*
* Copyright 2025 Alexander Vanhee
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#include <bge.h>
#include "bz-fading-clamp.h"
#include "util.h"
#define FADE_HEIGHT 75
#define CLAMP_LEEWAY 100
struct _BzFadingClamp
{
GtkWidget parent_instance;
BgeAnimation *animation;
GtkWidget *child;
int max_height;
int min_max_height;
int current_height;
int allocated_width;
gboolean will_change;
};
enum
{
PROP_0,
PROP_CHILD,
PROP_MAX_HEIGHT,
PROP_MIN_MAX_HEIGHT,
PROP_WILL_CHANGE,
N_PROPS
};
static GParamSpec *properties[N_PROPS];
G_DEFINE_TYPE (BzFadingClamp, bz_fading_clamp, GTK_TYPE_WIDGET)
static void
animate (BzFadingClamp *self,
const char *key,
double value,
gpointer user_data)
{
self->current_height = round (value);
gtk_widget_queue_resize (GTK_WIDGET (self));
}
static void
bz_fading_clamp_update_will_change (BzFadingClamp *self)
{
gboolean new_value = FALSE;
int natural_height;
int width;
if (self->child)
{
if (self->allocated_width > 0)
width = self->allocated_width;
else
gtk_widget_measure (self->child, GTK_ORIENTATION_HORIZONTAL, -1, NULL, &width, NULL, NULL);
gtk_widget_measure (self->child, GTK_ORIENTATION_VERTICAL, width, NULL, &natural_height, NULL, NULL);
new_value = natural_height > self->min_max_height + CLAMP_LEEWAY;
}
if (self->will_change != new_value)
{
self->will_change = new_value;
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_WILL_CHANGE]);
}
}
static void
bz_fading_clamp_dispose (GObject *object)
{
BzFadingClamp *self = BZ_FADING_CLAMP (object);
g_clear_object (&self->animation);
g_clear_pointer (&self->child, gtk_widget_unparent);
G_OBJECT_CLASS (bz_fading_clamp_parent_class)->dispose (object);
}
static void
bz_fading_clamp_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
BzFadingClamp *self = BZ_FADING_CLAMP (object);
switch (prop_id)
{
case PROP_CHILD:
g_value_set_object (value, self->child);
break;
case PROP_MAX_HEIGHT:
g_value_set_int (value, self->max_height);
break;
case PROP_MIN_MAX_HEIGHT:
g_value_set_int (value, self->min_max_height);
break;
case PROP_WILL_CHANGE:
g_value_set_boolean (value, self->will_change);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
bz_fading_clamp_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
BzFadingClamp *self = BZ_FADING_CLAMP (object);
switch (prop_id)
{
case PROP_CHILD:
bz_fading_clamp_set_child (self, g_value_get_object (value));
break;
case PROP_MAX_HEIGHT:
bz_fading_clamp_set_max_height (self, g_value_get_int (value));
break;
case PROP_MIN_MAX_HEIGHT:
self->min_max_height = g_value_get_int (value);
bz_fading_clamp_update_will_change (self);
gtk_widget_queue_resize (GTK_WIDGET (self));
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MIN_MAX_HEIGHT]);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static GtkSizeRequestMode
bz_fading_clamp_get_request_mode (GtkWidget *widget)
{
return GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH;
}
static void
bz_fading_clamp_measure (GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
int target_height = 0;
BzFadingClamp *self = BZ_FADING_CLAMP (widget);
if (!self->child)
{
*minimum = 0;
*natural = 0;
return;
}
if (orientation == GTK_ORIENTATION_HORIZONTAL)
gtk_widget_measure (self->child, orientation, for_size, minimum, natural, minimum_baseline, natural_baseline);
else
{
gtk_widget_measure (self->child, GTK_ORIENTATION_VERTICAL, for_size, minimum, natural, minimum_baseline, natural_baseline);
if (*natural <= self->max_height + CLAMP_LEEWAY)
target_height = *natural;
else
target_height = self->max_height;
bz_fading_clamp_update_will_change (self);
if (!bge_animation_has_key (self->animation, "height"))
self->current_height = target_height;
*minimum = self->current_height;
*natural = self->current_height;
}
}
static void
bz_fading_clamp_size_allocate (GtkWidget *widget,
int width,
int height,
int baseline)
{
BzFadingClamp *self = BZ_FADING_CLAMP (widget);
if (self->allocated_width != width)
{
self->allocated_width = width;
bz_fading_clamp_update_will_change (self);
}
if (self->child)
{
int child_height = 0;
int natural_height = 0;
gtk_widget_measure (self->child, GTK_ORIENTATION_VERTICAL, width, NULL, &natural_height, NULL, NULL);
if (natural_height > height)
child_height = natural_height;
else
child_height = height;
gtk_widget_allocate (self->child, width, child_height, baseline, NULL);
}
}
static void
bz_fading_clamp_snapshot (GtkWidget *widget, GtkSnapshot *snapshot)
{
BzFadingClamp *self = BZ_FADING_CLAMP (widget);
int width, height, natural_height;
int gradient_start;
