TRectangleTool - Some questions ...

[moelski]

Hi !

I want to implement TRectangleTool in my application.
Creating the the tool is easy:

Code: Select all

  RectTool := TRectangleTool.Create(self);
  RectTool.Text := 'Test';
  Chart1.Tools.Add(RectTool);

But then the problems getting bigger and bigger
1) How can I recognize that the mouse is over a TRectangleTool if the user clicks with the right mouse button? I want to show a special popupmenu for editing the TRectangleTool (text, font, callout, ...).
2) Normally the zoom don´t work for TRectangleTool. How can I change this? It would be great if the tool get´s the new correct position after zoom.

Did you have some example code for me?

[Narcís]

Hi Dominik,

1. You can use OnMouseDown event and tool's Clicked method like this:

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procedure TForm1.Chart1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if ((Button=mbRight) and (ChartTool1.Clicked(X,Y)))then
  begin
    //Write your code here.
  end;
end;

2. For this to work fine you should set the TRectangleTool position to a relative element in the chart (series, axes, legend, ...) and update this position every time the chart is being zoomed or scrolled, for example:

Code: Select all

procedure TForm1.FormCreate(Sender: TObject);
begin
  SetRectPos;
end;

procedure TForm1.SetRectPos;
begin
  Chart1.Draw;
  ChartTool1.Shape.CustomPosition:=true;
  ChartTool1.Shape.Left:=Series1.CalcXPos(5);
  ChartTool1.Shape.Top:=Series1.CalcYPos(5);
end;

procedure TForm1.Chart1Zoom(Sender: TObject);
begin
  SetRectPos;
end;

procedure TForm1.Chart1UndoZoom(Sender: TObject);
begin
  SetRectPos;
end;

procedure TForm1.Chart1Scroll(Sender: TObject);
begin
  SetRectPos;
end;

[moelski]

Hi Narcis,

ChartTool1.Shape.Left:=Series1.CalcXPos(5);
ChartTool1.Shape.Top:=Series1.CalcYPos(5);

Well this seems to be tricky ....
Would it be possible to do calculate the new position a little bit more dynamically? Here are my problems:
1) What will happend if series1 isn´t visible?
2) What will happen if no series is visible?

I have tried to use your code in this way:

Code: Select all

  TRectangleTool(Chart1.Tools[1]).Shape.Left           := Series1.CalcXPos(TRectangleTool(Chart1.Tools[1]).Shape.Left);
  TRectangleTool(Chart1.Tools[1]).Shape.Top            := Series1.CalcYPos(TRectangleTool(Chart1.Tools[1]).Shape.Top);

But this won´t work for me.

So could you please add a small piece of code which changes the position of the rectangle tool against it´s actual position.
And what about the Callouts. Must I recalculate the endpoint, too?

btw: Clicking on a rectangle tool works fine for me now !

[Narcís]

Hi moelski,

Well this seems to be tricky ....
Would it be possible to do calculate the new position a little bit more dynamically? Here are my problems:
1) What will happend if series1 isn´t visible?
2) What will happen if no series is visible?

This is dynamic because whenever the chart is zoomed or scrolled the rectangle position is changed accordingly as well. However this is just an example. If you don't relate rectangle's position to series you can make it relative to chart axes for example:

Code: Select all

procedure TForm1.SetRectPos;
begin
  Chart1.Draw;
  ChartTool1.Shape.CustomPosition:=true;
  ChartTool1.Shape.Left:=Chart1.Axes.Left.PosAxis + 10;
  ChartTool1.Shape.Top:=Chart1.Axes.Bottom.PosAxis - 10;
end;

I have tried to use your code in this way:
Code:
TRectangleTool(Chart1.Tools[1]).Shape.Left := Series1.CalcXPos(TRectangleTool(Chart1.Tools[1]).Shape.Left);
TRectangleTool(Chart1.Tools[1]).Shape.Top := Series1.CalcYPos(TRectangleTool(Chart1.Tools[1]).Shape.Top);

But this won´t work for me.

CalcXPos and CalcYPos methods doesn't work that way. Those methods return a pixel screen position from given series point ValueIndex. Look at the different methods provided for calculating from chart values to pixel screen coordinates and viceversa.

So could you please add a small piece of code which changes the position of the rectangle tool against it´s actual position.

A simple example would be something like this:

Code: Select all

procedure TForm1.SetRectPos;
begin
  Chart1.Draw;
  ChartTool1.Shape.CustomPosition:=true;
  ChartTool1.Shape.Left:=ChartTool1.Shape.Left + 10;
  ChartTool1.Shape.Top:=ChartTool1.Shape.Top - 10;
end;

Don't forget the Draw call in the SetRectPos method in all the examples I posted.

And what about the Callouts. Must I recalculate the endpoint, too?

Yes, the same for the callout needs to be done.

[moelski]

Hi Narcis,

thx for your answer but I won´t get it working

So could you please make a small demo application with the following features:
1) the RectangleTool has always the same width / heigth if you do zooming or panning.
2) the tool will be placed at the correct position after zooming / scrolling and don´t stay at the position before zooming / scrolling.

This would solve my problems. With that code I can implament the callout option by myself.

Thx in advance !!

[moelski]

Hi Narcis,

I spend a pro support mail. I think this is a bigger problem (for me).

Greetz Dominik