Bug 480639: Provide monitor-specific DPI scaling / zoom level

Added API Monitor.getZoom() to get zoom on Mac & Windows

Change-Id: Ib1990d0cbb2190323f7204dd14c6674d99278efd
Signed-off-by: Lakshmi Shanmugam <lshanmug@in.ibm.com>

9 files changed, 214 insertions, 25 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os.c b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os.c
index b1c54882a0..cdf5c9dac6 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os.c
@@ -652,6 +652,23 @@ JNIEXPORT jint JNICALL OS_NATIVE(CRYPT_1OBJID_1BLOB_1sizeof)
 }
 #endif
 
+#ifndef NO_Call
+JNIEXPORT void JNICALL OS_NATIVE(Call)
+	(JNIEnv *env, jclass that, jintLong arg0, jintLong arg1, jint arg2, jintArray arg3, jintArray arg4)
+{
+	jint *lparg3=NULL;
+	jint *lparg4=NULL;
+	OS_NATIVE_ENTER(env, that, Call_FUNC);
+	if (arg3) if ((lparg3 = (*env)->GetIntArrayElements(env, arg3, NULL)) == NULL) goto fail;
+	if (arg4) if ((lparg4 = (*env)->GetIntArrayElements(env, arg4, NULL)) == NULL) goto fail;
+	((void (*)())arg0)(arg1, arg2, lparg3, lparg4);
+fail:
+	if (arg4 && lparg4) (*env)->ReleaseIntArrayElements(env, arg4, lparg4, 0);
+	if (arg3 && lparg3) (*env)->ReleaseIntArrayElements(env, arg3, lparg3, 0);
+	OS_NATIVE_EXIT(env, that, Call_FUNC);
+}
+#endif
+
 #ifndef NO_CallNextHookEx
 JNIEXPORT jintLong JNICALL OS_NATIVE(CallNextHookEx)
 	(JNIEnv *env, jclass that, jintLong arg0, jint arg1, jintLong arg2, jintLong arg3)
@@ -2850,6 +2867,18 @@ fail:
 }
 #endif
 
+#ifndef NO_FreeLibrary
+JNIEXPORT jboolean JNICALL OS_NATIVE(FreeLibrary)
+	(JNIEnv *env, jclass that, jintLong arg0)
+{
+	jboolean rc = 0;
+	OS_NATIVE_ENTER(env, that, FreeLibrary_FUNC);
+	rc = (jboolean)FreeLibrary((HMODULE)arg0);
+	OS_NATIVE_EXIT(env, that, FreeLibrary_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO_GCP_1RESULTS_1sizeof
 JNIEXPORT jint JNICALL OS_NATIVE(GCP_1RESULTS_1sizeof)
 	(JNIEnv *env, jclass that)
@@ -4524,6 +4553,22 @@ JNIEXPORT jint JNICALL OS_NATIVE(GetPolyFillMode)
 }
 #endif
 
+#ifndef NO_GetProcAddress
+JNIEXPORT jintLong JNICALL OS_NATIVE(GetProcAddress)
+	(JNIEnv *env, jclass that, jintLong arg0, jbyteArray arg1)
+{
+	jbyte *lparg1=NULL;
+	jintLong rc = 0;
+	OS_NATIVE_ENTER(env, that, GetProcAddress_FUNC);
+	if (arg1) if ((lparg1 = (*env)->GetByteArrayElements(env, arg1, NULL)) == NULL) goto fail;
+	rc = (jintLong)GetProcAddress((HMODULE)arg0, (LPCTSTR)lparg1);
+fail:
+	if (arg1 && lparg1) (*env)->ReleaseByteArrayElements(env, arg1, lparg1, 0);
+	OS_NATIVE_EXIT(env, that, GetProcAddress_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO_GetProcessHeap
 JNIEXPORT jintLong JNICALL OS_NATIVE(GetProcessHeap)
 	(JNIEnv *env, jclass that)
@@ -6720,6 +6765,38 @@ JNIEXPORT jintLong JNICALL OS_NATIVE(LoadImageW)
 }
 #endif
 
