replace the old apply_constraints with wacky new approach involving

2002-10-18  Havoc Pennington  <hp@pobox.com>

	* src/stack.c (constrain_stacking): replace the old
	apply_constraints with wacky new approach involving graphing all
	the constraints then walking the graph.  Fixes #94876 and probably
	other stacking bugs as well, thanks to Arvind for tracking down
	the issue.

	(compute_layer): add FIXME and reference to bug #96140
This commit is contained in:
Havoc Pennington 2002-10-18 06:05:09 +00:00 committed by Havoc Pennington
parent 5c5de1c6b3
commit 370982b812
3 changed files with 317 additions and 50 deletions

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@ -1,3 +1,13 @@
2002-10-18 Havoc Pennington <hp@pobox.com>
* src/stack.c (constrain_stacking): replace the old
apply_constraints with wacky new approach involving graphing all
the constraints then walking the graph. Fixes #94876 and probably
other stacking bugs as well, thanks to Arvind for tracking down
the issue.
(compute_layer): add FIXME and reference to bug #96140
2002-10-17 Havoc Pennington <hp@redhat.com>
* src/stack.c (apply_constraints): don't place

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@ -358,6 +358,16 @@ compute_layer (MetaWindow *window)
* and a dialog transient for the normal window; you don't want the dialog
* above the dock if it wouldn't normally be.
*/
/* FIXME when promoting a window here,
* it's necessary to promote its transient children
* (or other windows constrained to be above it)
* as well, but we aren't handling that, and it's
* somewhat hard to fix.
*
* http://bugzilla.gnome.org/show_bug.cgi?id=96140
*/
MetaStackLayer group_max;
group_max = get_maximum_layer_in_group (window);
@ -400,39 +410,124 @@ compare_window_position (void *a,
return 0; /* not reached */
}
/*
* Stacking constraints
*
* Assume constraints of the form "AB" meaning "window A must be
* below window B"
*
* If we have windows stacked from bottom to top
* "ABC" then raise A we get "BCA". Say C is
* transient for B is transient for A. So
* we have constraints AB and BC.
*
* After raising A, we need to reapply the constraints.
* If we do this by raising one window at a time -
*
* start: BCA
* apply AB: CAB
* apply BC: ABC
*
* but apply constraints in the wrong order and it breaks:
*
* start: BCA
* apply BC: BCA
* apply AB: CAB
*
* We make a directed graph of the constraints by linking
* from "above windows" to "below windows as follows:
*
* AB -> BC -> CD
* \
* CE
*
* If we then walk that graph and apply the constraints in the order
* that they appear, we will apply them correctly. Note that the
* graph MAY have cycles, so we have to guard against that.
*
*/
typedef struct Constraint Constraint;
struct Constraint
{
MetaWindow *above;
MetaWindow *below;
/* used to keep the constraint in the
* list of constraints for window "below"
*/
Constraint *next;
/* used to create the graph. */
GSList *next_nodes;
/* constraint has been applied, used
* to detect cycles.
*/
unsigned int applied : 1;
/* constraint has a previous node in the graph,
* used to find places to start in the graph.
* (I think this also has the side effect
* of preventing cycles, since cycles will
* have no starting point - so maybe
* the "applied" flag isn't needed.)
*/
unsigned int has_prev : 1;
};
/* We index the array of constraints by window
* stack positions, just because the stack
* positions are a convenient index.
*/
static void
ensure_above (MetaWindow *above,
add_constraint (Constraint **constraints,
MetaWindow *above,
MetaWindow *below)
{
if (above->stack_position < below->stack_position)
Constraint *c;
/* check if constraint is a duplicate */
c = constraints[below->stack_position];
while (c != NULL)
{
/* move above to below->stack_position bumping below down the stack */
meta_window_set_stack_position (above, below->stack_position);
g_assert (below->stack_position + 1 == above->stack_position);
if (c->above == above)
return;
c = c->next;
}
meta_topic (META_DEBUG_STACK, "Above pos %d > below pos %d\n",
above->stack_position, below->stack_position);
/* if not, add the constraint */
c = g_new (Constraint, 1);
c->above = above;
c->below = below;
c->next = constraints[below->stack_position];
c->next_nodes = NULL;
c->applied = FALSE;
c->has_prev = FALSE;
constraints[below->stack_position] = c;
}
#define WINDOW_TRANSIENT_FOR_WHOLE_GROUP(w) \
((w->xtransient_for == None || \
w->transient_parent_is_root_window) && \
#define WINDOW_HAS_TRANSIENT_TYPE(w) \
(w->type == META_WINDOW_DIALOG || \
w->type == META_WINDOW_MODAL_DIALOG || \
w->type == META_WINDOW_TOOLBAR || \
w->type == META_WINDOW_MENU || \
w->type == META_WINDOW_UTILITY))
w->type == META_WINDOW_UTILITY)
#define WINDOW_TRANSIENT_FOR_WHOLE_GROUP(w) \
((w->xtransient_for == None || \
w->transient_parent_is_root_window) && \
WINDOW_HAS_TRANSIENT_TYPE (w))
static void
apply_constraints (GList *list)
create_constraints (Constraint **constraints,
GList *windows)
{
GList *tmp;
/* This algorithm could stand to be a bit less
* quadratic
*/
tmp = list;
tmp = windows;
while (tmp != NULL)
{
MetaWindow *w = tmp->data;
@ -456,12 +551,20 @@ apply_constraints (GList *list)
{
