data structures in TAChart lazarus / 55-TAChart ---------------------------------------------------------------------- greatUnknown · 2012-09-04 15:08 a) In [TARadialSeries] TPolarSeries there is a published property Source, with no read or write access.     Why not use the property in the ancestor class [TACustomSeries] TChartSeries by publishing     the existing property Source with the read and write methods? b) In [TACustomSource] TCustomChartSource there is a property Count with a read method which     is virtual abstract.  Why not add a write method procedure setCount (ACount: Integer); virtual; abstract;     which would allow changing the count as necessary c) In [TASources] TUserDefinedChartSource there is a field FPointsNumber accessible through the property     PointsNumber with read and write methods.  Why use this term instead of the Count term     used in other sources and just inherit the Count from the ancestor classes? d) I suspect this is all to protect Count from write access.  If so, why? ---------------------------------------------------------------------- Ask · 2012-09-04 17:25 QuoteTPolarSeries there is a published property Source, with no read or write access.     Why not use the property in the ancestor class [TACustomSeries] TChartSeries by publishing    the existing property Source with the read and write methods?The code does exactly that. Why do you think otherwise? Quoteprotect Count from write access.  If so, why?Basically, there are two strategies here -- implement SetCount and have it throw exception for the sources which do not allow changing number of points, or not implement SetCount and use other mechanism for those that do. Currently, changing number of points is supported by 2 out of 8 sources, so it is more economical to use first strategy. The difference is not large, so it is also a kind of historical accident. By the way, did the animated source help you? I have partially implemented it hoping for you feedback to continue. ---------------------------------------------------------------------- greatUnknown · 2012-09-04 19:04 QuoteThe code does exactly that. Why do you think otherwise? Because when I tried to access Source in TPolarSeries, I had compiler problems.  I'll have to check again. QuoteBy the way, did the animated source help you? I have partially implemented it hoping for you feedback to continue. Haven't had time to check it yet, but I looked at the demo quickly and it looks like what I need. I still have to absorb event-driven programming a bit more. I've been working on simpler display issues such as squaring the aspect of the graph display by manipulating extent.  For polar graphs, you can see why this is important. [attachments] ---------------------------------------------------------------------- Ask · 2012-09-04 19:44 Quotesquaring the aspect of the graph display by manipulating extent Try setting Chart.Proportional = true ---------------------------------------------------------------------- greatUnknown · 2012-09-04 19:49 So many options, so sparse documentation... ---------------------------------------------------------------------- wp · 2012-09-04 21:09 TAChart is a very flexible component, it cannot be expected to control everything with a handful of settings.  Documentation could be better, I agree, but the complete docs will be a thick book which nobody is reading... Anyway, there is some progress: Do you know these? http://wiki.lazarus.freepascal.org/TAChart_documentationhttp://wiki.la zarus.freepascal.org/TAChart_Tutorial:_Getting_startedhttp://wiki.laza rus.freepascal.org/TAChart_Tutorial:_ListChartSource,_Logarithmic_Axis ,_Fittinghttp://wiki.lazarus.freepascal.org/TAChart_Tutorial:_Userdefi ned_ChartSource ---------------------------------------------------------------------- greatUnknown · 2012-09-04 21:40 I've seen all of those, as well as going through most of the demos, but ASK, you, and others seem to be pumping out improvements faster than anyone can document them.  Not that I'm complaining... But it would be nice to have a reference of the various types and options without printing out - and analyzing - about fifty ta* units.  Just a list, with the public elements and a few words about what they do. Maybe a project for my "spare time", but I don't know the system and its interactions at all. ---------------------------------------------------------------------- Ask · 2012-09-05 02:16 Quotereference of the various types and optionshttp://wiki.lazarus.freepascal.org/TAChart_documentation is intended to be such reference. It is little less terse than a simple list, but still aims to be short yet comprehensive. It is, of course, not prefect -- thank you for noticing another omission. I have now documented Chart.Proportional property.