mutter/clutter/clutter-backend.c
Emmanuele Bassi b39223d8cb [backend] Constify font options
The font options accessors in ClutterBackend only deal with const
cairo_font_options_t values, since:

  - set_font_options() will copy the font options
  - get_font_options() will return a pointer to the internal
    font options

Not using const in these cases makes the API confusing and might lead
to erroneous calls to cairo_font_options_destroy().
2009-02-26 15:32:48 +00:00

668 lines
17 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-backend
* @short_description: Backend abstraction
*
* Clutter can be compiled against different backends. Each backend
* has to implement a set of functions, in order to be used by Clutter.
*
* #ClutterBackend is the base class abstracting the various implementation;
* it provides a basic API to query the backend for generic information
* and settings.
*
* #ClutterBackend is available since Clutter 0.4
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-backend.h"
#include "clutter-debug.h"
#include "clutter-fixed.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
G_DEFINE_ABSTRACT_TYPE (ClutterBackend, clutter_backend, G_TYPE_OBJECT);
#define DEFAULT_FONT_NAME "Sans 10"
#define CLUTTER_BACKEND_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), CLUTTER_TYPE_BACKEND, ClutterBackendPrivate))
struct _ClutterBackendPrivate
{
/* settings */
guint double_click_time;
guint double_click_distance;
gdouble resolution;
gdouble units_per_em;
cairo_font_options_t *font_options;
gchar *font_name;
};
enum
{
RESOLUTION_CHANGED,
FONT_CHANGED,
LAST_SIGNAL
};
static guint backend_signals[LAST_SIGNAL] = { 0, };
static void
clutter_backend_dispose (GObject *gobject)
{
ClutterBackendPrivate *priv = CLUTTER_BACKEND (gobject)->priv;
ClutterMainContext *clutter_context;
clutter_context = clutter_context_get_default ();
if (clutter_context && clutter_context->events_queue)
{
g_queue_foreach (clutter_context->events_queue,
(GFunc) clutter_event_free,
NULL);
g_queue_free (clutter_context->events_queue);
clutter_context->events_queue = NULL;
}
g_free (priv->font_name);
clutter_backend_set_font_options (CLUTTER_BACKEND (gobject), NULL);
G_OBJECT_CLASS (clutter_backend_parent_class)->dispose (gobject);
}
static inline void
update_units_per_em (ClutterBackend *backend)
{
ClutterBackendPrivate *priv = backend->priv;
const gchar *font_name;
gdouble dpi;
font_name = clutter_backend_get_font_name (backend);
dpi = clutter_backend_get_resolution (backend);
if (G_LIKELY (font_name != NULL && *font_name != '\0'))
{
PangoFontDescription *font_desc;
gdouble font_size = 0;
font_desc = pango_font_description_from_string (font_name);
if (G_LIKELY (font_desc != NULL))
{
gint pango_size;
gboolean is_absolute;
pango_size = pango_font_description_get_size (font_desc);
is_absolute =
pango_font_description_get_size_is_absolute (font_desc);
if (!is_absolute)
font_size = ((gdouble) font_size) / PANGO_SCALE;
pango_font_description_free (font_desc);
}
/* 10 points at 96 DPI is 12 pixels */
priv->units_per_em = 1.2 * font_size
* dpi
/ 96.0;
}
else
priv->units_per_em = -1.0;
}
static void
clutter_backend_real_resolution_changed (ClutterBackend *backend)
{
update_units_per_em (backend);
}
static void
clutter_backend_real_font_changed (ClutterBackend *backend)
{
update_units_per_em (backend);
}
static void
clutter_backend_class_init (ClutterBackendClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->dispose = clutter_backend_dispose;
g_type_class_add_private (gobject_class, sizeof (ClutterBackendPrivate));
backend_signals[RESOLUTION_CHANGED] =
g_signal_new (I_("resolution-changed"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBackendClass, resolution_changed),
NULL, NULL,
clutter_marshal_VOID__VOID,
G_TYPE_NONE, 0);
backend_signals[FONT_CHANGED] =
g_signal_new (I_("font-changed"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBackendClass, font_changed),
NULL, NULL,
clutter_marshal_VOID__VOID,
G_TYPE_NONE, 0);
klass->resolution_changed = clutter_backend_real_resolution_changed;
klass->font_changed = clutter_backend_real_font_changed;
}
static void
clutter_backend_init (ClutterBackend *backend)
{
ClutterBackendPrivate *priv;
priv = backend->priv = CLUTTER_BACKEND_GET_PRIVATE (backend);
priv->resolution = -1.0;
