gtk2/demos/gtk-demo/main.c

#include "config.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <gtk/gtk.h>
#include <glib/gstdio.h>

#include "demos.h"

static GtkTextBuffer *info_buffer;
static GtkTextBuffer *source_buffer;

static gchar *current_file = NULL;

static GtkWidget *notebook;

enum {
  TITLE_COLUMN,
  FILENAME_COLUMN,
  FUNC_COLUMN,
  STYLE_COLUMN,
  NUM_COLUMNS
};

typedef struct _CallbackData CallbackData;
struct _CallbackData
{
  GtkTreeModel *model;
  GtkTreePath *path;
};

#ifdef G_OS_WIN32

#undef DEMOCODEDIR

static char *
get_democodedir (void)
{
  static char *result = NULL;

  if (result == NULL)
    {
      result = g_win32_get_package_installation_directory_of_module (NULL);
      if (result == NULL)
        result = "unknown-location";

      result = g_strconcat (result, "\\share\\gtk-3.0\\demo", NULL);
    }

  return result;
}

#define DEMOCODEDIR get_democodedir ()

#endif

/**
 * demo_find_file:
 * @base: base filename
 * @err:  location to store error, or %NULL.
 *
 * Looks for @base first in the current directory, then in the
 * location GTK+ where it will be installed on make install,
 * returns the first file found.
 *
 * Return value: the filename, if found or %NULL
 */
gchar *
demo_find_file (const char *base,
                GError    **err)
{
  g_return_val_if_fail (err == NULL || *err == NULL, NULL);

  if (g_file_test ("gtk-logo-rgb.gif", G_FILE_TEST_EXISTS) &&
      g_file_test (base, G_FILE_TEST_EXISTS))
    return g_strdup (base);
  else
    {
      char *filename = g_build_filename (DEMOCODEDIR, base, NULL);
      if (!g_file_test (filename, G_FILE_TEST_EXISTS))
        {
          g_set_error (err, G_FILE_ERROR, G_FILE_ERROR_NOENT,
                       "Cannot find demo data file \"%s\"", base);
          g_free (filename);
          return NULL;
        }
      return filename;
    }
}

static void
window_closed_cb (GtkWidget *window, gpointer data)
{
  CallbackData *cbdata = data;
  GtkTreeIter iter;
  PangoStyle style;

  gtk_tree_model_get_iter (cbdata->model, &iter, cbdata->path);
  gtk_tree_model_get (GTK_TREE_MODEL (cbdata->model), &iter,
                      STYLE_COLUMN, &style,
                      -1);
  if (style == PANGO_STYLE_ITALIC)
    gtk_tree_store_set (GTK_TREE_STORE (cbdata->model), &iter,
                        STYLE_COLUMN, PANGO_STYLE_NORMAL,
                        -1);

  gtk_tree_path_free (cbdata->path);
  g_free (cbdata);
}

gboolean
read_line (FILE *stream, GString *str)
{
  int n_read = 0;

#ifdef HAVE_FLOCKFILE
  flockfile (stream);
#endif

  g_string_truncate (str, 0);

  while (1)
    {
      int c;

#ifdef HAVE_FLOCKFILE
      c = getc_unlocked (stream);
#else
      c = getc (stream);
#endif

      if (c == EOF)
        goto done;
      else
        n_read++;

      switch (c)
        {
        case '\r':
        case '\n':
          {
#ifdef HAVE_FLOCKFILE
            int next_c = getc_unlocked (stream);
#else
            int next_c = getc (stream);
#endif

            if (!(next_c == EOF ||
                  (c == '\r' && next_c == '\n') ||
                  (c == '\n' && next_c == '\r')))
              ungetc (next_c, stream);

            goto done;
          }
        default:
          g_string_append_c (str, c);
        }
    }

 done:

