[GRASS-dev] Cairo monitor driver

[Glynn Clements]

Hamish wrote:

> > Doing it client side can be a major performance hit. Apart from
> > anything else, all of the rendering has to be done in software; your
> > graphics hardware can't help.
> 
> Even if we use the much faster PNG(PPM) driver for fast GUI rendering, it sure
> would be nice to click a "quality mode" switch in the GUI to switch to the
> Cairo driver to create presentation quality output. For hardcopies (or softcopy
> raster output for presentation or web publication) quality is much more
> important than speed. (up the point it takes all night to render)  For the GUI
> speed becomes the important factor, quality is reduced to a nice bonus.

For presentation quality, I'm not sure that Cairo offers anything that
you can't get with PostScript. Either way, anti-aliasing should be
done using oversampling rather than at the primitive level.

The main obstacles are architectural, i.e. the use of integer
coordinates, hard-coded sizes (including line widths), and text
rasterisation (I can fix the last one easily enough for the PS
driver).

-- 
Glynn Clements <glynn at gclements.plus.com>