gnome-control-center/capplets/appearance/appearance-font.c

/*
 * Copyright (C) 2007 The GNOME Foundation
 * Written by Jonathan Blandford <jrb@gnome.org>
 *            Jens Granseuer <jensgr@gmx.net>
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "appearance.h"

#include <string.h>
#include <stdarg.h>
#include <math.h>

#ifdef HAVE_XFT2
#include <gdk/gdkx.h>
#include <X11/Xft/Xft.h>
#endif /* HAVE_XFT2 */

#include "capplet-util.h"
#include "gconf-property-editor.h"

#define GTK_FONT_KEY           "/desktop/gnome/interface/font_name"
#define DESKTOP_FONT_KEY       "/apps/nautilus/preferences/desktop_font"

#define METACITY_DIR "/apps/metacity/general"
#define WINDOW_TITLE_FONT_KEY METACITY_DIR "/titlebar_font"
#define WINDOW_TITLE_USES_SYSTEM_KEY METACITY_DIR "/titlebar_uses_system_font"
#define MONOSPACE_FONT_KEY "/desktop/gnome/interface/monospace_font_name"
#define DOCUMENT_FONT_KEY "/desktop/gnome/interface/document_font_name"

#ifdef HAVE_XFT2
#define FONT_RENDER_DIR "/desktop/gnome/font_rendering"
#define FONT_ANTIALIASING_KEY FONT_RENDER_DIR "/antialiasing"
#define FONT_HINTING_KEY      FONT_RENDER_DIR "/hinting"
#define FONT_RGBA_ORDER_KEY   FONT_RENDER_DIR "/rgba_order"
#define FONT_DPI_KEY          FONT_RENDER_DIR "/dpi"

/* X servers sometimes lie about the screen's physical dimensions, so we cannot
 * compute an accurate DPI value.  When this happens, the user gets fonts that
 * are too huge or too tiny.  So, we see what the server returns:  if it reports
 * something outside of the range [DPI_LOW_REASONABLE_VALUE,
 * DPI_HIGH_REASONABLE_VALUE], then we assume that it is lying and we use
 * DPI_FALLBACK instead.
 *
 * See get_dpi_from_gconf_or_server() below, and also
 * https://bugzilla.novell.com/show_bug.cgi?id=217790
 */
#define DPI_FALLBACK 96
#define DPI_LOW_REASONABLE_VALUE 50
#define DPI_HIGH_REASONABLE_VALUE 500
#endif /* HAVE_XFT2 */

static gboolean in_change = FALSE;
static gchar *old_font = NULL;

#define MAX_FONT_POINT_WITHOUT_WARNING 32
#define MAX_FONT_SIZE_WITHOUT_WARNING MAX_FONT_POINT_WITHOUT_WARNING*1024

#ifdef HAVE_XFT2

/*
 * Code for displaying previews of font rendering with various Xft options
 */

static void
sample_size_request (GtkWidget      *darea,
		     GtkRequisition *requisition)
{
  GdkPixbuf *pixbuf = g_object_get_data (G_OBJECT (darea), "sample-pixbuf");

  requisition->width = gdk_pixbuf_get_width (pixbuf) + 2;
  requisition->height = gdk_pixbuf_get_height (pixbuf) + 2;
}

static void
sample_expose (GtkWidget      *darea,
	       GdkEventExpose *expose)
{
  GdkPixbuf *pixbuf = g_object_get_data (G_OBJECT (darea), "sample-pixbuf");
  int width = gdk_pixbuf_get_width (pixbuf);
  int height = gdk_pixbuf_get_height (pixbuf);

  int x = (darea->allocation.width - width) / 2;
  int y = (darea->allocation.height - height) / 2;

  gdk_draw_rectangle (darea->window, darea->style->white_gc, TRUE,
		      0, 0,
		      darea->allocation.width, darea->allocation.height);
  gdk_draw_rectangle (darea->window, darea->style->black_gc, FALSE,
		      0, 0,
		      darea->allocation.width - 1, darea->allocation.height - 1);

  gdk_pixbuf_render_to_drawable (pixbuf, darea->window, NULL,
				 0, 0, x, y, width, height,
				 GDK_RGB_DITHER_NORMAL, 0, 0);
}

typedef enum {
  ANTIALIAS_NONE,
  ANTIALIAS_GRAYSCALE,
  ANTIALIAS_RGBA
} Antialiasing;

