[cairo] Backwards glyphs?

[Carl Worth]

On Wed, 2008-10-22 at 11:50 -0300, Ian Britten wrote:
> - Configuring a Cartesian (lower-left origin) world transform on it.

I presume this is something like:

	cairo_translate (cr, 0, height);
	cairo_scale (cr, 1.0, -1.0); 

or so?

> Generally, everything is working as expected with my rendering.
> Lines, polygons, and images all draw correctly.  Even for the glyphs,
> they're at the correct position, with the specified size, colour, etc.
> It's just that the individual glyphs are backwards... :(

A transformation like the above would be expected to invert your glyphs,
yes, (vertically, not horizontally).

> Am I expected to muck about with cairo_set_font_matrix(), even for
> simple rendering?  I was hoping just setting the size+position would
> result in the correct output...

Well, define "simple rendering" I guess. You're the one going outside
cairo's default coordinate system. ;-)

So, cairo_set_font_matrix with a matrix that will again invert the Y
axis would be one way to solve this, yes. Another possibility would be
to draw your glyphs with something like this:

	cairo_move_to (cr, x, y);
	cairo_save (cr);
	cairo_scale (cr, 1.0, -1.0);
	cairo_show_text (cr, "text here");
	cairo_restore (cr);

Hopefully that's still simple enough and saves you having to muck with
the font matrix.

I've not tested this, so if it doesn't work then blame me for typing too
fast.

-Carl

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : http://lists.cairographics.org/archives/cairo/attachments/20081022/1b5eb7f7/attachment.pgp