priv->units_per_em = -1.0;
}
void
_clutter_backend_add_options (ClutterBackend *backend,
GOptionGroup *group)
{
ClutterBackendClass *klass;
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->add_options)
klass->add_options (backend, group);
}
gboolean
_clutter_backend_pre_parse (ClutterBackend *backend,
GError **error)
{
ClutterBackendClass *klass;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), FALSE);
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->pre_parse)
return klass->pre_parse (backend, error);
return TRUE;
}
gboolean
_clutter_backend_post_parse (ClutterBackend *backend,
GError **error)
{
ClutterBackendClass *klass;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), FALSE);
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->post_parse)
return klass->post_parse (backend, error);
return TRUE;
}
ClutterActor *
_clutter_backend_create_stage (ClutterBackend *backend,
ClutterStage *wrapper,
GError **error)
{
ClutterMainContext *context;
ClutterBackendClass *klass;
ClutterActor *stage = NULL;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), FALSE);
g_return_val_if_fail (CLUTTER_IS_STAGE (wrapper), FALSE);
context = clutter_context_get_default ();
if (!context->stage_manager)
context->stage_manager = clutter_stage_manager_get_default ();
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->create_stage)
stage = klass->create_stage (backend, wrapper, error);
if (!stage)
return NULL;
g_assert (CLUTTER_IS_STAGE_WINDOW (stage));
_clutter_stage_set_window (wrapper, CLUTTER_STAGE_WINDOW (stage));
_clutter_stage_manager_add_stage (context->stage_manager, wrapper);
return stage;
}
void
_clutter_backend_redraw (ClutterBackend *backend,
ClutterStage *stage)
{
ClutterBackendClass *klass;
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (G_LIKELY (klass->redraw))
klass->redraw (backend, stage);
}
void
_clutter_backend_ensure_context (ClutterBackend *backend,
ClutterStage *stage)
{
ClutterBackendClass *klass;
static ClutterStage *current_context_stage = NULL;
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
g_return_if_fail (CLUTTER_IS_STAGE (stage));
if (current_context_stage != stage || !CLUTTER_ACTOR_IS_REALIZED (stage))
{
if (!CLUTTER_ACTOR_IS_REALIZED (stage))
{
CLUTTER_NOTE (MULTISTAGE, "Stage is not realized, unsetting");
stage = NULL;
}
else
CLUTTER_NOTE (MULTISTAGE, "Setting the new stage [%p]", stage);
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (G_LIKELY (klass->ensure_context))
klass->ensure_context (backend, stage);
/* FIXME: With a NULL stage and thus no active context it may make more
* sense to clean the context but then re call with the default stage
* so at least there is some kind of context in place (as to avoid
* potential issue of GL calls with no context)
*/
current_context_stage = stage;
/* if the new stage has a different size than the previous one
* we need to update the viewport; we do it by simply setting the
* SYNC_MATRICES flag and letting the next redraw cycle take care
* of calling glViewport()
*/
if (current_context_stage)
{
CLUTTER_SET_PRIVATE_FLAGS (current_context_stage,
CLUTTER_ACTOR_SYNC_MATRICES);
}
}
else
CLUTTER_NOTE (MULTISTAGE, "Stage is the same");
}
ClutterFeatureFlags
_clutter_backend_get_features (ClutterBackend *backend)
{
ClutterBackendClass *klass;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->get_features)
return klass->get_features (backend);
return 0;
}
void
_clutter_backend_init_events (ClutterBackend *backend)
{
ClutterBackendClass *klass;
ClutterMainContext *clutter_context;
clutter_context = clutter_context_get_default ();
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
g_return_if_fail (clutter_context != NULL);
clutter_context->events_queue = g_queue_new ();
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->init_events)
klass->init_events (backend);
}
ClutterUnit
_clutter_backend_get_units_per_em (ClutterBackend *backend)
{
ClutterBackendPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
priv = backend->priv;
if (G_UNLIKELY (priv->units_per_em < 0))
update_units_per_em (backend);
return priv->units_per_em;
}
/**
* clutter_get_default_backend1:
*
* Retrieves the default #ClutterBackend used by Clutter. The
* #ClutterBackend holds backend-specific configuration options.
