Bug 515502 - [HiDPI][Win10] SWT to receive/handle DPI changeI20180814-0900

notification from OS

Change-Id: Ic0b851b76cbd5b270f4d4337de6ac6f2fb81812c
Signed-off-by: Niraj Modi <niraj.modi@in.ibm.com>

4 files changed, 50 insertions, 3 deletions

diff --git a/bundles/org.eclipse.swt/.settings/.api_filters b/bundles/org.eclipse.swt/.settings/.api_filters
index bcc9c37500..2b7877280c 100644
--- a/bundles/org.eclipse.swt/.settings/.api_filters
+++ b/bundles/org.eclipse.swt/.settings/.api_filters
@@ -1227,6 +1227,12 @@
                 <message_argument value="OpenUrl"/>
             </message_arguments>
         </filter>
+        <filter id="336658481">
+            <message_arguments>
+                <message_argument value="org.eclipse.swt.SWT"/>
+                <message_argument value="ZoomChanged"/>
+            </message_arguments>
+        </filter>
         <filter comment="@since 3.8 is valid in the 3.100 stream" id="1141899266">
             <message_arguments>
                 <message_argument value="3.8"/>
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 a7c4c48119..a9de9f7239 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
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2017 IBM Corporation and others.
+ * Copyright (c) 2000, 2018 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -1885,6 +1885,7 @@ public class OS extends C {
 	public static final int WM_CUT = 0x300;
 	public static final int WM_DEADCHAR = 0x103;
 	public static final int WM_DESTROY = 0x2;
+	public static final int WM_DPICHANGED = 0x02E0;
 	public static final int WM_DRAWITEM = 0x2b;
 	public static final int WM_ENDSESSION = 0x16;
 	public static final int WM_ENTERIDLE = 0x121;
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
index ea709c0fb6..bec63ae242 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2015 IBM Corporation and others.
+ * Copyright (c) 2000, 2018 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -856,6 +856,26 @@ public class SWT {
 	 */
 	public static final int OpenUrl = 54;
 
+	/**
+	 * The SWT zoom change event type (value is 55).
+	 *
+	 * <p>
+	 * This event is sent on <code>Shell</code> when the SWT zoom has changed. SWT
+	 * zoom changes when the system DPI or scale factor changes dynamically.
+	 * </p>
+	 * <p>
+	 * Note: This operation is a hint and is not supported on platforms that do not
+	 * have this concept. Currently supported on Windows10 only.
+	 * </p>
+	 *
+	 * @see org.eclipse.swt.widgets.Widget#addListener
+	 * @see org.eclipse.swt.widgets.Display#addFilter
+	 * @see org.eclipse.swt.widgets.Event
+	 *
+	 * @since 3.108
+	 */
+	public static final int ZoomChanged = 55;
+
 	/* Event Details */
 
 	/**
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
index e4e50d9bc5..a759761064 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2017 IBM Corporation and others.
+ * Copyright (c) 2000, 2018 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -4855,6 +4855,7 @@ long /*int*/ windowProc (long /*int*/ hwnd, int msg, long /*int*/ wParam, long /
 		case OS.WM_XBUTTONDBLCLK:		result = WM_XBUTTONDBLCLK (wParam, lParam); break;
 		case OS.WM_XBUTTONDOWN:			result = WM_XBUTTONDOWN (wParam, lParam); break;
 		case OS.WM_XBUTTONUP:			result = WM_XBUTTONUP (wParam, lParam); break;
+		case OS.WM_DPICHANGED:			result = WM_DPICHANGED (wParam, lParam); break;
 	}
 	if (result != null) return result.value;
 	// widget could be disposed at this point
@@ -4937,6 +4938,25 @@ LRESULT WM_DESTROY (long /*int*/ wParam, long /*int*/ lParam) {
 	return null;
 }
 
+LRESULT WM_DPICHANGED (long /*int*/ wParam, long /*int*/ lParam) {
+	// Map DPI to Zoom and compare
+	int nativeZoom = DPIUtil.mapDPIToZoom (OS.HIWORD (wParam));
+	int newSWTZoom = DPIUtil.getZoomForAutoscaleProperty (nativeZoom);
+	int oldSWTZoom = DPIUtil.getDeviceZoom();
+
+	// Throw the DPI change event if zoom value changes
+	if (newSWTZoom != oldSWTZoom) {
+		Event event = new Event();
+		event.type = SWT.ZoomChanged;
+		event.widget = this;
+		event.detail = newSWTZoom;
+		event.doit = true;
+		notifyListeners(SWT.ZoomChanged, event);
+		return LRESULT.ZERO;
+	}
+	return LRESULT.ONE;
+}
+
 LRESULT WM_DRAWITEM (long /*int*/ wParam, long /*int*/ lParam) {
 	DRAWITEMSTRUCT struct = new DRAWITEMSTRUCT ();
 	OS.MoveMemory (struct, lParam, DRAWITEMSTRUCT.sizeof);