2 files changed, 29 insertions, 1 deletions

diff --git a/include/client/window.h b/include/client/window.h
index 98d19a2b..e07e3509 100644
--- a/include/client/window.h
+++ b/include/client/window.h
@@ -27,11 +27,20 @@ struct cursor {
         struct wl_poitner *pointer;
 };
 
+enum scroll_direction {
+        SCROLL_UP,
+        SCROLL_DOWN,
+        SCROLL_LEFT,
+        SCROLL_RIGHT,
+};
+
 struct pointer_input {
         int last_x;
         int last_y;
 
         void (*notify_button)(struct window *window, int x, int y, uint32_t button);
+
+        void (*notify_scroll)(struct window *window, enum scroll_direction direction);
 };
 
 struct window {
diff --git a/wayland/window.c b/wayland/window.c
index 2a76654b..dfa6a997 100644
--- a/wayland/window.c
+++ b/wayland/window.c
@@ -47,7 +47,26 @@ static void pointer_handle_button(void *data, struct wl_pointer *pointer, uint32
 }
 
 static void pointer_handle_axis(void *data, struct wl_pointer *pointer,
-                    uint32_t time, uint32_t axis, wl_fixed_t value) {
+                                uint32_t time, uint32_t axis, wl_fixed_t value) {
+        struct window *window = data;
+        enum scroll_direction direction;
+
+        switch (axis) {
+        case 0:
+                direction = wl_fixed_to_double(value) < 0 ? SCROLL_UP : SCROLL_DOWN;
+                break;
+        case 1:
+                direction = wl_fixed_to_double(value) < 0 ? SCROLL_LEFT : SCROLL_RIGHT;
+                break;
+        default:
+                if (!sway_assert(false, "Unexpected axis value")) {
+                        return;
+                }
+        }
+
+        if (window->pointer_input.notify_scroll) {
+                window->pointer_input.notify_scroll(window, direction);
+        }
 }
 
 static const struct wl_pointer_listener pointer_listener = {