xlsgen 4.9 adds HTML markup to all rich label formattings, not only in cells.

Rich label formatting is in many other places, notably text boxes, comments, vector shapes, chart elements (titles, data labels, ...), and the only way so far to put more than one formatting run in rich labels was to create multiple styles and pass them. In other word, there wasn't for the rich label object model, the same mechanism that was added years ago for cells, which is the ability to either pass styles (one style for each formatting run) or use HTML markup.

So what xlsgen 4.9 introduces is the ability to use HTML markup as well in general purpose rich labels. Of course, you can also read existing formatting runs and obtain the HTML markup. Last but not least, the automatic source code generator tool exposes the HTML markup in rich labels.

So if you open Excel, insert a text box, write this This is blue text in it, save the file, then open the automatic source code generator, you'll get the following source code fragment in the programming language of your choice, here C/C++ :

xlsgen::IXlsTextBoxPtr textbox001s0 = wksht001->NewTextBox(4, 3, 9, 7, 38, 208, 128, 896);
xlsgen::IXlsRichLabelPtr richLabel001s000c0 = wksht001->NewRichLabel();
richLabel001s000c0->HtmlLabel = L"<font color=#000000 size=11 name=\"Calibri\"><b>This is </b></font><font color=#00B0F0 size=11 name=\"Calibri\"><b>blue </b></font>" \
L"<font color=#000000 size=11 name=\"Calibri\"><b>text</b></font>";
textbox001s0->RichLabel = richLabel001s000c0;

Before this, here is what you had to write :

xlsgen::IXlsTextBoxPtr textbox001s0 = wksht001->NewTextBox(4, 3, 9, 7, 38, 208, 128, 896);

xlsgen::IXlsStylePtr styleDefault = wksht001->NewStyle();
styleDefault->Font->Bold = TRUE;
styleDefault->Apply();

xlsgen::IXlsStylePtr styleBlue = styleDefault->Duplicate();
styleBlue->Font->Color = 0x0000FF;
styleBlue->Apply();

xlsgen::IXlsRichLabelPtr richLabel001s000c0 = wksht001->NewRichLabel();
richLabel001s000c0->Label(L"This is ", styleDefault);
richLabel001s000c0->Label(L"blue ", styleBlue);
richLabel001s000c0->Label(L"text", styleDefault);

textbox001s0->RichLabel = richLabel001s000c0;