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PIKApp/libpikawidgets/pikazoommodel.c

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/* LIBPIKA - The PIKA Library
* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
*
* pikazoommodel.c
* Copyright (C) 2005 David Odin <dindinx@gimp.org>
*
* 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 3 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
* <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <gtk/gtk.h>
#include "pikawidgetstypes.h"
#include "libpikabase/pikabase.h"
#include "libpikamath/pikamath.h"
#include "pikahelpui.h"
#include "pikawidgetsmarshal.h"
#include "pikazoommodel.h"
/**
* SECTION: pikazoommodel
* @title: PikaZoomModel
* @short_description: A model for zoom values.
*
* A model for zoom values.
**/
#define ZOOM_MIN (1.0 / 256.0)
#define ZOOM_MAX (256.0)
enum
{
ZOOMED,
LAST_SIGNAL
};
enum
{
PROP_0,
PROP_VALUE,
PROP_MINIMUM,
PROP_MAXIMUM,
PROP_FRACTION,
PROP_PERCENTAGE,
N_PROPS
};
struct _PikaZoomModelPrivate
{
gdouble value;
gdouble minimum;
gdouble maximum;
};
#define GET_PRIVATE(obj) (((PikaZoomModel *) (obj))->priv)
static void pika_zoom_model_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec);
static void pika_zoom_model_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec);
static guint zoom_model_signals[LAST_SIGNAL] = { 0, };
static GParamSpec *object_props[N_PROPS] = { NULL, };
G_DEFINE_TYPE_WITH_PRIVATE (PikaZoomModel, pika_zoom_model, G_TYPE_OBJECT)
#define parent_class pika_zoom_model_parent_class
static void
pika_zoom_model_class_init (PikaZoomModelClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
/**
* PikaZoomModel::zoomed:
* @model: the object that received the signal
* @old_factor: the zoom factor before it changes
* @new_factor: the zoom factor after it has changed.
*
* Emitted when the zoom factor of the zoom model changes.
*/
zoom_model_signals[ZOOMED] =
g_signal_new ("zoomed",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (PikaZoomModelClass,
zoomed),
NULL, NULL,
_pika_widgets_marshal_VOID__DOUBLE_DOUBLE,
G_TYPE_NONE, 2,
G_TYPE_DOUBLE, G_TYPE_DOUBLE);
object_class->set_property = pika_zoom_model_set_property;
object_class->get_property = pika_zoom_model_get_property;
/**
* PikaZoomModel:value:
*
* The zoom factor.
*/
object_props[PROP_VALUE] = g_param_spec_double ("value",
"Value",
"Zoom factor",
ZOOM_MIN, ZOOM_MAX,
1.0,
PIKA_PARAM_READWRITE);
/**
* PikaZoomModel:minimum:
*
* The minimum zoom factor.
*/
object_props[PROP_MINIMUM] = g_param_spec_double ("minimum",
"Minimum",
"Lower limit for the zoom factor",
ZOOM_MIN, ZOOM_MAX,
ZOOM_MIN,
PIKA_PARAM_READWRITE);
/**
* PikaZoomModel:maximum:
*
* The maximum zoom factor.
*/
object_props[PROP_MAXIMUM] = g_param_spec_double ("maximum",
"Maximum",
"Upper limit for the zoom factor",
ZOOM_MIN, ZOOM_MAX,
ZOOM_MAX,
PIKA_PARAM_READWRITE);
/**
* PikaZoomModel:fraction:
*
* The zoom factor expressed as a fraction.
*/
object_props[PROP_FRACTION] = g_param_spec_string ("fraction",
"Fraction",
"The zoom factor expressed as a fraction",
"1:1",
PIKA_PARAM_READABLE);
/**
* PikaZoomModel:percentage:
*
* The zoom factor expressed as percentage.
