not quite sure if this is a bug or programmer error -- but either way,
two separate tests i've done with similar results.

the first:
trying to write arabic text in a gtk_text_buffer, where some characters are in a
different color than other characters.

i tried the following:
tb = gtk_text_buffer_new(NULL);
gtk_text_buffer_get_start_iter(tb, &textIter);
tag = gtk_text_buffer_create_tag(tb, "black_settings", "justification",
      GTK_JUSTIFY_RIGHT, "wrap-mode", GTK_WRAP_WORD, "font", 
      "Verdana 24", "foreground", "black", NULL);
tag2 = gtk_text_buffer_create_tag(tb, "blue_settings", "justification",
      GTK_JUSTIFY_RIGHT, "wrap-mode", GTK_WRAP_WORD, "font", 
      "Verdana 24", "foreground", "blue", NULL);
gtk_text_buffer_insert(tb, &textIter, "Correct:\n", strlen("Correct:\n"));
gtk_text_buffer_insert_with_tags(tb, &textIter, str, -1, tag, NULL);

gtk_text_buffer_insert(tb, &textIter, "\n\nNow:\n", strlen("\n\nNow:\n"));
gtk_text_buffer_insert_with_tags(tb, &textIter, str, 33, tag, NULL);
gtk_text_buffer_insert_with_tags(tb, &textIter, str+33, -1, tag2, NULL);


the output of this is broken shaping, as can be seen in this screenshot taking
of a gtk# version of the above program:
http://piousity.net/images/arabic_html-04.29.2005.png



the second thing i tried was due to me thinking that the above might be
an error on my understanding of the apis.  so i tried something simpler -
populating a label and changing some of the colors of the label.

there are two subcases, one works, and one doesn't:

str = readArabicTextFromXML();
asprintf(&s2, "<span size=\"x-large\" foreground=\"blue\">%s</span><span
size=\"x-large\" foreground=\"red\">%s</span>",
        substr(str, 0, 33), substr(str, 33, strlen(str)));

pango_parse_markup(s2, -1, 0, &attrList, NULL, NULL, NULL);
window1 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window1), _("window1"));

label1 = gtk_label_new (str);
gtk_label_set_attributes(GTK_LABEL(label1), attrList);


in this case, although the substr splits it into two strings, where the first
letter of the second word is part of the first string and the remainder of the
second word is part of the second string, the first word comes up blue and the
second comes up red [rather than the first word and first letter of second word
being blue and the rest being red].

alternately, if you change the asprintf to be identical with the exception of
the fact that you remove the color being red from the second half, it works as
expected.


what i really want to do is be able to insert arabic text in a gtk_text_buffer,
being able to have different colors amongst some of the letters, without
breaking shaping.  any help would be appreciated.  thanks.