From ad3a4c677bf28f054482d03394bbd7b12ba33a0c Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Mon, 23 Sep 2024 12:50:28 -0400
Subject: [PATCH] wayland: Clean up cursor scaling
Handle named and custom cursor scaling in a cleaner manner, and account for edge cases where named cursor sizes may not exactly match the required size.
---
src/video/wayland/SDL_waylandmouse.c | 218 ++++++++++++++++-----------
1 file changed, 129 insertions(+), 89 deletions(-)
diff --git a/src/video/wayland/SDL_waylandmouse.c b/src/video/wayland/SDL_waylandmouse.c
index 7b21a25491ad8..f503e2de290ea 100644
--- a/src/video/wayland/SDL_waylandmouse.c
+++ b/src/video/wayland/SDL_waylandmouse.c
@@ -48,18 +48,16 @@ static bool Wayland_SetRelativeMouseMode(bool enabled);
typedef struct
{
struct Wayland_SHMBuffer shmBuffer;
-
- int dst_width;
- int dst_height;
double scale;
-
struct wl_list node;
-} Wayland_CachedCustomCursor;
+} Wayland_ScaledCustomCursor;
typedef struct
{
SDL_Surface *sdl_cursor_surface;
- struct wl_list cursor_cache;
+ int hot_x;
+ int hot_y;
+ struct wl_list scaled_cursor_cache;
} Wayland_CustomCursor;
typedef struct
@@ -91,8 +89,6 @@ struct SDL_CursorData
struct wl_surface *surface;
struct wp_viewport *viewport;
- int hot_x, hot_y;
-
bool is_system_cursor;
};
@@ -338,39 +334,35 @@ static void cursor_frame_done(void *data, struct wl_callback *cb, uint32_t time)
wl_surface_commit(c->surface);
}
-static bool wayland_get_system_cursor(SDL_VideoData *vdata, SDL_CursorData *cdata, double *scale)
+static bool Wayland_GetSystemCursor(SDL_VideoData *vdata, SDL_CursorData *cdata, int *scale, int *dst_size, int *hot_x, int *hot_y)
{
struct wl_cursor_theme *theme = NULL;
struct wl_cursor *cursor;
const char *css_name = "default";
const char *fallback_name = NULL;
-
- int size = dbus_cursor_size;
-
- SDL_Window *focus;
+ double scale_factor = 1.0;
+ int theme_size = dbus_cursor_size;
// Fallback envvar if the DBus properties don't exist
- if (size <= 0) {
+ if (theme_size <= 0) {
const char *xcursor_size = SDL_getenv("XCURSOR_SIZE");
if (xcursor_size) {
- size = SDL_atoi(xcursor_size);
+ theme_size = SDL_atoi(xcursor_size);
}
}
- if (size <= 0) {
- size = 24;
+ if (theme_size <= 0) {
+ theme_size = 24;
}
// First, find the appropriate theme based on the current scale...
- focus = SDL_GetMouse()->focus;
+ SDL_Window *focus = SDL_GetMouse()->focus;
if (focus) {
// TODO: Use the fractional scale once GNOME supports viewports on cursor surfaces.
- *scale = SDL_ceil(focus->internal->scale_factor);
- } else {
- *scale = 1.0;
+ scale_factor = SDL_ceil(focus->internal->scale_factor);
}
- size *= (int)*scale;
+ const int scaled_size = (int)SDL_lround(theme_size * scale_factor);
for (int i = 0; i < vdata->num_cursor_themes; ++i) {
- if (vdata->cursor_themes[i].size == size) {
+ if (vdata->cursor_themes[i].size == scaled_size) {
theme = vdata->cursor_themes[i].theme;
break;
}
@@ -390,8 +382,8 @@ static bool wayland_get_system_cursor(SDL_VideoData *vdata, SDL_CursorData *cdat
xcursor_theme = SDL_getenv("XCURSOR_THEME");
}
- theme = WAYLAND_wl_cursor_theme_load(xcursor_theme, size, vdata->shm);
- vdata->cursor_themes[vdata->num_cursor_themes].size = size;
+ theme = WAYLAND_wl_cursor_theme_load(xcursor_theme, scaled_size, vdata->shm);
+ vdata->cursor_themes[vdata->num_cursor_themes].size = scaled_size;
vdata->cursor_themes[vdata->num_cursor_themes++].theme = theme;
}
@@ -429,66 +421,116 @@ static bool wayland_get_system_cursor(SDL_VideoData *vdata, SDL_CursorData *cdat
cdata->cursor_data.system.frames[i].duration = cursor->images[i]->delay;
cdata->cursor_data.system.total_duration += cursor->images[i]->delay;
}
- cdata->hot_x = cursor->images[0]->hotspot_x;
- cdata->hot_y = cursor->images[0]->hotspot_y;
+
+ *scale = SDL_ceil(scale_factor) == scale_factor ? (int)scale_factor : 0;
+ *dst_size = theme_size;
+
+ // Calculate the hotspot offset if the cursor is being scaled.
