mutter/src/backends/meta-cursor-sprite-xcursor.c
Jonas Ådahl 40c345d6f3 cursor-sprite-xcursor: Emulate Wayland hotspot limitations
For HiDPI pointer cursors backed by Wayland surfaces, the hotspot must
be placed using integers on the logical pixel grid. In practice what
this means is that if the client loads a cursor sprite with the buffer
scale 2, and it's hotspot is not dividable by 2, it will be rounded
down to an integer that can. E.g. a wl_surface with buffer scale 2 and a
cursor image with hotspot coordinate (7, 7) will have the coordinate
(3.5, 3.5) in surface coordinate space, and will in practice be rounded
down to (3, 3) as the hotspot position in wl_pointer only takes
integers.

To not potentially shift by 1 pixel on HiDPI monitors when switching
between wl_surface backend cursor sprites and built-in ones, make the
built in one emulate the restrictions put up by the Wayland protocol.

This also initializes the theme scale of the xcursor sprite instances to
1, as they may not have been set prior to being used, it'll only happen
in response to "prepare-at" signals being emitted prior to rendering.

Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/1092

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1107
2020-03-26 08:47:37 +00:00

308 lines
9.0 KiB
C

/*
* Copyright 2013, 2018 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "config.h"
#include "backends/meta-cursor-sprite-xcursor.h"
#include "backends/meta-cursor.h"
#include "backends/meta-cursor-renderer.h"
#include "clutter/clutter.h"
#include "cogl/cogl.h"
#include "meta/prefs.h"
#include "meta/util.h"
struct _MetaCursorSpriteXcursor
{
MetaCursorSprite parent;
MetaCursor cursor;
int current_frame;
XcursorImages *xcursor_images;
int theme_scale;
gboolean theme_dirty;
};
G_DEFINE_TYPE (MetaCursorSpriteXcursor, meta_cursor_sprite_xcursor,
META_TYPE_CURSOR_SPRITE)
static const char *
translate_meta_cursor (MetaCursor cursor)
{
switch (cursor)
{
case META_CURSOR_DEFAULT:
return "left_ptr";
case META_CURSOR_NORTH_RESIZE:
return "top_side";
case META_CURSOR_SOUTH_RESIZE:
return "bottom_side";
case META_CURSOR_WEST_RESIZE:
return "left_side";
case META_CURSOR_EAST_RESIZE:
return "right_side";
case META_CURSOR_SE_RESIZE:
return "bottom_right_corner";
case META_CURSOR_SW_RESIZE:
return "bottom_left_corner";
case META_CURSOR_NE_RESIZE:
return "top_right_corner";
case META_CURSOR_NW_RESIZE:
return "top_left_corner";
case META_CURSOR_MOVE_OR_RESIZE_WINDOW:
return "fleur";
case META_CURSOR_BUSY:
return "watch";
case META_CURSOR_DND_IN_DRAG:
return "dnd-none";
case META_CURSOR_DND_MOVE:
return "dnd-move";
case META_CURSOR_DND_COPY:
return "dnd-copy";
case META_CURSOR_DND_UNSUPPORTED_TARGET:
return "dnd-none";
case META_CURSOR_POINTING_HAND:
return "hand2";
case META_CURSOR_CROSSHAIR:
return "crosshair";
case META_CURSOR_IBEAM:
return "xterm";
case META_CURSOR_NONE:
case META_CURSOR_LAST:
break;
}
g_assert_not_reached ();
return NULL;
}
MetaCursor
meta_cursor_sprite_xcursor_get_cursor (MetaCursorSpriteXcursor *sprite_xcursor)
{
return sprite_xcursor->cursor;
}
Cursor
meta_create_x_cursor (Display *xdisplay,
MetaCursor cursor)
{
return XcursorLibraryLoadCursor (xdisplay, translate_meta_cursor (cursor));
}
static XcursorImages *
load_cursor_on_client (MetaCursor cursor, int scale)
{
return XcursorLibraryLoadImages (translate_meta_cursor (cursor),
meta_prefs_get_cursor_theme (),
meta_prefs_get_cursor_size () * scale);
}
static void
load_from_current_xcursor_image (MetaCursorSpriteXcursor *sprite_xcursor)
{
MetaCursorSprite *sprite = META_CURSOR_SPRITE (sprite_xcursor);
XcursorImage *xc_image;
int width, height, rowstride;
CoglPixelFormat cogl_format;
ClutterBackend *clutter_backend;
CoglContext *cogl_context;
CoglTexture2D *texture;
GError *error = NULL;
int hotspot_x, hotspot_y;
g_assert (!meta_cursor_sprite_get_cogl_texture (sprite));
xc_image = meta_cursor_sprite_xcursor_get_current_image (sprite_xcursor);
width = (int) xc_image->width;
height = (int) xc_image->height;
rowstride = width * 4;
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
cogl_format = COGL_PIXEL_FORMAT_BGRA_8888;
#else
cogl_format = COGL_PIXEL_FORMAT_ARGB_8888;
#endif
clutter_backend = clutter_get_default_backend ();
cogl_context = clutter_backend_get_cogl_context (clutter_backend);
texture = cogl_texture_2d_new_from_data (cogl_context,
