mutter/clutter/clutter-settings.c

/**
 * SECTION:clutter-settings
 * @Title: ClutterSettings
 * @Short_Description: Settings configuration
 *
 * Clutter depends on some settings to perform operations like detecting
 * multiple button press events, or font options to render text.
 *
 * Usually, Clutter will strive to use the platform's settings in order
 * to be as much integrated as possible. It is, however, possible to
 * change these settings on a per-application basis, by using the
 * #ClutterSettings singleton object and setting its properties. It is
 * also possible, for toolkit developers, to retrieve the settings from
 * the #ClutterSettings properties when implementing new UI elements,
 * for instance the default font name.
 *
 * #ClutterSettings is available since Clutter 1.4
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "clutter-settings.h"

#include "clutter-debug.h"
#include "clutter-private.h"

#define DEFAULT_FONT_NAME       "Sans 12"

#define CLUTTER_SETTINGS_CLASS(klass)           (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_SETTINGS, ClutterSettingsClass))
#define CLUTTER_IS_SETTINGS_CLASS(klass)        (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_SETTINGS))
#define CLUTTER_SETTINGS_GET_CLASS(obj)         (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_SETTINGS, ClutterSettingsClass))

/**
 * ClutterSettings:
 *
 * <structname>ClutterSettings</structname> is an opaque structure whose
 * members cannot be directly accessed.
 *
 * Since: 1.4
 */
struct _ClutterSettings
{
  GObject parent_instance;

  ClutterBackend *backend;

  gint double_click_time;
  gint double_click_distance;

  gint dnd_drag_threshold;

  gdouble resolution;

  gchar *font_name;

  gint xft_hinting;
  gint xft_antialias;
  gchar *xft_hint_style;
  gchar *xft_rgba;
};

struct _ClutterSettingsClass
{
  GObjectClass parent_class;
};

enum
{
  PROP_0,

  PROP_BACKEND,

  PROP_DOUBLE_CLICK_TIME,
  PROP_DOUBLE_CLICK_DISTANCE,

  PROP_DND_DRAG_THRESHOLD,

  PROP_FONT_NAME,

  PROP_FONT_ANTIALIAS,
  PROP_FONT_DPI,
  PROP_FONT_HINTING,
  PROP_FONT_HINT_STYLE,
  PROP_FONT_RGBA,

  PROP_LAST
};

static GParamSpec *obj_props[PROP_LAST];

G_DEFINE_TYPE (ClutterSettings, clutter_settings, G_TYPE_OBJECT);

static inline void
settings_update_font_options (ClutterSettings *self)
{
  cairo_hint_style_t hint_style = CAIRO_HINT_STYLE_NONE;
  cairo_antialias_t antialias_mode = CAIRO_ANTIALIAS_GRAY;
  cairo_subpixel_order_t subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT;
  cairo_font_options_t *options;

  options = cairo_font_options_create ();

  cairo_font_options_set_hint_metrics (options, CAIRO_HINT_METRICS_ON);

  if (self->xft_hinting >= 0 &&
      self->xft_hint_style == NULL)
    {
      hint_style = CAIRO_HINT_STYLE_NONE;
    }
  else if (self->xft_hint_style != NULL)
    {
      if (strcmp (self->xft_hint_style, "hintnone") == 0)
        hint_style = CAIRO_HINT_STYLE_NONE;
      else if (strcmp (self->xft_hint_style, "hintslight") == 0)
        hint_style = CAIRO_HINT_STYLE_SLIGHT;
      else if (strcmp (self->xft_hint_style, "hintmedium") == 0)
        hint_style = CAIRO_HINT_STYLE_MEDIUM;
      else if (strcmp (self->xft_hint_style, "hintfull") == 0)
        hint_style = CAIRO_HINT_STYLE_FULL;
    }

  cairo_font_options_set_hint_style (options, hint_style);

