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clutter/clutter/clutter-units.c

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/* -*- 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 Bassi <ebassi@openedhand.com>
*
* Copyright (C) 2007 OpenedHand
*
* 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/>.
*
*
*/
/**
* SECTION:clutter-units
* @short_description: A logical distance unit
*
* #ClutterUnits is a structure holding a logical distance value along with
* its type, expressed as a value of the #ClutterUnitType enumeration. It is
* possible to use #ClutterUnits to store a position or a size in units
* different than pixels, and convert them whenever needed (for instance
* inside the #ClutterActorClass.allocate() virtual function, or inside the
* #ClutterActorClass.get_preferred_width() and #ClutterActorClass.get_preferred_height()
* virtual functions.
*
* In order to register a #ClutterUnits property, the #ClutterParamSpecUnits
* #GParamSpec sub-class should be used:
*
* |[
* GParamSpec *pspec;
*
* pspec = clutter_param_spec_units ("active-width",
* "Width",
* "Width of the active area, in millimeters",
* CLUTTER_UNIT_MM,
* 0.0, 12.0,
* 12.0,
* G_PARAM_READWRITE);
* g_object_class_install_property (gobject_class, PROP_WIDTH, pspec);
* ]|
*
* A #GValue holding units can be manipulated using clutter_value_set_units()
* and clutter_value_get_units(). #GValue<!-- -->s containing a #ClutterUnits
* value can also be transformed to #GValue<!-- -->s initialized with
* %G_TYPE_INT, %G_TYPE_FLOAT and %G_TYPE_STRING through implicit conversion
* and using g_value_transform().
*
* #ClutterUnits is available since Clutter 1.0
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <glib-object.h>
#include <gobject/gvaluecollector.h>
#include "clutter-backend-private.h"
#include "clutter-interval.h"
#include "clutter-private.h"
#include "clutter-units.h"
#define DPI_FALLBACK (96.0)
#define FLOAT_EPSILON (1e-30)
static gfloat
units_mm_to_pixels (gfloat mm)
{
ClutterBackend *backend;
gdouble dpi;
backend = clutter_get_default_backend ();
dpi = clutter_backend_get_resolution (backend);
if (dpi < 0)
dpi = DPI_FALLBACK;
return mm * dpi / 25.4;
}
static gfloat
units_cm_to_pixels (gfloat cm)
{
return units_mm_to_pixels (cm * 10);
}
static gfloat
units_pt_to_pixels (gfloat pt)
{
ClutterBackend *backend;
gdouble dpi;
backend = clutter_get_default_backend ();
dpi = clutter_backend_get_resolution (backend);
if (dpi < 0)
dpi = DPI_FALLBACK;
return pt * dpi / 72.0;
}
static gfloat
units_em_to_pixels (const gchar *font_name,
gfloat em)
{
ClutterBackend *backend = clutter_get_default_backend ();
if (font_name == NULL || *font_name == '\0')
return em * _clutter_backend_get_units_per_em (backend, NULL);
else
{
PangoFontDescription *font_desc;
gfloat res;
font_desc = pango_font_description_from_string (font_name);
if (font_desc == NULL)
res = -1.0;
else
{
res = em * _clutter_backend_get_units_per_em (backend, font_desc);
pango_font_description_free (font_desc);
}
return res;
}
}
/**
* clutter_units_from_mm:
* @units: (out caller-allocates): a #ClutterUnits
* @mm: millimeters
*
* Stores a value in millimiters inside @units
*
* Since: 1.0
*/
void
clutter_units_from_mm (ClutterUnits *units,
gfloat mm)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_MM;
units->value = mm;
units->pixels = units_mm_to_pixels (mm);
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_from_cm:
* @units: (out caller-allocates): a #ClutterUnits
* @cm: centimeters
*
* Stores a value in centimeters inside @units
*
* Since: 1.2
*/
void
clutter_units_from_cm (ClutterUnits *units,
gfloat cm)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_CM;
units->value = cm;
units->pixels = units_cm_to_pixels (cm);
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_from_pt:
* @units: (out caller-allocates): a #ClutterUnits
* @pt: typographic points
*
* Stores a value in typographic points inside @units
*
* Since: 1.0
*/
void
clutter_units_from_pt (ClutterUnits *units,
gfloat pt)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_POINT;
units->value = pt;
units->pixels = units_pt_to_pixels (pt);
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_from_em:
* @units: (out caller-allocates): a #ClutterUnits
* @em: em
*
* Stores a value in em inside @units, using the default font