static GConfEnumStringPair antialias_enums[] = {
  { ANTIALIAS_NONE,      "none" },
  { ANTIALIAS_GRAYSCALE, "grayscale" },
  { ANTIALIAS_RGBA,      "rgba" },
  { -1,                  NULL }
};

typedef enum {
  HINT_NONE,
  HINT_SLIGHT,
  HINT_MEDIUM,
  HINT_FULL
} Hinting;

static GConfEnumStringPair hint_enums[] = {
  { HINT_NONE,   "none" },
  { HINT_SLIGHT, "slight" },
  { HINT_MEDIUM, "medium" },
  { HINT_FULL,   "full" },
  { -1,          NULL }
};

typedef enum {
  RGBA_RGB,
  RGBA_BGR,
  RGBA_VRGB,
  RGBA_VBGR
} RgbaOrder;

static GConfEnumStringPair rgba_order_enums[] = {
  { RGBA_RGB,  "rgb" },
  { RGBA_BGR,  "bgr" },
  { RGBA_VRGB, "vrgb" },
  { RGBA_VBGR, "vbgr" },
  { -1,         NULL }
};

static XftFont *
open_pattern (FcPattern   *pattern,
	      Antialiasing antialiasing,
	      Hinting      hinting)
{
#ifdef FC_HINT_STYLE
  static const int hintstyles[] = {
     FC_HINT_NONE, FC_HINT_SLIGHT, FC_HINT_MEDIUM, FC_HINT_FULL
  };
#endif /* FC_HINT_STYLE */

  FcPattern *res_pattern;
  FcResult result;
  XftFont *font;

  Display *xdisplay = gdk_x11_get_default_xdisplay ();
  int screen = gdk_x11_get_default_screen ();

  res_pattern = XftFontMatch (xdisplay, screen, pattern, &result);
  if (res_pattern == NULL)
    return NULL;

  FcPatternDel (res_pattern, FC_HINTING);
  FcPatternAddBool (res_pattern, FC_HINTING, hinting != HINT_NONE);

#ifdef FC_HINT_STYLE
  FcPatternDel (res_pattern, FC_HINT_STYLE);
  FcPatternAddInteger (res_pattern, FC_HINT_STYLE, hintstyles[hinting]);
#endif /* FC_HINT_STYLE */

  FcPatternDel (res_pattern, FC_ANTIALIAS);
  FcPatternAddBool (res_pattern, FC_ANTIALIAS, antialiasing != ANTIALIAS_NONE);

  FcPatternDel (res_pattern, FC_RGBA);
  FcPatternAddInteger (res_pattern, FC_RGBA,
		       antialiasing == ANTIALIAS_RGBA ? FC_RGBA_RGB : FC_RGBA_NONE);

  FcPatternDel (res_pattern, FC_DPI);
  FcPatternAddInteger (res_pattern, FC_DPI, 96);

  font = XftFontOpenPattern (xdisplay, res_pattern);
  if (!font)
    FcPatternDestroy (res_pattern);

  return font;
}

static void
setup_font_sample (GtkWidget   *darea,
		   Antialiasing antialiasing,
		   Hinting      hinting)
{
  const char *string1 = "abcfgop AO ";
  const char *string2 = "abcfgop";

  XftColor black, white;
  XRenderColor rendcolor;

  Display *xdisplay = gdk_x11_get_default_xdisplay ();

  GdkColormap *colormap = gdk_rgb_get_colormap ();
  Colormap xcolormap = GDK_COLORMAP_XCOLORMAP (colormap);

  GdkVisual *visual = gdk_colormap_get_visual (colormap);
  Visual *xvisual = GDK_VISUAL_XVISUAL (visual);

  FcPattern *pattern;
  XftFont *font1, *font2;
  XGlyphInfo extents1 = { 0 };
  XGlyphInfo extents2 = { 0 };
  GdkPixmap *pixmap;
  XftDraw *draw;
  GdkPixbuf *tmp_pixbuf, *pixbuf;

  int width, height;
  int ascent, descent;

  pattern = FcPatternBuild (NULL,
			    FC_FAMILY, FcTypeString, "Serif",
			    FC_SLANT, FcTypeInteger, FC_SLANT_ROMAN,
			    FC_SIZE, FcTypeDouble, 18.,
			    NULL);
  font1 = open_pattern (pattern, antialiasing, hinting);
  FcPatternDestroy (pattern);

