Merge branch 'osx-dpi'

DPI-related improvements in wxOSX.

See https://github.com/wxWidgets/wxWidgets/pull/1984

include/wx/osx/window.h

@@ -120,6 +120,8 @@ public:
     virtual bool UnregisterHotKey(int hotkeyId) wxOVERRIDE;
 #endif // wxUSE_HOTKEY
 
+    virtual wxSize GetDPI() const wxOVERRIDE;
+
 #if wxUSE_DRAG_AND_DROP
     virtual void SetDropTarget( wxDropTarget *dropTarget ) wxOVERRIDE;
 
@@ -149,6 +151,7 @@ public:
     // --------------
 
     void OnMouseEvent( wxMouseEvent &event );
+    void OnDPIChanged( wxDPIChangedEvent& event );
 
     void MacOnScroll( wxScrollEvent&event );
 
@@ -291,6 +294,9 @@ public:
     // internal response to size events
     virtual void MacOnInternalSize() {}
 
+    // Return the DPI corresponding to the given scale factor.
+    static wxSize       OSXMakeDPIFromScaleFactor(double scaleFactor);
+
 protected:
     // For controls like radio buttons which are genuinely composite
     wxList              m_subControls;

src/osx/carbon/dcscreen.cpp

@@ -34,6 +34,7 @@ wxScreenDCImpl::wxScreenDCImpl( wxDC *owner ) :
     SetGraphicsContext( wxGraphicsContext::Create() );
     m_ok = true ;
 #endif
+    m_contentScaleFactor = wxOSXGetMainScreenContentScaleFactor();
 }
 
 wxScreenDCImpl::~wxScreenDCImpl()

src/osx/cocoa/nonownedwnd.mm

@@ -321,6 +321,7 @@ static void *EffectiveAppearanceContext = &EffectiveAppearanceContext;
 - (BOOL)windowShouldClose:(id)window;
 - (BOOL)windowShouldZoom:(NSWindow *)window toFrame:(NSRect)newFrame;
 - (void)windowWillEnterFullScreen:(NSNotification *)notification;
+- (void)windowDidChangeBackingProperties:(NSNotification *)notification;
 
 @end
 
@@ -613,6 +614,42 @@ extern int wxOSXGetIdFromSelector(SEL action );
     }
 }
 
+// from https://developer.apple.com/library/archive/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/CapturingScreenContents/CapturingScreenContents.html
+
+- (void)windowDidChangeBackingProperties:(NSNotification *)notification
+{
+    NSWindow* theWindow = (NSWindow*)[notification object];
+    wxNonOwnedWindowCocoaImpl* windowimpl = [theWindow WX_implementation];
+    wxNonOwnedWindow* wxpeer = windowimpl ? windowimpl->GetWXPeer() : NULL;
+    if (wxpeer)
+    {
+        CGFloat newBackingScaleFactor = [theWindow backingScaleFactor];
+        CGFloat oldBackingScaleFactor = [[[notification userInfo]
+                                          objectForKey:@"NSBackingPropertyOldScaleFactorKey"]
+                                         doubleValue];
+        if (newBackingScaleFactor != oldBackingScaleFactor)
+        {
+            const wxSize oldDPI = wxWindow::OSXMakeDPIFromScaleFactor(oldBackingScaleFactor);
+            const wxSize newDPI = wxWindow::OSXMakeDPIFromScaleFactor(newBackingScaleFactor);
+
+            wxDPIChangedEvent event(oldDPI, newDPI);
+            event.SetEventObject(wxpeer);
+            wxpeer->HandleWindowEvent(event);
+
+        }
+
+        NSColorSpace *newColorSpace = [theWindow colorSpace];
+        NSColorSpace *oldColorSpace = [[notification userInfo]
+                                       objectForKey:@"NSBackingPropertyOldColorSpaceKey"];
+        if (![newColorSpace isEqual:oldColorSpace])
+        {
+            wxSysColourChangedEvent event;
+            event.SetEventObject(wxpeer);
+            wxpeer->HandleWindowEvent(event);
+        }
+    }
+}
+
 - (void)addObservers:(NSWindow*)win
 {
     [win addObserver:self forKeyPath:@"effectiveAppearance"

src/osx/window_osx.cpp

@@ -14,6 +14,7 @@
 
 #ifndef WX_PRECOMP
     #include "wx/log.h"
+    #include "wx/math.h"
     #include "wx/app.h"
     #include "wx/utils.h"
     #include "wx/panel.h"
@@ -79,6 +80,7 @@
 
 wxBEGIN_EVENT_TABLE(wxWindowMac, wxWindowBase)
     EVT_MOUSE_EVENTS(wxWindowMac::OnMouseEvent)
+    EVT_DPI_CHANGED(wxWindowMac::OnDPIChanged)
 wxEND_EVENT_TABLE()
 
 #define wxMAC_DEBUG_REDRAW 0
@@ -2345,6 +2347,25 @@ void wxWindowMac::OnMouseEvent( wxMouseEvent &event )
     }
 }
 
+// propagate the dpi changed event to the subwindows
+void wxWindowMac::OnDPIChanged(wxDPIChangedEvent& event)
+{
+    wxWindowList::compatibility_iterator node = GetChildren().GetFirst();
+    while ( node )
+    {
+        // Only propagate to non-top-level windows
+        wxWindow *win = node->GetData();
+        if ( !win->IsTopLevel() )
+        {
+            wxDPIChangedEvent event2( event.GetOldDPI(), event.GetNewDPI() );
+            event2.SetEventObject(win);
+            win->GetEventHandler()->ProcessEvent(event2);
+        }
+
+        node = node->GetNext();
+    }
+}
+
 void wxWindowMac::TriggerScrollEvent( wxEventType WXUNUSED(scrollEvent) )
 {
 }
@@ -2599,6 +2620,25 @@ bool wxWindowMac::OSXHandleKeyEvent( wxKeyEvent& event )
     return handled ;
 }
 
+/* static */
+wxSize wxWindowMac::OSXMakeDPIFromScaleFactor(double scaleFactor)
+{
+    const int dpi = wxRound(scaleFactor*72.0);
+
+    return wxSize(dpi, dpi);
+}
+
+wxSize wxWindowMac::GetDPI() const
+{
+    double scaleFactor;
+    if ( wxNonOwnedWindow* tlw = MacGetTopLevelWindow() )
+        scaleFactor = tlw->GetContentScaleFactor();
+    else
+        scaleFactor = wxOSXGetMainScreenContentScaleFactor();
+
+    return OSXMakeDPIFromScaleFactor(scaleFactor);
+}
+
 //
 // wxWidgetImpl
 //