Steema Central

arekay wrote:I get strange hovering behavior with a simple TLineSeries in VCL. In this example, my cursor is over the third point in the line, which is highlighted correctly, but only the first segment (connection between two points) is highlighted. The highlighted segment is always one behind the point being hovered on; if I highlight the fourth (rightmost) point, the second segment is highlighted. Is this supposed to happen?

arekay wrote: I would like to turn off the segment highlighting while keeping the point highlighting, but I cannot find a way to do it.

var ClickedIndex: Integer;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Series1.Selected.Hover.Visible:=False;

  Series1.OnGetPointerStyle:=Series1GetPointerStyle;
end;

procedure TForm1.Chart1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var i, ValueIndex : Integer;
    tmpP          : TPoint;
begin
  ClickedIndex:=Series1.Clicked(X, Y);

  tmpP:=Point(Series1.CalcXPos(ClickedIndex), Series1.CalcYPos(ClickedIndex));
  if Series1.Pointer.Clicked(Series1.Pointer.Style, tmpP, Chart1.GetCursorPos.X, Chart1.GetCursorPos.Y) then
     Chart1.Draw
  else
     ClickedIndex:=-1;
end;

function TForm1.Series1GetPointerStyle(Sender: TChartSeries;
  ValueIndex: Integer): TSeriesPointerStyle;
begin
  with (Sender as TLineSeries).Pointer do
  begin
    result:=Style;
    Brush.Color:=Sender.Color;
    Pen.Color:=clBlack;

    if (ValueIndex<>-1) and (ClickedIndex=ValueIndex) then
       Pen.Color:=clRed;
  end;
end;

arekay wrote:Another slightly odd thing that this test showed me is that in 3D mode the line segment between two points can be hovered over, but in 2D mode only the points can be hovered over. Is this intentional? Can line hovering be added for 2D, or made optional?

arekay wrote:Actually, an idea that would make hovering better for my application, and maybe some others', would be to give the option of highlighting the line segments on both sides of the point being hovered over, rather than only the forward one (because clicking on and dragging that point will alter both line segments). If it would be possible to include an option like that in the future, it would be nice.

Yeray wrote:However, the highlighting both line segments when hovering a pointer, as you request, is also an option to consider.
An idea would be to add a property (ie Pointer.HoverStyle) to select what line segments to show when hovering a pointer. I've added it to the public tracker:
http://bugs.teechart.net/show_bug.cgi?id=1936

Changed Pointer.HoverStyle property to HoverElement, a property for all the series, at TChartSeries. It's a set, with the possible values:

- hePrevious: Disabled by default. When active, highlights the element previous to the element below the mouse.

- heNext: Disabled by default. When active, highlight the element next to the element below the mouse.

- heCurrent: Enabled by default. When active, highlights the element below the mouse.

- heJoin: Disabled by default. When active, Pointer and Mark are treated as the same hover element.

Elements are: line segments, area segments, pointers, or pointer+mark.

See the project attached to test all the new properties