[Chart] A bunch of features and fixes.

[Tim Docker]

I don't think it's really worth creating a separate package depending on 
Chart.

I will shortly push these changes:

Fri Jan  6 02:49:11 EST 2012  malcolm.wallace at me.com
   * Add explicit opacity option for areaSpots and areaSpots4D

Wed Feb  1 08:06:08 EST 2012  tim at dockerz.net
   * Added prefixes to field names in SparkLine and SparkOptions to 
match existing conventions.

Wed Feb  1 07:58:09 EST 2012  tim at dockerz.net
   * Added sparkSize function, added sparklines test to the all_tests script

Wed Jun 22 03:45:24 EST 2011  malcolm.wallace at me.com
   * Demo for SparkLines.

Sun Jun 12 21:03:51 EST 2011  malcolm.wallace at me.com
   * Add Sparklines, based on the original hsparkline package, but using 
Cairo.


I'm not keen on this change:

Tue Jan 31 04:39:14 EST 2012  malcolm.wallace at me.com
   * An easier way of making a log axis.

The PlotValue type class is appropriate for many types (currently there 
are  5 instances). Your new method autoLogAxis is only ever going to be 
implemented for a small subset of these - most likely only Double. What 
was the difficuly in creating a log axis without this change? Test4.hs 
shows this being done the old way.

Tim


On 01/02/12 01:43, malcolm.wallace wrote:
>
>
>> Thanks - I'll work my way though looking at these. I've started with 
>> the sparkline stuff. It looks fine (and useful). Two comments:
>>
>> 1) field names in the SparkLine and SparkOption structures. As you 
>> would have no doubt noticed, I add a prefix to all public structure 
>> to avoid naming overlaps.
>
> Yes, that is my usual practice as well.  I think I just copied the 
> data structure from the existing sparklines package on hackage, which 
> is why I did not remember to change this.  Feel free to adjust to taste.
>
> I did also wonder whether it might make sense to release the 
> sparklines as a separate package, depending on Chart?
>
> Regards,
>     Malcolm
>