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Learning_GTK4_tree/gtk/gtkconstraintguide.c

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/* gtkconstraintguide.c: Flexible space for constraints
* Copyright 2019 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
* Author: Matthias Clasen
*/
/**
* GtkConstraintGuide:
*
* A `GtkConstraintGuide` is an invisible layout element in a
* `GtkConstraintLayout`.
*
* The `GtkConstraintLayout` treats guides like widgets. They
* can be used as the source or target of a `GtkConstraint`.
*
* Guides have a minimum, maximum and natural size. Depending
* on the constraints that are applied, they can act like a
* guideline that widgets can be aligned to, or like *flexible
* space*.
*
* Unlike a `GtkWidget`, a `GtkConstraintGuide` will not be drawn.
*/
#include "config.h"
#include "gtkconstraintguide.h"
#include "gtkconstraintguideprivate.h"
#include "gtkconstraintlayoutprivate.h"
#include "gtkconstraintexpressionprivate.h"
#include "gtkconstraintsolverprivate.h"
#include "gtkdebug.h"
#include "gtkprivate.h"
typedef enum {
MIN_WIDTH,
MIN_HEIGHT,
NAT_WIDTH,
NAT_HEIGHT,
MAX_WIDTH,
MAX_HEIGHT,
LAST_VALUE
} GuideValue;
struct _GtkConstraintGuide
{
GObject parent_instance;
char *name;
int strength;
int values[LAST_VALUE];
GtkConstraintLayout *layout;
/* HashTable<static string, Variable>; a hash table of variables,
* one for each attribute; we use these to query and suggest the
* values for the solver. The string is static and does not need
* to be freed.
*/
GHashTable *bound_attributes;
GtkConstraintRef *constraints[LAST_VALUE];
};
struct _GtkConstraintGuideClass {
GObjectClass parent_class;
};
enum {
PROP_MIN_WIDTH = 1,
PROP_MIN_HEIGHT,
PROP_NAT_WIDTH,
PROP_NAT_HEIGHT,
PROP_MAX_WIDTH,
PROP_MAX_HEIGHT,
PROP_STRENGTH,
PROP_NAME,
LAST_PROP
};
static GParamSpec *guide_props[LAST_PROP];
static void
gtk_constraint_guide_constraint_target_iface_init (GtkConstraintTargetInterface *iface)
{
}
G_DEFINE_TYPE_WITH_CODE (GtkConstraintGuide, gtk_constraint_guide, G_TYPE_OBJECT,
G_IMPLEMENT_INTERFACE (GTK_TYPE_CONSTRAINT_TARGET,
gtk_constraint_guide_constraint_target_iface_init))
static void
gtk_constraint_guide_init (GtkConstraintGuide *guide)
{
guide->strength = GTK_CONSTRAINT_STRENGTH_MEDIUM;
guide->values[MIN_WIDTH] = 0;
guide->values[MIN_HEIGHT] = 0;
guide->values[NAT_WIDTH] = 0;
guide->values[NAT_HEIGHT] = 0;
guide->values[MAX_WIDTH] = G_MAXINT;
guide->values[MAX_HEIGHT] = G_MAXINT;
guide->bound_attributes =
g_hash_table_new_full (g_str_hash, g_str_equal,
NULL,
(GDestroyNotify) gtk_constraint_variable_unref);
}
static void
gtk_constraint_guide_update_constraint (GtkConstraintGuide *guide,
GuideValue index)
{
GtkConstraintSolver *solver;
GtkConstraintVariable *var;
if (!guide->layout)
return;
solver = gtk_constraint_layout_get_solver (guide->layout);
if (!solver)
return;
if (guide->constraints[index] != NULL)
{
gtk_constraint_solver_remove_constraint (solver, guide->constraints[index]);
guide->constraints[index] = NULL;
}
if (index == MIN_WIDTH || index == NAT_WIDTH || index == MAX_WIDTH)
var = gtk_constraint_layout_get_attribute (guide->layout, GTK_CONSTRAINT_ATTRIBUTE_WIDTH, "guide", NULL, guide->bound_attributes);
else
var = gtk_constraint_layout_get_attribute (guide->layout, GTK_CONSTRAINT_ATTRIBUTE_HEIGHT, "guide", NULL, guide->bound_attributes);
/* We always install min-size constraints,
* but we avoid nat-size constraints if min == max
* and we avoid max-size constraints if max == G_MAXINT
*/
if (index == MIN_WIDTH || index == MIN_HEIGHT)
{
guide->constraints[index] =
gtk_constraint_solver_add_constraint (solver,
var,
GTK_CONSTRAINT_RELATION_GE,
gtk_constraint_expression_new (guide->values[index]),
GTK_CONSTRAINT_STRENGTH_REQUIRED);
}
else if ((index == NAT_WIDTH && guide->values[MIN_WIDTH] != guide->values[MAX_WIDTH]) ||
(index == NAT_HEIGHT && guide->values[MIN_HEIGHT] != guide->values[MAX_HEIGHT]))