  pattern = FcPatternBuild (NULL,
			    FC_FAMILY, FcTypeString, "Serif",
			    FC_SLANT, FcTypeInteger, FC_SLANT_ITALIC,
			    FC_SIZE, FcTypeDouble, 20.,
			    NULL);
  font2 = open_pattern (pattern, antialiasing, hinting);
  FcPatternDestroy (pattern);

  ascent = 0;
  descent = 0;
  if (font1) {
    XftTextExtentsUtf8 (xdisplay, font1, (unsigned char *) string1,
			strlen (string1), &extents1);
    ascent = MAX (ascent, font1->ascent);
    descent = MAX (descent, font1->descent);
  }

  if (font2) {
    XftTextExtentsUtf8 (xdisplay, font2, (unsigned char *) string2,
			strlen (string2), &extents2);
    ascent = MAX (ascent, font2->ascent);
    descent = MAX (descent, font2->descent);
  }

  width = extents1.xOff + extents2.xOff + 4;
  height = ascent + descent + 2;

  pixmap = gdk_pixmap_new (NULL, width, height, visual->depth);

  draw = XftDrawCreate (xdisplay, GDK_DRAWABLE_XID (pixmap), xvisual, xcolormap);

  rendcolor.red = 0;
  rendcolor.green = 0;
  rendcolor.blue = 0;
  rendcolor.alpha = 0xffff;
  XftColorAllocValue (xdisplay, xvisual, xcolormap, &rendcolor, &black);

  rendcolor.red = 0xffff;
  rendcolor.green = 0xffff;
  rendcolor.blue = 0xffff;
  rendcolor.alpha = 0xffff;
  XftColorAllocValue (xdisplay, xvisual, xcolormap, &rendcolor, &white);
  XftDrawRect (draw, &white, 0, 0, width, height);
  if (font1)
    XftDrawStringUtf8 (draw, &black, font1,
		       2, 2 + ascent,
		       (unsigned char *) string1, strlen (string1));
  if (font2)
    XftDrawStringUtf8 (draw, &black, font2,
		       2 + extents1.xOff, 2 + ascent,
		       (unsigned char *) string2, strlen (string2));

  XftDrawDestroy (draw);

  if (font1)
    XftFontClose (xdisplay, font1);
  if (font2)
    XftFontClose (xdisplay, font2);

  tmp_pixbuf = gdk_pixbuf_get_from_drawable (NULL, pixmap, colormap, 0, 0, 0, 0, width, height);
  pixbuf = gdk_pixbuf_scale_simple (tmp_pixbuf, 1 * width, 1 * height, GDK_INTERP_TILES);

  g_object_unref (pixmap);
  g_object_unref (tmp_pixbuf);

  g_object_set_data_full (G_OBJECT (darea), "sample-pixbuf",
			  pixbuf, (GDestroyNotify) g_object_unref);

  g_signal_connect (darea, "size_request", G_CALLBACK (sample_size_request), NULL);
  g_signal_connect (darea, "expose_event", G_CALLBACK (sample_expose), NULL);
}

/*
 * Code implementing a group of radio buttons with different Xft option combinations.
 * If one of the buttons is matched by the GConf key, we pick it. Otherwise we
 * show the group as inconsistent.
 */
static void
font_render_get_gconf (GConfClient  *client,
		       Antialiasing *antialiasing,
		       Hinting      *hinting)
{
  gchar *antialias_str = gconf_client_get_string (client, FONT_ANTIALIASING_KEY, NULL);
  gchar *hint_str = gconf_client_get_string (client, FONT_HINTING_KEY, NULL);
  gint val;

  val = ANTIALIAS_GRAYSCALE;
  if (antialias_str) {
    gconf_string_to_enum (antialias_enums, antialias_str, &val);
    g_free (antialias_str);
  }
  *antialiasing = val;

  val = HINT_FULL;
  if (hint_str) {
    gconf_string_to_enum (hint_enums, hint_str, &val);
    g_free (hint_str);
  }
  *hinting = val;
}

typedef struct {
  Antialiasing antialiasing;
  Hinting hinting;
  GtkToggleButton *radio;
} FontPair;

static GSList *font_pairs = NULL;

static void
font_render_load (GConfClient *client)
{
  Antialiasing antialiasing;
  Hinting hinting;
  gboolean inconsistent = TRUE;
  GSList *tmp_list;

  font_render_get_gconf (client, &antialiasing, &hinting);

  in_change = TRUE;

  for (tmp_list = font_pairs; tmp_list; tmp_list = tmp_list->next) {
    FontPair *pair = tmp_list->data;

