TChart find valueindex with mousemove over bottom

问题:

Delphi 7 and TChart version 2014Delphi7

I have a 3d TChart with 16 bar series and 16 values. (a 16x16 3d bar chart)

When I move the mouse over the bottom axis I need to know the valueindex of the series the mouse is over.

I want to hide(transparency=75) all other values so only the bars for that index are displayed. (show only that index for all series so displayed is in effect a 1x16 chart)

How can I get the index the mouse is over?

回答1:

The Series' Clicked(X,Y) function returns -1 if the series isn't under the (X,Y) position (in pixels). If the series is under the (X,Y) position (in pixels), it returns the index of the point under the series.

Here you have a simple example using the OnMouseMove event:

uses Series;

procedure TForm1.FormCreate(Sender: TObject);
var i: Integer;
begin
  Chart1.View3D:=false;

  for i:=0 to 2 do
    Chart1.AddSeries(TBarSeries).FillSampleValues(3);
end;

procedure TForm1.Chart1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var seriesIndex, valueIndex: Integer;
begin
  Caption:='No series under the mouse';

  for seriesIndex:=Chart1.SeriesCount-1 downto 0 do
  begin
    valueIndex:=Chart1[seriesIndex].Clicked(X,Y);
    if valueIndex>-1 then
      Caption:='Series under the mouse. SeriesIndex: ' + IntToStr(seriesIndex) + ', ValueIndex: ' + IntToStr(valueIndex);
  end;
end;