#ifdef HAVE_FLOCKFILE
  funlockfile (stream);
#endif

  return n_read > 0;
}


/* Stupid syntax highlighting.
 *
 * No regex was used in the making of this highlighting.
 * It should only work for simple cases.  This is good, as
 * that's all we should have in the demos.
 */
/* This code should not be used elsewhere, except perhaps as an example of how
 * to iterate through a text buffer.
 */
enum {
  STATE_NORMAL,
  STATE_IN_COMMENT
};

static gchar *tokens[] =
{
  "/*",
  "\"",
  NULL
};

static gchar *types[] =
{
  "static",
  "const ",
  "void",
  "gint",
  " int ",
  " char ",
  "gchar ",
  "gfloat",
  "float",
  "double",
  "gint8",
  "gint16",
  "gint32",
  "guint",
  "guint8",
  "guint16",
  "guint32",
  "guchar",
  "glong",
  "gboolean" ,
  "gshort",
  "gushort",
  "gulong",
  "gdouble",
  "gldouble",
  "gpointer",
  "NULL",
  "GList",
  "GSList",
  "FALSE",
  "TRUE",
  "FILE ",
  "GtkColorSelection ",
  "GtkWidget ",
  "GtkButton ",
  "GdkColor ",
  "GdkRectangle ",
  "GdkEventExpose ",
  "GdkGC ",
  "GdkPixbufLoader ",
  "GdkPixbuf ",
  "GError",
  "size_t",
  "GtkAboutDialog ",
  "GtkAction ",
  "GtkActionEntry ",
  "GtkRadioActionEntry ",
  "GtkIconFactory ",
  "GtkStockItem ",
  "GtkIconSet ",
  "GtkTextBuffer ",
  "GtkStatusbar ",
  "GtkTextIter ",
  "GtkTextMark ",
  "GdkEventWindowState ",
  "GtkActionGroup ",
  "GtkUIManager ",
  "GtkRadioAction ",
  "GtkActionClass ",
  "GtkToggleActionEntry ",
  "GtkAssistant ",
  "GtkBuilder ",
  "GtkSizeGroup ",
  "GtkTreeModel ",
  "GtkTreeSelection ",
  "GdkDisplay ",
  "GdkScreen ",
  "GdkWindow ",
  "GdkEventButton ",
  "GdkCursor ",
  "GtkTreeIter ",
  "GtkTreeViewColumn ",
  "GdkDisplayManager ",
  "GtkClipboard ",
  "GtkIconSize ",
  "GtkImage ",
  "GdkDragContext ",
  "GtkSelectionData ",
  "GtkDialog ",
  "GtkMenuItem ",
  "GtkListStore ",
  "GtkCellLayout ",
  "GtkCellRenderer ",
  "GtkTreePath ",
  "GtkTreeStore ",
  "GtkEntry ",
  "GtkEditable ",
  "GtkEditableInterface ",
  "GdkPixmap ",
  "GdkEventConfigure ",
  "GdkEventMotion ",
  "GdkModifierType ",
  "GtkEntryCompletion ",
  "GtkToolItem ",
  "GDir ",
  "GtkIconView ",
  "GtkCellRendererText ",
  "GtkContainer ",
  "GtkAccelGroup ",
  "GtkPaned ",
  "GtkPrintOperation ",
  "GtkPrintContext ",
  "cairo_t ",
  "PangoLayout "
  "PangoFontDescription ",
  "PangoRenderer ",
  "PangoMatrix ",
  "PangoContext ",
  "PangoLayout ",
  "GtkTable ",
  "GtkToggleButton ",
  "GString ",
  "GtkIconSize ",
  "GtkTreeView ",
  "GtkTextTag ",
  "GdkEvent ",
  "GdkEventKey ",
  "GtkTextView ",
  "GdkEventVisibility ",
  "GdkBitmap ",
  "GtkTextChildAnchor ",
  "GArray ",
  "GtkCellEditable ",
  "GtkCellRendererToggle ",
  NULL
};

static gchar *control[] =
{
  " if ",
  " while ",
  " else",
  " do ",
  " for ",
  "?",
  ":",
  "return ",
  "goto ",
  NULL
};
void
parse_chars (gchar     *text,
             gchar    **end_ptr,
             gint      *state,
             gchar    **tag,
             gboolean   start)
{
  gint i;
  gchar *next_token;