    if (antialiasing == pair->antialiasing && hinting == pair->hinting) {
      gtk_toggle_button_set_active (pair->radio, TRUE);
      inconsistent = FALSE;
      break;
    }
  }

  for (tmp_list = font_pairs; tmp_list; tmp_list = tmp_list->next) {
    FontPair *pair = tmp_list->data;

    gtk_toggle_button_set_inconsistent (pair->radio, inconsistent);
  }

  in_change = FALSE;
}

static void
font_render_changed (GConfClient *client,
                     guint        cnxn_id,
                     GConfEntry  *entry,
                     gpointer     user_data)
{
  font_render_load (client);
}

static void
font_radio_toggled (GtkToggleButton *toggle_button,
		    FontPair        *pair)
{
  GConfClient *client = gconf_client_get_default ();

  if (!in_change) {
    gconf_client_set_string (client, FONT_ANTIALIASING_KEY,
			     gconf_enum_to_string (antialias_enums, pair->antialiasing),
			     NULL);
    gconf_client_set_string (client, FONT_HINTING_KEY,
			     gconf_enum_to_string (hint_enums, pair->hinting),
			     NULL);
  }

  /* Restore back to the previous state until we get notification */
  font_render_load (client);
  g_object_unref (client);
}

static void
setup_font_pair (GtkWidget    *radio,
		 GtkWidget    *darea,
		 Antialiasing  antialiasing,
		 Hinting       hinting)
{
  FontPair *pair = g_new (FontPair, 1);

  pair->antialiasing = antialiasing;
  pair->hinting = hinting;
  pair->radio = GTK_TOGGLE_BUTTON (radio);

  setup_font_sample (darea, antialiasing, hinting);
  font_pairs = g_slist_prepend (font_pairs, pair);

  g_signal_connect (radio, "toggled",
		    G_CALLBACK (font_radio_toggled), pair);
}
#endif /* HAVE_XFT2 */

static void
metacity_titlebar_load_sensitivity (AppearanceData *data)
{
  gtk_widget_set_sensitive (glade_xml_get_widget (data->xml, "window_title_font"),
			    !gconf_client_get_bool (data->client,
						    WINDOW_TITLE_USES_SYSTEM_KEY,
						    NULL));
}

static void
metacity_changed (GConfClient *client,
		  guint        cnxn_id,
		  GConfEntry  *entry,
		  gpointer     user_data)
{
  metacity_titlebar_load_sensitivity (user_data);
}

/* returns 0 if the font is safe, otherwise returns the size in points. */
static gint
font_dangerous (const char *font)
{
  PangoFontDescription *pfd;
  gboolean retval = 0;

  pfd = pango_font_description_from_string (font);
  if (pfd == NULL)
    /* an invalid font was passed in.  This isn't our problem. */
    return 0;

  if ((pango_font_description_get_set_fields (pfd) & PANGO_FONT_MASK_SIZE) &&
      (pango_font_description_get_size (pfd) >= MAX_FONT_SIZE_WITHOUT_WARNING)) {
    retval = pango_font_description_get_size (pfd)/1024;
  }
  pango_font_description_free (pfd);

  return retval;
}

static GConfValue *
application_font_to_gconf (GConfPropertyEditor *peditor,
			   GConfValue          *value)
{
  GConfValue *new_value;
  const char *new_font;
  GtkWidget *font_button;
  gint danger_level;

  font_button = GTK_WIDGET (gconf_property_editor_get_ui_control (peditor));
  g_return_val_if_fail (font_button != NULL, NULL);

  new_value = gconf_value_new (GCONF_VALUE_STRING);
  new_font = gconf_value_get_string (value);
  if (font_dangerous (old_font)) {
    /* If we're already too large, we don't warn again. */
    gconf_value_set_string (new_value, new_font);
    return new_value;
  }

  danger_level = font_dangerous (new_font);
  if (danger_level) {
    GtkWidget *warning_dialog, *apply_button;
    const gchar *warning_label;
    gchar *warning_label2;

    warning_label = _("Font may be too large");

