Examples: Win32: Fixed handling of mouse wheel messages to support finer position messages (typically sent by track-pads). (#1874)

CHANGELOG.txt

@@ -77,6 +77,7 @@ Other Changes:
  - ImFontConfig: Added GlyphMinAdvanceX/GlyphMaxAdvanceX settings useful to make a font appears monospaced, particularly useful for icon fonts. (#1869)
  - ImFontAtlas: Added GetGlyphRangesChineseSimplifiedCommon() helper that returns a list of ~2500 most common Simplified Chinese characters. (#1859) [@JX-Master, @ocornut]
  - Examples: GLFW: Made it possible to Shutdown/Init the backend again (by reseting the time storage properly). (#1827) [@ice1000]
+ - Examples: Win32: Fixed handling of mouse wheel messages to support finer position messages (typically sent by track-pads). (#1874) [zx64]  
  - Examples: Allegro5: Added support for ImGuiConfigFlags_NoMouseCursorChange flag.
  - Misc: Updated stb_textedit from 1.09 + patches to 1.12 + minor patches.
  - Internals: PushItemFlag() flags are inherited by BeginChild().

examples/imgui_impl_win32.cpp

@@ -13,6 +13,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2018-06-10: Inputs: Fixed handling of mouse wheel messages to support fine position messages (typically sent by track-pads).
 //  2018-06-08: Misc: Extracted imgui_impl_win32.cpp/.h away from the old combined DX9/DX10/DX11/DX12 examples.
 //  2018-03-20: Misc: Setup io.BackendFlags ImGuiBackendFlags_HasMouseCursors and ImGuiBackendFlags_HasSetMousePos flags + honor ImGuiConfigFlags_NoMouseCursorChange flag.
 //  2018-02-20: Inputs: Added support for mouse cursors (ImGui::GetMouseCursor() value and WM_SETCURSOR message handling).
@@ -210,10 +211,10 @@ IMGUI_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wPa
         return 0;
     }
     case WM_MOUSEWHEEL:
-        io.MouseWheel += GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        io.MouseWheel += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
         return 0;
     case WM_MOUSEHWHEEL:
-        io.MouseWheelH += GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        io.MouseWheelH += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
         return 0;
     case WM_KEYDOWN:
     case WM_SYSKEYDOWN: