Merge branch 'display-funcs'

Implement all global functions in terms of wxDisplay and add
wxDisplay::GetPPI().

See https://github.com/wxWidgets/wxWidgets/pull/963

interface/wx/display.h

@@ -12,8 +12,6 @@
 
     @library{wxcore}
     @category{cfg}
-
-    @see wxClientDisplayRect(), wxDisplaySize(), wxDisplaySizeMM()
 */
 class wxDisplay
 {
@@ -109,6 +107,19 @@ public:
     */
     wxString GetName() const;
 
+    /**
+        Returns display resolution in pixels per inch.
+
+        Horizontal and vertical resolution are returned in @c x and @c y
+        components of the wxSize object respectively.
+
+        If the resolution information is not available, returns @code wxSize(0,
+        0) @endcode.
+
+        @since 3.1.2
+     */
+    wxSize GetPPI() const;
+
     /**
         Returns @true if the display is the primary display. The primary
         display is the one whose index is 0.

interface/wx/gdicmn.h

@@ -1183,6 +1183,10 @@ const wxSize wxDefaultSize;
 /**
     Returns @true if the display is colour, @false otherwise.
 
+    @note Use of this function is not recommended in the new code as it only
+        works for the primary display. Use wxDisplay::GetDepth() to retrieve
+        the depth of the appropriate display and compare it with 1 instead.
+
     @header{wx/gdicmn.h}
 */
 bool wxColourDisplay();
@@ -1191,6 +1195,10 @@ bool wxColourDisplay();
     Returns the depth of the display (a value of 1 denotes a monochrome
     display).
 
+    @note Use of this function is not recommended in the new code as it only
+        works for the primary display. Use wxDisplay::GetDepth() to retrieve
+        the depth of the appropriate display instead.
+
     @header{wx/gdicmn.h}
 */
 int wxDisplayDepth();
@@ -1248,6 +1256,10 @@ wxRect wxGetClientDisplayRect();
     The @c x component of the returned wxSize object contains the horizontal
     resolution and the @c y one -- the vertical resolution.
 
+    @note Use of this function is not recommended in the new code as it only
+        works for the primary display. Use wxDisplay::GetPPI() to retrieve
+        the resolution of the appropriate display instead.
+
     @header{wx/gdicmn.h}
 
     @see wxDisplay
@@ -1262,6 +1274,10 @@ wxSize wxGetDisplayPPI();
 /**
     Returns the display size in pixels.
 
+    @note Use of this function is not recommended in the new code as it only
+        works for the primary display. Use wxDisplay::GetGeometry() to retrieve
+        the size of the appropriate display instead.
+
     Either of output pointers can be @NULL if the caller is not interested in
     the corresponding value.
 
@@ -1277,6 +1293,10 @@ void wxDisplaySize(int* width, int* height);
 /**
     Returns the display size in pixels.
 
+    @note Use of this function is not recommended in the new code as it only
+        works for the primary display. Use wxDisplay::GetGeometry() to retrieve
+        the size of the appropriate display instead.
+
     @see wxDisplay
 
     @header{wx/gdicmn.h}

interface/wx/vidmode.h

@@ -15,8 +15,6 @@
 
     @stdobjects
     ::wxDefaultVideoMode
-
-    @see wxClientDisplayRect(), wxDisplaySize(), wxDisplaySizeMM()
 */
 struct wxVideoMode
 {