stack areas again :-)

[TestAlways]

8.06, D2007

I have spent all afternoon (3+ hours now-) trying to figure out how to get the attached demo to work. There are three different datasets in the demo, and none of them look right--maybe I am trying to accomplish something that is not possible.

I want the area to be full, with no dead area in the chart. The stacked areas should fill the area of the sum of the values.

Can this be done for all 3 datasets with the same code? If so, what am I missing?

Ed Dressel

[bookman]

Ed,

I'm not exactly sure what you're ultimately looking for, so I plotted your data in Excel (one of your cases), and then tweaked your code so the plots looked similar (at least to me). Is this kinda what you had in mind?

pic1.png (31.05 KiB) Viewed 20611 times

[TestAlways]

What I am wanting is a little different. When a series goes to zero, I want it to step down right away, not draw a line to zero. Here is a sample chart that steps down:



The green area series works perfectly here.

Let me explain what I am showing--the chart represents income during retirement. The green chart is income is from a cash account that runs out of money in year 16. If I show a step down from there to year 17, it appear it still has money after that. But actually it is running out in year 16, and it should step down (as shown above)

I can do this with charts that do not have many series, but when a large number of series are to be drawn, and/or when a series starts in the middle of the chart, I cannot get the chart to display correctly.

Ed Dressel

[bookman]

Ed,

Ahh, I understand the problem. I've tried a few things (probably like you) and always end up with a little unfilled triangle somewhere.

My only thoughts, if the Steema folks don't have a solution:

Bar Graph. Data seems tailor made for that...
Custom Drawing. Either custom draw the little triangle, or draw polygons in lieu of the series.

Best of luck.

[Narcís]

Hello Ed and bookman,

First of all notice that to use stacked area series you need to have same number of points and those must have the same X values. This not being the case might lead to such problems. Also, we have implemented a fix for stacked area series with negative values for next maintenance release but this may not apply to the issue discussed here.

[TestAlways]

First of all notice that to use stacked area series you need to have same number of points and those must have the same X values. This not being the case might lead to such problems.

I was aware of that and int he header of the demo app put the number of points for each series:



I also included the ability to see the data for each stacked area.

I am not sure how to do this--or if it can be done--on a generic basis.

Ed Dressel

[Narcís]

Hi Ed,

To get a chart similar to the image you posted on 1st June you could try using 3 series and add null values to green or pink series where values shouldn't exist. I recommend you to have a look at the All Features\Welcome!\Chart Styles\Area\Area TreatNulls example in the new features example, available at TeeChart's program group.

If this doesn't help, do you think any of the 3 datasets in your original project contains a data structure as in mentioned chart? Otherwise, could you please attach a simple example project or, at least, some date which should produce such chart structure? We will try to help you getting it.

Thanks in advance.

[TestAlways]

I recommend you to have a look at the All Features\Welcome!\Chart Styles\Area\Area TreatNulls example in the new features example, available at TeeChart's program group.

I installed the 8.06 with full source, which doesn't look like it includes the demo. Is there any way to just get the demo without installing over the top of the existing code?

Thank you,

Ed Dressel

[Yeray]

Hi Ed,

As you know, the compiled demo has a sources tab, so that's all you need, isn't it?

[TestAlways]

I found a fix--I do self stacking. Here is a screen shot of what I am looking for (the unevenness in the chart on the slope is due to rounding errors--I didn't type in the decimals for the data):



I changed the code so that it stacks itself:

Code: Select all

for I := High(lChartData) downto Low(lChartData) do
begin
  Chart1.FreeAllSeries;
  lChartData := GetChartData;
  for I := High(lChartData) downto Low(lChartData) do
  begin
    lsrs := CreateChartSeries(I, maNone);;
    for J := 0 to High(lChartData[I]) do
    begin
      lIncome := 0;
      for K := 0 to I do
        lIncome := lIncome + lChartData[K, J];
      if (lIncome > 0) then
        lsrs.AddXY(J, lIncome, IntToStr(J))
      else
        lsrs.AddNullXY(J, 0, IntToStr(J));
    end;
  end;
end;

I could not get this result with the maStacked option.

I have attached the project for anyone wanting to review it.

Ed Dressel

[Narcís]

Hi Ed,

Excellent, thanks for sharing