Re: turn on italics in TextView

[cecashon aol com]

Hi Doug,

You can try using the "insert-text" callback to set your italics on the inserted text. This is what I came up 
with to test. The signal is connected after so that the update occurs first. Careful about not changing the 
location iter also since there is a warning in the documentation about doing so. Might not need to worry 
about it here but something to be aware of.

https://developer.gnome.org/gtk3/stable/GtkTextBuffer.html#GtkTextBuffer-insert-text

Eric


/*
  gcc -Wall textview2.c -o textview2 `pkg-config --cflags --libs gtk+-3.0`
  Tested on GTK3.18 and Ubuntu16.04
*/

#include<gtk/gtk.h>

static gboolean italic=FALSE;

static void toggle_italic(GtkToggleButton *toggle1, gpointer data)
  {
    GtkWidget *label=gtk_bin_get_child(GTK_BIN(toggle1));
    if(gtk_toggle_button_get_active(toggle1))
      {
        gtk_label_set_markup(GTK_LABEL(label), "<span style='italic'>Italics</span>");
        italic=TRUE;
      }
    else
      {
        gtk_label_set_text(GTK_LABEL(label), "Italics");
        italic=FALSE;
      }
    gtk_widget_grab_focus(GTK_WIDGET(data));
  }
static void new_text(GtkTextBuffer *textbuffer, GtkTextIter *location, gchar *text, gint len, gpointer 
user_data)
  {
    if(italic)
      {
        GtkTextIter *start=gtk_text_iter_copy(location);
        GtkTextIter *end=gtk_text_iter_copy(location);
        gtk_text_iter_backward_chars(start, len);
        gtk_text_buffer_apply_tag_by_name(textbuffer, "tag1", start, end);
        gtk_text_iter_free(start);
        gtk_text_iter_free(end);
      }
  }
int main (int argc, char *argv[])
  {
    gtk_init(&argc, &argv);

    GtkWidget *window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(GTK_WINDOW(window), "Textview");
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
    g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);

    GtkWidget *text_view1=gtk_text_view_new();
    gtk_text_view_set_wrap_mode(GTK_TEXT_VIEW(text_view1), GTK_WRAP_CHAR);
    gtk_widget_set_vexpand(text_view1, TRUE);
    gtk_widget_set_hexpand(text_view1, TRUE);

    GtkTextBuffer *buffer=gtk_text_view_get_buffer(GTK_TEXT_VIEW(text_view1));
    gtk_text_buffer_create_tag(buffer, "tag1", "style", PANGO_STYLE_ITALIC, NULL);
    g_signal_connect_after(buffer, "insert-text", G_CALLBACK(new_text), NULL);

    GtkWidget *toggle1=gtk_toggle_button_new_with_label("Italics");
    g_signal_connect(toggle1, "toggled", G_CALLBACK(toggle_italic), text_view1);

    GtkWidget *grid=gtk_grid_new();
    gtk_container_set_border_width(GTK_CONTAINER(grid), 8);
    gtk_grid_set_row_spacing(GTK_GRID(grid), 12);
    gtk_grid_attach(GTK_GRID(grid), text_view1, 0, 0, 1, 1);
    gtk_grid_attach(GTK_GRID(grid), toggle1, 0, 1, 1, 1);
    
    gtk_container_add(GTK_CONTAINER(window), grid);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
  }