*/
object_props[PROP_PERCENTAGE] = g_param_spec_string ("percentage",
"Percentage",
"The zoom factor expressed as a percentage",
"100%",
PIKA_PARAM_READABLE);
g_object_class_install_properties (object_class, N_PROPS, object_props);
}
static void
pika_zoom_model_init (PikaZoomModel *model)
{
PikaZoomModelPrivate *priv;
model->priv = pika_zoom_model_get_instance_private (model);
priv = GET_PRIVATE (model);
priv->value = 1.0;
priv->minimum = ZOOM_MIN;
priv->maximum = ZOOM_MAX;
}
static void
pika_zoom_model_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (object);
gdouble previous_value;
previous_value = priv->value;
g_object_freeze_notify (object);
switch (property_id)
{
case PROP_VALUE:
priv->value = g_value_get_double (value);
g_object_notify_by_pspec (object, object_props[PROP_VALUE]);
g_object_notify_by_pspec (object, object_props[PROP_FRACTION]);
g_object_notify_by_pspec (object, object_props[PROP_PERCENTAGE]);
break;
case PROP_MINIMUM:
priv->minimum = MIN (g_value_get_double (value), priv->maximum);
break;
case PROP_MAXIMUM:
priv->maximum = MAX (g_value_get_double (value), priv->minimum);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
if (priv->value > priv->maximum || priv->value < priv->minimum)
{
priv->value = CLAMP (priv->value, priv->minimum, priv->maximum);
g_object_notify_by_pspec (object, object_props[PROP_VALUE]);
g_object_notify_by_pspec (object, object_props[PROP_FRACTION]);
g_object_notify_by_pspec (object, object_props[PROP_PERCENTAGE]);
}
g_object_thaw_notify (object);
if (priv->value != previous_value)
{
g_signal_emit (object, zoom_model_signals[ZOOMED],
0, previous_value, priv->value);
}
}
static void
pika_zoom_model_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (object);
gchar *tmp;
switch (property_id)
{
case PROP_VALUE:
g_value_set_double (value, priv->value);
break;
case PROP_MINIMUM:
g_value_set_double (value, priv->minimum);
break;
case PROP_MAXIMUM:
g_value_set_double (value, priv->maximum);
break;
case PROP_FRACTION:
{
gint numerator;
gint denominator;
pika_zoom_model_get_fraction (PIKA_ZOOM_MODEL (object),
&numerator, &denominator);
tmp = g_strdup_printf ("%d:%d", numerator, denominator);
g_value_set_string (value, tmp);
g_free (tmp);
}
break;
case PROP_PERCENTAGE:
tmp = g_strdup_printf (priv->value >= 0.15 ? "%.0f%%" : "%.2f%%",
priv->value * 100.0);
g_value_set_string (value, tmp);
g_free (tmp);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
pika_zoom_model_zoom_in (PikaZoomModel *model)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (model);
if (priv->value < priv->maximum)
pika_zoom_model_zoom (model, PIKA_ZOOM_IN, 0.0);
}
static void
pika_zoom_model_zoom_out (PikaZoomModel *model)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (model);
if (priv->value > priv->minimum)
pika_zoom_model_zoom (model, PIKA_ZOOM_OUT, 0.0);
}
/**
* pika_zoom_model_new:
*
* Creates a new #PikaZoomModel.
*
* Returns: a new #PikaZoomModel.
*
* Since PIKA 2.4
**/
PikaZoomModel *
pika_zoom_model_new (void)
{
return g_object_new (PIKA_TYPE_ZOOM_MODEL, NULL);
}
/**
* pika_zoom_model_set_range:
* @model: a #PikaZoomModel
* @min: new lower limit for zoom factor
* @max: new upper limit for zoom factor
*
* Sets the allowed range of the @model.
*
* Since PIKA 2.4
**/
void
pika_zoom_model_set_range (PikaZoomModel *model,
gdouble min,
gdouble max)
{
g_return_if_fail (PIKA_IS_ZOOM_MODEL (model));
g_return_if_fail (min < max);
g_return_if_fail (min >= ZOOM_MIN);
g_return_if_fail (max <= ZOOM_MAX);
g_object_set (model,
"minimum", min,
"maximum", max,
NULL);
}
/**
* pika_zoom_model_zoom:
* @model: a #PikaZoomModel
* @zoom_type: the #PikaZoomType
* @scale: ignored unless @zoom_type == %PIKA_ZOOM_TO
*
* Since PIKA 2.4
**/
void
pika_zoom_model_zoom (PikaZoomModel *model,
PikaZoomType zoom_type,
gdouble scale)
{
gdouble delta = 0.0;
g_return_if_fail (PIKA_IS_ZOOM_MODEL (model));
if (zoom_type == PIKA_ZOOM_SMOOTH)
delta = scale;
if (zoom_type != PIKA_ZOOM_TO)
scale = pika_zoom_model_get_factor (model);
g_object_set (model,
"value", pika_zoom_model_zoom_step (zoom_type, scale, delta),
NULL);
}
/**
* pika_zoom_model_get_factor:
* @model: a #PikaZoomModel
*
* Retrieves the current zoom factor of @model.
