wayland: Use D-Bus to retrieve the cursor size and theme on GNOME

GNOME exposes the cursor size and theme via the org.freedesktop.portal.Settings interface of the xdg-desktop portal, so query these values via D-Bus, if available.

The XCURSOR_SIZE/XCURSOR_THEME envvars will be tried first, so as not to override any user specified sizes or themes, then D-Bus, then, failing that, it will fall back to default values.
This commit is contained in:
Frank Praznik 2022-08-02 12:56:56 -04:00 committed by Sam Lantinga
parent 944111dbcf
commit 0b9868b026

View File

@ -55,6 +55,106 @@ typedef struct {
void *shm_data;
} Wayland_CursorData;
#ifdef SDL_USE_LIBDBUS
#include "../../core/linux/SDL_dbus.h"
static DBusMessage*
wayland_read_dbus_setting(SDL_DBusContext *dbus, const char *key)
{
static const char *iface = "org.gnome.desktop.interface";
DBusMessage *reply = NULL;
DBusMessage *msg = dbus->message_new_method_call("org.freedesktop.portal.Desktop", /* Node */
"/org/freedesktop/portal/desktop", /* Path */
"org.freedesktop.portal.Settings", /* Interface */
"Read"); /* Method */
if (msg) {
if (dbus->message_append_args(msg, DBUS_TYPE_STRING, &iface, DBUS_TYPE_STRING, &key, DBUS_TYPE_INVALID)) {
reply = dbus->connection_send_with_reply_and_block(dbus->session_conn, msg, DBUS_TIMEOUT_USE_DEFAULT, NULL);
}
dbus->message_unref(msg);
}
return reply;
}
static SDL_bool
wayland_parse_dbus_reply(SDL_DBusContext *dbus, DBusMessage *reply, int type, void *value)
{
DBusMessageIter iter[3];
dbus->message_iter_init(reply, &iter[0]);
if (dbus->message_iter_get_arg_type(&iter[0]) != DBUS_TYPE_VARIANT) {
return SDL_FALSE;
}
dbus->message_iter_recurse(&iter[0], &iter[1]);
if (dbus->message_iter_get_arg_type(&iter[1]) != DBUS_TYPE_VARIANT) {
return SDL_FALSE;
}
dbus->message_iter_recurse(&iter[1], &iter[2]);
if (dbus->message_iter_get_arg_type(&iter[2]) != type) {
return SDL_FALSE;
}
dbus->message_iter_get_basic(&iter[2], value);
return SDL_TRUE;
}
static SDL_bool
wayland_dbus_read_cursor_size(int *size)
{
static const char *cursor_size_value = "cursor-size";
DBusMessage *reply;
SDL_DBusContext *dbus = SDL_DBus_GetContext();
if (!dbus || !size) {
return SDL_FALSE;
}
if ((reply = wayland_read_dbus_setting(dbus, cursor_size_value))) {
if (wayland_parse_dbus_reply(dbus, reply, DBUS_TYPE_INT32, size)) {
dbus->message_unref(reply);
return SDL_TRUE;
}
dbus->message_unref(reply);
}
return SDL_FALSE;
}
static SDL_bool
wayland_dbus_read_cursor_theme(char **theme)
{
static const char *cursor_theme_value = "cursor-theme";
DBusMessage *reply;
SDL_DBusContext *dbus = SDL_DBus_GetContext();
if (!dbus || !theme) {
return SDL_FALSE;
}
if ((reply = wayland_read_dbus_setting(dbus, cursor_theme_value))) {
const char *temp;
if (wayland_parse_dbus_reply(dbus, reply, DBUS_TYPE_STRING, &temp)) {
*theme = SDL_strdup(temp);
dbus->message_unref(reply);
return SDL_TRUE;
}
dbus->message_unref(reply);
}
return SDL_FALSE;
}
#endif
static SDL_bool
wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorData *cdata, float *scale)
{
@ -68,20 +168,25 @@ wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorData *cdata, float
SDL_WindowData *focusdata;
int i;
/* FIXME: We need to be able to query the cursor size from the desktop at
* some point! For a while this was 32, but when testing on real desktops it
* seems like most of them default to 24. We'll need a protocol to get this
* for real, but for now this is a pretty safe bet.
* -flibit
/*
* GNOME based desktops expose the cursor size and theme via the
* org.freedesktop.portal.Settings interface of the xdg-desktop portal.
* Try XCURSOR_SIZE and XCURSOR_THEME first, so user specified sizes and
* themes take precedence over all, then try D-Bus if the envvar isn't
* set, then fall back to the defaults if none of the preceding values
* are available or valid.
*/
xcursor_size = SDL_getenv("XCURSOR_SIZE");
if (xcursor_size != NULL) {
if ((xcursor_size = SDL_getenv("XCURSOR_SIZE"))) {
size = SDL_atoi(xcursor_size);
}
#if SDL_USE_LIBDBUS
if (size <= 0) {
wayland_dbus_read_cursor_size(&size);
}
#endif
if (size <= 0) {
size = 24;
}
/* First, find the appropriate theme based on the current scale... */
focus = SDL_GetMouse()->focus;
if (focus == NULL) {
@ -98,15 +203,29 @@ wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorData *cdata, float
}
}
if (theme == NULL) {
char *xcursor_theme = NULL;
SDL_bool free_theme_str = SDL_FALSE;
vdata->cursor_themes = SDL_realloc(vdata->cursor_themes,
sizeof(SDL_WaylandCursorTheme) * (vdata->num_cursor_themes + 1));
if (vdata->cursor_themes == NULL) {
SDL_OutOfMemory();
return SDL_FALSE;
}
theme = WAYLAND_wl_cursor_theme_load(SDL_getenv("XCURSOR_THEME"), size, vdata->shm);
xcursor_theme = SDL_getenv("XCURSOR_THEME");
#if SDL_USE_LIBDBUS
if (xcursor_theme == NULL) {
/* Allocates the string with SDL_strdup, which must be freed. */
free_theme_str = wayland_dbus_read_cursor_theme(&xcursor_theme);
}
#endif
theme = WAYLAND_wl_cursor_theme_load(xcursor_theme, size, vdata->shm);
vdata->cursor_themes[vdata->num_cursor_themes].size = size;
vdata->cursor_themes[vdata->num_cursor_themes++].theme = theme;
if (free_theme_str) {
SDL_free(xcursor_theme);
}
}
/* Next, find the cursor from the theme... */