Re: cursor-type as bar

[Markus Gritsch]

Juri Linkov wrote:
> > I would like to use a bar cursor, instead of a block cursor.
> > (setq default-frame-alist '((cursor-type . (bar . 2))))
>
> I use the same cursor type and have the same problem.
>
> > The problem is, that the bar cursor is drawn like a block cursor, only
> > using a smaller width.
>
> Actually, the way currently the bar cursor is drawn is worse than drawing
> the block cursor.  The block cursor inverts the colors of the underlying
> character, but the bar cursor partially or completely overlaps it.
>
> > To really be usable, the bar cursor should be drawn *between* the
> > characters, e.g. shifting it width/2 pixels to the left.
>
> I agree this would be much better, but what to do if the distance between
> the characters in pixels is less than the width of the bar cursor?
> It seems overlapping is unavoidable.

Yes, I agree.  Even when shifting the cursor so that it is located 
between the characters there will be some overlaping in certain cases. 
However, I would not invert the colors of the underlying character.

I tried to find the location where the cursor is drawn, and made the 
following experimental change, where the cursor is shifted by a 
hardcoded value of 1 to the left.

--- w32term_orig.c      2006-03-12 10:17:44.019393600 +0100
+++ w32term.c   2006-03-09 20:20:07.546683200 +0100
@@ -5021,7 +5021,7 @@

       if (kind == BAR_CURSOR)
        {
-         w32_fill_area (f, hdc, cursor_color, x,
+         w32_fill_area (f, hdc, cursor_color, x - 1,
                         WINDOW_TO_FRAME_PIXEL_Y (w, w->phys_cursor.y),
                         width, row->height);
        }

The problem is, that when moving the cursor, both caracters, left and 
right of the caret must be repainted.  Currently only the character 
where the cursor was before moving it gets updated.  The result can be 
seen in the attachment.  Unfortunately I was not able to find out, how 
to redraw also the character before the one which gets already repainted.

Kind regards,
Markus