FastCalc question

[Bert B.]

One way to speed up drawing is setting Axes.FastCalc to True. After some testing I didn't see any difference on screen, but the performance of drawing a chart is slightly better.

Is there any situation where setting it to False is better?

My suggestion is to remove this property and set the behaviour to True. Everyone will benefit from the increased performance without additional work.
As second benefit can be found in TeEngine: TChartAxis.SetCalcPosValue where the if-statement 'if ParentChart.Axes.IFastCalc' can be removed.
What do you think?

Bert

[Sandra]

Hello Bert,

I am afraid that won't be possible remove this property and set the behaviour to True, so you need setting Axes.FastCalc= false for definition of behaviour about property FastCalc that you can find in TeeChar Vcl Library Reference:
This property controls if calculations from series values to screen pixel coordinates will be performed with "overflow checking" or not.
FastCalc is False by default.
When False, calculations are checked against Microsoft Windows GDI limits (XP,2000 and NT have bigger limits than Me,98 and 95).
When True, calculations are done using fast assembler code, without checking GDI overflows.
The main use of FastCalc=True is for real-time charts to obtain more drawing speed, when we know points will not be outside the chart space by a really big amount of pixels.
The default calculation (with checking) is necessary when zooming-in a chart many times, to avoid confusing Windows GDI with very big pixel coordinates.

Thanks,

[Bert B.]

OK, thanks for the explanation.