win32: support multitouch

Use the multitouch API. To disable system's defualt mouse emulation,
set --native-touch=yes.

DOCS/interface-changes/input-touch-emulate-mouse.txt

@@ -0,0 +1 @@
+add --input-touch-emulate-mouse option

DOCS/interface-changes/native-touch.txt

@@ -0,0 +1 @@
+add --native-touch option

DOCS/man/options.rst

@@ -4101,6 +4101,11 @@ Input
     Whether this applies depends on the VO backend and how it handles
     keyboard input. Does not apply to terminal input.
 
+``--native-touch=<yes|no>``
+    (Windows only)
+    Use system native touch events, instead of receiving them as emulated mouse
+    events (default: no). This is required for multi-touch support.
+
 ``--input-ar-delay``
     Delay in milliseconds before we start to autorepeat a key (default: 200).
     Set it to 0 to disable.
@@ -4281,6 +4286,13 @@ Input
     disabled by default in libmpv as well - it should be enabled if you want
     the mpv default key bindings.
 
+``--input-touch-emulate-mouse=<yes|no>``
+    When multi-touch support is enabled (either required by the platform,
+    or enabled by ``--native-touch``), emulate mouse move and button presses
+    for the touch events (default: yes). This is useful for compatibility
+    for mouse key bindings and scripts which read mouse positions for platforms
+    which do not support ``--native-touch=no`` (e.g. Wayland).
+
 OSD
 ---
 

input/input.c

@@ -187,6 +187,7 @@ struct input_opts {
     bool test;
     bool allow_win_drag;
     bool preprocess_wheel;
+    bool touch_emulate_mouse;
 };
 
 const struct m_sub_options input_config = {
@@ -207,6 +208,7 @@ const struct m_sub_options input_config = {
         {"input-vo-keyboard", OPT_BOOL(vo_key_input)},
         {"input-media-keys", OPT_BOOL(use_media_keys)},
         {"input-preprocess-wheel", OPT_BOOL(preprocess_wheel)},
+        {"input-touch-emulate-mouse", OPT_BOOL(touch_emulate_mouse)},
 #if HAVE_SDL2_GAMEPAD
         {"input-gamepad", OPT_BOOL(use_gamepad)},
 #endif
@@ -227,6 +229,7 @@ const struct m_sub_options input_config = {
         .vo_key_input = true,
         .allow_win_drag = true,
         .preprocess_wheel = true,
+        .touch_emulate_mouse = true,
     },
     .change_flags = UPDATE_INPUT,
 };
@@ -732,6 +735,11 @@ static void feed_key(struct input_ctx *ictx, int code, double scale,
         release_down_cmd(ictx, false);
         return;
     }
+    if (code == MP_TOUCH_RELEASE_ALL) {
+        MP_TRACE(ictx, "release all touch\n");
+        ictx->num_touch_points = 0;
+        return;
+    }
     if (!opts->enable_mouse_movements && MP_KEY_IS_MOUSE(unmod) && !force_mouse)
         return;
     if (unmod == MP_KEY_MOUSE_LEAVE || unmod == MP_KEY_MOUSE_ENTER) {
@@ -927,6 +935,9 @@ static void update_touch_point(struct input_ctx *ictx, int idx, int id, int x, i
         return;
     ictx->touch_points[idx].x = x;
     ictx->touch_points[idx].y = y;
+    // Emulate mouse input from the primary touch point (the first one added)
+    if (ictx->opts->touch_emulate_mouse && idx == 0)
+        set_mouse_pos(ictx, x, y);
     notify_touch_update(ictx);
 }
 
@@ -943,6 +954,11 @@ void mp_input_add_touch_point(struct input_ctx *ictx, int id, int x, int y)
                  ictx->num_touch_points, id, x, y);
         MP_TARRAY_APPEND(ictx, ictx->touch_points, ictx->num_touch_points,
                          (struct touch_point){id, x, y});
+        // Emulate MBTN_LEFT down if this is the only touch point
+        if (ictx->opts->touch_emulate_mouse && ictx->num_touch_points == 1) {
+            set_mouse_pos(ictx, x, y);
+            feed_key(ictx, MP_MBTN_LEFT | MP_KEY_STATE_DOWN, 1, false);
+        }
         notify_touch_update(ictx);
     }
     input_unlock(ictx);
@@ -967,6 +983,9 @@ void mp_input_remove_touch_point(struct input_ctx *ictx, int id)
     if (idx != -1) {
         MP_TRACE(ictx, "Touch point %d remove (id %d)\n", idx, id);
         MP_TARRAY_REMOVE_AT(ictx->touch_points, ictx->num_touch_points, idx);
+        // Emulate MBTN_LEFT up if there are no touch points left
+        if (ictx->opts->touch_emulate_mouse && ictx->num_touch_points == 0)
+            feed_key(ictx, MP_MBTN_LEFT | MP_KEY_STATE_UP, 1, false);
         notify_touch_update(ictx);
     }
     input_unlock(ictx);