    if (danger_level > MAX_FONT_POINT_WITHOUT_WARNING) {
      warning_label2 = g_strdup_printf (ngettext (
			"The font selected is %d point large, "
			"and may make it difficult to effectively "
			"use the computer.  It is recommended that "
			"you select a size smaller than %d.",
			"The font selected is %d points large, "
			"and may make it difficult to effectively "
			"use the computer. It is recommended that "
			"you select a size smaller than %d.",
			danger_level),
			danger_level,
			MAX_FONT_POINT_WITHOUT_WARNING);
    } else {
      warning_label2 = g_strdup_printf (ngettext (
			"The font selected is %d point large, "
			"and may make it difficult to effectively "
			"use the computer.  It is recommended that "
			"you select a smaller sized font.",
			"The font selected is %d points large, "
			"and may make it difficult to effectively "
			"use the computer. It is recommended that "
			"you select a smaller sized font.",
			danger_level),
			danger_level);
    }

    warning_dialog = gtk_message_dialog_new (NULL,
					     GTK_DIALOG_MODAL,
					     GTK_MESSAGE_WARNING,
					     GTK_BUTTONS_NONE,
					     warning_label);

    gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (warning_dialog),
					      warning_label2);

    gtk_dialog_add_button (GTK_DIALOG (warning_dialog),
			   _("Use previous font"), GTK_RESPONSE_CLOSE);

    apply_button = gtk_button_new_with_label (_("Use selected font"));

    gtk_button_set_image (GTK_BUTTON (apply_button), gtk_image_new_from_stock (GTK_STOCK_APPLY, GTK_ICON_SIZE_BUTTON));
    gtk_dialog_add_action_widget (GTK_DIALOG (warning_dialog), apply_button, GTK_RESPONSE_APPLY);
    GTK_WIDGET_SET_FLAGS (apply_button, GTK_CAN_DEFAULT);
    gtk_widget_show (apply_button);

    gtk_dialog_set_default_response (GTK_DIALOG (warning_dialog), GTK_RESPONSE_CLOSE);

    g_free (warning_label2);

    if (gtk_dialog_run (GTK_DIALOG (warning_dialog)) == GTK_RESPONSE_APPLY) {
      gconf_value_set_string (new_value, new_font);
    } else {
      gconf_value_set_string (new_value, old_font);
      gtk_font_button_set_font_name (GTK_FONT_BUTTON (font_button), old_font);
    }

    gtk_widget_destroy (warning_dialog);
  } else {
    gconf_value_set_string (new_value, new_font);
  }

  return new_value;
}

static void
application_font_changed (GtkWidget *font_button)
{
  const gchar *font;

  font = gtk_font_button_get_font_name (GTK_FONT_BUTTON (font_button));
  g_free (old_font);
  old_font = g_strdup (font);
}

#ifdef HAVE_XFT2
/*
 * EnumGroup - a group of radio buttons tied to a string enumeration
 *             value. We add this here because the gconf peditor
 *             equivalent of this is both painful to use (you have
 *             to supply functions to convert from enums to indices)
 *             and conceptually broken (the order of radio buttons
 *             in a group when using Glade is not predictable.
 */
typedef struct
{
  GConfClient *client;
  GSList *items;
  gchar *gconf_key;
  GConfEnumStringPair *enums;
  int default_value;
} EnumGroup;

typedef struct
{
  EnumGroup *group;
  GtkToggleButton *widget;
  int value;
} EnumItem;

static void
enum_group_load (EnumGroup *group)
{
  gchar *str = gconf_client_get_string (group->client, group->gconf_key, NULL);
  gint val = group->default_value;
  GSList *tmp_list;

  if (str)
    gconf_string_to_enum (group->enums, str, &val);

  g_free (str);

  in_change = TRUE;

  for (tmp_list = group->items; tmp_list; tmp_list = tmp_list->next) {
    EnumItem *item = tmp_list->data;

    if (val == item->value)
      gtk_toggle_button_set_active (item->widget, TRUE);
  }

  in_change = FALSE;
}

static void
enum_group_changed (GConfClient *client,
		    guint        cnxn_id,
		    GConfEntry  *entry,
		    gpointer     user_data)
{
  enum_group_load (user_data);
}

static void
enum_item_toggled (GtkToggleButton *toggle_button,
		   EnumItem        *item)
{
  EnumGroup *group = item->group;

  if (!in_change) {
    gconf_client_set_string (group->client, group->gconf_key,
			     gconf_enum_to_string (group->enums, item->value),
			     NULL);
  }

