From cbcf0c931278671f4db01ff384f4973a7be322eb Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Thu, 21 Jun 2012 08:52:29 +0000
Subject: Fixed STR #2644: support horizontal wheel movement under X11 and
 MSWindows.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9624 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/Fl_win32.cxx | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'src/Fl_win32.cxx')

diff --git a/src/Fl_win32.cxx b/src/Fl_win32.cxx
index 18a34dd05..e1107cb6a 100644
--- a/src/Fl_win32.cxx
+++ b/src/Fl_win32.cxx
@@ -1115,12 +1115,28 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lPar
   case WM_MOUSEWHEEL: {
     static int delta = 0; // running total of all motion
     delta += (SHORT)(HIWORD(wParam));
+    Fl::e_dx = 0;
     Fl::e_dy = -delta / WHEEL_DELTA;
     delta += Fl::e_dy * WHEEL_DELTA;
     if (Fl::e_dy) Fl::handle(FL_MOUSEWHEEL, window);
     return 0;
   }
 
+// This is only defined on Vista and upwards...
+#ifndef WM_MOUSEHWHEEL
+#define WM_MOUSEHWHEEL 0x020E
+#endif
+      
+  case WM_MOUSEHWHEEL: {
+      static int delta = 0; // running total of all motion
+      delta += (SHORT)(HIWORD(wParam));
+      Fl::e_dy = 0;
+      Fl::e_dx = delta / WHEEL_DELTA;
+      delta -= Fl::e_dx * WHEEL_DELTA;
+      if (Fl::e_dx) Fl::handle(FL_MOUSEWHEEL, window);
+      return 0;
+    }
+
   case WM_GETMINMAXINFO:
     Fl_X::i(window)->set_minmax((LPMINMAXINFO)lParam);
     break;
-- 
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