+#ifndef NO_LoadLibraryA
+JNIEXPORT jintLong JNICALL OS_NATIVE(LoadLibraryA)
+	(JNIEnv *env, jclass that, jbyteArray arg0)
+{
+	jbyte *lparg0=NULL;
+	jintLong rc = 0;
+	OS_NATIVE_ENTER(env, that, LoadLibraryA_FUNC);
+	if (arg0) if ((lparg0 = (*env)->GetByteArrayElements(env, arg0, NULL)) == NULL) goto fail;
+	rc = (jintLong)LoadLibraryA((LPSTR)lparg0);
+fail:
+	if (arg0 && lparg0) (*env)->ReleaseByteArrayElements(env, arg0, lparg0, 0);
+	OS_NATIVE_EXIT(env, that, LoadLibraryA_FUNC);
+	return rc;
+}
+#endif
+
+#ifndef NO_LoadLibraryW
+JNIEXPORT jintLong JNICALL OS_NATIVE(LoadLibraryW)
+	(JNIEnv *env, jclass that, jcharArray arg0)
+{
+	jchar *lparg0=NULL;
+	jintLong rc = 0;
+	OS_NATIVE_ENTER(env, that, LoadLibraryW_FUNC);
+	if (arg0) if ((lparg0 = (*env)->GetCharArrayElements(env, arg0, NULL)) == NULL) goto fail;
+	rc = (jintLong)LoadLibraryW((LPWSTR)lparg0);
+fail:
+	if (arg0 && lparg0) (*env)->ReleaseCharArrayElements(env, arg0, lparg0, 0);
+	OS_NATIVE_EXIT(env, that, LoadLibraryW_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO_LocalFree
 JNIEXPORT jintLong JNICALL OS_NATIVE(LocalFree)
 	(JNIEnv *env, jclass that, jintLong arg0)
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.c b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.c
index 57b1770c28..535c93ce32 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.c
@@ -59,6 +59,7 @@ char * OS_nativeFunctionNames[] = {
 	"CRYPT_1BIT_1BLOB_1sizeof",
 	"CRYPT_1INTEGER_1BLOB_1sizeof",
 	"CRYPT_1OBJID_1BLOB_1sizeof",
+	"Call",
 	"CallNextHookEx",
 	"CallWindowProcA",
 	"CallWindowProcW",
@@ -217,6 +218,7 @@ char * OS_nativeFunctionNames[] = {
 	"FillRect",
 	"FormatMessageA",
 	"FormatMessageW",
+	"FreeLibrary",
 	"GCP_1RESULTS_1sizeof",
 	"GESTURECONFIG_1sizeof",
 	"GESTUREINFO_1sizeof",
@@ -362,6 +364,7 @@ char * OS_nativeFunctionNames[] = {
 	"GetParent",
 	"GetPixel",
 	"GetPolyFillMode",
+	"GetProcAddress",
 	"GetProcessHeap",
 	"GetProfileStringA",
 	"GetProfileStringW",
@@ -533,6 +536,8 @@ char * OS_nativeFunctionNames[] = {
 	"LoadIconW",
 	"LoadImageA",
 	"LoadImageW",
+	"LoadLibraryA",
+	"LoadLibraryW",
 	"LocalFree",
 	"MAKELPARAM",
 	"MAKELRESULT",
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.h b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.h
index e2ba7db1a7..1e689e704a 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.h
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/library/os_stats.h
@@ -69,6 +69,7 @@ typedef enum {
 	CRYPT_1BIT_1BLOB_1sizeof_FUNC,
 	CRYPT_1INTEGER_1BLOB_1sizeof_FUNC,
 	CRYPT_1OBJID_1BLOB_1sizeof_FUNC,
+	Call_FUNC,
 	CallNextHookEx_FUNC,
 	CallWindowProcA_FUNC,
 	CallWindowProcW_FUNC,
@@ -227,6 +228,7 @@ typedef enum {
 	FillRect_FUNC,
 	FormatMessageA_FUNC,
 	FormatMessageW_FUNC,
+	FreeLibrary_FUNC,
 	GCP_1RESULTS_1sizeof_FUNC,
 	GESTURECONFIG_1sizeof_FUNC,
 	GESTUREINFO_1sizeof_FUNC,
@@ -372,6 +374,7 @@ typedef enum {
 	GetParent_FUNC,
 	GetPixel_FUNC,
 	GetPolyFillMode_FUNC,
+	GetProcAddress_FUNC,
 	GetProcessHeap_FUNC,
 	GetProfileStringA_FUNC,
 	GetProfileStringW_FUNC,
@@ -543,6 +546,8 @@ typedef enum {
 	LoadIconW_FUNC,
 	LoadImageA_FUNC,
 	LoadImageW_FUNC,
+	LoadLibraryA_FUNC,
+	LoadLibraryW_FUNC,
 	LocalFree_FUNC,
 	MAKELPARAM_FUNC,
 	MAKELRESULT_FUNC,
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java
index 0f6fd03e7b..620a81f219 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java
@@ -958,6 +958,7 @@ public class OS extends C {
 	public static final int MCN_SELECT = MCN_FIRST + 4;
 	public static final int MCS_NOTODAY = 0x0010;
 	public static final int MDIS_ALLCHILDSTYLES = 0x0001;
+	public static final int MDT_EFFECTIVE_DPI = 0;
 	public static final int MFS_CHECKED = 0x8;
 	public static final int MFS_DISABLED = 0x3;
 	public static final int MFS_GRAYED = 0x3;
@@ -2166,6 +2167,26 @@ public static final native int WINDOWPLACEMENT_sizeof ();
 public static final native int WINDOWPOS_sizeof ();
 public static final native int WNDCLASS_sizeof ();
 
