Windows: Add PUGL_DARK_FRAME hint

This allows dark applications to visually integrate more nicely in Windows 10.
A little thing, but it really goes a long way to make programs not look out of
place and half-baked.

8 files changed, 38 insertions, 7 deletions

diff --git a/bindings/cpp/include/pugl/pugl.hpp b/bindings/cpp/include/pugl/pugl.hpp
index 90c5de6..257ccd2 100644
--- a/bindings/cpp/include/pugl/pugl.hpp
+++ b/bindings/cpp/include/pugl/pugl.hpp
@@ -378,9 +378,11 @@ enum class ViewHint {
   ignoreKeyRepeat,     ///< @copydoc PUGL_IGNORE_KEY_REPEAT
   refreshRate,         ///< @copydoc PUGL_REFRESH_RATE
   viewType,            ///< @copydoc PUGL_VIEW_TYPE
+  darkFrame,           ///< @copydoc PUGL_DARK_FRAME
 };
 
-static_assert(static_cast<ViewHint>(PUGL_VIEW_TYPE) == ViewHint::viewType, "");
+static_assert(static_cast<ViewHint>(PUGL_DARK_FRAME) == ViewHint::darkFrame,
+              "");
 
 using ViewHintValue = PuglViewHintValue; ///< @copydoc PuglViewHintValue
 
diff --git a/examples/pugl_management_demo.c b/examples/pugl_management_demo.c
index 30a026e..766bee1 100644
--- a/examples/pugl_management_demo.c
+++ b/examples/pugl_management_demo.c
@@ -50,20 +50,20 @@ onExpose(PuglView* const view, const PuglExposeEvent* const event)
   cairo_clip_preserve(cr);
 
   // Draw background
-  cairo_set_source_rgb(cr, 0.2, 0.2, 0.2);
+  cairo_set_source_rgb(cr, 0.1, 0.1, 0.1);
   cairo_set_line_width(cr, 4.0);
   cairo_fill(cr);
 
   // Set up text renering
   char                 buf[128] = {0};
   cairo_text_extents_t extents  = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
-  cairo_set_font_size(cr, 32.0);
+  cairo_set_font_size(cr, 30.0);
 
   // Draw time label
   snprintf(buf, sizeof(buf), "Draw time: %g", puglGetTime(world));
   cairo_text_extents(cr, buf, &extents);
   cairo_move_to(cr, cx - extents.width / 2.0, cy + extents.height / 2.0 - 48.0);
-  cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
+  cairo_set_source_rgb(cr, 0.9, 0.9, 0.9);
   cairo_show_text(cr, buf);
 
   // Draw style label
@@ -112,13 +112,15 @@ toggleDialog(DemoApp* const app)
     puglSetHandle(app->dialogView.view, &app->dialogView);
     puglSetTransientParent(app->dialogView.view,
                            puglGetNativeView(app->mainView.view));
+
+    puglSetViewString(app->dialogView.view, PUGL_WINDOW_TITLE, "Dialog");
+    puglSetViewHint(app->dialogView.view, PUGL_DARK_FRAME, PUGL_TRUE);
     puglSetSizeHint(app->dialogView.view, PUGL_DEFAULT_SIZE, 320, 240);
     puglSetSizeHint(app->dialogView.view, PUGL_MIN_SIZE, 160, 120);
     puglSetViewHint(app->dialogView.view, PUGL_IGNORE_KEY_REPEAT, true);
     puglSetViewHint(app->dialogView.view, PUGL_RESIZABLE, true);
     puglSetViewHint(
       app->dialogView.view, PUGL_VIEW_TYPE, PUGL_VIEW_TYPE_DIALOG);
-    puglSetViewString(app->dialogView.view, PUGL_WINDOW_TITLE, "Dialog");
   }
 