  /* Handle comments first */
  if (*state == STATE_IN_COMMENT)
    {
      *end_ptr = strstr (text, "*/");
      if (*end_ptr)
        {
          *end_ptr += 2;
          *state = STATE_NORMAL;
          *tag = "comment";
        }
      return;
    }

  *tag = NULL;
  *end_ptr = NULL;

  /* check for comment */
  if (!strncmp (text, "/*", 2))
    {
      *end_ptr = strstr (text, "*/");
      if (*end_ptr)
        *end_ptr += 2;
      else
        *state = STATE_IN_COMMENT;
      *tag = "comment";
      return;
    }

  /* check for preprocessor defines */
  if (*text == '#' && start)
    {
      *end_ptr = NULL;
      *tag = "preprocessor";
      return;
    }

  /* functions */
  if (start && * text != '\t' && *text != ' ' && *text != '{' && *text != '}')
    {
      if (strstr (text, "("))
        {
          *end_ptr = strstr (text, "(");
          *tag = "function";
          return;
        }
    }
  /* check for types */
  for (i = 0; types[i] != NULL; i++)
    if (!strncmp (text, types[i], strlen (types[i])) ||
        (start && types[i][0] == ' ' && !strncmp (text, types[i] + 1, strlen (types[i]) - 1)))
      {
        *end_ptr = text + strlen (types[i]);
        *tag = "type";
        return;
      }

  /* check for control */
  for (i = 0; control[i] != NULL; i++)
    if (!strncmp (text, control[i], strlen (control[i])))
      {
        *end_ptr = text + strlen (control[i]);
        *tag = "control";
        return;
      }

  /* check for string */
  if (text[0] == '"')
    {
      gint maybe_escape = FALSE;

      *end_ptr = text + 1;
      *tag = "string";
      while (**end_ptr != '\000')
        {
          if (**end_ptr == '\"' && !maybe_escape)
            {
              *end_ptr += 1;
              return;
            }
          if (**end_ptr == '\\')
            maybe_escape = TRUE;
          else
            maybe_escape = FALSE;
          *end_ptr += 1;
        }
      return;
    }

  /* not at the start of a tag.  Find the next one. */
  for (i = 0; tokens[i] != NULL; i++)
    {
      next_token = strstr (text, tokens[i]);
      if (next_token)
        {
          if (*end_ptr)
            *end_ptr = (*end_ptr<next_token)?*end_ptr:next_token;
          else
            *end_ptr = next_token;
        }
    }

  for (i = 0; types[i] != NULL; i++)
    {
      next_token = strstr (text, types[i]);
      if (next_token)
        {
          if (*end_ptr)
            *end_ptr = (*end_ptr<next_token)?*end_ptr:next_token;
          else
            *end_ptr = next_token;
        }
    }

  for (i = 0; control[i] != NULL; i++)
    {
      next_token = strstr (text, control[i]);
      if (next_token)
        {
          if (*end_ptr)
            *end_ptr = (*end_ptr<next_token)?*end_ptr:next_token;
          else
            *end_ptr = next_token;
        }
    }
}

/* While not as cool as c-mode, this will do as a quick attempt at highlighting */
static void
fontify (void)
{
  GtkTextIter start_iter, next_iter, tmp_iter;
  gint state;
  gchar *text;
  gchar *start_ptr, *end_ptr;
  gchar *tag;

  state = STATE_NORMAL;

  gtk_text_buffer_get_iter_at_offset (source_buffer, &start_iter, 0);

  next_iter = start_iter;
  while (gtk_text_iter_forward_line (&next_iter))
    {
      gboolean start = TRUE;
      start_ptr = text = gtk_text_iter_get_text (&start_iter, &next_iter);

      do
        {
          parse_chars (start_ptr, &end_ptr, &state, &tag, start);

          start = FALSE;
          if (end_ptr)
            {
              tmp_iter = start_iter;
              gtk_text_iter_forward_chars (&tmp_iter, end_ptr - start_ptr);
            }
          else
            {
              tmp_iter = next_iter;
            }
          if (tag)
            gtk_text_buffer_apply_tag_by_name (source_buffer, tag, &start_iter, &tmp_iter);

