mouse wheel scroll hack2

1 files changed, 30 insertions, 3 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
index 6893e4ed6c..02fceaaca5 100755
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
@@ -235,16 +235,41 @@ LRESULT WM_HSCROLL (int wParam, int lParam) {
 LRESULT WM_MOUSEWHEEL (int wParam, int lParam) {

 	LRESULT result = super.WM_MOUSEWHEEL (wParam, lParam);

 	if (result != null) return result;

-	int position = verticalBar == null ? 0 : verticalBar.getSelection ();

+	

+	// Implement scrolling for Canvas type widgets.

+	// For all native widgets, rely on the native widget to handle WM_MOUSEWHEEL

+	if ((state & CANVAS) != 0) {

+		if (verticalBar == null && horizontalBar == null) return LRESULT.ZERO;

+		int wheelDelta = (short)-(wParam >> 16);

+		if (wheelDelta < OS.WHEEL_DELTA) return new LRESULT(0);

+		int[] value = new int[1];

+   		OS.SystemParametersInfo(OS.SPI_GETWHEELSCROLLLINES, 0, value, 0);

+		int increment = value[0] * wheelDelta / OS.WHEEL_DELTA;

+		System.out.println("Scroll canvas by "+increment);

+		

+		return LRESULT.ZERO;

+	}

+		

+	// When the native widget scrolls inside the WM_MOUSEWHEEL event, no WM_VSCROLL or WM_HSCROLL event 

+	// is sent and the application does not get notified that the widget has scrolled.  

+	// Check for a change in the scrollbar position and notify the application. 

+	int vPosition = verticalBar == null ? 0 : verticalBar.getSelection ();

+	int hPosition = horizontalBar == null ? 0 : horizontalBar.getSelection ();

 	int code = callWindowProc (OS.WM_MOUSEWHEEL, wParam, lParam);

 	if (verticalBar != null) {

-		if (verticalBar.getSelection() != position) {

+		if (verticalBar.getSelection() != vPosition) {

 			Event event = new Event ();

 			event.detail = SWT.DRAG; 

-			//CAN SEND MULTIPLE

 			verticalBar.sendEvent (SWT.Selection, event);

 		}

 	}

+	if (horizontalBar != null) {

+		if (horizontalBar.getSelection() != hPosition) {

+			Event event = new Event ();

+			event.detail = SWT.DRAG; 

+			horizontalBar.sendEvent (SWT.Selection, event);

+		}

+	}

 	return new LRESULT (code);

 }

 

@@ -257,6 +282,8 @@ LRESULT WM_SIZE (int wParam, int lParam) {
 }

 

 LRESULT WM_VSCROLL (int wParam, int lParam) {

+	new Error().printStackTrace();

+	

 	LRESULT result = super.WM_VSCROLL (wParam, lParam);

 	if (result != null) return result;