turn on italics in TextView

[Doug McCasland <dougm bravoecho net>]

Hi,

I am trying GTK3 TextView, in C. I know how to apply tags, such as italics,
bold, etc., to a region of text.

But how do I "turn on" a style (italics, bold, etc) while typing in the
buffer? For example, suppose I am typing text and there are no styles set.
Then I want to type in italics. I want to apply the italic tag to the
insert point, after which whatever I typed would be in italics.

I notice that when you place the insert cursor to the right of any existing
styled text, the tags of the previous character are inherited, but only if
the style is in effect before and after the insert point. Interestingly,
the trailing newline can be stylized (invisibly), so when the insert point
is at the end of a line and the last visible character has a style, then
that style is inherited.

I've looked at some methods that use a key-press signal and then apply a
text tag to the region of the untagged character just typed, but that is
slow and looks odd on screen -- the plain char is displayed and then
replaced by the tagged char.

I've also tried:

gtk_text_buffer_insert_markup(buf, &iter, "<i>", -1);

but that gets a Warning: Invalid markup string: ... Element 'markup' was
closed, but the currently open element is 'i' and has no effect on the
displayed text. Using <i></i> gets no warning but also has no effect. I
finally resorted to:

gtk_text_buffer_insert_markup(buf, &iter, "<i> </i>", -1); // 2 spaces

gtk_text_iter_backward_char (&iter);

gtk_text_buffer_place_cursor(buf, &iter);

which lets me start typing in italics between 2 new (tagged) spaces --
that's not so bad.

But clicking an "I" button to start typing in italics -- that is a basic
editing function that has been around for decades. It must be possible in
GTK somehow?

thanks