5527b6e483
We're going to round the workspace backgrounds in the new overview for gnome-shell 40. So far corner-rounding was only possible for StWidgets because the rounded clipping was done using cairo drawing. We now need rounded clipping for ClutterActors too because backgrounds are drawn using ClutterActors (or more specifically a ClutterContent). To implement that, first a ClutterOffscreenEffect subclass together with a fragment shader from GSK (see gskSetOutputColor() [1] in the GSK GL renderer code) was investigated, and while that was generic and worked quite well, it was extremely slow for the case of drawing wallpapers because of all the FBOs that had to be allocated. This is the new, more performant approach: Use the same fragment shader, but perform the rounded clipping right in MetaBackgroundContent while we're painting the wallpaper. This has almost no performance impact, with the downside of not being a generic solution. To allow for rounded clipping not only at the edges of the wallpaper, but using any given bounding rectangle, the API exposes not only the radius, but also a bounding rect. [1] https://gitlab.gnome.org/GNOME/gtk/-/blob/master/gsk/resources/glsl/preamble.fs.glsl Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1717> |
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| .. | ||
| plugins | ||
| clutter-utils.c | ||
| clutter-utils.h | ||
| cogl-utils.c | ||
| cogl-utils.h | ||
| compositor-private.h | ||
| compositor.c | ||
| meta-background-actor-private.h | ||
| meta-background-actor.c | ||
| meta-background-content-private.h | ||
| meta-background-content.c | ||
| meta-background-group.c | ||
| meta-background-image.c | ||
| meta-background-private.h | ||
| meta-background.c | ||
| meta-compositor-native.c | ||
| meta-compositor-native.h | ||
| meta-compositor-server.c | ||
| meta-compositor-server.h | ||
| meta-compositor-x11.c | ||
| meta-compositor-x11.h | ||
| meta-cullable.c | ||
| meta-cullable.h | ||
| meta-dnd-actor-private.h | ||
| meta-dnd-actor.c | ||
| meta-dnd.c | ||
| meta-feedback-actor-private.h | ||
| meta-feedback-actor.c | ||
| meta-later-private.h | ||
| meta-later.c | ||
| meta-module.c | ||
| meta-module.h | ||
| meta-plugin-manager.c | ||
| meta-plugin-manager.h | ||
| meta-plugin.c | ||
| meta-shadow-factory.c | ||
| meta-shaped-texture-private.h | ||
| meta-shaped-texture.c | ||
| meta-surface-actor-wayland.c | ||
| meta-surface-actor-wayland.h | ||
| meta-surface-actor-x11.c | ||
| meta-surface-actor-x11.h | ||
| meta-surface-actor.c | ||
| meta-surface-actor.h | ||
| meta-sync-ring.c | ||
| meta-sync-ring.h | ||
| meta-texture-tower.c | ||
| meta-texture-tower.h | ||
| meta-window-actor-private.h | ||
| meta-window-actor-wayland.c | ||
| meta-window-actor-wayland.h | ||
| meta-window-actor-x11.c | ||
| meta-window-actor-x11.h | ||
| meta-window-actor.c | ||
| meta-window-group-private.h | ||
| meta-window-group.c | ||
| meta-window-shape.c | ||
| README | ||
| region-utils.c | ||
| region-utils.h | ||
Intro
=====
In general, the compositor splits the window from the contents of
the window from the shape of the window. In other words, a window
has contents, and the contents of the window have a shape. This is
represented by the actor hierarchy:
+--------------------------------------+
| MetaWindowActor |
| +----------------------------------+ |
| | MetaSurfaceActor | |
| | +------------------------------+ | |
| | | MetaShapedTexture | | |
| | | | | |
| | | | | |
| | | | | |
| | | | | |
| | +------------------------------+ | |
| +----------------------------------+ |
+--------------------------------------+
Surfaces may also contain subsurfaces. The MetaWindowActor and
MetaSurfaceActor subclasses that will be created depend on the client
type, and the display server type.
## Subsurfaces
Additionally, there is also the case of subsurfaces: surfaces that
are child of other surfaces. That is also represented in the actor
hierarchy by having one or many MetaSurfaceActors (the subsurfaces)
added as children of a parent MetaSurfaceActor. There are no limits
to how many subsurfaces a surface may have. With subsurfaces, the
actor hierarchy looks like this:
MetaWindowActor
↳ MetaSurfaceActor (surface)
↳ MetaShapedTexture
↳ MetaSurfaceActor (subsurface)
↳ MetaShapedTexture
↳ MetaSurfaceActor (sub-subsurface)
↳ MetaShapedTexture
↳ MetaSurfaceActor (subsurface)
↳ MetaShapedTexture
In this example, the main surface has 2 subsurfaces. One of these
subsurfaces contains a subsurface as well.
All MetaWindowActors contain at least one MetaSurfaceActor, and all
MetaSurfaceActors contain a MetaShapedTexture.
## Client and compositor
MetaWindowActor and its subclasses represent the client window's
type. A X11 client will have a MetaWindowActorX11 representing it,
and a Wayland client will have a MetaWindowActorWayland.
On the compositor side, the surface where the contents of the window
are drawn into are represented by MetaSurfaceActor subclasses. On a
Wayland session, windows are backed by a MetaSurfaceActorWayland
surface, whereas on X11 sessions, by MetaSurfaceActorX11.
XWayland windows are X11 client windows (MetaWindowActorX11) backed
by Wayland surfaces (MetaWindowActorWayland).
Env Vars
========
MUTTER_DISABLE_MIPMAPS - set to disable use of mipmaped windows.