+public static final int GetDpiForMonitor (long /*int*/ hmonitor, int dpiType, int [] dpiX, int [] dpiY) {
+		TCHAR lpLibFileName = new TCHAR (0, "Shcore.dll", true); //$NON-NLS-1$
+		long /*int*/ hModule = OS.LoadLibrary (lpLibFileName);
+		if (hModule != 0) {
+			String name = "GetDpiForMonitor\0"; //$NON-NLS-1$
+			byte [] lpProcName = new byte [name.length ()];
+			for (int i=0; i<lpProcName.length; i++) {
+				lpProcName [i] = (byte) name.charAt (i);
+			}
+			long /*int*/ DllGetDpiForMonitor = OS.GetProcAddress (hModule, lpProcName);
+			if (DllGetDpiForMonitor != 0) {
+				dpiX [0] = dpiY [0] = -1;
+	 			OS.Call (DllGetDpiForMonitor, hmonitor, dpiType, dpiX, dpiY);
+			}
+			OS.FreeLibrary (hModule);
+			return dpiX [0] == -1 ? -1 : 0; // return result if API call succeeded
+		}
+		return -1;
+}
+
 /** Ansi/Unicode wrappers */
 
 public static final long /*int*/ AddFontResourceEx (TCHAR lpszFilename, int fl, long /*int*/ pdv) {
@@ -2679,6 +2700,15 @@ public static final long /*int*/ LoadImage (long /*int*/ hinst, long /*int*/ lps
 	return LoadImageA (hinst, lpszName, uType, cxDesired, cyDesired, fuLoad);
 }
 
+public static final long /*int*/ LoadLibrary (TCHAR lpLibFileName) {
+	if (IsUnicode) {
+		char [] lpLibFileName1 = lpLibFileName == null ? null : lpLibFileName.chars;
+		return LoadLibraryW (lpLibFileName1);
+	}
+	byte [] lpLibFileName1 = lpLibFileName == null ? null : lpLibFileName.bytes;
+	return LoadLibraryA (lpLibFileName1);
+}
+
 public static final int MapVirtualKey (int uCode, int uMapType) {
 	if (IsUnicode) return MapVirtualKeyW (uCode, uMapType);
 	return MapVirtualKeyA (uCode, uMapType);
@@ -3253,6 +3283,7 @@ public static final native boolean BringWindowToTop (long /*int*/ hWnd);
 public static final native int BufferedPaintInit ();
 /** @method flags=dynamic */
 public static final native int BufferedPaintUnInit ();
+public static native void Call (long /*int*/ address, long /*int*/ hmonitor, int dpiType, int[] dpiX, int[] dpiY);
 /**
  * @param hhk cast=(HHOOK)
  * @param wParam cast=(WPARAM)
@@ -3743,6 +3774,8 @@ public static final native int FormatMessageA (int dwFlags, long /*int*/ lpSourc
  * @param Arguments cast=(va_list*)
  */
 public static final native int FormatMessageW (int dwFlags, long /*int*/ lpSource, int dwMessageId, int dwLanguageId, long /*int*/ [] lpBuffer, int nSize, long /*int*/ Arguments);
+/** @param hLibModule cast=(HMODULE) */
+public static final native boolean FreeLibrary (long /*int*/ hLibModule);
 /** @param dwLimit cast=(DWORD) */
 public static final native int GdiSetBatchLimit (int dwLimit);
 public static final native int GET_WHEEL_DELTA_WPARAM(long /*int*/ wParam);
@@ -4054,6 +4087,11 @@ public static final native boolean OpenPrinterW (char[] pPrinterName, long /*int
  * @param pDefault cast=(LPPRINTER_DEFAULTS)
  */
 public static final native boolean OpenPrinterA (byte[] pPrinterName, long /*int*/ [] phPrinter, long /*int*/ pDefault);
+/**
+ * @param hModule cast=(HMODULE)
+ * @param lpProcName cast=(LPCTSTR)
+ */
+public static final native long /*int*/ GetProcAddress (long /*int*/ hModule, byte [] lpProcName);
 public static final native long /*int*/ GetProcessHeap ();
 /**
  * @param lpAppName cast=(LPWSTR)
@@ -4494,6 +4532,10 @@ public static final native long /*int*/ LoadImageW (long /*int*/ hinst, long /*i
  * @param lpszName cast=(LPSTR)
  */
 public static final native long /*int*/ LoadImageA (long /*int*/ hinst, long /*int*/ lpszName, int uType, int cxDesired, int cyDesired, int fuLoad);
+/** @param lpLibFileName cast=(LPWSTR) */
+public static final native long /*int*/ LoadLibraryW (char [] lpLibFileName);
+/** @param lpLibFileName cast=(LPSTR) */
+public static final native long /*int*/ LoadLibraryA (byte [] lpLibFileName);
 /** @param hMem cast=(HLOCAL) */
 public static final native long /*int*/ LocalFree (long /*int*/ hMem);
 public static final native int LODWORD (long l);
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java b/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java
index db5b77ba3f..021e5b7988 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java
@@ -1693,6 +1693,7 @@ public Monitor [] getMonitors () {
 		monitor.clientY = (int)(primaryFrame.height - (visibleFrame.y + visibleFrame.height));
 		monitor.clientWidth = (int)visibleFrame.width;
 		monitor.clientHeight = (int)visibleFrame.height;
+		monitor.zoom = (int) (screen.backingScaleFactor() * 100);
 		monitors [i] = monitor;
 	}
 	return monitors;
@@ -1726,6 +1727,7 @@ public Monitor getPrimaryMonitor () {
 	monitor.clientY = (int)(frame.height - (visibleFrame.y + visibleFrame.height));
 	monitor.clientWidth = (int)visibleFrame.width;
 	monitor.clientHeight = (int)visibleFrame.height;
+	monitor.zoom = (int) (screen.backingScaleFactor() * 100);
 	return monitor;
 }
 