* name as returned by clutter_backend_get_font_name()
*
* Since: 1.0
*/
void
clutter_units_from_em (ClutterUnits *units,
gfloat em)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_EM;
units->value = em;
units->pixels = units_em_to_pixels (NULL, em);
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_from_em_for_font:
* @units: (out caller-allocates): a #ClutterUnits
* @font_name: (allow-none): the font name and size
* @em: em
*
* Stores a value in em inside @units using @font_name
*
* Since: 1.0
*/
void
clutter_units_from_em_for_font (ClutterUnits *units,
const gchar *font_name,
gfloat em)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_EM;
units->value = em;
units->pixels = units_em_to_pixels (font_name, em);
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_from_pixels:
* @units: (out caller-allocates): a #ClutterUnits
* @px: pixels
*
* Stores a value in pixels inside @units
*
* Since: 1.0
*/
void
clutter_units_from_pixels (ClutterUnits *units,
gint px)
{
ClutterBackend *backend;
g_return_if_fail (units != NULL);
backend = clutter_get_default_backend ();
units->unit_type = CLUTTER_UNIT_PIXEL;
units->value = px;
units->pixels = px;
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
}
/**
* clutter_units_get_unit_type:
* @units: a #ClutterUnits
*
* Retrieves the unit type of the value stored inside @units
*
* Return value: a unit type
*
* Since: 1.0
*/
ClutterUnitType
clutter_units_get_unit_type (const ClutterUnits *units)
{
g_return_val_if_fail (units != NULL, CLUTTER_UNIT_PIXEL);
return units->unit_type;
}
/**
* clutter_units_get_unit_value:
* @units: a #ClutterUnits
*
* Retrieves the value stored inside @units
*
* Return value: the value stored inside a #ClutterUnits
*
* Since: 1.0
*/
gfloat
clutter_units_get_unit_value (const ClutterUnits *units)
{
g_return_val_if_fail (units != NULL, 0.0);
return units->value;
}
/**
* clutter_units_copy:
* @units: the #ClutterUnits to copy
*
* Copies @units
*
* Return value: (transfer full): the newly created copy of a
* #ClutterUnits structure. Use clutter_units_free() to free
* the allocated resources
*
* Since: 1.0
*/
ClutterUnits *
clutter_units_copy (const ClutterUnits *units)
{
if (units != NULL)
return g_slice_dup (ClutterUnits, units);
return NULL;
}
/**
* clutter_units_free:
* @units: the #ClutterUnits to free
*
* Frees the resources allocated by @units
*
* You should only call this function on a #ClutterUnits
* created using clutter_units_copy()
*
* Since: 1.0
*/
void
clutter_units_free (ClutterUnits *units)
{
if (units != NULL)
g_slice_free (ClutterUnits, units);
}
/**
* clutter_units_to_pixels:
* @units: units to convert
*
* Converts a value in #ClutterUnits to pixels
*
* Return value: the value in pixels
*
* Since: 1.0
*/
gfloat
clutter_units_to_pixels (ClutterUnits *units)
{
ClutterBackend *backend;
g_return_val_if_fail (units != NULL, 0.0);
/* if the backend settings changed we evict the cached value */
backend = clutter_get_default_backend ();
if (units->serial != _clutter_backend_get_units_serial (backend))
units->pixels_set = FALSE;
if (units->pixels_set)
return units->pixels;
switch (units->unit_type)
{
case CLUTTER_UNIT_MM:
units->pixels = units_mm_to_pixels (units->value);
break;
case CLUTTER_UNIT_CM:
units->pixels = units_cm_to_pixels (units->value);
break;
case CLUTTER_UNIT_POINT:
units->pixels = units_pt_to_pixels (units->value);
break;
case CLUTTER_UNIT_EM:
units->pixels = units_em_to_pixels (NULL, units->value);
break;
case CLUTTER_UNIT_PIXEL:
units->pixels = units->value;
break;
}
units->pixels_set = TRUE;
units->serial = _clutter_backend_get_units_serial (backend);
return units->pixels;
}
/**
* clutter_units_from_string:
* @units: (out caller-allocates): a #ClutterUnits
* @str: the string to convert
*
* Parses a value and updates @units with it
*
* A #ClutterUnits expressed in string should match:
*
* |[
* units: wsp* unit-value wsp* unit-name? wsp*
* unit-value: number
* unit-name: 'px' | 'pt' | 'mm' | 'em' | 'cm'
* number: digit+
* | digit* sep digit+
* sep: '.' | ','
* digit: '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'
* wsp: (#0x20 | #0x9 | #0xA | #0xB | #0xC | #0xD)+
* ]|
*
* For instance, these are valid strings:
*
* |[
* 10 px
* 5.1 em
* 24 pt
* 12.6 mm
* .3 cm
* ]|
*
* While these are not:
*
* |[
* 42 cats
* omg!1!ponies
* ]|
*
* If no unit is specified, pixels are assumed.