width, height,
cogl_format,
rowstride,
(uint8_t *) xc_image->pixels,
&error);
if (!texture)
{
g_warning ("Failed to allocate cursor texture: %s\n", error->message);
g_error_free (error);
}
if (meta_is_wayland_compositor ())
{
hotspot_x = ((int) (xc_image->xhot / sprite_xcursor->theme_scale) *
sprite_xcursor->theme_scale);
hotspot_y = ((int) (xc_image->yhot / sprite_xcursor->theme_scale) *
sprite_xcursor->theme_scale);
}
else
{
hotspot_x = xc_image->xhot;
hotspot_y = xc_image->yhot;
}
meta_cursor_sprite_set_texture (sprite,
COGL_TEXTURE (texture),
hotspot_x, hotspot_y);
g_clear_pointer (&texture, cogl_object_unref);
}
void
meta_cursor_sprite_xcursor_set_theme_scale (MetaCursorSpriteXcursor *sprite_xcursor,
int theme_scale)
{
if (sprite_xcursor->theme_scale != theme_scale)
sprite_xcursor->theme_dirty = TRUE;
sprite_xcursor->theme_scale = theme_scale;
}
static gboolean
meta_cursor_sprite_xcursor_is_animated (MetaCursorSprite *sprite)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (sprite);
return (sprite_xcursor->xcursor_images &&
sprite_xcursor->xcursor_images->nimage > 1);
}
XcursorImage *
meta_cursor_sprite_xcursor_get_current_image (MetaCursorSpriteXcursor *sprite_xcursor)
{
return sprite_xcursor->xcursor_images->images[sprite_xcursor->current_frame];
}
static void
meta_cursor_sprite_xcursor_tick_frame (MetaCursorSprite *sprite)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (sprite);
if (!meta_cursor_sprite_is_animated (sprite))
return;
sprite_xcursor->current_frame++;
if (sprite_xcursor->current_frame >= sprite_xcursor->xcursor_images->nimage)
sprite_xcursor->current_frame = 0;
meta_cursor_sprite_clear_texture (sprite);
load_from_current_xcursor_image (sprite_xcursor);
}
static unsigned int
meta_cursor_sprite_xcursor_get_current_frame_time (MetaCursorSprite *sprite)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (sprite);
XcursorImages *xcursor_images;
g_return_val_if_fail (meta_cursor_sprite_is_animated (sprite), 0);
xcursor_images = sprite_xcursor->xcursor_images;
return xcursor_images->images[sprite_xcursor->current_frame]->delay;
}
static void
load_cursor_from_theme (MetaCursorSprite *sprite)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (sprite);
g_assert (sprite_xcursor->cursor != META_CURSOR_NONE);
sprite_xcursor->theme_dirty = FALSE;
/* We might be reloading with a different scale. If so clear the old data. */
if (sprite_xcursor->xcursor_images)
{
meta_cursor_sprite_clear_texture (sprite);
XcursorImagesDestroy (sprite_xcursor->xcursor_images);
}
sprite_xcursor->current_frame = 0;
sprite_xcursor->xcursor_images =
load_cursor_on_client (sprite_xcursor->cursor,
sprite_xcursor->theme_scale);
if (!sprite_xcursor->xcursor_images)
g_error ("Could not find cursor. Perhaps set XCURSOR_PATH?");
load_from_current_xcursor_image (sprite_xcursor);
}
static void
meta_cursor_sprite_xcursor_realize_texture (MetaCursorSprite *sprite)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (sprite);
if (sprite_xcursor->theme_dirty)
load_cursor_from_theme (sprite);
}
MetaCursorSpriteXcursor *
meta_cursor_sprite_xcursor_new (MetaCursor cursor)
{
MetaCursorSpriteXcursor *sprite_xcursor;
sprite_xcursor = g_object_new (META_TYPE_CURSOR_SPRITE_XCURSOR, NULL);
sprite_xcursor->cursor = cursor;
return sprite_xcursor;
}
static void
meta_cursor_sprite_xcursor_finalize (GObject *object)
{
MetaCursorSpriteXcursor *sprite_xcursor = META_CURSOR_SPRITE_XCURSOR (object);
g_clear_pointer (&sprite_xcursor->xcursor_images,
XcursorImagesDestroy);
G_OBJECT_CLASS (meta_cursor_sprite_xcursor_parent_class)->finalize (object);
}
static void
meta_cursor_sprite_xcursor_init (MetaCursorSpriteXcursor *sprite_xcursor)
{
sprite_xcursor->theme_scale = 1;
sprite_xcursor->theme_dirty = TRUE;
}
static void
meta_cursor_sprite_xcursor_class_init (MetaCursorSpriteXcursorClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
MetaCursorSpriteClass *cursor_sprite_class = META_CURSOR_SPRITE_CLASS (klass);
object_class->finalize = meta_cursor_sprite_xcursor_finalize;
cursor_sprite_class->realize_texture =
meta_cursor_sprite_xcursor_realize_texture;
cursor_sprite_class->is_animated = meta_cursor_sprite_xcursor_is_animated;
cursor_sprite_class->tick_frame = meta_cursor_sprite_xcursor_tick_frame;
cursor_sprite_class->get_current_frame_time =
meta_cursor_sprite_xcursor_get_current_frame_time;
}