MetaWindow *group_window = tmp2->data;
#if 0
/* old way of doing it */
if (!(meta_window_is_ancestor_of_transient (w, group_window)) &&
!WINDOW_TRANSIENT_FOR_WHOLE_GROUP (group_window))
!WINDOW_TRANSIENT_FOR_WHOLE_GROUP (group_window)) /* note */;/*note*/
#else
/* better way I think, so transient-for-group are constrained
* only above non-transient-type windows in their group
*/
if (!WINDOW_HAS_TRANSIENT_TYPE (group_window))
#endif
{
meta_topic (META_DEBUG_STACK, "Stacking %s above %s as it's a dialog transient for its group\n",
meta_topic (META_DEBUG_STACK, "Constraining %s above %s as it's transient for its group\n",
w->desc, group_window->desc);
ensure_above (w, group_window);
add_constraint (constraints, w, group_window);
}
tmp2 = tmp2->next;
@ -479,9 +582,9 @@ apply_constraints (GList *list)
if (parent)
{
meta_topic (META_DEBUG_STACK, "Stacking %s above %s due to transiency\n",
meta_topic (META_DEBUG_STACK, "Constraining %s above %s due to transiency\n",
w->desc, parent->desc);
ensure_above (w, parent);
add_constraint (constraints, w, parent);
}
}
@ -489,6 +592,181 @@ apply_constraints (GList *list)
}
}
static void
graph_constraints (Constraint **constraints,
int n_constraints)
{
int i;
i = 0;
while (i < n_constraints)
{
Constraint *c;
/* If we have "A below B" and "B below C" then AB -> BC so we
* add BC to next_nodes in AB.
*/
c = constraints[i];
while (c != NULL)
{
Constraint *n;
g_assert (c->below->stack_position == i);
/* Constraints where ->above is below are our
* next_nodes and we are their previous
*/
n = constraints[c->above->stack_position];
while (n != NULL)
{
c->next_nodes = g_slist_prepend (c->next_nodes,
n);
/* c is a previous node of n */
n->has_prev = TRUE;
n = n->next;
}
c = c->next;
}
++i;
}
}
static void
free_constraints (Constraint **constraints,
int n_constraints)
{
int i;
i = 0;
while (i < n_constraints)
{
Constraint *c;
c = constraints[i];
while (c != NULL)
{
Constraint *next = c->next;
g_slist_free (c->next_nodes);
g_free (c);
c = next;
}
++i;
}
}
static void
ensure_above (MetaWindow *above,
MetaWindow *below)
{
if (above->stack_position < below->stack_position)
{
/* move above to below->stack_position bumping below down the stack */
meta_window_set_stack_position (above, below->stack_position);
g_assert (below->stack_position + 1 == above->stack_position);
}
meta_topic (META_DEBUG_STACK, "%s above at %d > %s below at %d\n",
above->desc, above->stack_position,
below->desc, below->stack_position);
}
static void
traverse_constraint (Constraint *c)
{
GSList *tmp;
if (c->applied)
return;
ensure_above (c->above, c->below);
c->applied = TRUE;
tmp = c->next_nodes;
while (tmp != NULL)
{
traverse_constraint (tmp->data);
tmp = tmp->next;
}
}
static void
apply_constraints (Constraint **constraints,
int n_constraints)
{
GSList *heads;
GSList *tmp;
int i;
/* List all heads in an ordered constraint chain */
heads = NULL;
i = 0;
while (i < n_constraints)
{
Constraint *c;
c = constraints[i];
while (c != NULL)
{
if (!c->has_prev)
heads = g_slist_prepend (heads, c);
c = c->next;
}
++i;
}
/* Now traverse the chain and apply constraints */
tmp = heads;
while (tmp != NULL)
{
Constraint *c = tmp->data;
traverse_constraint (c);
tmp = tmp->next;
}
g_slist_free (heads);
}
static void
constrain_stacking (MetaStack *stack)
{
Constraint **constraints;
/* It'd be nice if this were all faster, probably */
if (!stack->need_constrain)
return;
meta_topic (META_DEBUG_STACK,
"Reapplying constraints\n");
constraints = g_new0 (Constraint*,
stack->n_positions);
create_constraints (constraints, stack->sorted);
graph_constraints (constraints, stack->n_positions);
apply_constraints (constraints, stack->n_positions);
free_constraints (constraints, stack->n_positions);
g_free (constraints);
stack->need_constrain = FALSE;
}
static void
meta_stack_ensure_sorted (MetaStack *stack)
{
@ -621,15 +899,7 @@ meta_stack_ensure_sorted (MetaStack *stack)
}
/* Update stack_position to reflect transiency constraints */
if (stack->need_constrain)
{
meta_topic (META_DEBUG_STACK,
"Reapplying constraints\n");
apply_constraints (stack->sorted);
stack->need_constrain = FALSE;
}
constrain_stacking (stack);
/* Sort stack->sorted with layers having priority over stack_position
*/

View File

@ -227,11 +227,12 @@ make_dialog (GtkWidget *parent,
GtkWidget *dialog;
char *str;
dialog = gtk_message_dialog_new (GTK_WINDOW (parent),
dialog = gtk_message_dialog_new (parent ? GTK_WINDOW (parent) : NULL,
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_INFO,
GTK_BUTTONS_CLOSE,
"Here is a dialog %d",
parent ? "Here is a dialog %d" :
"Here is a dialog %d with no transient parent",
depth);
str = g_strdup_printf ("%d dialog", depth);
@ -306,21 +307,7 @@ no_parent_dialog_cb (gpointer callback_data,
guint callback_action,
GtkWidget *widget)
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new (NULL,
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_INFO,
GTK_BUTTONS_CLOSE,
"Here is a dialog with no transient parent");
/* Close dialog on user response */
g_signal_connect (G_OBJECT (dialog),
"response",
G_CALLBACK (gtk_widget_destroy),
NULL);
gtk_widget_show (dialog);
make_dialog (NULL, 1);
}
static void