@@ -6542,3 +6544,9 @@ static long /*int*/ windowProc(long /*int*/ id, long /*int*/ sel, long /*int*/ a
 }
 
 }
+
+class MonitorUtil {
+	static int getZoom (Monitor monitor) {
+		return monitor.zoom;
+	}
+}
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java
index 17708de993..1ef8de15be 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/DPIUtil.java
@@ -39,6 +39,8 @@ public class DPIUtil {
 	private static AutoScaleMethod autoScaleMethodSetting = AutoScaleMethod.AUTO;
 	private static AutoScaleMethod autoScaleMethod = AutoScaleMethod.NEAREST;
 
+	private static String autoScaleValue;
+
 	/**
 	 * System property that controls the autoScale functionality.
 	 * <ul>
@@ -73,6 +75,8 @@ public class DPIUtil {
 	 */
 	private static final String SWT_AUTOSCALE_METHOD = "swt.autoScale.method";
 	static {
+		autoScaleValue = System.getProperty (SWT_AUTOSCALE);
+
 		String value = System.getProperty (SWT_AUTOSCALE_METHOD);
 		if (value != null) {
 			if (AutoScaleMethod.NEAREST.name().equalsIgnoreCase(value)) {
@@ -419,31 +423,7 @@ public static int getDeviceZoom() {
 
 public static void setDeviceZoom (int nativeDeviceZoom) {
 	DPIUtil.nativeDeviceZoom = nativeDeviceZoom;
-	int deviceZoom = 0;
-	String value = System.getProperty (SWT_AUTOSCALE);
- 	if (value != null) {
-		if ("false".equalsIgnoreCase (value)) {
-			deviceZoom = 100;
-		} else if ("quarter".equalsIgnoreCase (value)) {
-			deviceZoom = (int) (Math.round (nativeDeviceZoom / 25f) * 25);
-		} else if ("exact".equalsIgnoreCase (value)) {
-			deviceZoom = nativeDeviceZoom;
-		} else {
-			try {
-				int zoom = Integer.parseInt (value);
-				deviceZoom = Math.max (Math.min (zoom, 1600), 25);
-			} catch (NumberFormatException e) {
-				// unsupported value, use default
-			}
-		}
-	}
- 	if (deviceZoom == 0) { // || "integer".equalsIgnoreCase (value) || "integer200".equalsIgnoreCase (value)
-		deviceZoom = Math.max ((nativeDeviceZoom + 25) / 100 * 100, 100);
-		if (!"integer".equalsIgnoreCase(value)) {
-			// integer200, or default
-			deviceZoom = Math.min (deviceZoom, 200);
-		}
-	}
+	int deviceZoom = getZoomForAutoscaleProperty (nativeDeviceZoom);
 