+ if (scaled_size == cursor->images[0]->width) {
+ // If the theme has an exact size match, just divide by the scale.
+ *hot_x = (int)SDL_lround(cursor->images[0]->hotspot_x / scale_factor);
+ *hot_y = (int)SDL_lround(cursor->images[0]->hotspot_y / scale_factor);
+ } else {
+ if (vdata->viewporter) {
+ // Use a viewport if no exact size match is found to avoid a potential "buffer size is not divisible by scale" protocol error.
+ *scale = 0;
+
+ // Map the hotspot coordinates from the source to destination sizes.
+ const double hotspot_scale = (double)theme_size / (double)cursor->images[0]->width;
+ *hot_x = (int)SDL_lround(hotspot_scale * cursor->images[0]->hotspot_x);
+ *hot_y = (int)SDL_lround(hotspot_scale * cursor->images[0]->hotspot_y);
+ } else {
+ // No exact match, and viewports are unsupported. Find a safe integer scale.
+ for (; *scale > 1; --*scale) {
+ if (cursor->images[0]->width % *scale == 0) {
+ break;
+ }
+ }
+ *hot_x = cursor->images[0]->hotspot_x / *scale;
+ *hot_y = cursor->images[0]->hotspot_y / *scale;
+ }
+ }
+
return true;
}
-static Wayland_CachedCustomCursor *Wayland_GetCachedCustomCursor(SDL_Cursor *cursor)
+static Wayland_ScaledCustomCursor *Wayland_CacheScaledCustomCursor(SDL_CursorData *cdata, double scale)
+{
+ Wayland_ScaledCustomCursor *cache = NULL;
+
+ // Is this cursor already cached at the target scale?
+ if (!WAYLAND_wl_list_empty(&cdata->cursor_data.custom.scaled_cursor_cache)) {
+ Wayland_ScaledCustomCursor *c = NULL;
+ wl_list_for_each (c, &cdata->cursor_data.custom.scaled_cursor_cache, node) {
+ if (c->scale == scale) {
+ cache = c;
+ break;
+ }
+ }
+ }
+
+ if (!cache) {
+ cache = SDL_calloc(1, sizeof(Wayland_ScaledCustomCursor));
+ if (!cache) {
+ return NULL;
+ }
+
+ SDL_Surface *surface = SDL_GetSurfaceImage(cdata->cursor_data.custom.sdl_cursor_surface, (float)scale);
+ if (!surface) {
+ SDL_free(cache);
+ return NULL;
+ }
+
+ // Allocate the shared memory buffer for this cursor.
+ if (!Wayland_AllocSHMBuffer(surface->w, surface->h, &cache->shmBuffer)) {
+ SDL_free(cache);
+ SDL_DestroySurface(surface);
+ return NULL;
+ }
+
+ // Wayland requires premultiplied alpha for its surfaces.
