From f881a520fd7381a01232d8560a2825a66020974c Mon Sep 17 00:00:00 2001
From: "Avi Halachmi (:avih)" <avihpit@yahoo.com>
Date: Tue, 10 Mar 2015 20:25:30 +0200
Subject: [PATCH] win32: support get display fps

---
 video/out/w32_common.c | 54 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/video/out/w32_common.c b/video/out/w32_common.c
index a568880a58..db60c71aa2 100644
--- a/video/out/w32_common.c
+++ b/video/out/w32_common.c
@@ -105,6 +105,9 @@ struct vo_w32_state {
     int high_surrogate;
 
     ITaskbarList2 *taskbar_list;
+
+    // updates on move/resize/displaychange
+    double display_fps;
 };
 
 typedef struct tagDropTarget {
@@ -563,6 +566,48 @@ static void wakeup_gui_thread(void *ctx)
     PostMessage(w32->window, WM_USER, 0, 0);
 }
 
+static double vo_w32_get_display_fps(void)
+{
+    DEVMODE dm;
+    dm.dmSize = sizeof(DEVMODE);
+    dm.dmDriverExtra = 0;
+    if (!EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
+        return -1;
+
+    // May return 0 or 1 which "represent the display hardware's default refresh rate"
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/dd183565%28v=vs.85%29.aspx
+    // mpv validates this value with a threshold of 1, so don't return exactly 1
+    if (dm.dmDisplayFrequency == 1)
+        return 0;
+
+    // dm.dmDisplayFrequency is an integer which is rounded down, so it's
+    // highly likely that 23 represents 24/1.001, 59 represents 60/1.001, etc.
+    // A caller can always reproduce the original value by using floor.
+    double rv = dm.dmDisplayFrequency;
+    switch (dm.dmDisplayFrequency) {
+        case  23:
+        case  29:
+        case  59:
+        case  71:
+        case 119:
+            rv = (rv + 1) / 1.001;
+    }
+
+    return rv;
+}
+
+static void update_display_fps(void *ctx)
+{
+    struct vo_w32_state *w32 = ctx;
+
+    double fps = vo_w32_get_display_fps();
+    if (fps != w32->display_fps) {
+        w32->display_fps = fps;
+        signal_events(w32, VO_EVENT_WIN_STATE);
+        MP_VERBOSE(w32, "display-fps: %f\n", fps);
+    }
+}
+
 static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
                                 LPARAM lParam)
 {
@@ -588,6 +633,7 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         ClientToScreen(w32->window, &p);
         w32->window_x = p.x;
         w32->window_y = p.y;
+        update_display_fps(w32);  // if we moved between monitors
         MP_VERBOSE(w32, "move window: %d:%d\n", w32->window_x, w32->window_y);
         break;
     }
@@ -596,6 +642,7 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         if (GetClientRect(w32->window, &r) && r.right > 0 && r.bottom > 0) {
             w32->dw = r.right;
             w32->dh = r.bottom;
+            update_display_fps(w32); // if we moved between monitors
             signal_events(w32, VO_EVENT_RESIZE);
             MP_VERBOSE(w32, "resize window: %d:%d\n", w32->dw, w32->dh);
         }
@@ -745,6 +792,9 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         mouse_button = HIWORD(wParam) == 1 ? MP_MOUSE_BTN5 : MP_MOUSE_BTN6;
         mouse_button |= MP_KEY_STATE_UP;
         break;
+    case WM_DISPLAYCHANGE:
+        update_display_fps(w32);
+        break;
     }
 
     if (mouse_button) {
@@ -1279,6 +1329,10 @@ static int gui_thread_control(struct vo_w32_state *w32, int request, void *arg)
         talloc_free(title);
         return VO_TRUE;
     }
+    case VOCTRL_GET_DISPLAY_FPS:
+        update_display_fps(w32);
+        *(double*) arg = w32->display_fps;
+        return VO_TRUE;
     }
     return VO_NOTIMPL;
 }