57 lines
2.7 KiB
C
57 lines
2.7 KiB
C
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
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#ifndef META_WINDOW_GROUP_H
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#define META_WINDOW_GROUP_H
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#include <clutter/clutter.h>
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#include <meta/screen.h>
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/**
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* MetaWindowGroup:
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*
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* This class is a subclass of ClutterActor with special handling for
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* MetaWindowActor/MetaBackgroundActor/MetaBackgroundGroup when painting
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* children.
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*
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* When we are painting a stack of 5-10 maximized windows, the
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* standard bottom-to-top method of drawing every actor results in a
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* tremendous amount of overdraw and can easily max out the available
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* memory bandwidth on a low-end graphics chipset. It's even worse if
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* window textures are being accessed over the AGP bus.
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*
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* The basic technique applied here is to do a pre-pass before painting
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* where we walk window from top to bottom and compute the visible area
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* at each step by subtracting out the windows above it. The visible
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* area is passed to MetaWindowActor which uses it to clip the portion of
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* the window which drawn and avoid redrawing the shadow if it is completely
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* obscured.
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*
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* A caveat is that this is ineffective if applications are using ARGB
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* visuals, since we have no way of knowing whether a window obscures
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* the windows behind it or not. Alternate approaches using the depth
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* or stencil buffer rather than client side regions might be able to
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* handle alpha windows, but the combination of glAlphaFunc and stenciling
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* tends not to be efficient except on newer cards. (And on newer cards
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* we have lots of memory and bandwidth.)
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*/
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#define META_TYPE_WINDOW_GROUP (meta_window_group_get_type ())
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#define META_WINDOW_GROUP(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), META_TYPE_WINDOW_GROUP, MetaWindowGroup))
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#define META_WINDOW_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), META_TYPE_WINDOW_GROUP, MetaWindowGroupClass))
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#define META_IS_WINDOW_GROUP(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), META_TYPE_WINDOW_GROUP))
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#define META_IS_WINDOW_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), META_TYPE_WINDOW_GROUP))
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#define META_WINDOW_GROUP_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), META_TYPE_WINDOW_GROUP, MetaWindowGroupClass))
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typedef struct _MetaWindowGroup MetaWindowGroup;
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typedef struct _MetaWindowGroupClass MetaWindowGroupClass;
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typedef struct _MetaWindowGroupPrivate MetaWindowGroupPrivate;
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GType meta_window_group_get_type (void);
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ClutterActor *meta_window_group_new (MetaScreen *screen);
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gboolean meta_window_group_actor_is_untransformed (ClutterActor *actor,
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int *x_origin,
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int *y_origin);
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#endif /* META_WINDOW_GROUP_H */
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