*
* Returns: the current scale factor
*
* Since PIKA 2.4
**/
gdouble
pika_zoom_model_get_factor (PikaZoomModel *model)
{
g_return_val_if_fail (PIKA_IS_ZOOM_MODEL (model), 1.0);
return GET_PRIVATE (model)->value;
}
/**
* pika_zoom_model_get_fraction
* @model: a #PikaZoomModel
* @numerator: (out): return location for numerator
* @denominator: (out): return location for denominator
*
* Retrieves the current zoom factor of @model as a fraction.
*
* Since PIKA 2.4
**/
void
pika_zoom_model_get_fraction (PikaZoomModel *model,
gint *numerator,
gint *denominator)
{
gint p0, p1, p2;
gint q0, q1, q2;
gdouble zoom_factor;
gdouble remainder, next_cf;
gboolean swapped = FALSE;
g_return_if_fail (PIKA_IS_ZOOM_MODEL (model));
g_return_if_fail (numerator != NULL && denominator != NULL);
zoom_factor = pika_zoom_model_get_factor (model);
/* make sure that zooming behaves symmetrically */
if (zoom_factor < 1.0)
{
zoom_factor = 1.0 / zoom_factor;
swapped = TRUE;
}
/* calculate the continued fraction for the desired zoom factor */
p0 = 1;
q0 = 0;
p1 = floor (zoom_factor);
q1 = 1;
remainder = zoom_factor - p1;
while (fabs (remainder) >= 0.0001 &&
fabs (((gdouble) p1 / q1) - zoom_factor) > 0.0001)
{
remainder = 1.0 / remainder;
next_cf = floor (remainder);
p2 = next_cf * p1 + p0;
q2 = next_cf * q1 + q0;
/* Numerator and Denominator are limited by 256 */
/* also absurd ratios like 170:171 are excluded */
if (p2 > 256 || q2 > 256 || (p2 > 1 && q2 > 1 && p2 * q2 > 200))
break;
/* remember the last two fractions */
p0 = p1;
p1 = p2;
q0 = q1;
q1 = q2;
remainder = remainder - next_cf;
}
zoom_factor = (gdouble) p1 / q1;
/* hard upper and lower bounds for zoom ratio */
if (zoom_factor > 256.0)
{
p1 = 256;
q1 = 1;
}
else if (zoom_factor < 1.0 / 256.0)
{
p1 = 1;
q1 = 256;
}
if (swapped)
{
*numerator = q1;
*denominator = p1;
}
else
{
*numerator = p1;
*denominator = q1;
}
}
static GtkWidget *
zoom_button_new (const gchar *icon_name,
GtkIconSize icon_size)
{
GtkWidget *button;
GtkWidget *image;
image = gtk_image_new_from_icon_name (icon_name,
icon_size > 0 ?
icon_size : GTK_ICON_SIZE_BUTTON);
button = gtk_button_new ();
gtk_container_add (GTK_CONTAINER (button), image);
gtk_widget_show (image);
return button;
}
static void
zoom_in_button_callback (PikaZoomModel *model,
gdouble old,
gdouble new,
GtkWidget *button)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (model);
gtk_widget_set_sensitive (button, priv->value != priv->maximum);
}
static void
zoom_out_button_callback (PikaZoomModel *model,
gdouble old,
gdouble new,
GtkWidget *button)
{
PikaZoomModelPrivate *priv = GET_PRIVATE (model);
gtk_widget_set_sensitive (button, priv->value != priv->minimum);
}
/**
* pika_zoom_button_new:
* @model: a #PikaZoomModel
* @zoom_type:
* @icon_size: use 0 for a button with text labels
*
* Returns: (transfer full): a newly created GtkButton
*
* Since PIKA 2.4
**/
GtkWidget *
pika_zoom_button_new (PikaZoomModel *model,
PikaZoomType zoom_type,
GtkIconSize icon_size)
{
GtkWidget *button = NULL;
g_return_val_if_fail (PIKA_IS_ZOOM_MODEL (model), NULL);
switch (zoom_type)
{
case PIKA_ZOOM_IN:
button = zoom_button_new ("zoom-in", icon_size);
g_signal_connect_swapped (button, "clicked",
G_CALLBACK (pika_zoom_model_zoom_in),
model);
g_signal_connect_object (model, "zoomed",
G_CALLBACK (zoom_in_button_callback),
button, 0);
break;
case PIKA_ZOOM_OUT:
button = zoom_button_new ("zoom-out", icon_size);
g_signal_connect_swapped (button, "clicked",
G_CALLBACK (pika_zoom_model_zoom_out),
model);
g_signal_connect_object (model, "zoomed",
G_CALLBACK (zoom_out_button_callback),
button, 0);
break;
default:
g_warning ("sorry, no button for this zoom type (%d)", zoom_type);
break;
}
if (button)
{
gdouble zoom = pika_zoom_model_get_factor (model);
/* set initial button sensitivity */
g_signal_emit (model, zoom_model_signals[ZOOMED], 0, zoom, zoom);
if (icon_size > 0)
{
const gchar *desc;
if (pika_enum_get_value (PIKA_TYPE_ZOOM_TYPE, zoom_type,
NULL, NULL, &desc, NULL))
{
pika_help_set_help_data (button, desc, NULL);
}
}
}
return button;
}
/**
* pika_zoom_model_zoom_step:
* @zoom_type: the zoom type
* @scale: ignored unless @zoom_type == %PIKA_ZOOM_TO
* @delta: the delta from a smooth zoom event
*
* Utility function to calculate a new scale factor.
