mutter/clutter/clutter-backend.c
Emmanuele Bassi 83b4ec7a12 units: Cache the pixels value inside Units
When computing the pixels value of a ClutterUnits value we should
be caching the value to avoid recomputing for every call of
clutter_units_to_pixels(). We already have a flag telling us to
return the cached value, but we miss the mechanism to evict the
cache whenever the Backend settings affecting the conversion, that
is default font and resolution, change.

In order to implement the eviction we can use a "serial"; the
Backend will have an internal serial field which we retrieve and
put inside the ClutterUnits structure (we split one of the two
64 bit padding fields into two 32 bit fields to maintain ABI); every
time we call clutter_units_to_pixels() we compare the units serial
with that of the Backend; if they match and pixels_set is set to
TRUE then we just return the stored pixels value. If the serials
do not match then we unset the pixels_set flag and recompute the
pixels value.

We can verify this by adding a simple test unit checking that
by changing the resolution of ClutterBackend we get different
pixel values for 1 em.

http://bugzilla.openedhand.com/show_bug.cgi?id=1843
2009-10-16 15:25:37 +01:00

741 lines
19 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;
gfloat units_per_em;
gint32 units_serial;
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 gfloat
get_units_per_em (ClutterBackend *backend,
PangoFontDescription *font_desc)
{
gfloat units_per_em = -1.0;
gboolean free_font_desc = FALSE;
gdouble dpi;
dpi = clutter_backend_get_resolution (backend);
if (font_desc == NULL)
{
const gchar *font_name = clutter_backend_get_font_name (backend);
if (G_LIKELY (font_name != NULL && *font_name != '\0'))
{
font_desc = pango_font_description_from_string (font_name);
free_font_desc = TRUE;
}
}
if (font_desc != NULL)
{
gdouble font_size = 0;
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);
/* "absolute" means "device units" (usually, pixels); otherwise,
* it means logical units (points)
*/
if (is_absolute)
font_size = (gdouble) pango_size / PANGO_SCALE;
else
font_size = (gdouble) pango_size / PANGO_SCALE
* dpi
/ 96.0f;
/* 10 points at 96 DPI is 13.3 pixels */
units_per_em = (1.2f * font_size)
* dpi
/ 96.0f;
}
else
units_per_em = -1.0f;
if (free_font_desc)
pango_font_description_free (font_desc);
return units_per_em;
}
static void
clutter_backend_real_resolution_changed (ClutterBackend *backend)
{
ClutterBackendPrivate *priv = backend->priv;
priv->units_per_em = get_units_per_em (backend, NULL);
priv->units_serial += 1;
CLUTTER_NOTE (BACKEND, "Units per em: %.2f", backend->priv->units_per_em);
}
static void
clutter_backend_real_font_changed (ClutterBackend *backend)
{
ClutterBackendPrivate *priv = backend->priv;
priv->units_per_em = get_units_per_em (backend, NULL);
priv->units_serial += 1;
CLUTTER_NOTE (BACKEND, "Units per em: %.2f", backend->priv->units_per_em);
}
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;
priv->units_serial = 1;
}
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;
}
ClutterStageWindow *
_clutter_backend_create_stage (ClutterBackend *backend,
ClutterStage *wrapper,
GError **error)
{
ClutterBackendClass *klass;
ClutterStageManager *stage_manager;
ClutterStageWindow *stage_window;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), FALSE);
g_return_val_if_fail (CLUTTER_IS_STAGE (wrapper), FALSE);
stage_manager = clutter_stage_manager_get_default ();
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->create_stage)
stage_window = klass->create_stage (backend, wrapper, error);
if (!stage_window)
return NULL;
g_assert (CLUTTER_IS_STAGE_WINDOW (stage_window));
_clutter_stage_set_window (wrapper, stage_window);
_clutter_stage_manager_add_stage (stage_manager, wrapper);
return stage_window;
}
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);
}
gboolean
_clutter_backend_create_context (ClutterBackend *backend,
gboolean is_offscreen,
GError **error)
{
ClutterBackendClass *klass;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), FALSE);
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (klass->create_context)
return klass->create_context (backend, is_offscreen, error);
return TRUE;
}
void
_clutter_backend_ensure_context (ClutterBackend *backend,
ClutterStage *stage)
{
static ClutterStage *current_context_stage = NULL;
ClutterBackendClass *klass;
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))
{
ClutterStage *new_stage = NULL;
if (!CLUTTER_ACTOR_IS_REALIZED (stage))
{
new_stage = NULL;
CLUTTER_NOTE (MULTISTAGE,
"Stage [%p] is not realized, unsetting the stage",
stage);
}
else
{
new_stage = stage;
CLUTTER_NOTE (MULTISTAGE,
"Setting the new stage [%p]",
new_stage);
}
klass = CLUTTER_BACKEND_GET_CLASS (backend);
if (G_LIKELY (klass->ensure_context))
klass->ensure_context (backend, new_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 = new_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);
}
gfloat
_clutter_backend_get_units_per_em (ClutterBackend *backend,
PangoFontDescription *font_desc)
{
ClutterBackendPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
priv = backend->priv;
/* recompute for the font description, but do not cache the result */
if (font_desc != NULL)
return get_units_per_em (backend, font_desc);
if (priv->units_per_em < 0)
priv->units_per_em = get_units_per_em (backend, NULL);
return priv->units_per_em;
}
/**
* clutter_get_default_backend:
*
* 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);
g_signal_emit (backend, backend_signals[FONT_CHANGED], 0);
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;
/* if we have never been called then we need to set the
* default font and update everything that relies on the
* ::font-changed signal
*/
priv->font_name = g_strdup (DEFAULT_FONT_NAME);
g_signal_emit (backend, backend_signals[FONT_CHANGED], 0);
return priv->font_name;
}
gint32
_clutter_backend_get_units_serial (ClutterBackend *backend)
{
g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), 0);
return backend->priv->units_serial;
}