  /* Restore back to the previous state until we get notification */
  enum_group_load (group);
}

static EnumGroup *
enum_group_create (const gchar         *gconf_key,
		   GConfEnumStringPair *enums,
		   int                  default_value,
		   GtkWidget           *first_widget,
		   ...)
{
  EnumGroup *group;
  GtkWidget *widget;
  va_list args;

  group = g_new (EnumGroup, 1);

  group->client = gconf_client_get_default ();
  group->gconf_key = g_strdup (gconf_key);
  group->enums = enums;
  group->default_value = default_value;
  group->items = NULL;

  va_start (args, first_widget);

  widget = first_widget;
  while (widget) {
    EnumItem *item;

    item = g_new (EnumItem, 1);
    item->group = group;
    item->widget = GTK_TOGGLE_BUTTON (widget);
    item->value = va_arg (args, int);

    g_signal_connect (item->widget, "toggled",
		      G_CALLBACK (enum_item_toggled), item);

    group->items = g_slist_prepend (group->items, item);

    widget = va_arg (args, GtkWidget *);
  }

  va_end (args);

  enum_group_load (group);

  gconf_client_notify_add (group->client, gconf_key,
			   enum_group_changed,
			   group, NULL, NULL);

  return group;
}

static void
enum_group_destroy (EnumGroup *group)
{
  g_object_unref (group->client);
  g_free (group->gconf_key);

  g_slist_foreach (group->items, (GFunc) g_free, NULL);
  g_slist_free (group->items);

  g_free (group);
}

static double
dpi_from_pixels_and_mm (int pixels, int mm)
{
  double dpi;

  if (mm >= 1)
    dpi = pixels / (mm / 25.4);
  else
    dpi = 0;

  return dpi;
}

static double
get_dpi_from_x_server (void)
{
  GdkScreen *screen;
  double dpi;

  screen = gdk_screen_get_default ();
  if (screen) {
    double width_dpi, height_dpi;

    width_dpi = dpi_from_pixels_and_mm (gdk_screen_get_width (screen),
					gdk_screen_get_width_mm (screen));
    height_dpi = dpi_from_pixels_and_mm (gdk_screen_get_height (screen),
					 gdk_screen_get_height_mm (screen));

    if (width_dpi < DPI_LOW_REASONABLE_VALUE || width_dpi > DPI_HIGH_REASONABLE_VALUE ||
        height_dpi < DPI_LOW_REASONABLE_VALUE || height_dpi > DPI_HIGH_REASONABLE_VALUE)
      dpi = DPI_FALLBACK;
    else
      dpi = (width_dpi + height_dpi) / 2.0;
  } else {
    /* Huh!?  No screen? */
    dpi = DPI_FALLBACK;
  }

  return dpi;
}

/*
 * The font rendering details dialog
 */
static void
dpi_load (GConfClient   *client,
	  GtkSpinButton *spinner)
{
  GConfValue *value;
  gdouble dpi;

  value = gconf_client_get_without_default (client, FONT_DPI_KEY, NULL);

  if (value) {
    dpi = gconf_value_get_float (value);
    gconf_value_free (value);
  } else
    dpi = get_dpi_from_x_server ();

  if (dpi < DPI_LOW_REASONABLE_VALUE)
    dpi = DPI_LOW_REASONABLE_VALUE;

  in_change = TRUE;
  gtk_spin_button_set_value (spinner, dpi);
  in_change = FALSE;
}

static void
dpi_changed (GConfClient *client,
	     guint        cnxn_id,
	     GConfEntry  *entry,
	     gpointer     user_data)
{
  dpi_load (client, user_data);
}

static void
dpi_value_changed (GtkSpinButton *spinner,
		   GConfClient   *client)
{
  /* Like any time when using a spin button with GConf, there is
   * a race condition here. When we change, we send the new
   * value to GConf, then restore to the old value until
   * we get a response to emulate the proper model/view behavior.
   *
   * If the user changes the value faster than responses are
   * received from GConf, this may cause mildly strange effects.
   */
  gdouble new_dpi = gtk_spin_button_get_value (spinner);

  gconf_client_set_float (client, FONT_DPI_KEY, new_dpi, NULL);

  dpi_load (client, spinner);
}

static void
cb_details_response (GtkDialog *dialog, gint response_id)
{
  if (response_id == GTK_RESPONSE_HELP) {
    capplet_help (GTK_WINDOW (dialog),
		  "user-guide.xml",
		  "goscustdesk-38");
  } else
    gtk_widget_hide (GTK_WIDGET (dialog));
}

static void
cb_show_details (GtkWidget *button,
		 AppearanceData *data)
{
  if (!data->font_details) {
    GtkAdjustment *adjustment;
    GtkWidget *widget;
    EnumGroup *group;

    data->font_details = glade_xml_get_widget (data->xml, "render_details");

    gtk_window_set_transient_for (GTK_WINDOW (data->font_details),
				  GTK_WINDOW (glade_xml_get_widget (data->xml, "appearance_window")));

    widget = glade_xml_get_widget (data->xml, "dpi_spinner");

