mutter/clutter/clutter-units.h
Emmanuele Bassi 0d5e17ecd1 [units] Rework Units into logical distance value
Units as they have been implemented since Clutter 0.4 have always been
misdefined as "logical distance unit", while they were just pixels with
fractionary bits.

Units should be reworked to be opaque structures to hold a value and
its unit type, that can be then converted into pixels when Clutter needs
to paint or compute size requisitions and perform allocations.

The previous API should be completely removed to avoid collisions, and
a new type:

        ClutterUnits

should be added; the ability to install GObject properties using
ClutterUnits should be maintained.
2009-06-04 16:30:31 +01:00

170 lines
5.6 KiB
C

/* -*- mode:C; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By: Tomas Frydrych <tf@openedhand.com>
* Emmanuele Bassu <ebassi@linux.intel.com>
*
* Copyright (C) 2007, 2008 OpenedHand
* Copyright (C) 2009 Intel Corp.
*
* 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 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/>.
*/
#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <clutter/clutter.h> can be included directly."
#endif
#ifndef __CLUTTER_UNITS_H__
#define __CLUTTER_UNITS_H__
#include <glib-object.h>
#include <cogl/cogl.h>
G_BEGIN_DECLS
/**
* ClutterUnitType:
* @CLUTTER_UNIT_PIXEL: Unit expressed in pixels (with subpixel precision)
* @CLUTTER_UNIT_EM: Unit expressed in em
* @CLUTTER_UNIT_MM: Unit expressed in millimeters
* @CLUTTER_UNIT_POINT: Unit expressed in points
*
* The type of unit in which a value is expressed
*
* This enumeration might be expanded at later date
*
* Since: 1.0
*/
typedef enum {
CLUTTER_UNIT_PIXEL,
CLUTTER_UNIT_EM,
CLUTTER_UNIT_MM,
CLUTTER_UNIT_POINT
} ClutterUnitType;
/**
* ClutterUnits:
*
* An opaque structure, to be used to store sizing and positioning
* values along with their unit.
*
* Since: 1.0
*/
typedef struct _ClutterUnits ClutterUnits;
struct _ClutterUnits
{
/*< private >*/
ClutterUnitType unit_type;
gfloat value;
/* pre-filled by the provided constructors */
gfloat pixels;
guint pixels_set;
/* padding for eventual expansion */
gint64 __padding_1;
gint64 __padding_2;
};
GType clutter_units_get_type (void) G_GNUC_CONST;
ClutterUnitType clutter_units_get_unit_type (const ClutterUnits *units);
gfloat clutter_units_get_unit_value (const ClutterUnits *units);
ClutterUnits * clutter_units_copy (const ClutterUnits *units);
void clutter_units_free (ClutterUnits *units);
void clutter_units_pixels (ClutterUnits *units,
gint px);
void clutter_units_em (ClutterUnits *units,
gfloat em);
void clutter_units_em_for_font (ClutterUnits *units,
const gchar *font_name,
gfloat em);
void clutter_units_mm (ClutterUnits *units,
gfloat mm);
void clutter_units_pt (ClutterUnits *units,
gfloat pt);
gfloat clutter_units_to_pixels (ClutterUnits *units);
gchar * clutter_units_to_string (const ClutterUnits *units);
gboolean clutter_units_from_string (ClutterUnits *units,
const gchar *str);
#define CLUTTER_TYPE_UNITS (clutter_units_get_type ())
#define CLUTTER_TYPE_PARAM_UNITS (clutter_param_units_get_type ())
#define CLUTTER_PARAM_SPEC_UNITS(pspec) (G_TYPE_CHECK_INSTANCE_CAST ((pspec), CLUTTER_TYPE_PARAM_UNITS, ClutterParamSpecUnits))
#define CLUTTER_IS_PARAM_SPEC_UNITS(pspec) (G_TYPE_CHECK_INSTANCE_TYPE ((pspec), CLUTTER_TYPE_PARAM_UNITS))
/**
* CLUTTER_VALUE_HOLDS_UNIT:
* @x: a #GValue
*
* Evaluates to %TRUE if @x holds a #ClutterUnits value
*
* Since: 0.8
*/
#define CLUTTER_VALUE_HOLDS_UNITS(x) (G_VALUE_HOLDS ((x), CLUTTER_TYPE_UNITS))
typedef struct _ClutterParamSpecUnits ClutterParamSpecUnits;
/**
* ClutterParamSpecUnits:
* @default_type: default type
* @default_value: default value
* @minimum: lower boundary
* @maximum: higher boundary
*
* #GParamSpec subclass for unit based properties.
*
* Since: 1.0
*/
struct _ClutterParamSpecUnits
{
/*< private >*/
GParamSpec parent_instance;
/*< public >*/
ClutterUnitType default_type;
gfloat default_value;
gfloat minimum;
gfloat maximum;
};
GType clutter_param_units_get_type (void) G_GNUC_CONST;
GParamSpec * clutter_param_spec_units (const gchar *name,
const gchar *nick,
const gchar *blurb,
ClutterUnitType default_type,
gfloat minimum,
gfloat maximum,
gfloat default_value,
GParamFlags flags);
void clutter_value_set_units (GValue *value,
const ClutterUnits *units);
G_CONST_RETURN ClutterUnits *clutter_value_get_units (const GValue *value);
G_END_DECLS
#endif /* __CLUTTER_UNITS_H__ */