blob: 0e0dc18738d1776dc122fda140507187eaaddd17 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
#ifndef META_WINDOW_GROUP_H
#define META_WINDOW_GROUP_H
#include <clutter/clutter.h>
#include <meta/screen.h>
/**
* MetaWindowGroup:
*
* This class is a subclass of ClutterGroup with special handling for
* MetaWindowActor when painting the group. When we are painting a stack
* of 5-10 maximized windows, the standard bottom-to-top method of
* drawing every actor results in a tremendous amount of overdraw
* and can easily max out the available memory bandwidth on a low-end
* graphics chipset. It's even worse if window textures are being accessed
* over the AGP bus.
*
* The basic technique applied here is to do a pre-pass before painting
* where we walk window from top to bottom and compute the visible area
* at each step by subtracting out the windows above it. The visible
* area is passed to MetaWindowActor which uses it to clip the portion of
* the window which drawn and avoid redrawing the shadow if it is completely
* obscured.
*
* A caveat is that this is ineffective if applications are using ARGB
* visuals, since we have no way of knowing whether a window obscures
* the windows behind it or not. Alternate approaches using the depth
* or stencil buffer rather than client side regions might be able to
* handle alpha windows, but the combination of glAlphaFunc and stenciling
* tends not to be efficient except on newer cards. (And on newer cards
* we have lots of memory and bandwidth.)
*/
#define META_TYPE_WINDOW_GROUP (meta_window_group_get_type ())
#define META_WINDOW_GROUP(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), META_TYPE_WINDOW_GROUP, MetaWindowGroup))
#define META_WINDOW_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), META_TYPE_WINDOW_GROUP, MetaWindowGroupClass))
#define META_IS_WINDOW_GROUP(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), META_TYPE_WINDOW_GROUP))
#define META_IS_WINDOW_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), META_TYPE_WINDOW_GROUP))
#define META_WINDOW_GROUP_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), META_TYPE_WINDOW_GROUP, MetaWindowGroupClass))
typedef struct _MetaWindowGroup MetaWindowGroup;
typedef struct _MetaWindowGroupClass MetaWindowGroupClass;
typedef struct _MetaWindowGroupPrivate MetaWindowGroupPrivate;
GType meta_window_group_get_type (void);
ClutterActor *meta_window_group_new (MetaScreen *screen);
#endif /* META_WINDOW_GROUP_H */
|