*
* Returns: the new scale factor
*
* Since PIKA 2.4
**/
gdouble
pika_zoom_model_zoom_step (PikaZoomType zoom_type,
gdouble scale,
gdouble delta)
{
gint i, n_presets;
gdouble new_scale = 1.0;
/* This table is constructed to have fractions, that approximate
* sqrt(2)^k. This gives a smooth feeling regardless of the starting
* zoom level.
*
* Zooming in/out always jumps to a zoom step from the list below.
* However, we try to guarantee a certain size of the step, to
* avoid silly jumps from 101% to 100%.
*
* The factor 1.1 is chosen a bit arbitrary, but feels better
* than the geometric median of the zoom steps (2^(1/4)).
*/
#define ZOOM_MIN_STEP 1.1
const gdouble presets[] = {
1.0 / 256, 1.0 / 180, 1.0 / 128, 1.0 / 90,
1.0 / 64, 1.0 / 45, 1.0 / 32, 1.0 / 23,
1.0 / 16, 1.0 / 11, 1.0 / 8, 2.0 / 11,
1.0 / 4, 1.0 / 3, 1.0 / 2, 2.0 / 3,
1.0,
3.0 / 2, 2.0, 3.0,
4.0, 11.0 / 2, 8.0, 11.0,
16.0, 23.0, 32.0, 45.0,
64.0, 90.0, 128.0, 180.0,
256.0,
};
n_presets = G_N_ELEMENTS (presets);
switch (zoom_type)
{
case PIKA_ZOOM_IN:
scale *= ZOOM_MIN_STEP;
new_scale = presets[n_presets - 1];
for (i = n_presets - 1; i >= 0 && presets[i] > scale; i--)
new_scale = presets[i];
break;
case PIKA_ZOOM_OUT:
scale /= ZOOM_MIN_STEP;
new_scale = presets[0];
for (i = 0; i < n_presets && presets[i] < scale; i++)
new_scale = presets[i];
break;
case PIKA_ZOOM_IN_MORE:
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_IN, scale, 0.0);
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_IN, scale, 0.0);
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_IN, scale, 0.0);
new_scale = scale;
break;
case PIKA_ZOOM_OUT_MORE:
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_OUT, scale, 0.0);
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_OUT, scale, 0.0);
scale = pika_zoom_model_zoom_step (PIKA_ZOOM_OUT, scale, 0.0);
new_scale = scale;
break;
case PIKA_ZOOM_IN_MAX:
new_scale = ZOOM_MAX;
break;
case PIKA_ZOOM_OUT_MAX:
new_scale = ZOOM_MIN;
break;
case PIKA_ZOOM_TO:
new_scale = scale;
break;
case PIKA_ZOOM_SMOOTH:
if (delta > 0.0)
new_scale = scale * (1.0 + 0.1 * delta);
else if (delta < 0.0)
new_scale = scale / (1.0 + 0.1 * -delta);
else
new_scale = scale;
break;
case PIKA_ZOOM_PINCH:
if (delta > 0.0)
new_scale = scale * (1.0 + delta);
else if (delta < 0.0)
new_scale = scale / (1.0 + -delta);
else
new_scale = scale;
break;
}
return CLAMP (new_scale, ZOOM_MIN, ZOOM_MAX);
#undef ZOOM_MIN_STEP
}
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