Significance of "width != 1" in Pango layouts?

[Tony Graham <Tony Graham ireland sun com>]

The definition of pango_x_render_layout() in pangox.c (and similar
code in pangoft2.c, etc.) contains:

  if (width == -1 && align != PANGO_ALIGN_LEFT)
    {
      pango_layout_get_extents (layout, NULL, &logical_rect);
      width = logical_rect.width;
    }
  
  tmp_list = pango_layout_get_lines (layout);
  while (tmp_list)
    {
      PangoLayoutLine *line = tmp_list->data;
      int x_offset;
      
      pango_layout_line_get_extents (line, NULL, &logical_rect);

      if (width != 1 && align == PANGO_ALIGN_RIGHT)
	x_offset = width - logical_rect.width;
      else if (width != 1 && align == PANGO_ALIGN_CENTER)
	x_offset = (width - logical_rect.width) / 2;
      else
	x_offset = 0;

I believe that I understand the significance of the "width == -1" test
-- if true, the lines aren't wrapped -- but I don't understand the
significance of "width == 1", especially since I can't find any code
that explicitly sets a layouts width to 1.

Also, since the width is in Pango units, the width would have to be a
lot larger than 1 before the changes in x_offset made any visible
difference.

What is the significance of testing that width != 1?

Regards,


Tony Graham
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