.y + rect.height), zoom);
-
-	scaledRect.x = scaledTopLeft.x;
-	scaledRect.y = scaledTopLeft.y;
-	scaledRect.width = scaledBottomRight.x - scaledTopLeft.x;
-	scaledRect.height = scaledBottomRight.y - scaledTopLeft.y;
-	return scaledRect;
+	return scaleBounds(rect, 100, zoom);
 }
 /**
  * Returns a new scaled down Rectangle if enabled for Drawable class.
@@ -333,13 +324,13 @@ public static boolean isSmoothScalingEnabled() {
  */
 public static Rectangle scaleBounds (Rectangle rect, int targetZoom, int currentZoom) {
 	if (rect == null || targetZoom == currentZoom) return rect;
+	MonitorAwareRectangle fRect = FloatAwareGeometryFactory.createFrom(rect);
 	float scaleFactor = ((float)targetZoom) / (float)currentZoom;
-	Rectangle returnRect = new Rectangle (0,0,0,0);
-	returnRect.x = Math.round (rect.x * scaleFactor);
-	returnRect.y = Math.round (rect.y * scaleFactor);
-	returnRect.width = Math.round (rect.width * scaleFactor);
-	returnRect.height = Math.round (rect.height * scaleFactor);
-	return returnRect;
+	float scaledX = fRect.getX() * scaleFactor;
+	float scaledY = fRect.getY() * scaleFactor;
+	float scaledWidth = fRect.getWidth() * scaleFactor;
+	float scaledHeight = fRect.getHeight() * scaleFactor;
+	return new MonitorAwareRectangle(scaledX, scaledY, scaledWidth, scaledHeight);
 }
 
 /**
@@ -436,11 +427,11 @@ public static Point autoScaleUp(Point point) {
 
 public static Point scaleUp(Point point, int zoom) {
 	if (zoom == 100 || point == null) return point;
+	MonitorAwarePoint fPoint = FloatAwareGeometryFactory.createFrom(point);
 	float scaleFactor = getScalingFactor(zoom);
-	Point scaledPoint = new Point(0,0);
-	scaledPoint.x = Math.round (point.x * scaleFactor);
-	scaledPoint.y = Math.round (point.y * scaleFactor);
-	return scaledPoint;
+	float scaledX = fPoint.getX() * scaleFactor;
+	float scaledY = fPoint.getY() * scaleFactor;
+	return new MonitorAwarePoint(scaledX, scaledY, fPoint.getMonitor());
 }
 
 /**
@@ -463,16 +454,7 @@ public static Rectangle autoScaleUp(Rectangle rect) {
 }
 
 public static Rectangle scaleUp(Rectangle rect, int zoom) {
-	if (zoom == 100 || rect == null) return rect;
-	Rectangle scaledRect = new Rectangle(0,0,0,0);
-	Point scaledTopLeft = scaleUp (new Point(rect.x, rect.y), zoom);
-	Point scaledBottomRight = scaleUp (new Point(rect.x + rect.width, rect.y + rect.height), zoom);
-
-	scaledRect.x = scaledTopLeft.x;
-	scaledRect.y = scaledTopLeft.y;
-	scaledRect.width = scaledBottomRight.x - scaledTopLeft.x;
-	scaledRect.height = scaledBottomRight.y - scaledTopLeft.y;
-	return scaledRect;
+	return scaleBounds(rect, zoom, 100);
 }
 
 /**
@@ -751,4 +733,20 @@ public ImageData getImageData(int zoom) {
 		return DPIUtil.scaleImageData(device, imageData, zoom, currentZoom);
 	}
 }
+
+private class FloatAwareGeometryFactory {
+	static MonitorAwareRectangle createFrom(Rectangle rectangle) {
+		if (rectangle instanceof MonitorAwareRectangle monitorAwareRectangle) {
+			return monitorAwareRectangle;
+		}
+		return new MonitorAwareRectangle(rectangle.x, rectangle.y, rectangle.width, rectangle.height);
+	}
+
+	static MonitorAwarePoint createFrom(Point point) {
+		if (point instanceof MonitorAwarePoint monitorAwarePoint) {
+			return monitorAwarePoint;
+		}
+		return new MonitorAwarePoint(point.x, point.y);
+	}
+}
 }

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/DPIUtilTests.java

@@ -296,7 +296,7 @@ public void scaleUpPoint() {
 	@Test
 	public void scaleUpRectangle() {
 		Rectangle valueAt200 = new Rectangle(100, 150, 10, 14);
-		Rectangle valueAt150 = new Rectangle(75, 113, 8, 10);
+		Rectangle valueAt150 = new Rectangle(75, 113, 8, 11);
 		Rectangle valueAt100 = new Rectangle(50, 75, 5, 7);
 
 		Rectangle scaledValue = DPIUtil.autoScaleUp(valueAt100);
@@ -319,4 +319,40 @@ public void scaleUpRectangle() {
 		scaledValue = DPIUtil.scaleUp((Device) null, valueAt100, 100);
 		assertSame(valueAt100, scaledValue, "Scaling up Rectangle without zoom change with device failed");
 	}
+
+	@Test
+	public void scaleDownscaleUpRectangleInvertible() {
+		int[] zooms = new int[] {25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400};
+		for (int zoom1 : zooms) {
+			for (int zoom2 : zooms) {
+				for (int i = 1; i <= 10000; i++) {
+					Rectangle rect = new Rectangle(0, 0, i, i);
+					Rectangle scaleDown = DPIUtil.scaleDown(rect, zoom1);
+					Rectangle scaleUp = DPIUtil.scaleUp(scaleDown, zoom2);
+					scaleDown = DPIUtil.scaleDown(scaleUp, zoom2);
+					scaleUp = DPIUtil.scaleUp(scaleDown, zoom1);
+					assertEquals(rect.width, scaleUp.width);
+					assertEquals(rect.height, scaleUp.height);
+				}
+			}
+		}
+	}
+
+	@Test
+	public void scaleDownscaleUpPointInvertible() {
+		int[] zooms = new int[] {25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400};
+		for (int zoom1 : zooms) {
+			for (int zoom2 : zooms) {
+				for (int i = 1; i <= 10000; i++) {
+					Point pt = new Point(i, i);
+					Point scaleDown = DPIUtil.scaleDown(pt, zoom1);
+					Point scaleUp = DPIUtil.scaleUp(scaleDown, zoom2);
+					scaleDown = DPIUtil.scaleDown(scaleUp, zoom2);
+					scaleUp = DPIUtil.scaleUp(scaleDown, zoom1);
+					assertEquals(pt.x, scaleUp.x);
+					assertEquals(pt.y, scaleUp.y);
+				}
+			}
+		}
+	}
 }