  if (self->xft_rgba)
    {
      if (strcmp (self->xft_rgba, "rgb") == 0)
        subpixel_order = CAIRO_SUBPIXEL_ORDER_RGB;
      else if (strcmp (self->xft_rgba, "bgr") == 0)
        subpixel_order = CAIRO_SUBPIXEL_ORDER_BGR;
      else if (strcmp (self->xft_rgba, "vrgb") == 0)
        subpixel_order = CAIRO_SUBPIXEL_ORDER_VRGB;
      else if (strcmp (self->xft_rgba, "vbgr") == 0)
        subpixel_order = CAIRO_SUBPIXEL_ORDER_VBGR;
    }

  cairo_font_options_set_subpixel_order (options, subpixel_order);

  if (self->xft_antialias >= 0 && !self->xft_antialias)
    antialias_mode = CAIRO_ANTIALIAS_NONE;
  else if (subpixel_order != CAIRO_SUBPIXEL_ORDER_DEFAULT)
    antialias_mode = CAIRO_ANTIALIAS_SUBPIXEL;
  else if (self->xft_antialias >= 0)
    antialias_mode = CAIRO_ANTIALIAS_GRAY;

  cairo_font_options_set_antialias (options, antialias_mode);

  CLUTTER_NOTE (BACKEND, "New font options:\n"
                " - font-name:  %s\n"
                " - antialias:  %d\n"
                " - hinting:    %d\n"
                " - hint-style: %s\n"
                " - rgba:       %s\n"
                " - dpi:        %.2f",
                self->font_name != NULL ? self->font_name : DEFAULT_FONT_NAME,
                self->xft_antialias,
                self->xft_hinting,
                self->xft_hint_style != NULL ? self->xft_hint_style : "<null>",
                self->xft_rgba != NULL ? self->xft_rgba : "<null>",
                self->resolution);

  clutter_backend_set_font_options (self->backend, options);
  cairo_font_options_destroy (options);
}

static void
settings_update_font_name (ClutterSettings *self)
{
  CLUTTER_NOTE (BACKEND, "New font-name: %s", self->font_name);

  g_signal_emit_by_name (self->backend, "font-changed");
}

static void
settings_update_resolution (ClutterSettings *self)
{
  CLUTTER_NOTE (BACKEND, "New resolution: %.2f", self->resolution);

  g_signal_emit_by_name (self->backend, "resolution-changed");
}

static void
clutter_settings_finalize (GObject *gobject)
{
  ClutterSettings *self = CLUTTER_SETTINGS (gobject);

  g_free (self->font_name);
  g_free (self->xft_hint_style);
  g_free (self->xft_rgba);

  G_OBJECT_CLASS (clutter_settings_parent_class)->finalize (gobject);
}

static void
clutter_settings_set_property (GObject      *gobject,
                               guint         prop_id,
                               const GValue *value,
                               GParamSpec   *pspec)
{
  ClutterSettings *self = CLUTTER_SETTINGS (gobject);

  switch (prop_id)
    {
    case PROP_BACKEND:
      self->backend = g_value_get_object (value);
      break;

    case PROP_DOUBLE_CLICK_TIME:
      self->double_click_time = g_value_get_int (value);
      break;

    case PROP_DOUBLE_CLICK_DISTANCE:
      self->double_click_distance = g_value_get_int (value);
      break;

    case PROP_DND_DRAG_THRESHOLD:
      self->dnd_drag_threshold = g_value_get_int (value);
      break;

    case PROP_FONT_NAME:
      g_free (self->font_name);
      self->font_name = g_value_dup_string (value);
      settings_update_font_name (self);
      break;

    case PROP_FONT_ANTIALIAS:
      self->xft_antialias = g_value_get_int (value);
      settings_update_font_options (self);
      break;

    case PROP_FONT_DPI:
      self->resolution = (gdouble) g_value_get_int (value) / 1024.0;
      settings_update_resolution (self);
      break;

    case PROP_FONT_HINTING:
      self->xft_hinting = g_value_get_int (value);
      settings_update_font_options (self);
      break;

    case PROP_FONT_HINT_STYLE:
      g_free (self->xft_hint_style);
      self->xft_hint_style = g_value_dup_string (value);
      settings_update_font_options (self);
      break;

