Improve high DPI handling on macOS

src/SFML/Window/OSX/SFOpenGLView.h

@@ -78,6 +78,7 @@ namespace sf {
     BOOL                          m_cursorGrabbed;  ///< Is the mouse cursor trapped?
     CGFloat                       m_deltaXBuffer;   ///< See note about cursor grabbing above
     CGFloat                       m_deltaYBuffer;   ///< See note about cursor grabbing above
+    BOOL                          m_highDpi;        ///< Is high-DPI enabled?
 
     // Hidden text view used to convert key event to actual chars.
     // We use a silent responder to prevent sound alerts.
@@ -99,7 +100,7 @@ namespace sf {
 /// \return an initialized view
 ///
 ////////////////////////////////////////////////////////////
--(id)initWithFrame:(NSRect)frameRect fullscreen:(BOOL)isFullscreen;
+-(id)initWithFrame:(NSRect)frameRect fullscreen:(BOOL)isFullscreen highDpi:(BOOL)isHighDpi;
 
 ////////////////////////////////////////////////////////////
 /// \brief Finish the creation of the SFML OpenGL view

src/SFML/Window/OSX/SFOpenGLView.mm

@@ -86,11 +86,17 @@
 ////////////////////////////////////////////////////////
 -(id)initWithFrame:(NSRect)frameRect
 {
-    return [self initWithFrame:frameRect fullscreen:NO];
+    return [self initWithFrame:frameRect fullscreen:NO highDpi:NO];
 }
 
 ////////////////////////////////////////////////////////
 -(id)initWithFrame:(NSRect)frameRect fullscreen:(BOOL)isFullscreen
+{
+    return [self initWithFrame:frameRect fullscreen:isFullscreen highDpi:NO];
+}
+
+////////////////////////////////////////////////////////
+-(id)initWithFrame:(NSRect)frameRect fullscreen:(BOOL)isFullscreen highDpi:(BOOL)isHighDpi
 {
     if ((self = [super initWithFrame:frameRect]))
     {
@@ -118,8 +124,12 @@
         m_hiddenTextView = [[NSTextView alloc] initWithFrame:NSZeroRect];
         [m_hiddenTextView setNextResponder:m_silentResponder];
 
-        // Request high resolution on high DPI displays
-        [self setWantsBestResolutionOpenGLSurface:YES];
+        // If high DPI is requested, then use high resolution for the OpenGL view.
+        // Currently, isHighDpi is always expected to be NO, and so the OpenGL view will render scaled.
+        // Note: setWantsBestResolutionOpenGLSurface requires YES to work properly, rather than simply non-zero value.
+        // isHighDpi is an Objective-C BOOL, which can have non-zero values other than YES.
+        m_highDpi = isHighDpi ? YES : NO;
+        [self setWantsBestResolutionOpenGLSurface:m_highDpi];
 
         // At that point, the view isn't attached to a window. We defer the rest of
         // the initialization process to later.
@@ -224,7 +234,7 @@
     NSWindow* window = [self window];
     NSScreen* screen = window ? [window screen] : [NSScreen mainScreen];
     CGFloat oldScaleFactor = m_scaleFactor;
-    m_scaleFactor = [screen backingScaleFactor];
+    m_scaleFactor = m_highDpi ? [screen backingScaleFactor] : 1.0;
 
     // Send a resize event if the scaling factor changed
     if ((m_scaleFactor != oldScaleFactor) && (m_requester != 0)) {

src/SFML/Window/OSX/SFWindowController.h

@@ -62,6 +62,7 @@ namespace sf {
     sf::priv::WindowImplCocoa*  m_requester;        ///< Requester
     BOOL                        m_fullscreen;       ///< Indicate whether the window is fullscreen or not
     BOOL                        m_restoreResize;    ///< See note above
+    BOOL                        m_highDpi;          ///< Support high-DPI rendering or not
 }
 
 ////////////////////////////////////////////////////////////

src/SFML/Window/OSX/SFWindowController.mm

@@ -99,6 +99,7 @@
         m_requester = 0;
         m_fullscreen = NO; // assuming this is the case... too hard to handle anyway.
         m_restoreResize = NO;
+        m_highDpi = NO;
 
         // Retain the window for our own use.
         m_window = [window retain];
@@ -111,7 +112,8 @@
 
         // Create the view.
         m_oglView = [[SFOpenGLView alloc] initWithFrame:[[m_window contentView] frame]
-                                             fullscreen:NO];
+                                             fullscreen:NO
+                                                highDpi:NO];
 
         if (m_oglView == nil)
         {
@@ -153,6 +155,7 @@
         m_requester = 0;
         m_fullscreen = (style & sf::Style::Fullscreen);
         m_restoreResize = NO;
+        m_highDpi = NO;
 
         if (m_fullscreen)
             [self setupFullscreenViewWithMode:mode];
@@ -218,7 +221,8 @@
     NSRect oglRect = NSMakeRect(x, y, width, height);
 
     m_oglView = [[SFOpenGLView alloc] initWithFrame:oglRect
-                                         fullscreen:YES];
+                                         fullscreen:YES
+                                            highDpi:m_highDpi];
 
     if (m_oglView == nil)
     {
@@ -277,7 +281,8 @@
 
     // Create the view.
     m_oglView = [[SFOpenGLView alloc] initWithFrame:[[m_window contentView] frame]
-                                         fullscreen:NO];
+                                         fullscreen:NO
+                                            highDpi:m_highDpi];
 
     if (m_oglView == nil)
     {

src/SFML/Window/OSX/WindowImplCocoa.mm

@@ -130,9 +130,6 @@ m_showCursor(true)
     // Transform the app process.
     setUpProcess();
 
-    // Use backing size
-    scaleInWidthHeight(mode, nil);
-
     m_delegate = [[SFWindowController alloc] initWithMode:mode andStyle:style];
     [m_delegate changeTitle:sfStringToNSString(title)];
     [m_delegate setRequesterTo:this];
@@ -544,4 +541,3 @@ bool WindowImplCocoa::hasFocus() const
 } // namespace priv
 
 } // namespace sf
-