 	DPIUtil.deviceZoom = deviceZoom;
 	System.setProperty("org.eclipse.swt.internal.deviceZoom", Integer.toString(deviceZoom));
@@ -456,6 +436,34 @@ public static void setDeviceZoom (int nativeDeviceZoom) {
 	}
 }
 
+public static int getZoomForAutoscaleProperty (int nativeDeviceZoom) {
+	int zoom = 0;
+ 	if (autoScaleValue != null) {
+		if ("false".equalsIgnoreCase (autoScaleValue)) {
+			zoom = 100;
+		} else if ("quarter".equalsIgnoreCase (autoScaleValue)) {
+			zoom = (int) (Math.round (nativeDeviceZoom / 25f) * 25);
+		} else if ("exact".equalsIgnoreCase (autoScaleValue)) {
+			zoom = nativeDeviceZoom;
+		} else {
+			try {
+				int zoomValue = Integer.parseInt (autoScaleValue);
+				zoom = Math.max (Math.min (zoomValue, 1600), 25);
+			} catch (NumberFormatException e) {
+				// unsupported value, use default
+			}
+		}
+	}
+ 	if (zoom == 0) { // || "integer".equalsIgnoreCase (value) || "integer200".equalsIgnoreCase (value)
+		zoom = Math.max ((nativeDeviceZoom + 25) / 100 * 100, 100);
+		if (!"integer".equalsIgnoreCase(autoScaleValue)) {
+			// integer200, or default
+			zoom = Math.min (zoom, 200);
+		}
+	}
+	return zoom;
+}
+
 /**
  * AutoScale ImageDataProvider.
  */
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Monitor.java b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Monitor.java
index b797fd8193..6120916807 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Monitor.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Monitor.java
@@ -25,6 +25,7 @@ public final class Monitor {
 	long /*int*/ handle;
 	int x, y, width, height;
 	int clientX, clientY, clientWidth, clientHeight;
+	int zoom;
 
 /**
  * Prevents uninitialized instances from being created outside the package.
@@ -71,6 +72,17 @@ public Rectangle getClientArea () {
 	return new Rectangle (clientX, clientY, clientWidth, clientHeight);
 }
 
+/**
+ * Returns the zoom value for the monitor
+ *
+ * @return monitor's zoom value
+ *
+ * @since 3.107
+ */
+public int getZoom () {
+	return MonitorUtil.getZoom (this);
+}
+
 void setBounds (Rectangle rect) {
 	x = rect.x;
 	y = rect.y;
@@ -85,6 +97,10 @@ void setClientArea (Rectangle rect) {
 	clientHeight = rect.height;
 }
 
+void setZoom (int zoom) {
+	this.zoom = zoom;
+}
+
 /**
  * Returns an integer hash code for the receiver. Any two
  * objects that return <code>true</code> when passed to
@@ -94,6 +110,7 @@ void setClientArea (Rectangle rect) {
  * @return the receiver's hash
  *
  * @see #equals(Object)
+ *
  */
 @Override
 public int hashCode () {
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
index d17b7e5579..e00c1e60cf 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
@@ -5957,3 +5957,9 @@ protected long /*int*/ gsettingsProc (long /*int*/ gobject, long /*int*/ arg1, l
 
 
 }
+
+class MonitorUtil {
+	static int getZoom (Monitor monitor) {
+		return monitor.zoom;
+	}
+}
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java
index fc7698f4fa..e0aa444757 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java
@@ -4990,3 +4990,24 @@ static char [] withCrLf (char [] string) {
 }
 
 }
+
+class MonitorUtil {
+	static int getZoom (Monitor monitor) {
+		if (OS.WIN32_VERSION >= OS.VERSION (6, 3)) {
+			int[] dpiX = new int[1];
+			int[] dpiY = new int[1];
+			int result = OS.GetDpiForMonitor (monitor.handle, OS.MDT_EFFECTIVE_DPI, dpiX, dpiY);
+			result = (result == OS.S_OK) ? DPIUtil.mapDPIToZoom (dpiX[0]) : 100;
+			return DPIUtil.getZoomForAutoscaleProperty (result);
+		}
+		int dpi = getSystemDPI ();
+		return DPIUtil.mapDPIToZoom (dpi);
+	}
+
+	static int getSystemDPI () {
+		long /*int*/ hDC = OS.GetDC (0);
+		int dpi = OS.GetDeviceCaps (hDC, OS.LOGPIXELSX);
+		OS.ReleaseDC (0, hDC);
+		return dpi;
+	}
+}