gdi32 : Questions about SetDIBColorTable and GetDIBColorTable

Laurent Vromman laurent at vromman.org
Mon Apr 16 09:40:40 CDT 2007


Hi,

I am looking deeper inside gdi32 in order to continue helping wine after my first try on WidenPath.

Something looks strange to me in SetDIBColorTable and GetDIBColorTable.

GetDIBColorTable is structured like this : 

if (dc->funcs->pGetDIBColorTable)
    result = dc->funcs->pGetDIBColorTable;
else
{
    result = local implementation;
}
return result;

This looks normal. If dc->funcs->pGetDIBColorTable is available, wine uses it, else it uses a local implementation.
In both cases, the return value is the result of the chosen operation.

But I have more difficulties with SetDIBColorTable :

result = local implementation;

if (dc->funcs->pGetDIBColorTable)
    dc->funcs->pGetDIBColorTable;

return result;

Whatever happen next, the local implementation is used. Then if pGetDIBColorTable is available, it is used too. I see here a second call for the same thing, even if the local implementation succeed. Moreover, the result of dc->funcs->pGetDIBColorTable is not used as a return value.
Is there a mistake here, or is there something I do not understand ?

GetDIBColorTable uses the local implementation only if dc->funcs is not available. That is not the case for SetDIBColorTable, which runs first the local implementation.
What is the right policy to apply here ? 

I believe the call order of pSetDIBColorTable and the fact its return value is not used are errors. Am i wrong? If someone can confirm I am not, I will provide a patch in the next days.

Thank you for your help and time,

Laurent Vromman




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