From a1d455b0c52bb7315426471b97acc7e8aea3fdf3 Mon Sep 17 00:00:00 2001
From: Andri Yngvason <andri@yngvason.is>
Date: Tue, 14 Jul 2020 20:44:18 +0000
Subject: [PATCH] pointer: Set cursor on pointer enter

---
 include/pointer.h |  6 +++++
 meson.build       |  2 ++
 src/pointer.c     | 63 +++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/include/pointer.h b/include/pointer.h
index 469f154..cca04e7 100644
--- a/include/pointer.h
+++ b/include/pointer.h
@@ -18,6 +18,8 @@
 
 #include <wayland-client.h>
 
+struct wl_cursor_theme;
+
 enum pointer_button_mask {
 	POINTER_BUTTON_LEFT = 1 << 0,
 	POINTER_BUTTON_MIDDLE = 1 << 1,
@@ -29,8 +31,12 @@ struct pointer {
 	struct wl_pointer* wl_pointer;
 	struct wl_list link;
 
+	uint32_t serial;
 	enum pointer_button_mask pressed;
 	wl_fixed_t x, y;
+
+	struct wl_cursor_theme* cursor_theme;
+	struct wl_surface* cursor_surface;
 };
 
 struct pointer_collection {
diff --git a/meson.build b/meson.build
index 55e3904..8a4a8d8 100644
--- a/meson.build
+++ b/meson.build
@@ -30,6 +30,7 @@ librt = cc.find_library('rt', required: false)
 xkbcommon = dependency('xkbcommon')
 pixman = dependency('pixman-1')
 wayland_client = dependency('wayland-client')
+wayland_cursor = dependency('wayland-cursor')
 libvncclient = dependency('libvncclient')
 
 aml_project = subproject('aml', required: false)
@@ -60,6 +61,7 @@ dependencies = [
 	pixman,
 	aml,
 	wayland_client,
+	wayland_cursor,
 	libvncclient,
 	client_protos,
 ]
diff --git a/src/pointer.c b/src/pointer.c
index c414c0b..18d5078 100644
--- a/src/pointer.c
+++ b/src/pointer.c
@@ -19,10 +19,30 @@
 #include <stdint.h>
 #include <assert.h>
 #include <wayland-client.h>
+#include <wayland-cursor.h>
 #include <linux/input-event-codes.h>
 
 #include "pointer.h"
 
+extern struct wl_shm* wl_shm;
+extern struct wl_compositor* wl_compositor;
+
+static struct wl_cursor_theme* pointer_load_cursor_theme(void)
+{
+	const char* xcursor_theme = getenv("XCURSOR_THEME");
+	const char* xcursor_size_str = getenv("XCURSOR_SIZE");
+
+	unsigned long xcursor_size = 24;
+	if (xcursor_size_str) {
+		char* end;
+		unsigned long size = strtoul(xcursor_size_str, &end, 10);
+		if (!*end && *xcursor_size_str)
+			xcursor_size = size;
+	}
+
+	return wl_cursor_theme_load(xcursor_theme, xcursor_size, wl_shm);
+}
+
 struct pointer* pointer_new(struct wl_pointer* wl_pointer)
 {
 	struct pointer* self = calloc(1, sizeof(*self));
@@ -30,6 +50,8 @@ struct pointer* pointer_new(struct wl_pointer* wl_pointer)
 		return NULL;
 
 	self->wl_pointer = wl_pointer;
+	self->cursor_theme = pointer_load_cursor_theme();
+	self->cursor_surface = wl_compositor_create_surface(wl_compositor);
 
 	return self;
 }
@@ -37,6 +59,8 @@ struct pointer* pointer_new(struct wl_pointer* wl_pointer)
 void pointer_destroy(struct pointer* self)
 {
 	wl_pointer_destroy(self->wl_pointer);
+	wl_cursor_theme_destroy(self->cursor_theme);
+	wl_surface_destroy(self->cursor_surface);
 	free(self);
 }
 
@@ -75,17 +99,50 @@ struct pointer* pointer_collection_find_wl_pointer(
 	return NULL;
 }
 
+static void pointer_update_cursor(struct pointer* self)
+{
+	struct wl_cursor* cursor = wl_cursor_theme_get_cursor(
+			self->cursor_theme, "left_ptr");
+	assert(cursor && cursor->image_count > 0);
+
+	struct wl_cursor_image* image = cursor->images[0];
+
+	// TODO Set buffer scale
+	wl_surface_attach(self->cursor_surface,
+			wl_cursor_image_get_buffer(image), 0, 0);
+	wl_pointer_set_cursor(self->wl_pointer, self->serial,
+			self->cursor_surface, image->hotspot_x,
+			image->hotspot_y);
+	wl_surface_damage_buffer(self->cursor_surface, 0, 0, image->width,
+			image->height);
+	wl_surface_commit(self->cursor_surface);
+}
+
 static void pointer_enter(void* data, struct wl_pointer* wl_pointer,
 		uint32_t serial, struct wl_surface* surface, wl_fixed_t x,
 		wl_fixed_t y)
 {
-	// TODO
+	struct pointer_collection* self = data;
+	struct pointer* pointer =
+		pointer_collection_find_wl_pointer(self, wl_pointer);
+	assert(pointer);
+
+	pointer->serial = serial;
+
+	pointer_update_cursor(pointer);
 }
 
 static void pointer_leave(void* data, struct wl_pointer* wl_pointer,
 		uint32_t serial, struct wl_surface* surface)
 {
-	// TODO
+	struct pointer_collection* self = data;
+	struct pointer* pointer =
+		pointer_collection_find_wl_pointer(self, wl_pointer);
+	assert(pointer);
+
+	pointer->serial = serial;
+
+	// Do nothing?
 }
 
 static void pointer_motion(void* data, struct wl_pointer* wl_pointer,
@@ -122,6 +179,8 @@ static void pointer_button(void* data, struct wl_pointer* wl_pointer,
 		pointer_collection_find_wl_pointer(self, wl_pointer);
 	assert(pointer);
 
+	pointer->serial = serial;
+
 	switch (button) {
 	case BTN_LEFT:
 		pointer_set_button_state(pointer, POINTER_BUTTON_LEFT, state);