          start_iter = tmp_iter;
          start_ptr = end_ptr;
        }
      while (end_ptr);

      g_free (text);
      start_iter = next_iter;
    }
}

static GtkWidget *create_text (GtkTextBuffer **buffer, gboolean is_source);

static void
add_data_tab (const gchar *filename)
{
  GtkTextBuffer *buffer = NULL;
  gchar *full_filename;
  GError *err = NULL;
  gchar *text;
  GtkWidget *widget, *label;

  full_filename = demo_find_file (filename, &err);
  if (!full_filename ||
      !g_file_get_contents (full_filename, &text, NULL, &err))
    {
      g_warning ("%s", err->message);
      g_error_free (err);
      return;
    }

  widget = create_text (&buffer, FALSE);
  gtk_widget_show_all (widget);
  label = gtk_label_new (filename);
  gtk_widget_show (label);
  gtk_notebook_append_page (GTK_NOTEBOOK (notebook), widget, label);

  gtk_text_buffer_set_text (buffer, text, -1);

  g_free (full_filename);
  g_free (text);
}

static void
remove_data_tabs (void)
{
  gint i;

  for (i = gtk_notebook_get_n_pages (GTK_NOTEBOOK (notebook)) - 1; i > 1; i--)
    gtk_notebook_remove_page (GTK_NOTEBOOK (notebook), i);
}

void
load_file (const gchar *filename)
{
  FILE *file;
  GtkTextIter start, end;
  char *full_filename;
  GError *err = NULL;
  GString *buffer = g_string_new (NULL);
  int state = 0;
  gboolean in_para = 0;
  gchar **names;
  gint i;

  remove_data_tabs ();

  names = g_strsplit (filename, " ", -1);

  for (i = 1; names[i]; i++) {
    if (strlen (names[i]) > 0)
      add_data_tab (names[i]);
  }

  if (current_file && !strcmp (current_file, names[0]))
    {
      g_string_free (buffer, TRUE);
      return;
    }

  g_free (current_file);
  current_file = g_strdup (names[0]);

  gtk_text_buffer_get_bounds (info_buffer, &start, &end);
  gtk_text_buffer_delete (info_buffer, &start, &end);

  gtk_text_buffer_get_bounds (source_buffer, &start, &end);
  gtk_text_buffer_delete (source_buffer, &start, &end);

  full_filename = demo_find_file (names[0], &err);
  if (!full_filename)
    {
      g_warning ("%s", err->message);
      g_error_free (err);
      return;
    }

  file = g_fopen (full_filename, "r");

  if (!file)
    g_warning ("Cannot open %s: %s\n", full_filename, g_strerror (errno));

  g_free (full_filename);

  if (!file)
    return;

  gtk_text_buffer_get_iter_at_offset (info_buffer, &start, 0);
  while (read_line (file, buffer))
    {
      gchar *p = buffer->str;
      gchar *q;
      gchar *r;

      switch (state)
        {
        case 0:
          /* Reading title */
          while (*p == '/' || *p == '*' || g_ascii_isspace (*p))
            p++;
          r = p;
          while (*r != '\0')
            {
              while (*r != '/' && *r != ':' && *r != '\0')
                r++;
              if (*r == '/')
                {
                  r++;
                  p = r;
                }
              if (r[0] == ':' && r[1] == ':')
                *r = '\0';
            }
          q = p + strlen (p);
          while (q > p && g_ascii_isspace (*(q - 1)))
            q--;


          if (q > p)
            {
              int len_chars = g_utf8_pointer_to_offset (p, q);

              end = start;

              g_assert (strlen (p) >= q - p);
              gtk_text_buffer_insert (info_buffer, &end, p, q - p);
              start = end;

              gtk_text_iter_backward_chars (&start, len_chars);
              gtk_text_buffer_apply_tag_by_name (info_buffer, "title", &start, &end);

              start = end;

              while (*p && *p != '\n') p++;

              state++;
            }
          break;

        case 1:
          /* Reading body of info section */
          while (g_ascii_isspace (*p))
            p++;
          if (*p == '*' && *(p + 1) == '/')
            {
              gtk_text_buffer_get_iter_at_offset (source_buffer, &start, 0);
              state++;
            }
          else
            {
              int len;