    /* pick a sensible maximum dpi */
    adjustment = gtk_spin_button_get_adjustment (GTK_SPIN_BUTTON (widget));
    adjustment->upper = DPI_HIGH_REASONABLE_VALUE;

    dpi_load (data->client, GTK_SPIN_BUTTON (widget));
    g_signal_connect (widget, "value_changed",
		      G_CALLBACK (dpi_value_changed), data->client);

    gconf_client_notify_add (data->client, FONT_DPI_KEY,
			     dpi_changed, widget, NULL, NULL);

    setup_font_sample (glade_xml_get_widget (data->xml, "antialias_none_sample"),      ANTIALIAS_NONE,      HINT_FULL);
    setup_font_sample (glade_xml_get_widget (data->xml, "antialias_grayscale_sample"), ANTIALIAS_GRAYSCALE, HINT_FULL);
    setup_font_sample (glade_xml_get_widget (data->xml, "antialias_subpixel_sample"),  ANTIALIAS_RGBA,      HINT_FULL);

    group = enum_group_create (
    	FONT_ANTIALIASING_KEY, antialias_enums, ANTIALIAS_GRAYSCALE,
	glade_xml_get_widget (data->xml, "antialias_none_radio"),      ANTIALIAS_NONE,
	glade_xml_get_widget (data->xml, "antialias_grayscale_radio"), ANTIALIAS_GRAYSCALE,
	glade_xml_get_widget (data->xml, "antialias_subpixel_radio"),  ANTIALIAS_RGBA,
	NULL);
    data->font_groups = g_slist_prepend (data->font_groups, group);

    setup_font_sample (glade_xml_get_widget (data->xml, "hint_none_sample"),   ANTIALIAS_GRAYSCALE, HINT_NONE);
    setup_font_sample (glade_xml_get_widget (data->xml, "hint_slight_sample"), ANTIALIAS_GRAYSCALE, HINT_SLIGHT);
    setup_font_sample (glade_xml_get_widget (data->xml, "hint_medium_sample"), ANTIALIAS_GRAYSCALE, HINT_MEDIUM);
    setup_font_sample (glade_xml_get_widget (data->xml, "hint_full_sample"),   ANTIALIAS_GRAYSCALE, HINT_FULL);

    group = enum_group_create (
    	FONT_HINTING_KEY, hint_enums, HINT_FULL,
	glade_xml_get_widget (data->xml, "hint_none_radio"),   HINT_NONE,
	glade_xml_get_widget (data->xml, "hint_slight_radio"), HINT_SLIGHT,
	glade_xml_get_widget (data->xml, "hint_medium_radio"), HINT_MEDIUM,
	glade_xml_get_widget (data->xml, "hint_full_radio"),   HINT_FULL,
	NULL);
    data->font_groups = g_slist_prepend (data->font_groups, group);

    gtk_image_set_from_file (GTK_IMAGE (glade_xml_get_widget (data->xml, "subpixel_rgb_image")),
			     GNOMECC_PIXMAP_DIR "/subpixel-rgb.png");
    gtk_image_set_from_file (GTK_IMAGE (glade_xml_get_widget (data->xml, "subpixel_bgr_image")),
			     GNOMECC_PIXMAP_DIR "/subpixel-bgr.png");
    gtk_image_set_from_file (GTK_IMAGE (glade_xml_get_widget (data->xml, "subpixel_vrgb_image")),
			     GNOMECC_PIXMAP_DIR "/subpixel-vrgb.png");
    gtk_image_set_from_file (GTK_IMAGE (glade_xml_get_widget (data->xml, "subpixel_vbgr_image")),
			     GNOMECC_PIXMAP_DIR "/subpixel-vbgr.png");

    group = enum_group_create (
    	FONT_RGBA_ORDER_KEY, rgba_order_enums, RGBA_RGB,
	glade_xml_get_widget (data->xml, "subpixel_rgb_radio"),  RGBA_RGB,
	glade_xml_get_widget (data->xml, "subpixel_bgr_radio"),  RGBA_BGR,
	glade_xml_get_widget (data->xml, "subpixel_vrgb_radio"), RGBA_VRGB,
	glade_xml_get_widget (data->xml, "subpixel_vbgr_radio"), RGBA_VBGR,
	NULL);
    data->font_groups = g_slist_prepend (data->font_groups, group);