*
* Return value: %TRUE if the string was successfully parsed,
* and %FALSE otherwise
*
* Since: 1.0
*/
gboolean
clutter_units_from_string (ClutterUnits *units,
const gchar *str)
{
ClutterBackend *backend;
ClutterUnitType unit_type;
gfloat value;
g_return_val_if_fail (units != NULL, FALSE);
g_return_val_if_fail (str != NULL, FALSE);
/* strip leading space */
while (g_ascii_isspace (*str))
str++;
if (*str == '\0')
return FALSE;
/* integer part */
value = (gfloat) strtoul (str, (char **) &str, 10);
if (*str == '.' || *str == ',')
{
gfloat divisor = 0.1;
/* 5.cm is not a valid number */
if (!g_ascii_isdigit (*++str))
return FALSE;
while (g_ascii_isdigit (*str))
{
value += (*str - '0') * divisor;
divisor *= 0.1;
str++;
}
}
while (g_ascii_isspace (*str))
str++;
/* assume pixels by default, if no unit is specified */
if (*str == '\0')
unit_type = CLUTTER_UNIT_PIXEL;
else if (strncmp (str, "em", 2) == 0)
{
unit_type = CLUTTER_UNIT_EM;
str += 2;
}
else if (strncmp (str, "mm", 2) == 0)
{
unit_type = CLUTTER_UNIT_MM;
str += 2;
}
else if (strncmp (str, "cm", 2) == 0)
{
unit_type = CLUTTER_UNIT_CM;
str += 2;
}
else if (strncmp (str, "pt", 2) == 0)
{
unit_type = CLUTTER_UNIT_POINT;
str += 2;
}
else if (strncmp (str, "px", 2) == 0)
{
unit_type = CLUTTER_UNIT_PIXEL;
str += 2;
}
else
return FALSE;
/* ensure the unit is only followed by white space */
while (g_ascii_isspace (*str))
str++;
if (*str != '\0')
return FALSE;
backend = clutter_get_default_backend ();
units->unit_type = unit_type;
units->value = value;
units->pixels_set = FALSE;
units->serial = _clutter_backend_get_units_serial (backend);
return TRUE;
}
static const gchar *
clutter_unit_type_name (ClutterUnitType unit_type)
{
switch (unit_type)
{
case CLUTTER_UNIT_MM:
return "mm";
case CLUTTER_UNIT_CM:
return "cm";
case CLUTTER_UNIT_POINT:
return "pt";
case CLUTTER_UNIT_EM:
return "em";
case CLUTTER_UNIT_PIXEL:
return "px";
}
g_warning ("Invalid unit type %d", (int) unit_type);
return "<invalid>";
}
/**
* clutter_units_to_string:
* @units: a #ClutterUnits
*
* Converts @units into a string
*
* See clutter_units_from_string() for the units syntax and for
* examples of output
*
* Fractional values are truncated to the second decimal
* position for em, mm and cm, and to the first decimal position for
* typographic points. Pixels are integers.