{
gtk_constraint_variable_set_value (var, guide->values[index]);
guide->constraints[index] =
gtk_constraint_solver_add_stay_variable (solver,
var,
guide->strength);
}
else if ((index == MAX_WIDTH || index == MAX_HEIGHT) &&
guide->values[index] < G_MAXINT)
{
guide->constraints[index] =
gtk_constraint_solver_add_constraint (solver,
var,
GTK_CONSTRAINT_RELATION_LE,
gtk_constraint_expression_new (guide->values[index]),
GTK_CONSTRAINT_STRENGTH_REQUIRED);
}
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (guide->layout));
}
void
gtk_constraint_guide_update (GtkConstraintGuide *guide)
{
int i;
for (i = 0; i < LAST_VALUE; i++)
gtk_constraint_guide_update_constraint (guide, i);
}
void
gtk_constraint_guide_detach (GtkConstraintGuide *guide)
{
GtkConstraintSolver *solver;
int i;
if (!guide->layout)
return;
solver = gtk_constraint_layout_get_solver (guide->layout);
if (!solver)
return;
for (i = 0; i < LAST_VALUE; i++)
{
if (guide->constraints[i])
{
gtk_constraint_solver_remove_constraint (solver, guide->constraints[i]);
guide->constraints[i] = NULL;
}
}
g_hash_table_remove_all (guide->bound_attributes);
}
GtkConstraintVariable *
gtk_constraint_guide_get_attribute (GtkConstraintGuide *guide,
GtkConstraintAttribute attr)
{
GtkLayoutManager *manager = GTK_LAYOUT_MANAGER (guide->layout);
GtkWidget *widget = gtk_layout_manager_get_widget (manager);
return gtk_constraint_layout_get_attribute (guide->layout, attr, "guide", widget, guide->bound_attributes);
}
GtkConstraintLayout *
gtk_constraint_guide_get_layout (GtkConstraintGuide *guide)
{
return guide->layout;
}
void
gtk_constraint_guide_set_layout (GtkConstraintGuide *guide,
GtkConstraintLayout *layout)
{
guide->layout = layout;
}
static void
gtk_constraint_guide_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GtkConstraintGuide *self = GTK_CONSTRAINT_GUIDE (gobject);
int val;
GuideValue index;
switch (prop_id)
{
case PROP_MIN_WIDTH:
case PROP_MIN_HEIGHT:
case PROP_NAT_WIDTH:
case PROP_NAT_HEIGHT:
case PROP_MAX_WIDTH:
case PROP_MAX_HEIGHT:
val = g_value_get_int (value);
index = prop_id - 1;
if (self->values[index] != val)
{
self->values[index] = val;
g_object_notify_by_pspec (gobject, pspec);
gtk_constraint_guide_update_constraint (self, index);
if (index == MIN_WIDTH || index == MAX_WIDTH)
gtk_constraint_guide_update_constraint (self, NAT_WIDTH);
if (index == MIN_HEIGHT || index == MAX_HEIGHT)
gtk_constraint_guide_update_constraint (self, NAT_HEIGHT);
}
break;
case PROP_STRENGTH:
gtk_constraint_guide_set_strength (self, g_value_get_enum (value));
break;
case PROP_NAME:
gtk_constraint_guide_set_name (self, g_value_get_string (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
gtk_constraint_guide_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GtkConstraintGuide *self = GTK_CONSTRAINT_GUIDE (gobject);
switch (prop_id)
{
case PROP_MIN_WIDTH:
case PROP_MIN_HEIGHT:
case PROP_NAT_WIDTH:
case PROP_NAT_HEIGHT:
case PROP_MAX_WIDTH:
case PROP_MAX_HEIGHT:
g_value_set_int (value, self->values[prop_id - 1]);
break;
case PROP_STRENGTH:
g_value_set_enum (value, self->strength);
break;
case PROP_NAME:
g_value_set_string (value, self->name);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
gtk_constraint_guide_finalize (GObject *object)
{
GtkConstraintGuide *self = GTK_CONSTRAINT_GUIDE (object);
g_free (self->name);
g_clear_pointer (&self->bound_attributes, g_hash_table_unref);
G_OBJECT_CLASS (gtk_constraint_guide_parent_class)->finalize (object);
}
static void
gtk_constraint_guide_class_init (GtkConstraintGuideClass *class)
{
GObjectClass *object_class = G_OBJECT_CLASS (class);
object_class->finalize = gtk_constraint_guide_finalize;
object_class->set_property = gtk_constraint_guide_set_property;
object_class->get_property = gtk_constraint_guide_get_property;
/**
* GtkConstraintGuide:min-width:
*
* The minimum width of the guide.
