Weeknum functionality

[peters]

Hi,

Does TeeChart support weeknum date format in chart settings? I have weekly collected data and I want to label my X-axis as

01/2011, 02/2011 etc.

where first number is a week number in the year.

Thanks
Peters

[Yeray]

Hi Peters,

I'm afraid it's not supported automatically. But you can always format the axis labels at OnDrawLabel event as in the example at "All features\Welcome !\Axes\First and Last Labels".

[Narcís]

Hi Peters,

For completeness, you may use DateUtils.WeekOfTheYear method for that.

[peters]

Thanks for suggestions.

Maybe in the next releases you will consider something like ''ww/yyyy" in date formating options. It would be useful improvement .

Peters

[Yeray]

Hi Peters,

I've added it to the wish list to be implemented in future releases (TV52015832).

[peters]

Hi,

I have almost found a solution which looks like this:

Code: Select all

procedure TMyChart.ChartGetAxisLabel(Sender: TChartAxis;
  Series: TChartSeries; ValueIndex: Integer; var LabelText: String);
const
  WW = 'ww';
var
  WeekNum : string;
begin
  if Sender.IsDateTime and (pos(WW, Sender.DateTimeFormat) > 0) then
     try
       WeekNum := IntToStr(WeekOfTheYear(StrToDate(LabelText)));
     except
       WeekNum := 'ERR';
     end;
     LabelText := StringReplace(LabelText, WW, WeekNum, [rfReplaceAll]);
end;

The problem is that instead of LableText I need original X-axis value, because LabelText is ALREADY formated and StrToDate returns error during convertion. So my question is how to get here oryginal bottom axis value BEFORE formating.

Thanks
Peters

[peters]

Hi,

I have dug a little in the source code and I think I have a solution, but it would require changes in source code of TeEngine. Date formatting is done in LabelValue function. It gets its parameter (date value for x-label tick) from DoDeaultLabels procedure, but actual x-value is stored only in temporary tmpValue variable which is not published. So now I can see 3 solutions:

1) publish tmpValue as a property and than us it in OnGetAxisLabel
2) overwrite LabelValue function with code from my previous post
3) overwrite DateTimeToString standard VCL function and implement there the interpretation of "ww" formatting

Because of compatibility with next releases all of them are not safe. Maybe anyone has better idea? .

Thanks
Peters

[Yeray]

Hello Peters,

1) publish tmpValue as a property and than us it in OnGetAxisLabel
2) overwrite LabelValue function with code from my previous post
3) overwrite DateTimeToString standard VCL function and implement there the interpretation of "ww" formatting

The second option is the one I think could be interesting. It will be considered when TV52015832 will be deeply studied.
In the meanwhile, what about using Custom Labels?

Code: Select all

uses Series, DateUtils;

procedure TForm1.FormCreate(Sender: TObject);
var i, last: Integer;
    tmpDate: TDateTime;
    diff: Double;
begin
  Chart1.View3D:=false;
  Chart1.Legend.Visible:=false;
  Chart1.Axes.Bottom.LabelsAngle:=90;
  Chart1.Axes.Bottom.DateTimeFormat:='ww/yyyy';

  with Chart1.AddSeries(TFastLineSeries) as TFastLineSeries do
  begin
    XValues.DateTime:=true;

    tmpDate:=StrToDateTime('01/01/2011');
    AddXY(tmpDate, random*100);
    for i:=0 to 20 do
    begin
      tmpDate:=IncDay(tmpDate,7);
      AddXY(tmpDate, YValue[Count-1] + random*10-5);
    end;

    Chart1.Axes.Bottom.Increment:=DateTimeStep[dtOneWeek];
    Chart1.Axes.Bottom.Items.Clear;
    Chart1.Axes.Bottom.Items.Add(XValue[0],StringReplace(FormatDateTime(Chart1.Axes.Bottom.DateTimeFormat,XValue[0]), 'ww', IntToStr(WeekOfTheYear(XValue[0])), [rfReplaceAll]));
    last:=0;
    for i:=1 to Count-1 do
    begin
      if (XValue[i]-XValue[last] >= Chart1.Axes.Bottom.Increment) then
      begin
        Chart1.Axes.Bottom.Items.Add(XValue[i],StringReplace(FormatDateTime(Chart1.Axes.Bottom.DateTimeFormat,XValue[i]), 'ww', IntToStr(WeekOfTheYear(XValue[i])), [rfReplaceAll]));
        last:=i;
      end;
    end;
  end;
end;