Fix _glfwGetThemeCocoa

src/cocoa_window.m

@@ -1932,53 +1932,66 @@ GLFWtheme* _glfwGetThemeCocoa(_GLFWwindow* window)
 {
     _glfwInputError(GLFW_FEATURE_UNIMPLEMENTED, NULL); // TODO: remove
     
-    GLFWtheme theme;
+    // TODO: must use KVO to observe NSApplication NSAppearance for theme callback.
+    
+    GLFWtheme* theme = &window->theme;
     NSAppearanceName name = [window->ns.object appearance].name;
     
+    theme->baseTheme = 0;
+    theme->flags = 0;
+    
     if (name == NSAppearanceNameAqua)
     {
-        theme.baseTheme = GLFW_BASE_THEME_LIGHT;
+        theme->baseTheme = GLFW_BASE_THEME_LIGHT;
     }
     else if (name == NSAppearanceNameDarkAqua)
     {
-        theme.baseTheme = GLFW_BASE_THEME_DARK;
+        theme->baseTheme = GLFW_BASE_THEME_DARK;
     }
     else if (name == NSAppearanceNameVibrantLight)
     {
-        theme.baseTheme = GLFW_BASE_THEME_LIGHT;
+        theme->baseTheme = GLFW_BASE_THEME_LIGHT;
-        theme.flags |= GLFW_THEME_FLAG_VIBRANT;
+        theme->flags |= GLFW_THEME_FLAG_VIBRANT;
     }
     else if (name == NSAppearanceNameVibrantDark)
     {
-        theme.baseTheme = GLFW_BASE_THEME_DARK;
+        theme->baseTheme = GLFW_BASE_THEME_DARK;
-        theme.flags |= GLFW_THEME_FLAG_VIBRANT;
+        theme->flags |= GLFW_THEME_FLAG_VIBRANT;
     }
     if (name == NSAppearanceNameAccessibilityHighContrastAqua)
     {
-        theme.baseTheme = GLFW_BASE_THEME_LIGHT;
+        theme->baseTheme = GLFW_BASE_THEME_LIGHT;
-        theme.flags |= GLFW_THEME_FLAG_HIGH_CONTRAST;
+        theme->flags |= GLFW_THEME_FLAG_HIGH_CONTRAST;
     }
     else if (name == NSAppearanceNameAccessibilityHighContrastDarkAqua)
     {
-        theme.baseTheme = GLFW_BASE_THEME_DARK;
+        theme->baseTheme = GLFW_BASE_THEME_DARK;
-        theme.flags |= GLFW_THEME_FLAG_HIGH_CONTRAST;
+        theme->flags |= GLFW_THEME_FLAG_HIGH_CONTRAST;
     }
     else if (name == NSAppearanceNameAccessibilityHighContrastVibrantLight)
     {
-        theme.baseTheme = GLFW_BASE_THEME_LIGHT;
+        theme->baseTheme = GLFW_BASE_THEME_LIGHT;
-        theme.flags |= GLFW_THEME_FLAG_VIBRANT | GLFW_THEME_FLAG_HIGH_CONTRAST;
+        theme->flags |= GLFW_THEME_FLAG_VIBRANT | GLFW_THEME_FLAG_HIGH_CONTRAST;
     }
     else if (name == NSAppearanceNameAccessibilityHighContrastVibrantDark)
     {
-        theme.baseTheme = GLFW_BASE_THEME_DARK;
+        theme->baseTheme = GLFW_BASE_THEME_DARK;
-        theme.flags |= GLFW_THEME_FLAG_VIBRANT | GLFW_THEME_FLAG_HIGH_CONTRAST;
+        theme->flags |= GLFW_THEME_FLAG_VIBRANT | GLFW_THEME_FLAG_HIGH_CONTRAST;
     }
     
-    //return theme;
+    // TODO: this is not settable. Is there any reason in overriding a similar value? Does it apply to menu item highlights? If yes, then it must be overridden.
-    return NULL; // TODO: implement
+    // TODO: must use KVO to observe the controlAccentColor for the theme callback.
+    NSColor* color = [[NSColor controlAccentColor] colorUsingColorSpace:NSColorSpace.genericRGBColorSpace];
+    
+    theme->flags |= GLFW_THEME_FLAG_HAS_COLOR;
+    theme->color[0] = color.redComponent * 255;
+    theme->color[1] = color.greenComponent * 255;
+    theme->color[2] = color.blueComponent * 255;
+    theme->color[3] = color.alphaComponent * 255;
+    
+    return theme;
 }
 
-
 EGLenum _glfwGetEGLPlatformCocoa(EGLint** attribs)
 {
     if (_glfw.egl.ANGLE_platform_angle)

src/internal.h

@@ -570,6 +570,8 @@ struct _GLFWwindow
         GLFWcharmodsfun           charmods;
         GLFWdropfun               drop;
     } callbacks;
+    
+    GLFWtheme theme;
 
     // This is defined in platform.h
     GLFW_PLATFORM_WINDOW_STATE

tests/theming.c

@@ -50,6 +50,33 @@ static int cur_theme_color = 0;
 
 static GLFWtheme theme;
 
+static void print_theme(GLFWtheme* theme, const char* title)
+{
+    int n = 0;
+    
+    printf("%s: {\n", title);
+    printf("    Base: %s\n", theme->baseTheme == GLFW_BASE_THEME_LIGHT ? "light" : "dark");
+    printf("    Flags: [");
+    if (theme->flags & GLFW_THEME_FLAG_HAS_COLOR)
+    {
+        printf(n++ > 0 ? ", %s" : "%s", "HAS_COLOR");
+    }
+    if (theme->flags & GLFW_THEME_FLAG_VIBRANT)
+    {
+        printf(n++ > 0 ? ", %s" : "%s", "VIBRANT");
+    }
+    if (theme->flags & GLFW_THEME_FLAG_HIGH_CONTRAST)
+    {
+        printf(n++ > 0 ? ", %s" : "%s", "HIGH_CONTRAST");
+    }
+    printf("]\n");
+    if (theme->flags & GLFW_THEME_FLAG_HAS_COLOR)
+    {
+        printf("    Color: [%i, %i, %i, %i]\n", theme->color[0], theme->color[1], theme->color[2], theme->color[3]);
+    }
+    printf("}\n");
+}
+
 static void set_theme(GLFWwindow* window, int theme_color)
 {
     memcpy(theme.color, theme_colors[theme_color], 4);
@@ -110,9 +137,17 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action,
             cur_theme_color = (cur_theme_color + 1) % 6;
             set_theme(window, cur_theme_color);
             break;
+        case GLFW_KEY_P:
+            print_theme(glfwGetTheme(window), "Window theme");
+            break;
     }
 }
 
+static void theme_callback(GLFWtheme* theme)
+{
+    print_theme(theme, "System theme changed to");
+}
+
 int main(int argc, char** argv)
 {
     GLFWwindow* window;
@@ -144,6 +179,8 @@ int main(int argc, char** argv)
     theme.color[2] = 0;
     theme.color[3] = 0;
     set_theme(window, cur_theme_color);
+    
+    glfwSetSystemThemeCallback(theme_callback);
 
     while (!glfwWindowShouldClose(window))
     {