*
* Return value: (transfer none): the default backend. You should
* not ref or unref the returned object. Applications should rarely
* need to use this.
*
* Since: 0.4
*/
ClutterBackend *
clutter_get_default_backend (void)
{
ClutterMainContext *clutter_context;
clutter_context = clutter_context_get_default ();
return clutter_context->backend;
}
/* FIXME: below should probably be moved into clutter_main */
/**
* clutter_backend_set_double_click_time:
* @backend: a #ClutterBackend
* @msec: milliseconds between two button press events
*
* Sets the maximum time between two button press events, used to
* verify whether it's a double click event or not.
*
* Since: 0.4
*/
void
clutter_backend_set_double_click_time (ClutterBackend *backend,
guint msec)
{
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
backend->priv->double_click_time = msec;
}
/**
* clutter_backend_get_double_click_time:
* @backend: a #ClutterBackend
*
* Gets the maximum time between two button press events, as set
* by clutter_backend_set_double_click_time().
*
* Return value: a time in milliseconds
*
* Since: 0.4
*/
guint
clutter_backend_get_double_click_time (ClutterBackend *backend)
{
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
return backend->priv->double_click_time;
}
/**
* clutter_backend_set_double_click_distance:
* @backend: a #ClutterBackend
* @distance: a distance, in pixels
*
* Sets the maximum distance used to verify a double click event.
*
* Since: 0.4
*/
void
clutter_backend_set_double_click_distance (ClutterBackend *backend,
guint distance)
{
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
backend->priv->double_click_distance = distance;
}
/**
* clutter_backend_get_double_click_distance:
* @backend: a #ClutterBackend
*
* Retrieves the distance used to verify a double click event
*
* Return value: a distance, in pixels.
*
* Since: 0.4
*/
guint
clutter_backend_get_double_click_distance (ClutterBackend *backend)
{
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
return backend->priv->double_click_distance;
}
/**
* clutter_backend_set_resolution:
* @backend: a #ClutterBackend
* @dpi: the resolution in "dots per inch" (Physical inches aren't
* actually involved; the terminology is conventional).
*
* Sets the resolution for font handling on the screen. This is a
* scale factor between points specified in a #PangoFontDescription
* and cairo units. The default value is 96, meaning that a 10 point
* font will be 13 units high. (10 * 96. / 72. = 13.3).
*
* Applications should never need to call this function.
*
* Since: 0.4
*/
void
clutter_backend_set_resolution (ClutterBackend *backend,
gdouble dpi)
{
ClutterBackendPrivate *priv;
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
priv = backend->priv;
if (dpi < 0)
dpi = -1.0;
priv->resolution = dpi;
if (CLUTTER_CONTEXT ()->font_map)
cogl_pango_font_map_set_resolution (CLUTTER_CONTEXT ()->font_map, dpi);
g_signal_emit (backend, backend_signals[RESOLUTION_CHANGED], 0);
}
/**
* clutter_backend_get_resolution:
* @backend: a #ClutterBackend
*
* Gets the resolution for font handling on the screen; see
* clutter_backend_set_resolution() for full details.
