Began adding some win8.1 DPI functionality.

modules/juce_gui_basics/native/juce_win32_Windowing.cpp

@@ -102,17 +102,38 @@ bool Desktop::canUseSemiTransparentWindows() noexcept
 
 #endif
 
+#ifndef MONITOR_DPI_TYPE
+  enum Monitor_DPI_Type
+  {
+    MDT_Effective_DPI  = 0,
+    MDT_Angular_DPI    = 1,
+    MDT_Raw_DPI        = 2,
+    MDT_Default        = MDT_Effective_DPI
+  };
+
+  enum Process_DPI_Awareness
+  {
+    Process_DPI_Unaware            = 0,
+    Process_System_DPI_Aware       = 1,
+    Process_Per_Monitor_DPI_Aware  = 2
+  };
+#endif
+
 typedef BOOL (WINAPI* RegisterTouchWindowFunc) (HWND, ULONG);
 typedef BOOL (WINAPI* GetTouchInputInfoFunc) (HTOUCHINPUT, UINT, TOUCHINPUT*, int);
 typedef BOOL (WINAPI* CloseTouchInputHandleFunc) (HTOUCHINPUT);
 typedef BOOL (WINAPI* GetGestureInfoFunc) (HGESTUREINFO, GESTUREINFO*);
 typedef BOOL (WINAPI* SetProcessDPIAwareFunc)();
+typedef BOOL (WINAPI* SetProcessDPIAwarenessFunc) (Process_DPI_Awareness);
+typedef HRESULT (WINAPI* GetDPIForMonitorFunc) (HMONITOR, Monitor_DPI_Type, UINT*, UINT*);
 
-static RegisterTouchWindowFunc   registerTouchWindow = nullptr;
-static GetTouchInputInfoFunc     getTouchInputInfo = nullptr;
-static CloseTouchInputHandleFunc closeTouchInputHandle = nullptr;
-static GetGestureInfoFunc        getGestureInfo = nullptr;
-static SetProcessDPIAwareFunc    setProcessDPIAware = nullptr;
+static RegisterTouchWindowFunc    registerTouchWindow = nullptr;
+static GetTouchInputInfoFunc      getTouchInputInfo = nullptr;
+static CloseTouchInputHandleFunc  closeTouchInputHandle = nullptr;
+static GetGestureInfoFunc         getGestureInfo = nullptr;
+static SetProcessDPIAwareFunc     setProcessDPIAware = nullptr;
+static SetProcessDPIAwarenessFunc setProcessDPIAwareness = nullptr;
+static GetDPIForMonitorFunc       getDPIForMonitor = nullptr;
 
 static bool hasCheckedForMultiTouch = false;
 
@@ -158,17 +179,33 @@ static void setDPIAwareness()
 {
     if (JUCEApplicationBase::isStandaloneApp())
     {
-        if (setProcessDPIAware == nullptr)
+        if (setProcessDPIAwareness == nullptr)
         {
-            setProcessDPIAware = (SetProcessDPIAwareFunc) getUser32Function ("SetProcessDPIAware");
+            HMODULE shcoreModule = GetModuleHandleA ("SHCore.dll");
+
+            if (shcoreModule != 0)
+            {
+                setProcessDPIAwareness = (SetProcessDPIAwarenessFunc) GetProcAddress (shcoreModule, "SetProcessDpiAwareness");
+                getDPIForMonitor = (GetDPIForMonitorFunc) GetProcAddress (shcoreModule, "GetDpiForMonitor");
+
+                if (setProcessDPIAwareness != nullptr && getDPIForMonitor != nullptr
+//                     && SUCCEEDED (setProcessDPIAwareness (Process_Per_Monitor_DPI_Aware)))
+                     && SUCCEEDED (setProcessDPIAwareness (Process_System_DPI_Aware))) // (keep using this mode temporarily..)
+                    return;
+            }
+
+            if (setProcessDPIAware == nullptr)
+            {
+                setProcessDPIAware = (SetProcessDPIAwareFunc) getUser32Function ("SetProcessDPIAware");
 
-            if (setProcessDPIAware != nullptr)
-                setProcessDPIAware();
+                if (setProcessDPIAware != nullptr)
+                    setProcessDPIAware();
+            }
         }
     }
 }
 
-static double getDPI()
+static double getGlobalDPI()
 {
     setDPIAwareness();
 
