How to display text on GTK label using two different fonts? - c

Question

I have a GTK label and I am displaying text on it in Arial Rounded Mt Bold by using following code:
PangoFontDescription *df;
df = pango_font_description_new ();
pango_font_description_set_family(df,"Arial Rounded Mt Bold");
pango_font_description_set_size(df,fontsize*PANGO_SCALE);
gtk_widget_modify_font(Message_Label, df);
gtk_label_set_text(GTK_LABEL(Label), "Hello World");
pango_font_description_free (df);
Now this Hello World is displayed in Arial Rounded Mt Bold. But what if I want to display Hello in Arial Rounded Mt Bold and World in some other font for example Arial. Is this possible in GTK label. I am doing it in C. Any advice or any useful links. Thanks.

Answer 1

gtk_widget_modify_font() is deprecated and won't let you do what you want.
You can use a PangoAttrList, which combines attributes (including the individual components of a PangoFontDescriptor) over ranges of text. For instance:
PangoAttrList *attrlist;
PangoAttribute *attr;
PangoFontDescription *df;
attrlist = pango_attr_list_new();
// First, let's set up the base attributes.
// This part is copied from your code (and slightly bugfixed and reformatted):
df = pango_font_description_new();
pango_font_description_set_family(df, "Arial Rounded MT");
pango_font_description_set_size(df, fontsize * PANGO_SCALE);
pango_font_description_set_weight(df, PANGO_WEIGHT_BOLD);
// You can also use pango_font_description_new_from_string() and pass in a string like "Arial Rounded MT Bold (whatever fontsize is)".
// But here's where things change:
attr = pango_attr_font_desc_new(df);
// This is not documented, but pango_attr_font_desc_new() makes a copy of df, so let's release ours:
pango_font_description_free(df);
// Pango and GTK+ use UTF-8, so our string is indexed between 0 and 11.
// Note that the end_index is exclusive!
attr->start_index = 0;
attr->end_index = 11;
pango_attr_list_insert(attrlist, attr);
// And pango_attr_list_insert() takes ownership of attr, so we don't free it ourselves.
// As an alternative to all that, you can have each component of the PangoFontDescriptor be its own attribute; see the PangoAttribute documentation page.
// And now the attribute for the word "World".
attr = pango_attr_family_new("Arial");
// "World" starts at 6 and ends at 11.
attr->start_index = 6;
attr->end_index = 11;
pango_attr_list_insert(attrlist, attr);
// And finally, give the GtkLabel our attribute list.
gtk_label_set_attributes(GTK_LABEL(Label), attrlist);
// And (IIRC this is not documented either) gtk_label_set_attributes() takes a reference on the attribute list, so we can remove ours.
pango_attr_list_unref(attrlist);
You can also use gtk_label_set_markup() to use an HTML-like markup language to set both text and styles in one go:
gtk_label_set_markup(GTK_LABEL(Label),
"<span face=\"Arial Rounded MT\" size=\"(whatever fontsize * PANGO_SCALE is)\" weight=\"bold\">Hello <span face=\"Arial\">World</span></span>");
// Or even...
gtk_label_set_markup(GTK_LABEL(Label),
"<span font=\"Arial Rounded MT Bold (whatever fontsize is)\">Hello <span face=\"Arial\">World</span></span>");