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mutter-performance-source/clutter/clutter-units.c
Emmanuele Bassi 2b81d90dd7 Eliminate G_CONST_RETURN 
The G_CONST_RETURN define in GLib is, and has always been, a bit fuzzy.

We always used it to conform to the platform, at least for public-facing
API.

At first I assumed it has something to do with brain-damaged compilers
or with weird platforms where const was not really supported; sadly,
it's something much, much worse: it's a define that can be toggled at
compile-time to remove const from the signature of public API. This is a
truly terrifying feature that I assume was added in the past century,
and whose inception clearly had something to do with massive doses of
absynthe and opium — because any other explanation would make the
existence of such a feature even worse than assuming drugs had anything
to do with it.

Anyway, and pleasing the gods, this dubious feature is being
removed/deprecated in GLib; see bug:

  https://bugzilla.gnome.org/show_bug.cgi?id=644611

Before deprecation, though, we should just remove its usage from the
whole API. We should especially remove its usage from Cally's internals,
since there it never made sense in the first place.
2011-06-07 16:06:24 +01:00

934 lines
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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 #ClutterActor::allocate() virtual function, or inside the
* #ClutterActor::get_preferred_width() and #ClutterActor::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
* ]|
*
* <note><para>If no unit is specified, pixels are assumed.</para></note>
*
* 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
*
* <note>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.</note>
*
* 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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