input/keycodes.h

@@ -216,6 +216,8 @@
 #define MP_KEY_ANY_UNICODE      (MP_KEY_INTERN+5)
 // For mp_input_put_key(): release all keys that are down.
 #define MP_INPUT_RELEASE_ALL    (MP_KEY_INTERN+6)
+// For mp_input_put_key(): release all touch points.
+#define MP_TOUCH_RELEASE_ALL    (MP_KEY_INTERN+7)
 
 // Emit a command even on key-up (normally key-up is ignored). This means by
 // default they binding will be triggered on key-up instead of key-down.

options/options.c

@@ -169,6 +169,7 @@ static const m_option_t mp_vo_opt_list[] = {
     {"keepaspect-window", OPT_BOOL(keepaspect_window)},
     {"hidpi-window-scale", OPT_BOOL(hidpi_window_scale)},
     {"native-fs", OPT_BOOL(native_fs)},
+    {"native-touch", OPT_BOOL(native_touch)},
     {"show-in-taskbar", OPT_BOOL(show_in_taskbar)},
     {"display-fps-override", OPT_DOUBLE(display_fps_override),
         M_RANGE(0, DBL_MAX)},

options/options.h

@@ -56,6 +56,7 @@ typedef struct mp_vo_opts {
     bool keepaspect_window;
     bool hidpi_window_scale;
     bool native_fs;
+    bool native_touch;
     bool show_in_taskbar;
 
     int64_t WinID;

video/out/w32_common.c

@@ -1315,6 +1315,17 @@ static void update_cursor_passthrough(const struct vo_w32_state *w32)
     }
 }
 
+static void update_native_touch(const struct vo_w32_state *w32)
+{
+    if (w32->parent)
+        return;
+
+    if (w32->opts->native_touch)
+        RegisterTouchWindow(w32->window, 0);
+    else
+        UnregisterTouchWindow(w32->window);
+}
+
 static void set_ime_conversion_mode(const struct vo_w32_state *w32, DWORD mode)
 {
     if (w32->parent)
@@ -1713,6 +1724,26 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
     case WM_SHOWMENU:
         mp_win32_menu_show(w32->menu_ctx, w32->window);
         break;
+    case WM_TOUCH: {
+        UINT count = LOWORD(wParam);
+        TOUCHINPUT *inputs = talloc_array_ptrtype(NULL, inputs, count);
+        if (GetTouchInputInfo((HTOUCHINPUT)lParam, count, inputs, sizeof(TOUCHINPUT))) {
+            for (UINT i = 0; i < count; i++) {
+                TOUCHINPUT ti = inputs[i];
+                POINT pt = {TOUCH_COORD_TO_PIXEL(ti.x), TOUCH_COORD_TO_PIXEL(ti.y)};
+                ScreenToClient(w32->window, &pt);
+                if (ti.dwFlags & TOUCHEVENTF_DOWN)
+                    mp_input_add_touch_point(w32->input_ctx, ti.dwID, pt.x, pt.y);
+                else if (ti.dwFlags & TOUCHEVENTF_MOVE)
+                    mp_input_update_touch_point(w32->input_ctx, ti.dwID, pt.x, pt.y);
+                else if (ti.dwFlags & TOUCHEVENTF_UP)
+                    mp_input_remove_touch_point(w32->input_ctx, ti.dwID);
+            }
+        }
+        CloseTouchInputHandle((HTOUCHINPUT)lParam);
+        talloc_free(inputs);
+        return 0;
+    }
     }
 
