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Screen Point to Chart Coordinates

Posted: Thu Jul 20, 2017 8:04 am
by 16481290
Is there a way to obtain the Chart X and Y coordinates from a screen X, Y (mouse coordinates).

Thanks
Bernard

Re: Screen Point to Chart Coordinates

Posted: Fri Jul 21, 2017 6:36 am
by yeray
Hello,

You can use the Axis' CalcPosPoint to transform screen pixels to axis values. Ie:

Code: Select all

var XPixel: Integer;
    XValue: Double;
  //...
  XValue:=Chart1.Axes.Bottom.CalcPosPoint(XPixel);
Note you can also transform Axis values to screen pixels with CalcPosValue function. Ie:

Code: Select all

var XPixel: Integer;
    XValue: Double;
  //...
  XPixel:=Chart1.Axes.Bottom.CalcPosValue(XValue);
Another pair useful functions is the Series' CalcXPos/CalcYPos, returning the pixel position for a given ValueIndex. Ie:

Code: Select all

var XPixel, YPixel, ValueIndex: Integer;
    Series1: TPointSeries;
  //...
  XPixel:=Series1.CalcXPos(ValueIndex);
  YPixel:=Series1.CalcYPos(ValueIndex);

Re: Screen Point to Chart Coordinates

Posted: Wed Jul 26, 2017 12:30 am
by 16481290
Thanks for your response.

Where can I find the function 'CalcPosPixel' I have searched all of the directories under Steema TeeChart Pro VCL FMX 2017.22 but have not found it.

Bernard

Re: Screen Point to Chart Coordinates

Posted: Wed Jul 26, 2017 12:52 am
by 16481290
Never mind, I found it, in C++ Builder it's Chart1->Series->CalcXPosValue(.....

Thanks

Bernard