*
* Return value: the current resolution, or -1 if no resolution
* has been set.
*
* Since: 0.4
*/
gdouble
clutter_backend_get_resolution (ClutterBackend *backend)
{
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), -1.0);
return backend->priv->resolution;
}
/**
* clutter_backend_set_font_options:
* @backend: a #ClutterBackend
* @options: Cairo font options for the backend, or %NULL
*
* Sets the new font options for @backend. The #ClutterBackend will
* copy the #cairo_font_options_t.
*
* If @options is %NULL, the first following call to
* clutter_backend_get_font_options() will return the default font
* options for @backend.
*
* This function is intended for actors creating a Pango layout
* using the PangoCairo API.
*
* Since: 0.8
*/
void
clutter_backend_set_font_options (ClutterBackend *backend,
const cairo_font_options_t *options)
{
ClutterBackendPrivate *priv;
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
priv = backend->priv;
if (priv->font_options != options)
{
if (priv->font_options)
cairo_font_options_destroy (priv->font_options);
if (options)
priv->font_options = cairo_font_options_copy (options);
else
priv->font_options = NULL;
g_signal_emit (backend, backend_signals[FONT_CHANGED], 0);
}
}
/**
* clutter_backend_get_font_options:
* @backend: a #ClutterBackend
*
* Retrieves the font options for @backend.
*
* Return value: (transfer none): the font options of the #ClutterBackend.
* The returned #cairo_font_options_t is owned by the backend and should
* not be modified or freed
*
* Since: 0.8
*/
const cairo_font_options_t *
clutter_backend_get_font_options (ClutterBackend *backend)
{
ClutterBackendPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), NULL);
priv = backend->priv;
if (G_LIKELY (priv->font_options))
return priv->font_options;
priv->font_options = cairo_font_options_create ();
cairo_font_options_set_hint_style (priv->font_options,
CAIRO_HINT_STYLE_NONE);
cairo_font_options_set_subpixel_order (priv->font_options,
CAIRO_SUBPIXEL_ORDER_DEFAULT);
cairo_font_options_set_antialias (priv->font_options,
CAIRO_ANTIALIAS_DEFAULT);
return priv->font_options;
}
/**
* clutter_backend_set_font_name:
* @backend: a #ClutterBackend
* @font_name: the name of the font
*
* Sets the default font to be used by Clutter. The @font_name string
* must either be %NULL, which means that the font name from the
* default #ClutterBackend will be used; or be something that can
* be parsed by the pango_font_description_from_string() function.
*
* Since: 1.0
*/
void
clutter_backend_set_font_name (ClutterBackend *backend,
const gchar *font_name)
{
ClutterBackendPrivate *priv;
g_return_if_fail (CLUTTER_IS_BACKEND (backend));
priv = backend->priv;
g_free (priv->font_name);
if (font_name == NULL || *font_name == '\0')
priv->font_name = g_strdup (DEFAULT_FONT_NAME);
else
priv->font_name = g_strdup (font_name);
g_signal_emit (backend, backend_signals[FONT_CHANGED], 0);
}
/**
* clutter_backend_get_font_name:
* @backend: a #ClutterBackend
*
* Retrieves the default font name as set by
* clutter_backend_set_font_name().
*
* Return value: the font name for the backend. The returned string is
* owned by the #ClutterBackend and should never be modified or freed
*
* Since: 1.0
*/
G_CONST_RETURN gchar *
clutter_backend_get_font_name (ClutterBackend *backend)
{
ClutterBackendPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), NULL);
priv = backend->priv;
if (G_LIKELY (priv->font_name))
return priv->font_name;
priv->font_name = g_strdup (DEFAULT_FONT_NAME);
return priv->font_name;
}