[Lazarus] TAChart 2nd Y Axis

David M. Lawrence dave at fuzzo.com
Thu Jul 28 16:04:57 CEST 2011


Thanks, Alexander.

I have tried to deconstruct the code in the demo, but cannot understand 
it works, and my efforts to copy the code end in unspecified access 
violations.

In any event, I cannot set up simple multipiers like you have in the 
sample -- I have a database with hundreds of climate data files, and 
with new climate normals being released, would like to add hundreds 
more.  Each data set would have to be transformed individually.

It might be more helpful to be able to set max and min values in 
TUserDefinedChartSource -- you have that capability in 
TRandomChartSource (that much I did understand from the axis demo).

Thanks again,

Dave

On 7/28/2011 5:56 AM, Alexander Klenin wrote:
> On Thu, Jul 28, 2011 at 14:32, David M. Lawrence<dave at fuzzo.com>  wrote:
>> Was the 2nd-Y axis patch (No. 13832;
>> http://bugs.freepascal.org/view.php?id=13832) ever incorporated into the
>> Lazarus/TAChart release?  I'm new to Lazarus and don't quite know how to
>> interpret the bugtracker page.  I do know that I cannot find some of the
>> changes mentioned in the patches -- such as for TAGraph -- in the latest
>> version of TAGraph.
> The changes were not taken literally. Instead, I have implemented more general
> solution, allowing arbitrary number of axises with arbitrary transformations,
> but at the cost of some additional complexity.
>
>> I do scientific programming and am trying to update some of my older
>> Delphi/Pascal programs.  I need the ability to independently set YMax and
>> YMin values for both Y axes on climate diagrams (which plot both monthly
>> precipitation and temperature data) on the same chart.  Precipitation data
>> are plotted as bar graphs, temperature data are plotted by line series.  I
>> can get all the data series plotted, but I cannot get the precip and temp
>> data scaled properly.
> If you are using 0.9.30 release, see "axis" demo.
> If you are using trunk/snapshot, see "axistransf" demo.
>

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