[cairo] Writing a PangoLayoutLine on a line in cairo

[Behdad Esfahbod]

On Sat, 2007-02-03 at 14:59 -0500, Owen Taylor wrote:
> On Sat, 2007-02-03 at 21:48 +0200, Dov Grobgeld wrote:
> > I
> > In pango_cairo_show_layout() on the other hand, the layout logical
> > upper left corner is aligned at the current cairo point when drawing,
> > and I could not find any PangoLayout call that gets the distance from
> > the top of the logical rectangle to the baseline position. Is this a
> > bug, or did I miss something?
> 
> Well, one easy way to do it is to just draw the first line of the
> layout instead of the entire layout - since the y origin when drawing a
> single line is at the baseline of the line.
> 
>  PangoLayoutLine *line = pango_layout_get_lines(layout)->data;
>  pango_show_layout_line(cr, line);

Or:

 PangoLayoutLine *line = pango_layout_get_line(layout, 0);
 pango_cairo_show_layout_line(cr, line);


> If you want to draw an entire layout with the first line positioned
> at a particular y position, then you'd need to get the ascent of the
> first line:
> 
>  PangoRectangle rect;
>  pango_layout_line_get_extents(line, NULL, &rect); 
>  double ascent = (double)PANGO_ASCENT(rect) / PANGO_SCALE;

Or:

   PangoLayoutIter *iter = pango_layout_get_iter (layout);
   double baseline = (double) pango_layout_iter_get_baseline (layout) /
PANGO_SCALE;


> It might be handy to have a convenience function to get this -
> pango_layout_get_depth(), say, to steal terminology from TeX.
>
> 					- Owen
> 
> 
-- 
behdad
http://behdad.org/

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