    g_signal_connect (G_OBJECT (data->font_details),
		      "response",
		      G_CALLBACK (cb_details_response), NULL);
    g_signal_connect (G_OBJECT (data->font_details),
		      "delete_event",
		      G_CALLBACK (gtk_true), NULL);
  }

  gtk_window_present (GTK_WINDOW (data->font_details));
}
#endif /* HAVE_XFT2 */

void
font_init (AppearanceData *data)
{
  GObject *peditor;
  GtkWidget *widget;

  data->font_details = NULL;
  data->font_groups = NULL;

  gconf_client_add_dir (data->client, "/desktop/gnome/interface",
			GCONF_CLIENT_PRELOAD_ONELEVEL, NULL);
  gconf_client_add_dir (data->client, "/apps/nautilus/preferences",
			GCONF_CLIENT_PRELOAD_ONELEVEL, NULL);
  gconf_client_add_dir (data->client, METACITY_DIR,
			GCONF_CLIENT_PRELOAD_ONELEVEL, NULL);
#ifdef HAVE_XFT2
  gconf_client_add_dir (data->client, FONT_RENDER_DIR,
			GCONF_CLIENT_PRELOAD_ONELEVEL, NULL);
#endif  /* HAVE_XFT2 */

  widget = glade_xml_get_widget (data->xml, "application_font");
  peditor = gconf_peditor_new_font (NULL, GTK_FONT_KEY,
				    widget,
				    "conv-from-widget-cb", application_font_to_gconf,
				    NULL);
  g_signal_connect_swapped (peditor, "value-changed",
			    G_CALLBACK (application_font_changed),
			    widget);
  application_font_changed (widget);

  peditor = gconf_peditor_new_font (NULL, DOCUMENT_FONT_KEY,
				    glade_xml_get_widget (data->xml, "document_font"),
				    NULL);

  peditor = gconf_peditor_new_font (NULL, DESKTOP_FONT_KEY,
				    glade_xml_get_widget (data->xml, "desktop_font"),
				    NULL);

  peditor = gconf_peditor_new_font (NULL, WINDOW_TITLE_FONT_KEY,
				    glade_xml_get_widget (data->xml, "window_title_font"),
				    NULL);

  peditor = gconf_peditor_new_font (NULL, MONOSPACE_FONT_KEY,
				    glade_xml_get_widget (data->xml, "monospace_font"),
				    NULL);

  gconf_client_notify_add (data->client, WINDOW_TITLE_USES_SYSTEM_KEY,
			   metacity_changed,
			   data, NULL, NULL);

  metacity_titlebar_load_sensitivity (data);

#ifdef HAVE_XFT2
  setup_font_pair (glade_xml_get_widget (data->xml, "monochrome_radio"),
		   glade_xml_get_widget (data->xml, "monochrome_sample"),
		   ANTIALIAS_NONE, HINT_FULL);
  setup_font_pair (glade_xml_get_widget (data->xml, "best_shapes_radio"),
		   glade_xml_get_widget (data->xml, "best_shapes_sample"),
		   ANTIALIAS_GRAYSCALE, HINT_MEDIUM);
  setup_font_pair (glade_xml_get_widget (data->xml, "best_contrast_radio"),
		   glade_xml_get_widget (data->xml, "best_contrast_sample"),
		   ANTIALIAS_GRAYSCALE, HINT_FULL);
  setup_font_pair (glade_xml_get_widget (data->xml, "subpixel_radio"),
		   glade_xml_get_widget (data->xml, "subpixel_sample"),
		   ANTIALIAS_RGBA, HINT_FULL);

  font_render_load (data->client);

  gconf_client_notify_add (data->client, FONT_RENDER_DIR,
			   font_render_changed,
			   data->client, NULL, NULL);

  g_signal_connect (glade_xml_get_widget (data->xml, "details_button"),
		    "clicked", G_CALLBACK (cb_show_details), data);
#else /* !HAVE_XFT2 */
  gtk_widget_hide (glade_xml_get_widget (data->xml, "font_render_frame"));
#endif /* HAVE_XFT2 */
}

void
font_shutdown (AppearanceData *data)
{
  g_slist_foreach (data->font_groups, (GFunc) enum_group_destroy, NULL);
  g_slist_free (data->font_groups);
  g_slist_foreach (font_pairs, (GFunc) g_free, NULL);
  g_slist_free (font_pairs);
  g_free (old_font);
}