3 files changed, 37 insertions, 2 deletions

diff --git a/example/pointer.c b/example/pointer.c
index 42ac85fd..a427f0f2 100644
--- a/example/pointer.c
+++ b/example/pointer.c
@@ -23,6 +23,7 @@ struct sample_state {
 	struct wlr_renderer *renderer;
 	struct wlr_surface *cat_texture;
 	int cur_x, cur_y;
+	float default_color[4];
 	float clear_color[4];
 };
 
@@ -64,8 +65,7 @@ static void handle_pointer_button(struct pointer_state *pstate,
 	struct sample_state *sample = pstate->compositor->data;
 	float (*color)[4];
 	if (state == WLR_BUTTON_RELEASED) {
-		float _default[4] = { 0.25f, 0.25f, 0.25f, 1 };
-		color = &_default;
+		color = &sample->default_color;
 	} else {
 		float red[4] = { 0.25f, 0.25f, 0.25f, 1 };
 		red[button % 3] = 1;
@@ -74,8 +74,27 @@ static void handle_pointer_button(struct pointer_state *pstate,
 	memcpy(&sample->clear_color, color, sizeof(*color));
 }
 
+static void handle_pointer_axis(struct pointer_state *pstate,
+	enum wlr_axis_source source,
+	enum wlr_axis_orientation orientation,
+	double delta) {
+	struct sample_state *sample = pstate->compositor->data;
+	for (size_t i = 0; i < 3; ++i) {
+		sample->default_color[i] += delta > 0 ? -0.05f : 0.05f;
+		if (sample->default_color[i] > 1.0f) {
+			sample->default_color[i] = 1.0f;
+		}
+		if (sample->default_color[i] < 0.0f) {
+			sample->default_color[i] = 0.0f;
+		}
+	}
+	memcpy(&sample->clear_color, &sample->default_color,
+			sizeof(sample->clear_color));
+}
+
 int main(int argc, char *argv[]) {
 	struct sample_state state = {
+		.default_color = { 0.25f, 0.25f, 0.25f, 1 },
 		.clear_color = { 0.25f, 0.25f, 0.25f, 1 }
 	};
 	struct compositor_state compositor;
@@ -85,6 +104,7 @@ int main(int argc, char *argv[]) {
 	compositor.keyboard_key_cb = handle_keyboard_key;
 	compositor.pointer_motion_cb = handle_pointer_motion;
 	compositor.pointer_button_cb = handle_pointer_button;
+	compositor.pointer_axis_cb = handle_pointer_axis;
 
 	state.renderer = wlr_gles3_renderer_init();
 	state.cat_texture = wlr_render_surface_init(state.renderer);
diff --git a/example/shared.c b/example/shared.c
index 6a676343..6de16074 100644
--- a/example/shared.c
+++ b/example/shared.c
@@ -88,6 +88,15 @@ static void pointer_button_notify(struct wl_listener *listener, void *data) {
 	}
 }
 
+static void pointer_axis_notify(struct wl_listener *listener, void *data) {
+	struct wlr_pointer_axis *event = data;
+	struct pointer_state *pstate = wl_container_of(listener, pstate, axis);
+	if (pstate->compositor->pointer_axis_cb) {
+		pstate->compositor->pointer_axis_cb(pstate,
+				event->source, event->orientation, event->delta);
+	}
+}
+
 static void pointer_add(struct wlr_input_device *device, struct compositor_state *state) {
 	struct pointer_state *pstate = calloc(sizeof(struct pointer_state), 1);
 	pstate->device = device;
@@ -98,8 +107,10 @@ static void pointer_add(struct wlr_input_device *device, struct compositor_state
 	wl_list_init(&pstate->axis.link);
 	pstate->motion.notify = pointer_motion_notify;
 	pstate->button.notify = pointer_button_notify;
+	pstate->axis.notify = pointer_axis_notify;
 	wl_signal_add(&device->pointer->events.motion, &pstate->motion);
 	wl_signal_add(&device->pointer->events.button, &pstate->button);
+	wl_signal_add(&device->pointer->events.axis, &pstate->axis);
 	wl_list_insert(&state->pointers, &pstate->link);
 }
 
diff --git a/example/shared.h b/example/shared.h
index ca558f1c..7f0dade5 100644
--- a/example/shared.h
+++ b/example/shared.h
@@ -51,6 +51,10 @@ struct compositor_state {
 			double d_x, double d_y);
 	void (*pointer_button_cb)(struct pointer_state *s,
 			uint32_t button, enum wlr_button_state state);
+	void (*pointer_axis_cb)(struct pointer_state *s,
+		enum wlr_axis_source source,
+		enum wlr_axis_orientation orientation,
+		double delta);
 
 	struct wl_display *display;
 	struct wl_event_loop *event_loop;