mutter/src/compositor/meta-window-group.c

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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
#include <config.h>
#define _ISOC99_SOURCE /* for roundf */
#include <math.h>
#include <gdk/gdk.h> /* for gdk_rectangle_intersect() */
#include "compositor-private.h"
#include "meta-window-actor-private.h"
#include "meta-window-group.h"
#include "meta-background-actor-private.h"
struct _MetaWindowGroupClass
{
ClutterGroupClass parent_class;
};
struct _MetaWindowGroup
{
ClutterGroup parent;
MetaScreen *screen;
};
G_DEFINE_TYPE (MetaWindowGroup, meta_window_group, CLUTTER_TYPE_GROUP);
/* This file uses pixel-aligned region computation to determine what
* can be clipped out. This only really works if everything is aligned
* to the pixel grid - not scaled or rotated and at integer offsets.
*
* (This could be relaxed - if we turned off filtering for unscaled
* windows then windows would be, by definition aligned to the pixel
* grid. And for rectangular windows without a shape, the outline that
* we draw for an unrotated window is always a rectangle because we
* don't use antialasing for the window boundary - with or without
* filtering, with or without a scale. But figuring out exactly
* what pixels will be drawn by the graphics system in these cases
* gets tricky, so we just go for the easiest part - no scale,
* and at integer offsets.)
*
* The way we check for pixel-aligned is by looking at the
* transformation into screen space of the allocation box of an actor
* and and checking if the corners are "close enough" to integral
* pixel values.
*/
/* The definition of "close enough" to integral pixel values is
* equality when we convert to 24.8 fixed-point.
*/
static inline int
round_to_fixed (float x)
{
return roundf (x * 256);
}
/* This helper function checks if (according to our fixed point precision)
* the vertices @verts form a box of width @widthf and height @heightf
* located at integral coordinates. These coordinates are returned
* in @x_origin and @y_origin.
*/
static gboolean
vertices_are_untransformed (ClutterVertex *verts,
float widthf,
float heightf,
int *x_origin,
int *y_origin)
{
int width, height;
int v0x, v0y, v1x, v1y, v2x, v2y, v3x, v3y;
int x, y;
width = round_to_fixed (widthf); height = round_to_fixed (heightf);
v0x = round_to_fixed (verts[0].x); v0y = round_to_fixed (verts[0].y);
v1x = round_to_fixed (verts[1].x); v1y = round_to_fixed (verts[1].y);
v2x = round_to_fixed (verts[2].x); v2y = round_to_fixed (verts[2].y);
v3x = round_to_fixed (verts[3].x); v3y = round_to_fixed (verts[3].y);
/* Using shifting for converting fixed => int, gets things right for
* negative values. / 256. wouldn't do the same
*/
x = v0x >> 8;
y = v0y >> 8;
/* At integral coordinates? */
if (x * 256 != v0x || y * 256 != v0y)
return FALSE;
/* Not scaled? */
if (v1x - v0x != width || v2y - v0y != height)
return FALSE;
/* Not rotated/skewed? */
if (v0x != v2x || v0y != v1y ||
v3x != v1x || v3y != v2y)
return FALSE;
*x_origin = x;
*y_origin = y;
return TRUE;
}
/* Check if an actor is "untransformed" - which actually means transformed by
* at most a integer-translation. The integer translation, if any, is returned.
*/
static gboolean
actor_is_untransformed (ClutterActor *actor,
int *x_origin,
int *y_origin)
{
gfloat widthf, heightf;
ClutterVertex verts[4];
clutter_actor_get_size (actor, &widthf, &heightf);
clutter_actor_get_abs_allocation_vertices (actor, verts);
return vertices_are_untransformed (verts, widthf, heightf, x_origin, y_origin);
}
/* Help macros to scale from OpenGL <-1,1> coordinates system to
* window coordinates ranging [0,window-size]. Borrowed from clutter-utils.c
*/
#define MTX_GL_SCALE_X(x,w,v1,v2) ((((((x) / (w)) + 1.0f) / 2.0f) * (v1)) + (v2))
#define MTX_GL_SCALE_Y(y,w,v1,v2) ((v1) - (((((y) / (w)) + 1.0f) / 2.0f) * (v1)) + (v2))
/* Check if we're painting the MetaWindowGroup "untransformed". This can
* differ from the result of actor_is_untransformed(window_group) if we're
* inside a clone paint. The integer translation, if any, is returned.