   return puglShow(app->dialogView.view, PUGL_SHOW_RAISE);
@@ -240,6 +242,7 @@ main(int argc, char** argv)
   puglSetHandle(app.mainView.view, &app.mainView);
   puglSetSizeHint(app.mainView.view, PUGL_DEFAULT_SIZE, 640, 480);
   puglSetSizeHint(app.mainView.view, PUGL_MIN_SIZE, 320, 240);
+  puglSetViewHint(app.mainView.view, PUGL_DARK_FRAME, PUGL_TRUE);
   puglSetViewHint(app.mainView.view, PUGL_IGNORE_KEY_REPEAT, true);
   puglSetViewHint(app.mainView.view, PUGL_RESIZABLE, true);
   puglSetViewHint(app.mainView.view, PUGL_VIEW_TYPE, PUGL_VIEW_TYPE_NORMAL);
diff --git a/examples/pugl_shader_demo.c b/examples/pugl_shader_demo.c
index 5773a9d..5cd9c7c 100644
--- a/examples/pugl_shader_demo.c
+++ b/examples/pugl_shader_demo.c
@@ -265,6 +265,7 @@ setupPugl(PuglTestApp* app)
   puglSetViewHint(app->view, PUGL_DOUBLE_BUFFER, app->opts.doubleBuffer);
   puglSetViewHint(app->view, PUGL_SWAP_INTERVAL, app->opts.sync);
   puglSetViewHint(app->view, PUGL_IGNORE_KEY_REPEAT, PUGL_TRUE);
+  puglSetViewHint(app->view, PUGL_DARK_FRAME, PUGL_TRUE);
   puglSetHandle(app->view, app);
   puglSetEventFunc(app->view, onEvent);
 }
diff --git a/examples/pugl_vulkan_cpp_demo.cpp b/examples/pugl_vulkan_cpp_demo.cpp
index 7e652a5..2cfb1e8 100644
--- a/examples/pugl_vulkan_cpp_demo.cpp
+++ b/examples/pugl_vulkan_cpp_demo.cpp
@@ -1719,6 +1719,7 @@ run(const char* const      programPath,
   app.view.setSizeHint(pugl::SizeHint::minSize, width / 4U, height / 4U);
   app.view.setBackend(pugl::vulkanBackend());
   app.view.setHint(pugl::ViewHint::resizable, opts.resizable);
+  app.view.setHint(pugl::ViewHint::darkFrame, true);
   const pugl::Status st = app.view.realize();
   if (st != pugl::Status::success) {
     return logError("Failed to create window (%s)\n", pugl::strerror(st));
diff --git a/include/pugl/pugl.h b/include/pugl/pugl.h
index 4427c5a..801ae3c 100644
--- a/include/pugl/pugl.h
+++ b/include/pugl/pugl.h
@@ -923,10 +923,11 @@ typedef enum {
   PUGL_IGNORE_KEY_REPEAT,     ///< True if key repeat events are ignored
   PUGL_REFRESH_RATE,          ///< Refresh rate in Hz
   PUGL_VIEW_TYPE,             ///< View type (a #PuglViewType)
+  PUGL_DARK_FRAME,            ///< True if window frame should be dark
 } PuglViewHint;
 
 /// The number of #PuglViewHint values
-#define PUGL_NUM_VIEW_HINTS ((unsigned)PUGL_VIEW_TYPE + 1U)
+#define PUGL_NUM_VIEW_HINTS ((unsigned)PUGL_DARK_FRAME + 1U)
 
 /// A special view hint value
 typedef enum {
diff --git a/meson.build b/meson.build
index 652cd77..63f14bb 100644
--- a/meson.build
+++ b/meson.build
@@ -99,10 +99,11 @@ elif host_machine.system() == 'windows'
 
   user32_dep = cc.find_library('user32')
   shlwapi_dep = cc.find_library('shlwapi')
+  dwmapi_dep = cc.find_library('dwmapi')
 
   platform = 'win'
   platform_sources = files('src/win.c')
-  core_deps = [user32_dep, shlwapi_dep]
+  core_deps = [user32_dep, shlwapi_dep, dwmapi_dep]
   extension = '.c'
 
 else # X11
diff --git a/src/win.c b/src/win.c
index db3f98c..e9c621e 100644
--- a/src/win.c
+++ b/src/win.c
@@ -8,6 +8,7 @@
 
 #include "pugl/pugl.h"
 
+#include <dwmapi.h>
 #include <windows.h>
 #include <windowsx.h>
 
@@ -30,6 +31,11 @@
 #  define GWLP_USERDATA (-21)
 #endif
 
+#define PRE_20H1_DWMWA_USE_IMMERSIVE_DARK_MODE 19
+#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
+#  define DWMWA_USE_IMMERSIVE_DARK_MODE 20
+#endif
+
 #define PUGL_LOCAL_CLOSE_MSG (WM_USER + 50)
 #define PUGL_LOCAL_MARK_MSG (WM_USER + 51)
 #define PUGL_LOCAL_CLIENT_MSG (WM_USER + 52)
@@ -280,12 +286,26 @@ puglRealize(PuglView* view)
   }
 
   // Set basic window hints and attributes
+
   puglSetViewString(view, PUGL_WINDOW_TITLE, view->strings[PUGL_WINDOW_TITLE]);
   puglSetTransientParent(view, view->transientParent);
 
   view->impl->scaleFactor = puglWinGetViewScaleFactor(view);
   view->impl->cursor      = LoadCursor(NULL, IDC_ARROW);
 
+  if (view->hints[PUGL_DARK_FRAME]) {
+    const BOOL useDarkMode = TRUE;
+    if ((DwmSetWindowAttribute(view->impl->hwnd,
+                               DWMWA_USE_IMMERSIVE_DARK_MODE,
+                               &useDarkMode,
+                               sizeof(useDarkMode)) != S_OK)) {
+      DwmSetWindowAttribute(view->impl->hwnd,
+                            PRE_20H1_DWMWA_USE_IMMERSIVE_DARK_MODE,
+                            &useDarkMode,
+                            sizeof(useDarkMode));
+    }
+  }
+
   SetWindowLongPtr(impl->hwnd, GWLP_USERDATA, (LONG_PTR)view);
 
   return puglDispatchSimpleEvent(view, PUGL_REALIZE);
diff --git a/test/test_utils.h b/test/test_utils.h
index e26e970..785c8c7 100644
--- a/test/test_utils.h
+++ b/test/test_utils.h
@@ -296,6 +296,8 @@ puglViewHintString(const PuglViewHint hint)
     return "Refresh rate";
   case PUGL_VIEW_TYPE:
     return "View type";
+  case PUGL_DARK_FRAME:
+    return "Dark frame";
   }
 
   return "Unknown";