    case PROP_FONT_RGBA:
      g_free (self->xft_rgba);
      self->xft_rgba = g_value_dup_string (value);
      settings_update_font_options (self);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
      break;
    }
}

static void
clutter_settings_get_property (GObject    *gobject,
                               guint       prop_id,
                               GValue     *value,
                               GParamSpec *pspec)
{
  ClutterSettings *self = CLUTTER_SETTINGS (gobject);

  switch (prop_id)
    {
    case PROP_DOUBLE_CLICK_TIME:
      g_value_set_int (value, self->double_click_time);
      break;

    case PROP_DOUBLE_CLICK_DISTANCE:
      g_value_set_int (value, self->double_click_distance);
      break;

    case PROP_DND_DRAG_THRESHOLD:
      g_value_set_int (value, self->dnd_drag_threshold);
      break;

    case PROP_FONT_NAME:
      g_value_set_string (value, self->font_name);
      break;

    case PROP_FONT_ANTIALIAS:
      g_value_set_int (value, self->xft_antialias);
      break;

    case PROP_FONT_DPI:
      g_value_set_int (value, self->resolution * 1024);
      break;

    case PROP_FONT_HINTING:
      g_value_set_int (value, self->xft_hinting);
      break;

    case PROP_FONT_HINT_STYLE:
      g_value_set_string (value, self->xft_hint_style);
      break;

    case PROP_FONT_RGBA:
      g_value_set_string (value, self->xft_rgba);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
      break;
    }
}

static void
clutter_settings_notify (GObject    *gobject,
                         GParamSpec *pspec)
{
  ClutterSettings *self = CLUTTER_SETTINGS (gobject);

  g_signal_emit_by_name (self->backend, "settings-changed");
}

static void
clutter_settings_class_init (ClutterSettingsClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  /**
   * ClutterSettings:backend:
   *
   * A back pointer to the #ClutterBackend
   *
   * Since: 1.4
   */
  obj_props[PROP_BACKEND] =
    g_param_spec_object ("backend",
                         "Backend",
                         "A pointer to the backend",
                         CLUTTER_TYPE_BACKEND,
                         CLUTTER_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY);

  /**
   * ClutterSettings:double-click-time:
   *
   * The time, in milliseconds, that should elapse between button-press
   * events in order to increase the click count by 1.
   *
   * Since: 1.4
   */
  obj_props[PROP_DOUBLE_CLICK_TIME] =
    g_param_spec_int ("double-click-time",
                      P_("Double Click Time"),
                      P_("The time between clicks necessary to detect a multiple click"),
                      0, G_MAXINT,
                      250,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:double-click-distance:
   *
   * The maximum distance, in pixels, between button-press events that
   * determines whether or not to increase the click count by 1.
   *
   * Since: 1.4
   */
  obj_props[PROP_DOUBLE_CLICK_DISTANCE] =
    g_param_spec_int ("double-click-distance",
                      P_("Double Click Distance"),
                      P_("The distance between clicks necessary to detect a multiple click"),
                      0, G_MAXINT,
                      5,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:dnd-drag-threshold:
   *
   * The default distance that the cursor of a pointer device
   * should travel before a drag operation should start.
   *
   * Since: 1.8
   */
  obj_props[PROP_DND_DRAG_THRESHOLD] =
    g_param_spec_int ("dnd-drag-threshold",
                      P_("Drag Threshold"),
                      P_("The distance the cursor should travel before starting to drag"),
                      1, G_MAXINT,
                      8,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-name:
   *
   * The default font name that should be used by text actors, as
   * a string that can be passed to pango_font_description_from_string().
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_NAME] =
    g_param_spec_string ("font-name",
                         P_("Font Name"),
                         P_("The description of the default font, as one that could be parsed by Pango"),
                         NULL,
                         CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-antialias:
   *
   * Whether or not to use antialiasing when rendering text; a value
   * of 1 enables it unconditionally; a value of 0 disables it
   * unconditionally; and -1 will use the system's default.
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_ANTIALIAS] =
    g_param_spec_int ("font-antialias",
                      P_("Font Antialias"),
                      P_("Whether to use antialiasing (1 to enable, 0 to disable, and -1 to use the default)"),
                      -1, 1,
                      -1,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-dpi:
   *
   * The DPI used when rendering text, as a value of 1024 * dots/inch.
   *
   * If set to -1, the system's default will be used instead
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_DPI] =
    g_param_spec_int ("font-dpi",
                      P_("Font DPI"),
                      P_("The resolution of the font, in 1024 * dots/inch, or -1 to use the default"),
                      -1, 1024 * 1024,
                      -1,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-hinting:
   *
   * Whether or not to use hinting when rendering text; a value of 1
   * unconditionally enables it; a value of 0 unconditionally disables
   * it; and a value of -1 will use the system's default.
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_HINTING] =
    g_param_spec_int ("font-hinting",
                      P_("Font Hinting"),
                      P_("Whether to use hinting (1 to enable, 0 to disable and -1 to use the default)"),
                      -1, 1,
                      -1,
                      CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-hint-style:
   *
   * The style of the hinting used when rendering text. Valid values
   * are:
   * <itemizedlist>
   *   <listitem><simpara>hintnone</simpara></listitem>
   *   <listitem><simpara>hintslight</simpara></listitem>
   *   <listitem><simpara>hintmedium</simpara></listitem>
   *   <listitem><simpara>hintfull</simpara></listitem>
   * </itemizedlist>
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_HINT_STYLE] =
    g_param_spec_string ("font-hint-style",
                         P_("Font Hint Style"),
                         P_("The style of hinting (hintnone, hintslight, hintmedium, hintfull)"),
                         NULL,
                         CLUTTER_PARAM_READWRITE);

