win32: support taskbar button progress indicator

This adds support for the progress indicator taskbar extension
that was introduced with Windows 7 and Windows Server 2008 R2.

I don’t like this solution because it keeps its own state and
introduces another VOCTRL, but I couldn’t come up with anything
less messy.

closes #2399

2 files changed, 44 insertions, 0 deletions

diff --git a/video/out/vo.h b/video/out/vo.h
index 30948e149b..3a8231a295 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -76,6 +76,7 @@ enum mp_voctrl {
     VOCTRL_ALL_WORKSPACES,
 
     VOCTRL_UPDATE_WINDOW_TITLE,         // char*
+    VOCTRL_UPDATE_PLAYBACK_STATE,       // struct voctrl_playback_state*
 
     VOCTRL_SET_CURSOR_VISIBILITY,       // bool*
 
@@ -130,6 +131,12 @@ struct voctrl_get_equalizer_args {
 #define VO_NOTAVAIL     -2
 #define VO_NOTIMPL      -3
 
+// VOCTRL_UPDATE_PLAYBACK_STATE
+struct voctrl_playback_state {
+    bool paused;
+    int percent_pos;
+};
+
 enum {
     // VO does handle mp_image_params.rotate in 90 degree steps
     VO_CAP_ROTATE90     = 1 << 0,
diff --git a/video/out/w32_common.c b/video/out/w32_common.c
index 37e0057162..6f0bb82ed3 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;
+    ITaskbarList3 *taskbar_list3;
+    UINT tbtnCreatedMsg;
+    bool tbtnCreated;
 
     // updates on move/resize/displaychange
     double display_fps;
@@ -826,6 +829,11 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         break;
     }
 
+    if (message == w32->tbtnCreatedMsg) {
+        w32->tbtnCreated = true;
+        return 0;
+    }
+
     if (mouse_button) {
         mouse_button |= mod_state(w32);
         mp_input_put_key(w32->input_ctx, mouse_button);
@@ -1198,6 +1206,20 @@ static void *gui_thread(void *ptr)
                 w32->taskbar_list = NULL;
             }
         }
+
+        // ITaskbarList3 has methods for status indication on taskbar buttons,
+        // however that interface is only available on Win7/2008 R2 or newer
+        if (SUCCEEDED(CoCreateInstance(&CLSID_TaskbarList, NULL,
+                                       CLSCTX_INPROC_SERVER, &IID_ITaskbarList3,
+                                       (void**)&w32->taskbar_list3)))
+        {
+            if (FAILED(ITaskbarList3_HrInit(w32->taskbar_list3))) {
+                ITaskbarList3_Release(w32->taskbar_list3);
+                w32->taskbar_list3 = NULL;
+            } else {
+                w32->tbtnCreatedMsg = RegisterWindowMessage(L"TaskbarButtonCreated");
+            }
+        }
     } else {
         MP_ERR(w32, "Failed to initialize OLE/COM\n");
     }
@@ -1235,6 +1257,8 @@ done:
     }
     if (w32->taskbar_list)
         ITaskbarList2_Release(w32->taskbar_list);
+    if (w32->taskbar_list3)
+        ITaskbarList3_Release(w32->taskbar_list3);
     if (ole_ok)
         OleUninitialize();
     SetThreadExecutionState(ES_CONTINUOUS);
@@ -1348,6 +1372,19 @@ static int gui_thread_control(struct vo_w32_state *w32, int request, void *arg)
         talloc_free(title);
         return VO_TRUE;
     }
+    case VOCTRL_UPDATE_PLAYBACK_STATE: {
+        struct voctrl_playback_state *pstate =
+            (struct voctrl_playback_state *)arg;
+
+        if (w32->taskbar_list3 && w32->tbtnCreated) {
+            ITaskbarList3_SetProgressValue(w32->taskbar_list3, w32->window,
+                                           pstate->percent_pos, 100);
+            ITaskbarList3_SetProgressState(w32->taskbar_list3, w32->window,
+                                           pstate->paused ? TBPF_PAUSED :
+                                                            TBPF_NORMAL);
+        }
+        return VO_TRUE;
+    }
     case VOCTRL_GET_DISPLAY_FPS:
         update_display_fps(w32);
         *(double*) arg = w32->display_fps;