+ SDL_PremultiplyAlpha(surface->w, surface->h,
+ surface->format, surface->pixels, surface->pitch,
+ SDL_PIXELFORMAT_ARGB8888, cache->shmBuffer.shm_data, surface->w * 4, true);
+
+ cache->scale = scale;
+ WAYLAND_wl_list_insert(&cdata->cursor_data.custom.scaled_cursor_cache, &cache->node);
+ SDL_DestroySurface(surface);
+ }
+
+ return cache;
+}
+
+static bool Wayland_GetCustomCursor(SDL_Cursor *cursor, struct wl_buffer **buffer, int *scale, int *dst_width, int *dst_height, int *hot_x, int *hot_y)
{
SDL_VideoDevice *vd = SDL_GetVideoDevice();
SDL_VideoData *wd = vd->internal;
SDL_CursorData *data = cursor->internal;
- Wayland_CachedCustomCursor *cache;
SDL_Window *focus = SDL_GetMouseFocus();
- double scale = 1.0;
+ double scale_factor = 1.0;
if (focus && SDL_SurfaceHasAlternateImages(data->cursor_data.custom.sdl_cursor_surface)) {
- scale = focus->internal->scale_factor;
+ scale_factor = focus->internal->scale_factor;
}
// Only use fractional scale values if viewports are available.
if (!wd->viewporter) {
- scale = SDL_ceil(scale);
+ scale_factor = SDL_ceil(scale_factor);
}
- // Is this cursor already cached at the target scale?
- wl_list_for_each(cache, &data->cursor_data.custom.cursor_cache, node) {
- if (cache->scale == scale) {
- return cache;
- }
- }
-
- cache = SDL_calloc(1, sizeof(Wayland_CachedCustomCursor));
- if (!cache) {
- return NULL;
- }
-
- SDL_Surface *surface = SDL_GetSurfaceImage(data->cursor_data.custom.sdl_cursor_surface, (float)scale);
- if (!surface) {
- SDL_free(cache);
- return NULL;
- }
-
- // Allocate shared memory buffer for this cursor
- if (!Wayland_AllocSHMBuffer(surface->w, surface->h, &cache->shmBuffer)) {
- SDL_free(cache);
- SDL_DestroySurface(surface);
- return NULL;
+ Wayland_ScaledCustomCursor *c = Wayland_CacheScaledCustomCursor(data, scale_factor);
+ if (!c) {
+ return false;
}
- // Wayland requires premultiplied alpha for its surfaces.
- SDL_PremultiplyAlpha(surface->w, surface->h,
- surface->format, surface->pixels, surface->pitch,
- SDL_PIXELFORMAT_ARGB8888, cache->shmBuffer.shm_data, surface->w * 4, true);
-
- cache->dst_width = data->cursor_data.custom.sdl_cursor_surface->w;
- cache->dst_height = data->cursor_data.custom.sdl_cursor_surface->h;
- cache->scale = scale;
- WAYLAND_wl_list_insert(&data->cursor_data.custom.cursor_cache, &cache->node);
- SDL_DestroySurface(surface);
+ *buffer = c->shmBuffer.wl_buffer;
+ *scale = SDL_ceil(scale_factor) == scale_factor ? (int)scale_factor : 0;
+ *dst_width = data->cursor_data.custom.sdl_cursor_surface->w;
+ *dst_height = data->cursor_data.custom.sdl_cursor_surface->h;
+ *hot_x = data->cursor_data.custom.hot_x;
+ *hot_y = data->cursor_data.custom.hot_y;
- return cache;
+ return true;
}
static SDL_Cursor *Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
@@ -504,18 +546,17 @@ static SDL_Cursor *Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot
return NULL;
}
cursor->internal = data;
- WAYLAND_wl_list_init(&data->cursor_data.custom.cursor_cache);
- data->hot_x = hot_x;
- data->hot_y = hot_y;
+ WAYLAND_wl_list_init(&data->cursor_data.custom.scaled_cursor_cache);
+ data->cursor_data.custom.hot_x = hot_x;
+ data->cursor_data.custom.hot_y = hot_y;
data->surface = wl_compositor_create_surface(wd->compositor);
- wl_surface_set_user_data(data->surface, NULL);
data->cursor_data.custom.sdl_cursor_surface = surface;
++surface->refcount;
// If the cursor has only one size, just prepare it now.
