[win32] Fix pointer size scaling precision for custom cursors

The value in the registry for CursorBaseSize is not always divisible by
32, so integer division was causing loss of precision in pointer
scaling. This commit changes getPointerSizeScaleFactor() to return a
float using floating-point division, and ensures all usages of this
method in Cursor.java handle the scale as a float. The float is then
cast to int only when calling DPIUtil.scaleImageData, which only accepts
integer zoom values. This preserves as much precision as possible and
avoids rounding errors in pointer scaling for accessibility settings.

Author: ShahzaibIbrahim

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Cursor.java

@@ -352,14 +352,14 @@ private void setHandleForZoomLevel(CursorHandle handle, Integer zoom) {
  *         size, etc.)
  */
 
-private static int getPointerSizeScaleFactor() {
+private static float getPointerSizeScaleFactor() {
 	if (OsVersion.IS_WIN10_1809) {
 		int[] cursorBaseSize = OS.readRegistryDwords(OS.HKEY_CURRENT_USER, "Control Panel\\Cursors", "CursorBaseSize");
 		if (cursorBaseSize != null && cursorBaseSize.length > 0 && cursorBaseSize[0] > 0) {
-			return cursorBaseSize[0] / 32;
+			return cursorBaseSize[0] / 32.0f;
 		}
 	}
-	return 1;
+	return 1.0f;
 }
 
 @Override
@@ -648,8 +648,9 @@ public ImageDataCursorHandleProvider(ImageData source, int hotspotX, int hotspot
 
 	@Override
 	public CursorHandle createHandle(Device device, int zoom) {
-		int accessibilityFactor = getPointerSizeScaleFactor();
-		ImageData scaledSource = DPIUtil.scaleImageData(device, this.source, zoom * accessibilityFactor, DEFAULT_ZOOM);
+		float accessibilityFactor = getPointerSizeScaleFactor();
+		int scaledZoom = (int) (zoom * accessibilityFactor);
+		ImageData scaledSource = DPIUtil.scaleImageData(device, this.source, scaledZoom, DEFAULT_ZOOM);
 		return setupCursorFromImageData(device, scaledSource, null, getHotpotXInPixels(zoom),
 				getHotpotYInPixels(zoom));
 	}
@@ -680,8 +681,10 @@ private void validateMask(ImageData source, ImageData mask) {
 
 	@Override
 	public CursorHandle createHandle(Device device, int zoom) {
-		ImageData scaledSource = DPIUtil.scaleImageData(device, this.source, getPointerSizeScaleFactor() * zoom, DEFAULT_ZOOM);
-		ImageData scaledMask = this.mask != null ? DPIUtil.scaleImageData(device, mask, getPointerSizeScaleFactor() * zoom, DEFAULT_ZOOM)
+		float accessibilityFactor = getPointerSizeScaleFactor();
+		int scaledZoom = (int) (zoom * accessibilityFactor);
+		ImageData scaledSource = DPIUtil.scaleImageData(device, this.source, scaledZoom, DEFAULT_ZOOM);
+		ImageData scaledMask = this.mask != null ? DPIUtil.scaleImageData(device, mask, scaledZoom, DEFAULT_ZOOM)
 				: null;
 
 		return setupCursorFromImageData(device, scaledSource, scaledMask, getHotpotXInPixels(zoom),