Different colors for one lineseries with 3 y-values?
lazarus / 55-TAChart

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wittbo · 2018-01-18 06:23

I have one lineseries containing 3 Y-values. When setting the color
for the series, then all three lines get the same color, is it
possible to assign different colors to the lines corresponding to the
three y-values or do I have to choose three different lineseries?

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wp · 2018-01-18 08:18

You should add a TChartStyles component and assign it to the "Styles"
of the series. Right-click on the Styles component and add three items
- each one of them corresponds to a line of the multi-valued series,
set its Pen accordingly.

See also http://wiki.lazarus.freepascal.org/TAChart_Tutorial:_Stacked_
BarSeries#Using_ChartStyles.

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wp · 2018-01-18 08:43

If you want to display a legend item for each of the y values you must
enter the legend text in the element Text of its corresponding Style
item, and the LegendMultiplicity of the series must be set to lmStyle.

Please note that the current version of TAChart crashes here. Use the
trunk version of Lazarus where I fixed this a minute ago. Or apply the
fix manually:
Open TASeries.pas (in (lazarus)/components/tachart)Find the
implementation of procedure TLineSeries.GetLegendItems.Add "lb:
TBrush" to the "var" declarations.Modify the case "lmStyle" of
Legend.Multiplicity to becomeCode: Pascal  [Select][+][-]window.onload
= function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i var  lb: TBursh;   // <--- ADD...  case Legend.Multiplicty
of...    lmStyle:      if Styles <> nil then begin    // <-- ADD
"begin"        if Assigned(p) then lb := p.Brush else lb := nil;   //
<--- ADD        for s in Styles.Styles do         
AItems.Add(TLegendItemLinePointer.CreateWithBrush(           
IfThen((lp <> nil) and s.UsePen, s.Pen, lp) as TPen,           
IfThen(s.UseBrush, s.Brush, lb) as TBrush,   // <--- USE "lb" instead
of "p.Brush"            p,            LegendTextStyle(s)          )); 
    end;    // <--- ADD