Alvin Bruney said:
Have you tried setting the minValue for the specified axis? That should
work.
--
Regards,
Alvin Bruney
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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 worksheet. The PutValue call will
fail if the user currently edits a cell (perhaps in another workbook) or
double-clicks one of the sheet 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
= 1 + i;
}
CComSafeArray<VARIANT> arrVal(CHANNEL_COUNT);
for (int i = 0; i < CHANNEL_COUNT; ++i) {
arrVal = 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);
}
}