              while (*p == '*' || g_ascii_isspace (*p))
                p++;

              len = strlen (p);
              while (g_ascii_isspace (*(p + len - 1)))
                len--;

              if (len > 0)
                {
                  if (in_para)
                    gtk_text_buffer_insert (info_buffer, &start, " ", 1);

                  g_assert (strlen (p) >= len);
                  gtk_text_buffer_insert (info_buffer, &start, p, len);
                  in_para = 1;
                }
              else
                {
                  gtk_text_buffer_insert (info_buffer, &start, "\n", 1);
                  in_para = 0;
                }
            }
          break;

        case 2:
          /* Skipping blank lines */
          while (g_ascii_isspace (*p))
            p++;
          if (*p)
            {
              p = buffer->str;
              state++;
              /* Fall through */
            }
          else
            break;

        case 3:
          /* Reading program body */
          gtk_text_buffer_insert (source_buffer, &start, p, -1);
          gtk_text_buffer_insert (source_buffer, &start, "\n", 1);
          break;
        }
    }

  fclose (file);

  fontify ();

  g_string_free (buffer, TRUE);

  g_strfreev (names);
}

void
row_activated_cb (GtkTreeView       *tree_view,
                  GtkTreePath       *path,
                  GtkTreeViewColumn *column)
{
  GtkTreeIter iter;
  PangoStyle style;
  GDoDemoFunc func;
  GtkWidget *window;
  GtkTreeModel *model;

  model = gtk_tree_view_get_model (tree_view);

  gtk_tree_model_get_iter (model, &iter, path);
  gtk_tree_model_get (GTK_TREE_MODEL (model),
                      &iter,
                      FUNC_COLUMN, &func,
                      STYLE_COLUMN, &style,
                      -1);

  if (func)
    {
      gtk_tree_store_set (GTK_TREE_STORE (model),
                          &iter,
                          STYLE_COLUMN, (style == PANGO_STYLE_ITALIC ? PANGO_STYLE_NORMAL : PANGO_STYLE_ITALIC),
                          -1);
      window = (func) (gtk_widget_get_toplevel (GTK_WIDGET (tree_view)));

      if (window != NULL)
        {
          CallbackData *cbdata;

          cbdata = g_new (CallbackData, 1);
          cbdata->model = model;
          cbdata->path = gtk_tree_path_copy (path);

          g_signal_connect (window, "destroy",
                            G_CALLBACK (window_closed_cb), cbdata);
        }
    }
}

static void
selection_cb (GtkTreeSelection *selection,
              GtkTreeModel     *model)
{
  GtkTreeIter iter;
  GValue value = G_VALUE_INIT;

  if (! gtk_tree_selection_get_selected (selection, NULL, &iter))
    return;

  gtk_tree_model_get_value (model, &iter,
                            FILENAME_COLUMN,
                            &value);
  if (g_value_get_string (&value))
    load_file (g_value_get_string (&value));
  g_value_unset (&value);
}

static GtkWidget *
create_text (GtkTextBuffer **buffer,
             gboolean        is_source)
{
  GtkWidget *scrolled_window;
  GtkWidget *text_view;
  PangoFontDescription *font_desc;

  scrolled_window = gtk_scrolled_window_new (NULL, NULL);
  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
                                  GTK_POLICY_AUTOMATIC,
                                  GTK_POLICY_AUTOMATIC);
  gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scrolled_window),
                                       GTK_SHADOW_IN);

  text_view = gtk_text_view_new ();

