TDoublePoint in Chart
lazarus / 55-TAChart

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svdg · 2017-11-08 17:10

Maybe I'm not right here with my question and maybe it's a stupied
question.
I want to get the x,y position under the mouse cursor in an xy chart.
I find several solutions on this board, but they nearly always fall
back on introducing a variable type TDoublePoint.
If I do this, I get the error : Identifier not found "TDoublePoint".
I'm using Lazarus 1.6 under Windows 10 and Linux and get the same
error.
Did I forget something?
Any help would be appreciated.

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howardpc · 2017-11-08 17:41

You don't say which XY chart component you are using.
If it does not provide an OnMouseMove event, then you can use some
adaptation of this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
...LCLIntf, ...; ...var  pt: TPoint;begin  if GetCursorPos(pt) then
begin    pt:=ScreenToClient(pt);    WriteLn('mouseX=',pt.x,',
mouseY=',pt.y); // or use pt.x, pt.y to suit your need  end; end;
The raw pt value is a screen coordinate, so for most uses needs to be
transformed into coordinates appropriate to your form or control.

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wp · 2017-11-08 17:48

TDoublePoint is declared in TAChartUtils - this is the first place to
look for declarations not found. Other often-seeked units are
TACustomSeries, TACustomSource and TAGeometry.

"Secret" hint: Click on these words in the uses clause with the CTRL
key down to open these units in the source editor - now you can browse
and see which treasures they contain (works, of course, throughout any
source file).

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svdg · 2017-11-08 21:43

Thanks a lot!