*
* Return value: a newly allocated string containing the encoded
* #ClutterUnits value. Use g_free() to free the string
*
* Since: 1.0
*/
gchar *
clutter_units_to_string (const ClutterUnits *units)
{
const gchar *unit_name = NULL;
const gchar *fmt = NULL;
gchar buf[G_ASCII_DTOSTR_BUF_SIZE];
g_return_val_if_fail (units != NULL, NULL);
switch (units->unit_type)
{
/* special case: there is no such thing as "half a pixel", so
* we round up to the nearest integer using C default
*/
case CLUTTER_UNIT_PIXEL:
return g_strdup_printf ("%d px", (int) units->value);
case CLUTTER_UNIT_MM:
unit_name = "mm";
fmt = "%.2f";
break;
case CLUTTER_UNIT_CM:
unit_name = "cm";
fmt = "%.2f";
break;
case CLUTTER_UNIT_POINT:
unit_name = "pt";
fmt = "%.1f";
break;
case CLUTTER_UNIT_EM:
unit_name = "em";
fmt = "%.2f";
break;
default:
g_assert_not_reached ();
break;
}
g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, fmt, units->value);
return g_strconcat (buf, " ", unit_name, NULL);
}
/*
* ClutterInterval integration
*/
static gboolean
clutter_units_progress (const GValue *a,
const GValue *b,
gdouble progress,
GValue *retval)
{
ClutterUnits *a_units = (ClutterUnits *) clutter_value_get_units (a);
ClutterUnits *b_units = (ClutterUnits *) clutter_value_get_units (b);
ClutterUnits res;
gfloat a_px, b_px, value;
a_px = clutter_units_to_pixels (a_units);
b_px = clutter_units_to_pixels (b_units);
value = progress * (b_px - a_px) + a_px;
clutter_units_from_pixels (&res, value);
clutter_value_set_units (retval, &res);
return TRUE;
}
/*
* GValue and GParamSpec integration
*/
/* units to integer */
static void
clutter_value_transform_units_int (const GValue *src,
GValue *dest)
{
dest->data[0].v_int = clutter_units_to_pixels (src->data[0].v_pointer);
}
/* integer to units */
static void
clutter_value_transform_int_units (const GValue *src,
GValue *dest)
{
clutter_units_from_pixels (dest->data[0].v_pointer, src->data[0].v_int);
}
/* units to float */
static void
clutter_value_transform_units_float (const GValue *src,
GValue *dest)
{
dest->data[0].v_float = clutter_units_to_pixels (src->data[0].v_pointer);
}
/* float to units */
static void
clutter_value_transform_float_units (const GValue *src,
GValue *dest)
{
clutter_units_from_pixels (dest->data[0].v_pointer, src->data[0].v_float);
}
/* units to string */
static void
clutter_value_transform_units_string (const GValue *src,
GValue *dest)
{
gchar *string = clutter_units_to_string (src->data[0].v_pointer);
g_value_take_string (dest, string);
}
/* string to units */
static void
clutter_value_transform_string_units (const GValue *src,
GValue *dest)
{
ClutterUnits units = { CLUTTER_UNIT_PIXEL, 0.0f };
clutter_units_from_string (&units, g_value_get_string (src));
clutter_value_set_units (dest, &units);
}
G_DEFINE_BOXED_TYPE_WITH_CODE (ClutterUnits, clutter_units,
clutter_units_copy,
clutter_units_free,
CLUTTER_REGISTER_VALUE_TRANSFORM_TO (G_TYPE_INT, clutter_value_transform_units_int)
CLUTTER_REGISTER_VALUE_TRANSFORM_TO (G_TYPE_FLOAT, clutter_value_transform_units_float)
CLUTTER_REGISTER_VALUE_TRANSFORM_TO (G_TYPE_STRING, clutter_value_transform_units_string)
CLUTTER_REGISTER_VALUE_TRANSFORM_FROM (G_TYPE_INT, clutter_value_transform_int_units)
CLUTTER_REGISTER_VALUE_TRANSFORM_FROM (G_TYPE_FLOAT, clutter_value_transform_float_units)
CLUTTER_REGISTER_VALUE_TRANSFORM_FROM (G_TYPE_STRING, clutter_value_transform_string_units)
CLUTTER_REGISTER_INTERVAL_PROGRESS (clutter_units_progress));
/**
* clutter_value_set_units:
* @value: a #GValue initialized to %CLUTTER_TYPE_UNITS
* @units: the units to set
*
* Sets @value to @units
*
* Since: 0.8
*/
void
clutter_value_set_units (GValue *value,
const ClutterUnits *units)
{
g_return_if_fail (CLUTTER_VALUE_HOLDS_UNITS (value));
value->data[0].v_pointer = clutter_units_copy (units);
}
/**
* clutter_value_get_units:
* @value: a #GValue initialized to %CLUTTER_TYPE_UNITS
*
* Gets the #ClutterUnits contained in @value.
