From e55a845920cc06af664a51562be9927428adf5b5 Mon Sep 17 00:00:00 2001
From: Andri Yngvason <andri@yngvason.is>
Date: Sun, 19 Jul 2020 20:39:18 +0000
Subject: [PATCH] Add discrete pointer scroll

---
 include/pointer.h |  7 +++++++
 src/main.c        | 34 +++++++++++++++++++++++++++++++++-
 src/pointer.c     | 18 ++++++++++++++++--
 3 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/include/pointer.h b/include/pointer.h
index a426602..a51640b 100644
--- a/include/pointer.h
+++ b/include/pointer.h
@@ -30,6 +30,10 @@ enum pointer_button_mask {
 	POINTER_BUTTON_MIDDLE = 1 << 1,
 	POINTER_BUTTON_RIGHT = 1 << 2,
 	// TODO: More buttons
+	POINTER_SCROLL_UP = 1 << 3,
+	POINTER_SCROLL_DOWN = 1 << 4,
+	POINTER_SCROLL_LEFT = 1 << 5,
+	POINTER_SCROLL_RIGHT = 1 << 6,
 };
 
 struct pointer {
@@ -40,6 +44,9 @@ struct pointer {
 	enum pointer_button_mask pressed;
 	wl_fixed_t x, y;
 
+	int vertical_scroll_steps;
+	int horizontal_scroll_steps;
+
 	struct wl_cursor_theme* cursor_theme;
 	struct wl_surface* cursor_surface;
 
diff --git a/src/main.c b/src/main.c
index 1e63e96..5322cc6 100644
--- a/src/main.c
+++ b/src/main.c
@@ -365,7 +365,39 @@ void on_pointer_event(struct pointer_collection* collection,
 	int x = wl_fixed_to_int(pointer->x);
 	int y = wl_fixed_to_int(pointer->y);
 
-	vnc_client_send_pointer_event(client, x, y, pointer->pressed);
+	enum pointer_button_mask pressed = pointer->pressed;
+	int vertical_steps = pointer->vertical_scroll_steps;
+	int horizontal_steps = pointer->horizontal_scroll_steps;
+
+	if (!vertical_steps && !horizontal_steps) {
+		vnc_client_send_pointer_event(client, x, y, pressed);
+		return;
+	}
+
+	enum pointer_button_mask scroll_mask = 0;
+	if (vertical_steps < 0) {
+		vertical_steps *= -1;
+		scroll_mask |= POINTER_SCROLL_UP;
+	} else {
+		scroll_mask |= POINTER_SCROLL_DOWN;
+	}
+
+	if (horizontal_steps < 0) {
+		horizontal_steps *= -1;
+		scroll_mask |= POINTER_SCROLL_LEFT;
+	} else {
+		scroll_mask |= POINTER_SCROLL_RIGHT;
+	}
+
+	while (horizontal_steps > 0 || vertical_steps > 0) {
+		vnc_client_send_pointer_event(client, x, y, pressed | scroll_mask);
+		vnc_client_send_pointer_event(client, x, y, pressed);
+
+		if (--vertical_steps <= 0)
+			scroll_mask &= ~(POINTER_SCROLL_UP | POINTER_SCROLL_DOWN);
+		if (--horizontal_steps <= 0)
+			scroll_mask &= ~(POINTER_SCROLL_LEFT | POINTER_SCROLL_RIGHT);
+	}
 }
 
 void on_keyboard_event(struct keyboard_collection* collection,
diff --git a/src/pointer.c b/src/pointer.c
index 69fe30d..82daea9 100644
--- a/src/pointer.c
+++ b/src/pointer.c
@@ -221,7 +221,6 @@ static void pointer_button(void* data, struct wl_pointer* wl_pointer,
 	case BTN_MIDDLE:
 		pointer_set_button_state(pointer, POINTER_BUTTON_MIDDLE, state);
 		break;
-
 	// TODO: More buttons
 	}
 }
@@ -247,7 +246,19 @@ static void pointer_axis_stop(void* data, struct wl_pointer* wl_pointer,
 static void pointer_axis_discrete(void* data, struct wl_pointer* wl_pointer,
 		enum wl_pointer_axis axis, int steps)
 {
-	// TODO
+	struct pointer_collection* self = data;
+	struct pointer* pointer =
+		pointer_collection_find_wl_pointer(self, wl_pointer);
+
+	switch (axis) {
+	case WL_POINTER_AXIS_VERTICAL_SCROLL:
+		pointer->vertical_scroll_steps += steps;
+		break;
+	case WL_POINTER_AXIS_HORIZONTAL_SCROLL:
+		pointer->horizontal_scroll_steps += steps;
+		break;
+	default:;
+	}
 }
 
 static void pointer_frame(void* data, struct wl_pointer* wl_pointer)
@@ -257,6 +268,9 @@ static void pointer_frame(void* data, struct wl_pointer* wl_pointer)
 		pointer_collection_find_wl_pointer(self, wl_pointer);
 
 	self->on_frame(self, pointer);
+
+	pointer->vertical_scroll_steps = 0;
+	pointer->horizontal_scroll_steps = 0;
 }
 
 static struct wl_pointer_listener pointer_listener = {