     if (message == w32->tbtn_created_msg) {
@@ -1996,6 +2027,8 @@ static MP_THREAD_VOID gui_thread(void *ptr)
         update_backdrop(w32);
     if (w32->opts->cursor_passthrough)
         update_cursor_passthrough(w32);
+    if (w32->opts->native_touch)
+        update_native_touch(w32);
 
     if (SUCCEEDED(OleInitialize(NULL))) {
         ole_ok = true;
@@ -2193,6 +2226,8 @@ static int gui_thread_control(struct vo_w32_state *w32, int request, void *arg)
                 update_maximized_state(w32, false);
             } else if (changed_option == &vo_opts->window_corners) {
                 update_corners_pref(w32);
+            } else if (changed_option == &vo_opts->native_touch) {
+                update_native_touch(w32);
             } else if (changed_option == &vo_opts->geometry || changed_option == &vo_opts->autofit ||
                 changed_option == &vo_opts->autofit_smaller || changed_option == &vo_opts->autofit_larger)
             {

video/out/wayland_common.c

@@ -440,19 +440,16 @@ static void touch_handle_down(void *data, struct wl_touch *wl_touch,
 {
     struct vo_wayland_seat *s = data;
     struct vo_wayland_state *wl = s->wl;
-    wl->mouse_x = wl_fixed_to_int(x_w) * wl->scaling;
-    wl->mouse_y = wl_fixed_to_int(y_w) * wl->scaling;
+    int x = wl_fixed_to_int(x_w) * wl->scaling;
+    int y = wl_fixed_to_int(y_w) * wl->scaling;
 
-    mp_input_set_mouse_pos(wl->vo->input_ctx, wl->mouse_x, wl->mouse_y);
-    mp_input_put_key(wl->vo->input_ctx, MP_MBTN_LEFT | MP_KEY_STATE_DOWN);
+    mp_input_add_touch_point(wl->vo->input_ctx, id, x, y);
 
     enum xdg_toplevel_resize_edge edge;
     if (!mp_input_test_dragging(wl->vo->input_ctx, wl->mouse_x, wl->mouse_y) &&
         !wl->locked_size && check_for_resize(wl, wl->opts->edge_pixels_touch, &edge))
     {
         xdg_toplevel_resize(wl->xdg_toplevel, s->seat, serial, edge);
-        // Explicitly send an UP event after the client finishes a resize
-        mp_input_put_key(wl->vo->input_ctx, MP_MBTN_LEFT | MP_KEY_STATE_UP);
     } else {
         // Save the serial and seat for voctrl-initialized dragging requests.
         s->pointer_button_serial = serial;
@@ -465,7 +462,7 @@ static void touch_handle_up(void *data, struct wl_touch *wl_touch,
 {
     struct vo_wayland_seat *s = data;
     struct vo_wayland_state *wl = s->wl;
-    mp_input_put_key(wl->vo->input_ctx, MP_MBTN_LEFT | MP_KEY_STATE_UP);
+    mp_input_remove_touch_point(wl->vo->input_ctx, id);
     wl->last_button_seat = NULL;
 }
 
@@ -475,10 +472,10 @@ static void touch_handle_motion(void *data, struct wl_touch *wl_touch,
     struct vo_wayland_seat *s = data;
     struct vo_wayland_state *wl = s->wl;
 
-    wl->mouse_x = wl_fixed_to_int(x_w) * wl->scaling;
-    wl->mouse_y = wl_fixed_to_int(y_w) * wl->scaling;
+    int x = wl_fixed_to_int(x_w) * wl->scaling;
+    int y = wl_fixed_to_int(y_w) * wl->scaling;
 
-    mp_input_set_mouse_pos(wl->vo->input_ctx, wl->mouse_x, wl->mouse_y);
+    mp_input_update_touch_point(wl->vo->input_ctx, id, x, y);
 }
 
 static void touch_handle_frame(void *data, struct wl_touch *wl_touch)
@@ -487,6 +484,9 @@ static void touch_handle_frame(void *data, struct wl_touch *wl_touch)
 
 static void touch_handle_cancel(void *data, struct wl_touch *wl_touch)
 {
+    struct vo_wayland_seat *s = data;
+    struct vo_wayland_state *wl = s->wl;
+    mp_input_put_key(wl->vo->input_ctx, MP_TOUCH_RELEASE_ALL);
 }
 
 static void touch_handle_shape(void *data, struct wl_touch *wl_touch,