  /**
   * ClutterSettings:font-subpixel-order:
   *
   * The type of sub-pixel antialiasing used when rendering text. Valid
   * values are:
   * <itemizedlist>
   *   <listitem><simpara>none</simpara></listitem>
   *   <listitem><simpara>rgb</simpara></listitem>
   *   <listitem><simpara>bgr</simpara></listitem>
   *   <listitem><simpara>vrgb</simpara></listitem>
   *   <listitem><simpara>vbgr</simpara></listitem>
   * </itemizedlist>
   *
   * Since: 1.4
   */
  obj_props[PROP_FONT_RGBA] =
    g_param_spec_string ("font-subpixel-order",
                         P_("Font Subpixel Order"),
                         P_("The type of subpixel antialiasing (none, rgb, bgr, vrgb, vbgr)"),
                         NULL,
                         CLUTTER_PARAM_READWRITE);

  gobject_class->set_property = clutter_settings_set_property;
  gobject_class->get_property = clutter_settings_get_property;
  gobject_class->notify = clutter_settings_notify;
  gobject_class->finalize = clutter_settings_finalize;
  g_object_class_install_properties (gobject_class, PROP_LAST, obj_props);
}

static void
clutter_settings_init (ClutterSettings *self)
{
  self->resolution = -1.0;

  self->double_click_time = 250;
  self->double_click_distance = 5;

  self->dnd_drag_threshold = 8;

  self->font_name = g_strdup (DEFAULT_FONT_NAME);

  self->xft_antialias = -1;
  self->xft_hinting = -1;
  self->xft_hint_style = NULL;
  self->xft_rgba = NULL;
}

/**
 * clutter_settings_get_default:
 *
 * Retrieves the singleton instance of #ClutterSettings
 *
 * Return value: (transfer none): the instance of #ClutterSettings. The
 *   returned object is owned by Clutter and it should not be unreferenced
 *   directly
 *
 * Since: 1.4
 */
ClutterSettings *
clutter_settings_get_default (void)
{
  ClutterMainContext *context = _clutter_context_get_default ();

  if (G_LIKELY (context->settings != NULL))
    return context->settings;

  context->settings = g_object_new (CLUTTER_TYPE_SETTINGS,
                                    "backend", context->backend,
                                    NULL);

  return context->settings;
}