[cairo] Fixing cairo_show_text to advance the current point

Owen Taylor otaylor at redhat.com
Tue Aug 23 16:39:13 PDT 2005

On Tue, 2005-08-23 at 15:38 -0700, Carl Worth wrote:
> We've never actually written documentation for what cairo_show_text
> does, but I believe that in addition to displaying the provided text
> it should advance the current point according to the advance values of
> the extents of the given text.
> This would be consistent with the behavior of the "show" operator in
> PostScript.
> This allows a composite string to be displayed with multiple calls to
> cairo_show_text without the user ever needing to ask for any
> extents. This seems quite consistent with the "toy" use cases for
> cairo_show_text.
> The attached patch implements this behavior along with a test case
> that shows how it can be used.
> It is rather late in the game, (we're planning to release cairo 1.0
> today), for a semantic change like this, but cairo/BUGS has had the
> following since about forever:
> 	cairo_show_text is not updating the current point by the
> 	string's advance values.
> Any objections to this going in?


 - The Pango functions that show text are not going to be changed
   at this point. (show_layout, show_layout_line, 

 - Your patch doesn't change show_glyphs(), and I tend to agree
   with that.

So, the question is - is the gain in convenience for the toy API
worth the possible confusion and the need to document the 

That would be my only question. Other than that the change seems


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