*/
guide_props[PROP_MIN_WIDTH] =
g_param_spec_int ("min-width", NULL, NULL,
0, G_MAXINT, 0,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:min-height:
*
* The minimum height of the guide.
*/
guide_props[PROP_MIN_HEIGHT] =
g_param_spec_int ("min-height", NULL, NULL,
0, G_MAXINT, 0,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:nat-width:
*
* The preferred, or natural, width of the guide.
*/
guide_props[PROP_NAT_WIDTH] =
g_param_spec_int ("nat-width", NULL, NULL,
0, G_MAXINT, 0,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:nat-height:
*
* The preferred, or natural, height of the guide.
*/
guide_props[PROP_NAT_HEIGHT] =
g_param_spec_int ("nat-height", NULL, NULL,
0, G_MAXINT, 0,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:max-width:
*
* The maximum width of the guide.
*/
guide_props[PROP_MAX_WIDTH] =
g_param_spec_int ("max-width", NULL, NULL,
0, G_MAXINT, G_MAXINT,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:max-height:
*
* The maximum height of the guide.
*/
guide_props[PROP_MAX_HEIGHT] =
g_param_spec_int ("max-height", NULL, NULL,
0, G_MAXINT, G_MAXINT,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:strength: (attributes org.gtk.Property.get=gtk_constraint_guide_get_strength org.gtk.Property.set=gtk_constraint_guide_set_strength)
*
* The `GtkConstraintStrength` to be used for the constraint on
* the natural size of the guide.
*/
guide_props[PROP_STRENGTH] =
g_param_spec_enum ("strength", NULL, NULL,
GTK_TYPE_CONSTRAINT_STRENGTH,
GTK_CONSTRAINT_STRENGTH_MEDIUM,
G_PARAM_READWRITE|
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkConstraintGuide:name: (attributes org.gtk.Property.get=gtk_constraint_guide_get_name org.gtk.Property.set=gtk_constraint_guide_set_name)
*
* A name that identifies the `GtkConstraintGuide`, for debugging.
*/
guide_props[PROP_NAME] =
g_param_spec_string ("name", NULL, NULL,
NULL,
G_PARAM_READWRITE);
g_object_class_install_properties (object_class, LAST_PROP, guide_props);
}
/**
* gtk_constraint_guide_new:
*
* Creates a new `GtkConstraintGuide` object.
*
* Return: a new `GtkConstraintGuide` object.
*/
GtkConstraintGuide *
gtk_constraint_guide_new (void)
{
return g_object_new (GTK_TYPE_CONSTRAINT_GUIDE, NULL);
}
/**
* gtk_constraint_guide_set_min_size:
* @guide: a `GtkConstraintGuide` object
* @width: the new minimum width, or -1 to not change it
* @height: the new minimum height, or -1 to not change it
*
* Sets the minimum size of @guide.
*
* If @guide is attached to a `GtkConstraintLayout`,
* the constraints will be updated to reflect the new size.
*/
void
gtk_constraint_guide_set_min_size (GtkConstraintGuide *guide,
int width,
int height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
g_return_if_fail (width >= -1);
g_return_if_fail (height >= -1);
g_object_freeze_notify (G_OBJECT (guide));
if (width != -1)
g_object_set (guide, "min-width", width, NULL);
if (height != -1)
g_object_set (guide, "min-height", height, NULL);
g_object_thaw_notify (G_OBJECT (guide));
}
/**
* gtk_constraint_guide_get_min_size:
* @guide: a `GtkConstraintGuide` object
* @width: (out) (optional): return location for the minimum width
* @height: (out) (optional): return location for the minimum height
*
* Gets the minimum size of @guide.
*/
void
gtk_constraint_guide_get_min_size (GtkConstraintGuide *guide,
int *width,
int *height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
if (width)
*width = guide->values[MIN_WIDTH];
if (height)
*height = guide->values[MIN_HEIGHT];
}
/**
* gtk_constraint_guide_set_nat_size:
* @guide: a `GtkConstraintGuide` object
* @width: the new natural width, or -1 to not change it
* @height: the new natural height, or -1 to not change it
*
* Sets the natural size of @guide.
*
* If @guide is attached to a `GtkConstraintLayout`,
* the constraints will be updated to reflect the new size.
