Win32DPIUtils:pointToPixel shouldn't have residual

This commit contributes to scaling points and rectangles from point to
pixels while making sure they do not have any residuals since the OS doesn't
support sub-pixel drawing.

contributes to #62

Author: amartya4256

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/Win32DPIUtils.java

@@ -225,7 +225,8 @@ public static Point pointToPixel(Point point, int zoom) {
 		float scaleFactor = DPIUtil.getScalingFactor(zoom);
 		float scaledX = fPoint.getX() * scaleFactor;
 		float scaledY = fPoint.getY() * scaleFactor;
-		return new Point.OfFloat(scaledX, scaledY);
+		Point scaledPoint = new Point.OfFloat(scaledX, scaledY);
+		return new Point.OfFloat(scaledPoint.x, scaledPoint.y);
 	}
 
 	public static Point pointToPixel(Drawable drawable, Point point, int zoom) {
@@ -248,7 +249,8 @@ public static Rectangle pointToPixel(Rectangle rect, int zoom) {
 	}
 
 	private static Rectangle pointToPixel(Rectangle.OfFloat rect, int zoom) {
-		return scaleBounds(rect, zoom, 100);
+		Rectangle scaledRectangle = scaleBounds(rect, zoom, 100);
+		return new Rectangle.OfFloat(scaledRectangle.x, scaledRectangle.y, scaledRectangle.width, scaledRectangle.height);
 	}
 
 	public static Rectangle pointToPixel(Drawable drawable, Rectangle rect, int zoom) {

tests/org.eclipse.swt.tests.win32/JUnit Tests/org/eclipse/swt/tests/win32/Win32DPIUtilTests.java

@@ -222,15 +222,27 @@ public void scaleUpRectangle() {
 
 	@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 zoom : zooms) {
+			for (int i = 1; i <= 10000; i++) {
+				Rectangle rect = new Rectangle.OfFloat(0, 0, i, i);
+				Rectangle scaleDown = Win32DPIUtils.pixelToPoint(rect, zoom);
+				Rectangle scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom);
+				assertEquals(rect.width, scaleUp.width);
+				assertEquals(rect.height, scaleUp.height);
+			}
+		}
+	}
+
+	@Test
+	public void scaleBoundsRectangleInvertible() {
 		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.OfFloat(0, 0, i, i);
-					Rectangle scaleDown = Win32DPIUtils.pixelToPoint(rect, zoom1);
-					Rectangle scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom2);
-					scaleDown = Win32DPIUtils.pixelToPoint(scaleUp, zoom2);
-					scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom1);
+					Rectangle scaleDown = Win32DPIUtils.scaleBounds(rect, zoom1, zoom2);
+					Rectangle scaleUp = Win32DPIUtils.scaleBounds(scaleDown, zoom2, zoom1);
 					assertEquals(rect.width, scaleUp.width);
 					assertEquals(rect.height, scaleUp.height);
 				}
@@ -240,18 +252,14 @@ public void scaleDownscaleUpRectangleInvertible() {
 
 	@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 = Win32DPIUtils.pixelToPoint(pt, zoom1);
-					Point scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom2);
-					scaleDown = Win32DPIUtils.pixelToPoint(scaleUp, zoom2);
-					scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom1);
-					assertEquals(pt.x, scaleUp.x);
-					assertEquals(pt.y, scaleUp.y);
-				}
+		int[] zooms = new int[] {100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400};
+		for (int zoom : zooms) {
+			for (int i = 1; i <= 10000; i++) {
+				Point pt = new Point(i, i);
+				Point scaleDown = Win32DPIUtils.pixelToPoint(pt, zoom);
+				Point scaleUp = Win32DPIUtils.pointToPixel(scaleDown, zoom);
+				assertEquals(pt.x, scaleUp.x);
+				assertEquals(pt.y, scaleUp.y);
 			}
 		}
 	}