*
* Return value: the units inside the passed #GValue
*
* Since: 0.8
*/
const ClutterUnits *
clutter_value_get_units (const GValue *value)
{
g_return_val_if_fail (CLUTTER_VALUE_HOLDS_UNITS (value), NULL);
return value->data[0].v_pointer;
}
static void
param_units_init (GParamSpec *pspec)
{
ClutterParamSpecUnits *uspec = CLUTTER_PARAM_SPEC_UNITS (pspec);
uspec->minimum = -G_MAXFLOAT;
uspec->maximum = G_MAXFLOAT;
uspec->default_value = 0.0f;
uspec->default_type = CLUTTER_UNIT_PIXEL;
}
static void
param_units_set_default (GParamSpec *pspec,
GValue *value)
{
ClutterParamSpecUnits *uspec = CLUTTER_PARAM_SPEC_UNITS (pspec);
ClutterUnits units;
units.unit_type = uspec->default_type;
units.value = uspec->default_value;
units.pixels_set = FALSE;
clutter_value_set_units (value, &units);
}
static gboolean
param_units_validate (GParamSpec *pspec,
GValue *value)
{
ClutterParamSpecUnits *uspec = CLUTTER_PARAM_SPEC_UNITS (pspec);
ClutterUnits *units = value->data[0].v_pointer;
ClutterUnitType otype = units->unit_type;
gfloat oval = units->value;
g_assert (CLUTTER_IS_PARAM_SPEC_UNITS (pspec));
if (otype != uspec->default_type)
{
gchar *str = clutter_units_to_string (units);
g_warning ("The units value of '%s' does not have the same unit "
"type as declared by the ClutterParamSpecUnits of '%s'",
str,
clutter_unit_type_name (uspec->default_type));
g_free (str);
return FALSE;
}
units->value = CLAMP (units->value,
uspec->minimum,
uspec->maximum);
return units->value != oval;
}
static gint
param_units_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2)
{
ClutterUnits *units1 = value1->data[0].v_pointer;
ClutterUnits *units2 = value2->data[0].v_pointer;
gfloat v1, v2;
if (units1->unit_type == units2->unit_type)
{
v1 = units1->value;
v2 = units2->value;
}
else
{
v1 = clutter_units_to_pixels (units1);
v2 = clutter_units_to_pixels (units2);
}
if (v1 < v2)
return - (v2 - v1 > FLOAT_EPSILON);
else
return v1 - v2 > FLOAT_EPSILON;
}
GType
clutter_param_units_get_type (void)
{
static GType pspec_type = 0;
if (G_UNLIKELY (pspec_type == 0))
{
const GParamSpecTypeInfo pspec_info = {
sizeof (ClutterParamSpecUnits),
16,
param_units_init,
CLUTTER_TYPE_UNITS,
NULL,
param_units_set_default,
param_units_validate,
param_units_values_cmp,
};
pspec_type = g_param_type_register_static (I_("ClutterParamSpecUnit"),
&pspec_info);
}
return pspec_type;
}
/**
* clutter_param_spec_units: (skip)
* @name: name of the property
* @nick: short name
* @blurb: description (can be translatable)
* @default_type: the default type for the #ClutterUnits
* @minimum: lower boundary
* @maximum: higher boundary
* @default_value: default value
* @flags: flags for the param spec
*
* Creates a #GParamSpec for properties using #ClutterUnits.
*
* Return value: the newly created #GParamSpec
*
* Since: 1.0
*/
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)
{
ClutterParamSpecUnits *uspec;
g_return_val_if_fail (default_value >= minimum && default_value <= maximum,
NULL);
uspec = g_param_spec_internal (CLUTTER_TYPE_PARAM_UNITS,
name, nick, blurb,
flags);
uspec->default_type = default_type;
uspec->minimum = minimum;
uspec->maximum = maximum;
uspec->default_value = default_value;
return G_PARAM_SPEC (uspec);
}
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