  *buffer = gtk_text_buffer_new (NULL);
  gtk_text_view_set_buffer (GTK_TEXT_VIEW (text_view), *buffer);
  gtk_text_view_set_editable (GTK_TEXT_VIEW (text_view), FALSE);
  gtk_text_view_set_cursor_visible (GTK_TEXT_VIEW (text_view), FALSE);

  gtk_container_add (GTK_CONTAINER (scrolled_window), text_view);

  if (is_source)
    {
      font_desc = pango_font_description_from_string ("monospace");
      gtk_widget_override_font (text_view, font_desc);
      pango_font_description_free (font_desc);

      gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (text_view),
                                   GTK_WRAP_NONE);
    }
  else
    {
      /* Make it a bit nicer for text. */
      gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (text_view),
                                   GTK_WRAP_WORD);
      gtk_text_view_set_pixels_above_lines (GTK_TEXT_VIEW (text_view),
                                            2);
      gtk_text_view_set_pixels_below_lines (GTK_TEXT_VIEW (text_view),
                                            2);
    }

  return scrolled_window;
}

static GtkWidget *
create_tree (void)
{
  GtkTreeSelection *selection;
  GtkCellRenderer *cell;
  GtkWidget *tree_view;
  GtkTreeViewColumn *column;
  GtkTreeStore *model;
  GtkTreeIter iter;
  GtkWidget *box, *label, *scrolled_window;

  Demo *d = gtk_demos;

  model = gtk_tree_store_new (NUM_COLUMNS, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_POINTER, G_TYPE_INT);
  tree_view = gtk_tree_view_new ();
  gtk_tree_view_set_model (GTK_TREE_VIEW (tree_view), GTK_TREE_MODEL (model));
  selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (tree_view));

  gtk_tree_selection_set_mode (GTK_TREE_SELECTION (selection),
                               GTK_SELECTION_BROWSE);
  gtk_widget_set_size_request (tree_view, 200, -1);

  /* this code only supports 1 level of children. If we
   * want more we probably have to use a recursing function.
   */
  while (d->title)
    {
      Demo *children = d->children;

      gtk_tree_store_append (GTK_TREE_STORE (model), &iter, NULL);

      gtk_tree_store_set (GTK_TREE_STORE (model),
                          &iter,
                          TITLE_COLUMN, d->title,
                          FILENAME_COLUMN, d->filename,
                          FUNC_COLUMN, d->func,
                          STYLE_COLUMN, PANGO_STYLE_NORMAL,
                          -1);

      d++;

      if (!children)
        continue;

      while (children->title)
        {
          GtkTreeIter child_iter;

          gtk_tree_store_append (GTK_TREE_STORE (model), &child_iter, &iter);

          gtk_tree_store_set (GTK_TREE_STORE (model),
                              &child_iter,
                              TITLE_COLUMN, children->title,
                              FILENAME_COLUMN, children->filename,
                              FUNC_COLUMN, children->func,
                              STYLE_COLUMN, PANGO_STYLE_NORMAL,
                              -1);

          children++;
        }
    }

  cell = gtk_cell_renderer_text_new ();

  column = gtk_tree_view_column_new_with_attributes ("Widget (double click for demo)",
                                                     cell,
                                                     "text", TITLE_COLUMN,
                                                     "style", STYLE_COLUMN,
                                                     NULL);

  gtk_tree_view_append_column (GTK_TREE_VIEW (tree_view),
                               GTK_TREE_VIEW_COLUMN (column));

  gtk_tree_model_get_iter_first (GTK_TREE_MODEL (model), &iter);
  gtk_tree_selection_select_iter (GTK_TREE_SELECTION (selection), &iter);

  g_signal_connect (selection, "changed", G_CALLBACK (selection_cb), model);
  g_signal_connect (tree_view, "row_activated", G_CALLBACK (row_activated_cb), model);

  gtk_tree_view_collapse_all (GTK_TREE_VIEW (tree_view));
  gtk_tree_view_set_headers_visible (GTK_TREE_VIEW (tree_view), FALSE);

  scrolled_window = gtk_scrolled_window_new (NULL, NULL);
  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
                                  GTK_POLICY_NEVER,
                                  GTK_POLICY_AUTOMATIC);
  gtk_container_add (GTK_CONTAINER (scrolled_window), tree_view);

  label = gtk_label_new ("Widget (double click for demo)");

  box = gtk_notebook_new ();
  gtk_notebook_append_page (GTK_NOTEBOOK (box), scrolled_window, label);

  gtk_widget_grab_focus (tree_view);

   g_object_unref (model);

  return box;
}

static void
setup_default_icon (void)
{
  GdkPixbuf *pixbuf;
  char *filename;
  GError *err;

  err = NULL;

  pixbuf = NULL;
  filename = demo_find_file ("gtk-logo-rgb.gif", &err);
  if (filename)
    {
      pixbuf = gdk_pixbuf_new_from_file (filename, &err);
      g_free (filename);
    }