*/
static gboolean
painting_untransformed (MetaWindowGroup *window_group,
int *x_origin,
int *y_origin)
{
CoglMatrix modelview, projection, modelview_projection;
ClutterVertex vertices[4];
int width, height;
float viewport[4];
int i;
cogl_get_modelview_matrix (&modelview);
cogl_get_projection_matrix (&projection);
cogl_matrix_multiply (&modelview_projection,
&projection,
&modelview);
meta_screen_get_size (window_group->screen, &width, &height);
vertices[0].x = 0;
vertices[0].y = 0;
vertices[0].z = 0;
vertices[1].x = width;
vertices[1].y = 0;
vertices[1].z = 0;
vertices[2].x = 0;
vertices[2].y = height;
vertices[2].z = 0;
vertices[3].x = width;
vertices[3].y = height;
vertices[3].z = 0;
cogl_get_viewport (viewport);
for (i = 0; i < 4; i++)
{
float w = 1;
cogl_matrix_transform_point (&modelview_projection, &vertices[i].x, &vertices[i].y, &vertices[i].z, &w);
vertices[i].x = MTX_GL_SCALE_X (vertices[i].x, w,
viewport[2], viewport[0]);
vertices[i].y = MTX_GL_SCALE_Y (vertices[i].y, w,
viewport[3], viewport[1]);
}
return vertices_are_untransformed (vertices, width, height, x_origin, y_origin);
}
static void
meta_window_group_paint (ClutterActor *actor)
{
cairo_region_t *visible_region;
ClutterActor *stage;
cairo_rectangle_int_t visible_rect;
GList *children, *l;
int paint_x_origin, paint_y_origin;
int actor_x_origin, actor_y_origin;
int paint_x_offset, paint_y_offset;
MetaWindowGroup *window_group = META_WINDOW_GROUP (actor);
MetaCompScreen *info = meta_screen_get_compositor_data (window_group->screen);
/* Normally we expect an actor to be drawn at it's position on the screen.
* However, if we're inside the paint of a ClutterClone, that won't be the
* case and we need to compensate. We look at the position of the window
* group under the current model-view matrix and the position of the actor.
* If they are both simply integer translations, then we can compensate
* easily, otherwise we give up.
*
* Possible cleanup: work entirely in paint space - we can compute the
* combination of the model-view matrix with the local matrix for each child
* actor and get a total transformation for that actor for how we are
* painting currently, and never worry about how actors are positioned
* on the stage.
*/
if (!painting_untransformed (window_group, &paint_x_origin, &paint_y_origin) ||
!actor_is_untransformed (actor, &actor_x_origin, &actor_y_origin))
{
CLUTTER_ACTOR_CLASS (meta_window_group_parent_class)->paint (actor);
return;
}
paint_x_offset = paint_x_origin - actor_x_origin;
paint_y_offset = paint_y_origin - actor_y_origin;
/* We walk the list from top to bottom (opposite of painting order),
* and subtract the opaque area of each window out of the visible
* region that we pass to the windows below.
