Re: column chart with logarithmic scaling

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From: Alvin Bruney [ASP.NET MVP] (www.lulu.com/owc)
Date: 03/15/05 

Date: Tue, 15 Mar 2005 18:25:34 -0500

Sorry for the delay my laptop was down for a couple days.

couple things
- i'm not sure what you benefit you are getting by declaring the chart on
the heap, why isn't it a stack object?

My add-in is supposed to work with excel 2000 and later
> versions, so I #import the excel 2000 typelib in my ATL project. But I am
> really not sure about owc. All I know is that the user will have excel
> installed. Is OWC always installed or can the user unselect it during
> setup? And what typelib should I use so that regardless of the excel
> version my code always works?

if you are working with office 2000 servicing owc version 9, it is safe to
assume that the owc is installed. if you are targetting office xp which is
the same family of office 2000 products, you will have to write a sniffer
routine to detect whether or not the user has the owc installed. with
versions 10 and 11, owc is standalone so there really is no guarantee that
it will be on the users system.

for the larger issue, it seems that the OWC makes certain assumptions on the
data with respect to the values that it plots. Without knowing these
assumptions, I cannot classify it as a bug. I'd recommend that you submit an
incident report to microsoft product support to find resolution on the
issue. They can crack the OWC chart code open and find the assumptions. Less
tylenol that way... 

-- 
Regards,
Alvin Bruney
[Shameless Author Plug]
The Microsoft Office Web Components Black Book with .NET
available at www.lulu.com/owc
_________________________
"Dirk" <dirk.kapusta@discussions.microsoft.com> wrote in message 
news:e7baa0cIFHA.3472@TK2MSFTNGP09.phx.gbl...
>
> "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> a écrit dans le message de 
> news: Of3iI$ZIFHA.3076@tk2msftngp13.phx.gbl...
>> Have you tried setting the minValue for the specified axis? That should
>> work.
>>
>> --
>> Regards,
>> Alvin Bruney
>>
>> [Shameless Author Plug]
>> The Microsoft Office Web Components Black Book with .NET
>> available at www.lulu.com/owc
>> ------------------------------------------------------------
> Hello Alvin
>
> Perhaps I was a bit unclear. I have specified a minimum of 0.1 and the 
> values axis really starts there, but the bars are not drawn below value 1. 
> This is the case for all values >= 1.0 (I have attached a picture of this 
> scenario). If the values are < 1 they are drawn from the value 1 down to 
> their real value. Further below is the code that creates the chart. The 
> code uses version 9 of msowc.dll and the chart is hosted on a dialog of an 
> Excel COM add-in. I use this modal dialog during some data aquisition from 
> an external measurement device. The add-in has event handlers to get the 
> data and then puts it into a prepared work***. The PutValue call will 
> fail if the user currently edits a cell (perhaps in another workbook) or 
> double-clicks one of the *** tabs and Excel would display a dialog 
> saying the workbook is protected. During this time Excel will not allow 
> PutValue calls for the Range object and the data would be lost. The only 
> reliable way I have found is to display a modal dialog during the 
> measurement procedure that disallows any other interaction with Excel.
> Therefore I looked at the web components to get a chart on my dialog. 
> Actually I was very pleased to find out that owc version allows maximum 
> values on a  log scale axis that are not integer powers of 10, e.g. 300. 
> This cannot be achieved with normal excel charts.
> The only problem I see with owc relates to compatibility. I have seen a 
> lot of posts about this. My add-in is supposed to work with excel 2000 and 
> later versions, so I #import the excel 2000 typelib in my ATL project. But 
> I am really not sure about owc. All I know is that the user will have 
> excel installed. Is OWC always installed or can the user unselect it 
> during setup? And what typelib should I use so that regardless of the 
> excel version my code always works?
>
> void MeasInfoDlg::CreateChart()
> {
>  try
>  {
>    chart_.Attach(GetDlgItem(IDC_CHART2));
>    IUnknownPtr pIUnk;
>    HRESULT hr = chart_.QueryControl(&pIUnk);
>    ATLASSERT(SUCCEEDED(hr));
>    if (SUCCEEDED(hr))
>    {
>      OWC::WCWebChartPtr webChart = pIUnk;
>      webChart->AllowAboutDialog = VARIANT_FALSE;
>
>      OWC::WCChartPtr ch = webChart->Charts->Add(-1);
>      ch->Type = OWC::chChartTypeColumnClustered;
>
>      // set up values axis
>      OWC::WCAxisPtr yAxis = ch->Axes->Item[0];
>      yAxis->HasTitle = VARIANT_TRUE;
>      yAxis->Title->Caption = L"Values";
>      yAxis->Scaling->Type = OWC::chScaleTypeLogarithmic;
>      yAxis->Scaling->Minimum = 0.1;
>
>      // set up category axis
>      OWC::WCAxisPtr xAxis = ch->Axes->Item[1];
>      xAxis->HasTitle = VARIANT_TRUE;
>      xAxis->Title->Caption = L"Categories";
>
>      yAxis->CrossingAxis = xAxis;
>      xAxis->CrossesAtValue = 0.1;
>
>      CComSafeArray<VARIANT> arrCat(CHANNEL_COUNT);
>      for (int i = 0; i < CHANNEL_COUNT; ++i) {
>        arrCat[i] = 1 + i;
>      }
>
>      CComSafeArray<VARIANT> arrVal(CHANNEL_COUNT);
>      for (int i = 0; i < CHANNEL_COUNT; ++i) {
>        arrVal[i] = 10 * (CHANNEL_COUNT - i + 1);
>      }
>
>      _variant_t varCat;
>      varCat.parray = arrCat.Detach();
>      varCat.vt = VT_ARRAY | VT_VARIANT;
>      ch->SetData(OWC::chDimCategories, OWC::chDataLiteral, varCat);
>
>      _variant_t varVal;
>      varVal.parray = arrVal.Detach();
>      varVal.vt = VT_ARRAY | VT_VARIANT;
>      OWC::WCSeriesPtr series = ch->SeriesCollection->Add(-1);
>      series->SetData(OWC::chDimValues, OWC::chDataLiteral, varVal);
>
>      webChart->ExportPicture(L"c:\\chart01.gif", L"GIF", -1, -1);
>    }
>
>  }
>  catch(const _com_error &e)
>  {
>    _bstr_t desc = e.Description();
>    ATLTRACE2(atlTraceGeneral, 0, _T("%s : %X\n"), (!desc) ? _T("-") : 
> (LPCTSTR)desc, e.Error);
>  }
> }
>
>
>
>
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