  /* Ignoring this error (passing NULL instead of &err above)
   * would probably be reasonable for most apps.  We're just
   * showing off.
   */
  if (err)
    {
      GtkWidget *dialog;

      dialog = gtk_message_dialog_new (NULL, 0,
                                       GTK_MESSAGE_ERROR,
                                       GTK_BUTTONS_CLOSE,
                                       "Failed to read icon file: %s",
                                       err->message);
      g_error_free (err);

      g_signal_connect (dialog, "response",
                        G_CALLBACK (gtk_widget_destroy), NULL);
    }

  if (pixbuf)
    {
      GList *list;
      GdkPixbuf *transparent;

      /* The gtk-logo-rgb icon has a white background, make it transparent */
      transparent = gdk_pixbuf_add_alpha (pixbuf, TRUE, 0xff, 0xff, 0xff);

      list = NULL;
      list = g_list_append (list, transparent);
      gtk_window_set_default_icon_list (list);
      g_list_free (list);
      g_object_unref (pixbuf);
      g_object_unref (transparent);
    }
}

int
main (int argc, char **argv)
{
  GtkWidget *window;
  GtkWidget *hbox;
  GtkWidget *tree;

  /* Most code in gtk-demo is intended to be exemplary, but not
   * these few lines, which are just a hack so gtk-demo will work
   * in the GTK tree without installing it.
   */
  if (g_file_test ("../../modules/input/immodules.cache", G_FILE_TEST_EXISTS))
    {
      g_setenv ("GTK_IM_MODULE_FILE", "../../modules/input/immodules.cache", TRUE);
    }
  /* -- End of hack -- */

  gtk_init (&argc, &argv);

  setup_default_icon ();

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "GTK+ Code Demos");
  g_signal_connect_after (window, "destroy",
                    G_CALLBACK (gtk_main_quit), NULL);

  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 0);
  gtk_container_add (GTK_CONTAINER (window), hbox);

  tree = create_tree ();
  gtk_box_pack_start (GTK_BOX (hbox), tree, FALSE, FALSE, 0);

  notebook = gtk_notebook_new ();
  gtk_box_pack_start (GTK_BOX (hbox), notebook, TRUE, TRUE, 0);

  gtk_notebook_append_page (GTK_NOTEBOOK (notebook),
                            create_text (&info_buffer, FALSE),
                            gtk_label_new_with_mnemonic ("_Info"));

  gtk_text_buffer_create_tag (info_buffer, "title",
                              "font", "Sans 18",
                              NULL);
  g_object_unref (info_buffer);

  gtk_notebook_append_page (GTK_NOTEBOOK (notebook),
                            create_text (&source_buffer, TRUE),
                            gtk_label_new_with_mnemonic ("_Source"));


  gtk_text_buffer_create_tag (source_buffer, "comment",
                              "foreground", "DodgerBlue",
                              NULL);
  gtk_text_buffer_create_tag (source_buffer, "type",
                              "foreground", "ForestGreen",
                              NULL);
  gtk_text_buffer_create_tag (source_buffer, "string",
                              "foreground", "RosyBrown",
                              "weight", PANGO_WEIGHT_BOLD,
                              NULL);
  gtk_text_buffer_create_tag (source_buffer, "control",
                              "foreground", "purple",
                              NULL);
  gtk_text_buffer_create_tag (source_buffer, "preprocessor",
                              "style", PANGO_STYLE_OBLIQUE,
                              "foreground", "burlywood4",
                              NULL);
  gtk_text_buffer_create_tag (source_buffer, "function",
                              "weight", PANGO_WEIGHT_BOLD,
                              "foreground", "DarkGoldenrod4",
                              NULL);
  g_object_unref (source_buffer);

  gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
  gtk_widget_show_all (window);

  load_file (gtk_demos[0].filename);

  gtk_main ();

  return 0;
}