Re: [Haskell-cafe] Re: Why binding to existing widget toolkits doesn't make any sense

On Fri, Jan 30, 2009 at 4:25 PM, Bryan O'Sullivan wrote:

On Fri, Jan 30, 2009 at 1:11 PM, Antony Courtney wrote:

...

A 2-D vector graphics library such as Java2D ( or Quartz on OS/X or GDI+ on Windows ) supports things like computing tight bounding rectangles for arbitrary shapes, hit testing for determining whether a point is inside or outside a shape and constructive area geometry for shape compositing and clipping without dropping down to a raster representation.

These are the kinds of capabilities provided by Cairo, which is very pleasant to use (PDF-style imaging model) and quite portable. There are already Cairo bindings provided by gtk2hs, too.

Hi Bryan, Nice to hear from you! Been a while... Just had a quick look and it does indeed appear that Cairo now supports some of the features I mention above (bounds calculations and hit testing). Cairo has clearly come a long way from when I was last working on Fruit and Haven in 2003/2004; back then it looked like it only provided a way to render or rasterize vector graphics on to bitmap surfaces and not much else. It's not clear to me if the Cairo API in its current form supports vector-level clipping or constructive area geometry, and it looks like the API is still pretty render-centric (e.g. is it possible to obtain the vector representation of rendering text in a particular font?). That might make it challenging to use Cairo for something like the Haven API, but maybe one can live without that level of generality. In any case: delighted to see progress on this front! Hopefully some enterprising Haskell hacker will wrap Cairo in a nice purely functional API. -Antony