*/
void
gtk_constraint_guide_set_nat_size (GtkConstraintGuide *guide,
int width,
int height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
g_return_if_fail (width >= -1);
g_return_if_fail (height >= -1);
g_object_freeze_notify (G_OBJECT (guide));
if (width != -1)
g_object_set (guide, "nat-width", width, NULL);
if (height != -1)
g_object_set (guide, "nat-height", height, NULL);
g_object_thaw_notify (G_OBJECT (guide));
}
/**
* gtk_constraint_guide_get_nat_size:
* @guide: a `GtkConstraintGuide` object
* @width: (out) (optional): return location for the natural width
* @height: (out) (optional): return location for the natural height
*
* Gets the natural size of @guide.
*/
void
gtk_constraint_guide_get_nat_size (GtkConstraintGuide *guide,
int *width,
int *height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
if (width)
*width = guide->values[NAT_WIDTH];
if (height)
*height = guide->values[NAT_HEIGHT];
}
/**
* gtk_constraint_guide_set_max_size:
* @guide: a `GtkConstraintGuide` object
* @width: the new maximum width, or -1 to not change it
* @height: the new maximum height, or -1 to not change it
*
* Sets the maximum size of @guide.
*
* If @guide is attached to a `GtkConstraintLayout`,
* the constraints will be updated to reflect the new size.
*/
void
gtk_constraint_guide_set_max_size (GtkConstraintGuide *guide,
int width,
int height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
g_return_if_fail (width >= -1);
g_return_if_fail (height >= -1);
g_object_freeze_notify (G_OBJECT (guide));
if (width != -1)
g_object_set (guide, "max-width", width, NULL);
if (height != -1)
g_object_set (guide, "max-height", height, NULL);
g_object_thaw_notify (G_OBJECT (guide));
}
/**
* gtk_constraint_guide_get_max_size:
* @guide: a `GtkConstraintGuide` object
* @width: (out) (optional): return location for the maximum width
* @height: (out) (optional): return location for the maximum height
*
* Gets the maximum size of @guide.
*/
void
gtk_constraint_guide_get_max_size (GtkConstraintGuide *guide,
int *width,
int *height)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
if (width)
*width = guide->values[MAX_WIDTH];
if (height)
*height = guide->values[MAX_HEIGHT];
}
/**
* gtk_constraint_guide_get_name: (attributes org.gtk.Method.get_property=name)
* @guide: a `GtkConstraintGuide`
*
* Retrieves the name set using gtk_constraint_guide_set_name().
*
* Returns: (transfer none) (nullable): the name of the guide
*/
const char *
gtk_constraint_guide_get_name (GtkConstraintGuide *guide)
{
g_return_val_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide), NULL);
return guide->name;
}
/**
* gtk_constraint_guide_set_name: (attributes org.gtk.Method.set_property=name)
* @guide: a `GtkConstraintGuide`
* @name: (nullable): a name for the @guide
*
* Sets a name for the given `GtkConstraintGuide`.
*
* The name is useful for debugging purposes.
*/
void
gtk_constraint_guide_set_name (GtkConstraintGuide *guide,
const char *name)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
g_free (guide->name);
guide->name = g_strdup (name);
g_object_notify_by_pspec (G_OBJECT (guide), guide_props[PROP_NAME]);
}
/**
* gtk_constraint_guide_get_strength: (attributes org.gtk.Method.get_property=strength)
* @guide: a `GtkConstraintGuide`
*
* Retrieves the strength set using gtk_constraint_guide_set_strength().
*
* Returns: the strength of the constraint on the natural size
*/
GtkConstraintStrength
gtk_constraint_guide_get_strength (GtkConstraintGuide *guide)
{
g_return_val_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide),
GTK_CONSTRAINT_STRENGTH_MEDIUM);
return guide->strength;
}
/**
* gtk_constraint_guide_set_strength: (attributes org.gtk.Method.set_property=strength)
* @guide: a `GtkConstraintGuide`
* @strength: the strength of the constraint
*
* Sets the strength of the constraint on the natural size of the
* given `GtkConstraintGuide`.
*/
void
gtk_constraint_guide_set_strength (GtkConstraintGuide *guide,
GtkConstraintStrength strength)
{
g_return_if_fail (GTK_IS_CONSTRAINT_GUIDE (guide));
if (guide->strength == strength)
return;
guide->strength = strength;
g_object_notify_by_pspec (G_OBJECT (guide), guide_props[PROP_STRENGTH]);
gtk_constraint_guide_update_constraint (guide, NAT_WIDTH);
gtk_constraint_guide_update_constraint (guide, NAT_HEIGHT);
}
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