if (!SDL_SurfaceHasAlternateImages(surface)) {
- Wayland_GetCachedCustomCursor(cursor);
+ Wayland_CacheScaledCustomCursor(data, 1.0);
}
}
@@ -565,8 +606,8 @@ static void Wayland_FreeCursorData(SDL_CursorData *d)
}
SDL_free(d->cursor_data.system.frames);
} else {
- Wayland_CachedCustomCursor *c, *temp;
- wl_list_for_each_safe(c, temp, &d->cursor_data.custom.cursor_cache, node) {
+ Wayland_ScaledCustomCursor *c, *temp;
+ wl_list_for_each_safe(c, temp, &d->cursor_data.custom.scaled_cursor_cache, node) {
Wayland_ReleaseSHMBuffer(&c->shmBuffer);
SDL_free(c);
}
@@ -681,9 +722,12 @@ static bool Wayland_ShowCursor(SDL_Cursor *cursor)
SDL_VideoData *d = vd->internal;
struct SDL_WaylandInput *input = d->input;
struct wl_pointer *pointer = d->pointer;
- double scale = 1.0;
+ struct wl_buffer *buffer = NULL;
+ int scale = 1;
int dst_width = 0;
int dst_height = 0;
+ int hot_x;
+ int hot_y;
if (!pointer) {
return false;
@@ -700,19 +744,18 @@ static bool Wayland_ShowCursor(SDL_Cursor *cursor)
SDL_CursorData *data = cursor->internal;
if (data->is_system_cursor) {
+ // If the cursor shape protocol is supported, the compositor will draw nicely scaled cursors for us, so nothing more to do.
if (input->cursor_shape) {
Wayland_SetSystemCursorShape(input, data->cursor_data.system.id);
input->current_cursor = data;
-
return true;
}
- if (!wayland_get_system_cursor(d, data, &scale)) {
+ if (!Wayland_GetSystemCursor(d, data, &scale, &dst_width, &hot_x, &hot_y)) {
return false;
}
- }
- if (data->is_system_cursor) {
+ dst_height = dst_width;
wl_surface_attach(data->surface, data->cursor_data.system.frames[0].wl_buffer, 0, 0);
// If more than one frame is available, create a frame callback to run the animation.
@@ -724,34 +767,31 @@ static bool Wayland_ShowCursor(SDL_Cursor *cursor)
wl_callback_add_listener(data->cursor_data.system.frame_callback, &cursor_frame_listener, data);
}
} else {
- Wayland_CachedCustomCursor *cached = Wayland_GetCachedCustomCursor(cursor);
- if (!cached) {
+ if (!Wayland_GetCustomCursor(cursor, &buffer, &scale, &dst_width, &dst_height, &hot_x, &hot_y)) {
return false;
}
- dst_width = cached->dst_width;
- dst_height = cached->dst_height;
- scale = cached->scale;
- wl_surface_attach(data->surface, cached->shmBuffer.wl_buffer, 0, 0);
+
+ wl_surface_attach(data->surface, buffer, 0, 0);
}
- // TODO: Make the viewport path the default in all cases once GNOME finally supports viewports on cursor surfaces.
- if (SDL_ceil(scale) != scale && d->viewporter) {
+ // A scale value of 0 indicates that a viewport with the returned destination size should be used.
+ if (!scale) {
if (!data->viewport) {
data->viewport = wp_viewporter_get_viewport(d->viewporter, data->surface);
}
wl_surface_set_buffer_scale(data->surface, 1);
wp_viewport_set_source(data->viewport, wl_fixed_from_int(-1), wl_fixed_from_int(-1), wl_fixed_from_int(-1), wl_fixed_from_int(-1));
wp_viewport_set_destination(data->viewport, dst_width, dst_height);
- wl_pointer_set_cursor(pointer, input->pointer_enter_serial, data->surface, data->hot_x, data->hot_y);
} else {
if (data->viewport) {
wp_viewport_destroy(data->viewport);
data->viewport = NULL;
}
- wl_surface_set_buffer_scale(data->surface, (int32_t)scale);
- wl_pointer_set_cursor(pointer, input->pointer_enter_serial, data->surface, (int32_t)(data->hot_x / scale), (int32_t)(data->hot_y / scale));
+ wl_surface_set_buffer_scale(data->surface, scale);
}
+ wl_pointer_set_cursor(pointer, input->pointer_enter_serial, data->surface, hot_x, hot_y);
+
if (wl_surface_get_version(data->surface) >= WL_SURFACE_DAMAGE_BUFFER_SINCE_VERSION) {
wl_surface_damage_buffer(data->surface, 0, 0, SDL_MAX_SINT32, SDL_MAX_SINT32);
} else {