@@ -181,7 +218,7 @@ static double getDPI()
 
 double Desktop::getDefaultMasterScale()
 {
-    return JUCEApplicationBase::isStandaloneApp() ? getDPI() / 96.0
+    return JUCEApplicationBase::isStandaloneApp() ? getGlobalDPI() / 96.0
                                                   : 1.0;
 }
 
@@ -2246,6 +2283,10 @@ private:
         }
     }
 
+    void handleDPIChange() // happens when a window moves to a screen with a different DPI.
+    {
+    }
+
     //==============================================================================
 public:
     static LRESULT CALLBACK windowProc (HWND h, UINT message, WPARAM wParam, LPARAM lParam)
@@ -2488,6 +2529,10 @@ private:
                 doSettingChange();
                 break;
 
+            case 0x2e0: // WM_DPICHANGED
+                handleDPIChange();
+                break;
+
             case WM_INITMENU:
                 initialiseSysMenu ((HMENU) wParam);
                 break;
@@ -3183,10 +3228,12 @@ void Desktop::setKioskComponent (Component* kioskModeComponent, bool enableOrDis
 //==============================================================================
 struct MonitorInfo
 {
-    MonitorInfo (Rectangle<int> rect, bool main) noexcept  : isMain (main), bounds (rect) {}
+    MonitorInfo (Rectangle<int> rect, bool main, double d) noexcept
+        : isMain (main), bounds (rect), dpi (d) {}
 
     Rectangle<int> bounds;
     bool isMain;
+    double dpi;
 };
 
 static BOOL CALLBACK enumMonitorsProc (HMONITOR hm, HDC, LPRECT r, LPARAM userInfo)
@@ -3195,7 +3242,17 @@ static BOOL CALLBACK enumMonitorsProc (HMONITOR hm, HDC, LPRECT r, LPARAM userIn
     info.cbSize = sizeof (info);
     GetMonitorInfo (hm, &info);
     const bool isMain = (info.dwFlags & 1 /* MONITORINFOF_PRIMARY */) != 0;
-    ((Array<MonitorInfo>*) userInfo)->add (MonitorInfo (rectangleFromRECT (*r), isMain));
+    double dpi = 0;
+
+    if (getDPIForMonitor != nullptr)
+    {
+        UINT dpiX = 0, dpiY = 0;
+
+        if (SUCCEEDED (getDPIForMonitor (hm, MDT_Default, &dpiX, &dpiY)))
+            dpi = (dpiX + dpiY) / 2.0;
+    }
+
+    ((Array<MonitorInfo>*) userInfo)->add (MonitorInfo (rectangleFromRECT (*r), isMain, dpi));
 
     return TRUE;
 }
@@ -3207,8 +3264,10 @@ void Desktop::Displays::findDisplays (float masterScale)
     Array<MonitorInfo> monitors;
     EnumDisplayMonitors (0, 0, &enumMonitorsProc, (LPARAM) &monitors);
 
+    const double globalDPI = getGlobalDPI();
+
     if (monitors.size() == 0)
-        monitors.add (MonitorInfo (rectangleFromRECT (getWindowRect (GetDesktopWindow())), true));
+        monitors.add (MonitorInfo (rectangleFromRECT (getWindowRect (GetDesktopWindow())), true, globalDPI));
 
     // make sure the first in the list is the main monitor
     for (int i = 1; i < monitors.size(); ++i)
@@ -3218,15 +3277,22 @@ void Desktop::Displays::findDisplays (float masterScale)
     RECT workArea;
     SystemParametersInfo (SPI_GETWORKAREA, 0, &workArea, 0);
 
-    const double dpi = getDPI(); // (this has only one value for all monitors)
-
     for (int i = 0; i < monitors.size(); ++i)
     {
         Display d;
         d.userArea  = d.totalArea = monitors.getReference(i).bounds / masterScale;
         d.isMain    = monitors.getReference(i).isMain;
-        d.scale     = masterScale;
-        d.dpi       = dpi;
+        d.dpi       = monitors.getReference(i).dpi;
+
+        if (d.dpi == 0)
+        {
+            d.scale = masterScale;
+            d.dpi = globalDPI;
+        }
+        else
+        {
+            d.scale = d.dpi / 96.0;
+        }
 
         if (d.isMain)
             d.userArea = d.userArea.getIntersection (rectangleFromRECT (workArea) / masterScale);