*/
children = clutter_container_get_children (CLUTTER_CONTAINER (actor));
children = g_list_reverse (children);
/* Get the clipped redraw bounds from Clutter so that we can avoid
* painting shadows on windows that don't need to be painted in this
* frame. In the case of a multihead setup with mismatched monitor
* sizes, we could intersect this with an accurate union of the
* monitors to avoid painting shadows that are visible only in the
* holes. */
stage = clutter_actor_get_stage (actor);
clutter_stage_get_redraw_clip_bounds (CLUTTER_STAGE (stage),
&visible_rect);
visible_region = cairo_region_create_rectangle (&visible_rect);
if (info->unredirected_window != NULL)
{
cairo_rectangle_int_t unredirected_rect;
meta_window_actor_get_shape_bounds (META_WINDOW_ACTOR (info->unredirected_window), &unredirected_rect);
cairo_region_subtract_rectangle (visible_region, &unredirected_rect);
}
for (l = children; l; l = l->next)
{
if (!CLUTTER_ACTOR_IS_VISIBLE (l->data))
continue;
if (l->data == info->unredirected_window)
continue;
/* If an actor has effects applied, then that can change the area
* it paints and the opacity, so we no longer can figure out what
* portion of the actor is obscured and what portion of the screen
* it obscures, so we skip the actor.
*
* This has a secondary beneficial effect: if a ClutterOffscreenEffect
* is applied to an actor, then our clipped redraws interfere with the
* caching of the FBO - even if we only need to draw a small portion
* of the window right now, ClutterOffscreenEffect may use other portions
* of the FBO later. So, skipping actors with effects applied also
* prevents these bugs.
*
* Theoretically, we should check clutter_actor_get_offscreen_redirect()
* as well for the same reason, but omitted for simplicity in the
* hopes that no-one will do that.
*/
if (clutter_actor_has_effects (l->data))
continue;
if (META_IS_WINDOW_ACTOR (l->data))
{
MetaWindowActor *window_actor = l->data;
int x, y;
if (!actor_is_untransformed (CLUTTER_ACTOR (window_actor), &x, &y))
continue;
x += paint_x_offset;
y += paint_y_offset;
/* Temporarily move to the coordinate system of the actor */
cairo_region_translate (visible_region, - x, - y);
meta_window_actor_set_visible_region (window_actor, visible_region);
if (clutter_actor_get_paint_opacity (CLUTTER_ACTOR (window_actor)) == 0xff)
{
cairo_region_t *obscured_region = meta_window_actor_get_obscured_region (window_actor);
if (obscured_region)
cairo_region_subtract (visible_region, obscured_region);
}
meta_window_actor_set_visible_region_beneath (window_actor, visible_region);
cairo_region_translate (visible_region, x, y);
}
else if (META_IS_BACKGROUND_ACTOR (l->data))
{
MetaBackgroundActor *background_actor = l->data;
int x, y;
if (!actor_is_untransformed (CLUTTER_ACTOR (background_actor), &x, &y))
continue;
x += paint_x_offset;
y += paint_y_offset;
cairo_region_translate (visible_region, - x, - y);
meta_background_actor_set_visible_region (background_actor, visible_region);
cairo_region_translate (visible_region, x, y);
}
}
cairo_region_destroy (visible_region);
CLUTTER_ACTOR_CLASS (meta_window_group_parent_class)->paint (actor);
/* Now that we are done painting, unset the visible regions (they will
* mess up painting clones of our actors)
*/
for (l = children; l; l = l->next)
{
if (META_IS_WINDOW_ACTOR (l->data))
{
MetaWindowActor *window_actor = l->data;
meta_window_actor_reset_visible_regions (window_actor);
}
else if (META_IS_BACKGROUND_ACTOR (l->data))
{
MetaBackgroundActor *background_actor = l->data;
meta_background_actor_set_visible_region (background_actor, NULL);
}
}
g_list_free (children);
}
static void
meta_window_group_class_init (MetaWindowGroupClass *klass)
{
ClutterActorClass *actor_class = CLUTTER_ACTOR_CLASS (klass);
actor_class->paint = meta_window_group_paint;
}
static void
meta_window_group_init (MetaWindowGroup *window_group)
{
}
ClutterActor *
meta_window_group_new (MetaScreen *screen)
{
MetaWindowGroup *window_group;
window_group = g_object_new (META_TYPE_WINDOW_GROUP, NULL);
window_group->screen = screen;
return CLUTTER_ACTOR (window_group);
}