graphene_rect_t gradient_rect;
GskColorStop stops[2];
graphene_point_t start_point, end_point;
int effective_fade_height;
float stop_offset;
if (!self->child || !gtk_widget_get_visible (self->child))
return;
width = gtk_widget_get_width (widget);
height = gtk_widget_get_height (widget);
if (height <= 0)
return;
gtk_widget_measure (self->child, GTK_ORIENTATION_VERTICAL, width, NULL, &natural_height, NULL, NULL);
if (natural_height <= height)
{
gtk_widget_snapshot_child (widget, self->child, snapshot);
return;
}
effective_fade_height = MIN (natural_height - height, FADE_HEIGHT);
gtk_snapshot_push_mask (snapshot, GSK_MASK_MODE_ALPHA);
gradient_start = height - effective_fade_height;
graphene_rect_init (&gradient_rect, 0, 0, width, height);
stop_offset = CLAMP ((float) gradient_start / height, 0.0f, 1.0f);
stops[0] = (GskColorStop){
stop_offset, { 1, 1, 1, 1 }
};
stops[1] = (GskColorStop){
1.0, { 1, 1, 1, 0 }
};
graphene_point_init (&start_point, 0, 0);
graphene_point_init (&end_point, 0, height);
gtk_snapshot_append_linear_gradient (snapshot, &gradient_rect, &start_point, &end_point, stops, 2);
gtk_snapshot_pop (snapshot);
gtk_widget_snapshot_child (widget, self->child, snapshot);
gtk_snapshot_pop (snapshot);
}
static void
bz_fading_clamp_class_init (BzFadingClampClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
object_class->dispose = bz_fading_clamp_dispose;
object_class->get_property = bz_fading_clamp_get_property;
object_class->set_property = bz_fading_clamp_set_property;
widget_class->get_request_mode = bz_fading_clamp_get_request_mode;
widget_class->measure = bz_fading_clamp_measure;
widget_class->size_allocate = bz_fading_clamp_size_allocate;
widget_class->snapshot = bz_fading_clamp_snapshot;
properties[PROP_CHILD] =
g_param_spec_object ("child", NULL, NULL, GTK_TYPE_WIDGET,
G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
properties[PROP_MAX_HEIGHT] =
g_param_spec_int ("max-height", NULL, NULL, 0, G_MAXINT, 300,
G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
properties[PROP_MIN_MAX_HEIGHT] =
g_param_spec_int ("min-max-height", NULL, NULL, 0, G_MAXINT, 150,
G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
properties[PROP_WILL_CHANGE] =
g_param_spec_boolean ("will-change", NULL, NULL, FALSE,
G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY);
g_object_class_install_properties (object_class, N_PROPS, properties);
}
static void
bz_fading_clamp_init (BzFadingClamp *self)
{
self->animation = bge_animation_new (GTK_WIDGET (self));
self->max_height = 300;
self->min_max_height = 150;
self->current_height = CLAMP_LEEWAY;
self->allocated_width = 0;
self->will_change = FALSE;
}
GtkWidget *
bz_fading_clamp_new (void)
{
return g_object_new (BZ_TYPE_FADING_CLAMP, NULL);
}
void
bz_fading_clamp_set_child (BzFadingClamp *self, GtkWidget *child)
{
g_return_if_fail (BZ_IS_FADING_CLAMP (self));
g_return_if_fail (child == NULL || GTK_IS_WIDGET (child));
if (self->child == child)
return;
g_clear_pointer (&self->child, gtk_widget_unparent);
if (child)
{
self->child = child;
gtk_widget_set_parent (child, GTK_WIDGET (self));
self->current_height = 0;
}
bz_fading_clamp_update_will_change (self);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_CHILD]);
gtk_widget_queue_resize (GTK_WIDGET (self));
}
GtkWidget *
bz_fading_clamp_get_child (BzFadingClamp *self)
{
g_return_val_if_fail (BZ_IS_FADING_CLAMP (self), NULL);
return self->child;
}
void
bz_fading_clamp_set_max_height (BzFadingClamp *self, int max_height)
{
int natural_height = 0;
int target_height = 0;
int width = 0;
g_return_if_fail (BZ_IS_FADING_CLAMP (self));
if (self->max_height == max_height)
return;
self->max_height = max_height;
if (self->child)
{
if (self->allocated_width > 0)
width = self->allocated_width;
else
gtk_widget_measure (self->child, GTK_ORIENTATION_HORIZONTAL, -1, NULL, &width, NULL, NULL);
gtk_widget_measure (self->child, GTK_ORIENTATION_VERTICAL, width, NULL, &natural_height, NULL, NULL);
if (natural_height <= max_height + CLAMP_LEEWAY)
target_height = natural_height;
else
target_height = max_height;
}
else
target_height = max_height;
bge_animation_add_spring (
self->animation, "height",
self->current_height, target_height,
1.25, 1.0, 800.0,
(BgeAnimationCallback) animate,
NULL, NULL, NULL);
bz_fading_clamp_update_will_change (self);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MAX_HEIGHT]);
}
int
bz_fading_clamp_get_max_height (BzFadingClamp *self)
{
g_return_val_if_fail (BZ_IS_FADING_CLAMP (self), 0);
return self->max_height;
}
