Add GLFW_SCALE_FRAMEBUFFER window hint

This adds the GLFW_SCALE_FRAMEBUFFER window hint, enabling control of
framebuffer scaling across Wayland and macOS.  On macOS, this window
hint is a new name for GLFW_COCOA_RETINA_FRAMEBUFFER, and both hint
names will modify the same hint.

This is now a more symmetric counterpart to GLFW_SCALE_TO_MONITOR and,
weirdly, they each apply neatly to half of the supported platforms.

This commit is mostly documentation updates to better integrate and
contrast these two scaling mechanisms.

src/cocoa_platform.h

@@ -145,7 +145,7 @@ typedef struct _GLFWwindowNS
 
     GLFWbool        maximized;
     GLFWbool        occluded;
-    GLFWbool        retina;
+    GLFWbool        scaleFramebuffer;
 
     // Cached window properties to filter out duplicate events
     int             width, height;

src/cocoa_window.m

@@ -513,7 +513,7 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
     if (xscale != window->ns.xscale || yscale != window->ns.yscale)
     {
-        if (window->ns.retina && window->ns.layer)
+        if (window->ns.scaleFramebuffer && window->ns.layer)
             [window->ns.layer setContentsScale:[window->ns.object backingScaleFactor]];
 
         window->ns.xscale = xscale;
@@ -872,7 +872,7 @@ static GLFWbool createNativeWindow(_GLFWwindow* window,
         [window->ns.object setFrameAutosaveName:@(wndconfig->ns.frameName)];
 
     window->ns.view = [[GLFWContentView alloc] initWithGlfwWindow:window];
-    window->ns.retina = wndconfig->ns.retina;
+    window->ns.scaleFramebuffer = wndconfig->scaleFramebuffer;
 
     if (fbconfig->transparent)
     {
@@ -1969,7 +1969,7 @@ VkResult _glfwCreateWindowSurfaceCocoa(VkInstance instance,
         return VK_ERROR_EXTENSION_NOT_PRESENT;
     }
 
-    if (window->ns.retina)
+    if (window->ns.scaleFramebuffer)
         [window->ns.layer setContentsScale:[window->ns.object backingScaleFactor]];
 
     [window->ns.view setLayer:window->ns.layer];

src/internal.h

@@ -402,8 +402,8 @@ struct _GLFWwndconfig
     GLFWbool      focusOnShow;
     GLFWbool      mousePassthrough;
     GLFWbool      scaleToMonitor;
+    GLFWbool      scaleFramebuffer;
     struct {
-        GLFWbool  retina;
         char      frameName[256];
     } ns;
     struct {

src/nsgl_context.m

@@ -333,7 +333,7 @@ GLFWbool _glfwCreateContextNSGL(_GLFWwindow* window,
                                   forParameter:NSOpenGLContextParameterSurfaceOpacity];
     }
 
-    [window->ns.view setWantsBestResolutionOpenGLSurface:window->ns.retina];
+    [window->ns.view setWantsBestResolutionOpenGLSurface:window->ns.scaleFramebuffer];
 
     [window->context.nsgl.object setView:window->ns.view];
 

src/window.c

@@ -274,6 +274,7 @@ void glfwDefaultWindowHints(void)
     _glfw.hints.window.focusOnShow  = GLFW_TRUE;
     _glfw.hints.window.xpos         = GLFW_ANY_POSITION;
     _glfw.hints.window.ypos         = GLFW_ANY_POSITION;
+    _glfw.hints.window.scaleFramebuffer = GLFW_TRUE;
 
     // The default is 24 bits of color, 24 bits of depth and 8 bits of stencil,
     // double buffered
@@ -288,9 +289,6 @@ void glfwDefaultWindowHints(void)
 
     // The default is to select the highest available refresh rate
     _glfw.hints.refreshRate = GLFW_DONT_CARE;
-
-    // The default is to use full Retina resolution framebuffers
-    _glfw.hints.window.ns.retina = GLFW_TRUE;
 }
 
 GLFWAPI void glfwWindowHint(int hint, int value)
@@ -374,9 +372,6 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_POSITION_Y:
             _glfw.hints.window.ypos = value;
             return;
-        case GLFW_COCOA_RETINA_FRAMEBUFFER:
-            _glfw.hints.window.ns.retina = value ? GLFW_TRUE : GLFW_FALSE;
-            return;
         case GLFW_WIN32_KEYBOARD_MENU:
             _glfw.hints.window.win32.keymenu = value ? GLFW_TRUE : GLFW_FALSE;
             return;
@@ -389,6 +384,10 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_SCALE_TO_MONITOR:
             _glfw.hints.window.scaleToMonitor = value ? GLFW_TRUE : GLFW_FALSE;
             return;
+        case GLFW_SCALE_FRAMEBUFFER:
+        case GLFW_COCOA_RETINA_FRAMEBUFFER:
+            _glfw.hints.window.scaleFramebuffer = value ? GLFW_TRUE : GLFW_FALSE;
+            return;
         case GLFW_CENTER_CURSOR:
             _glfw.hints.window.centerCursor = value ? GLFW_TRUE : GLFW_FALSE;
             return;

src/wl_platform.h

@@ -355,6 +355,7 @@ typedef struct _GLFWwindowWayland
     GLFWbool                    fullscreen;
     GLFWbool                    hovered;
     GLFWbool                    transparent;
+    GLFWbool                    scaleFramebuffer;
     struct wl_surface*          surface;
     struct wl_callback*         callback;
 

src/wl_window.c

@@ -369,6 +369,9 @@ void _glfwUpdateBufferScaleFromOutputsWayland(_GLFWwindow* window)
         return;
     }
 
+    if (!window->wl.scaleFramebuffer)
+        return;
+
     // Get the scale factor from the highest scale monitor.
     int32_t maxScale = 1;
 
@@ -980,6 +983,7 @@ static GLFWbool createNativeSurface(_GLFWwindow* window,
     window->wl.bufferScale = 1;
     window->wl.title = _glfw_strdup(wndconfig->title);
     window->wl.appId = _glfw_strdup(wndconfig->wl.appId);
+    window->wl.scaleFramebuffer = wndconfig->scaleFramebuffer;
 
     window->wl.maximized = wndconfig->maximized;