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<HTML>
<head><title>wxBitmapDataObject</title></head>
<BODY BGCOLOR=#FFFFFF>
<A NAME="wxbitmapdataobject"></A><CENTER>
<A HREF="wx.htm"><img align=center src="contents.gif" BORDER=0 ALT="Contents"></A> <A HREF="wx22.htm#classref"><img align=center src="up.gif" BORDER=0 ALT="Up"></A> <A HREF="wx34.htm#wxbitmapbutton"><img align=center src="back.gif" BORDER=0 ALT="Previous"></A> <A HREF="wx36.htm#wxbrush"><img align=center src="forward.gif" BORDER=0 ALT="Next"></A> </CENTER><HR>
<H2>wxBitmapDataObject</H2>
<P>
wxBitmapDataObject is a specialization of wxDataObject for bitmap data. It can be
used without change to paste data into the <A HREF="wx44.htm#wxclipboard">wxClipboard</A>
or a <A HREF="wx81.htm#wxdropsource">wxDropSource</A>. A user may wish to derive a new class
from this class for providing a bitmap on-demand in order to minimize memory consumption
when offering data in several formats, such as a bitmap and GIF.<P>
In order to offer bitmap data on-demand <A HREF="wx35.htm#wxbitmapdataobjectgetsize">GetSize</A>
and <A HREF="wx35.htm#wxbitmapdataobjectwritedata">WriteData</A> will have to be overridden.<P>
<B><FONT COLOR="#FF0000">Derived from</FONT></B><P>
<A HREF="wx61.htm#wxdataobject">wxDataObject</A><P>
<B><FONT COLOR="#FF0000">Include files</FONT></B><P>
<wx/dataobj.h><P>
<B><FONT COLOR="#FF0000">See also</FONT></B><P>
<A HREF="wx61.htm#wxdataobject">wxDataObject</A><P>
<B><FONT COLOR="#FF0000">Members</FONT></B><P>
<A HREF="#wxbitmapdataobjectwxbitmapdataobject">wxBitmapDataObject::wxBitmapDataObject</A><BR>
<A HREF="#wxbitmapdataobjectgetsize">wxBitmapDataObject::GetSize</A><BR>
<A HREF="#wxbitmapdataobjectgettext">wxBitmapDataObject::GetBitmap</A><BR>
<A HREF="#wxbitmapdataobjectsetbitmap">wxBitmapDataObject::SetBitmap</A><BR>
<A HREF="#wxbitmapdataobjectwritedata">wxBitmapDataObject::WriteData</A><BR>
<A HREF="#wxbitmapdataobjectwritebitmap">wxBitmapDataObject::WriteBitmap</A><BR>
<P>
<HR>
<A NAME="wxbitmapdataobjectwxbitmapdataobject"></A>
<H3>wxBitmapDataObject::wxBitmapDataObject</H3>
<P>
<B></B> <B>wxBitmapDataObject</B>()<P>
Default constructor. Call <A HREF="wx35.htm#wxbitmapdataobjectsetbitmap">SetBitmap</A> later
or override <A HREF="wx35.htm#wxbitmapdataobjectwritedata">WriteData</A> and
<A HREF="wx35.htm#wxbitmapdataobjectgetsize">GetSize</A> for providing data on-demand.<P>
<B></B> <B>wxBitmapDataObject</B>(<B>const wxBitmap& </B><I>bitmap</I>)<P>
Constructor, passing a bitmap.<P>
<HR>
<A NAME="wxbitmapdataobjectgetsize"></A>
<H3>wxBitmapDataObject::GetSize</H3>
<P>
<B>virtual size_t</B> <B>GetSize</B>() <B>const</B><P>
Returns the data size. By default, returns the size of the bitmap data
set in the constructor or using <A HREF="wx35.htm#wxbitmapdataobjectsetbitmap">SetBitmap</A>.
This can be overridden to provide size data on-demand. Note that you'd
have to call the inherited GetSize method as this is the only way
to get to know the transfer size of the bitmap in a platform dependent
way - a bitmap has different size under GTK and Windows. In practice,
this would look like this:<P>
<PRE>
size_t MyBitmapDataObject::GetSize()
{
// Get bitmap from global container. This container
// should be able to "produce" data in all formats
// offered by the application but store it only in
// one format to reduce memory consumption.
wxBitmap my_bitmap = my_global_container->GetBitmap();
// temporarily set bitmap
SetBitmap( my_bitmap );
size_t ret = wxBitmapDataObject::GetSize();
// unset bitmap again
SetBitmap( wxNullBitmap );
retrun ret;
}
</PRE>
TODO: Offer a nicer way to do this. Maybe by providing a platform
dependent function in this class like <P>
<PRE>
size_t GetBitmapSize( const wxBitmap &bitmap )
</PRE>
<HR>
<A NAME="wxbitmapdataobjectgettext"></A>
<H3>wxBitmapDataObject::GetBitmap</H3>
<P>
<B>virtual wxBitmap</B> <B>GetBitmap</B>() <B>const</B><P>
Returns the bitmap associated with the data object. You may wish to override
this method when offering data on-demand, but this is not required by
wxWindows' internals. Use this method to get data in bitmap form from
the <A HREF="wx44.htm#wxclipboard">wxClipboard</A>.<P>
<HR>
<A NAME="wxbitmapdataobjectsetbitmap"></A>
<H3>wxBitmapDataObject::SetBitmap</H3>
<P>
<B>virtual void</B> <B>SetBitmap</B>(<B>const wxBitmap& </B><I>bitmap</I>)<P>
Sets the bitmap associated with the data object. This method is called
internally when retrieving data from the <A HREF="wx44.htm#wxclipboard">wxClipboard</A>
and may be used to paste data to the clipboard directly (instead of
on-demand).<P>
<HR>
<A NAME="wxbitmapdataobjectwritedata"></A>
<H3>wxBitmapDataObject::WriteData</H3>
<P>
<B>virtual void</B> <B>WriteData</B>(<B>void</B><I>*dest</I> ) <B>const</B><P>
Write the data owned by this class to <I>dest</I>. By default, this
calls <A HREF="wx35.htm#wxbitmapdataobjectwritebitmap">WriteBitmap</A> with the bitmap
set in the constructor or using <A HREF="wx35.htm#wxbitmapdataobjectsetbitmap">SetBitmap</A>.
This can be overridden to provide bitmap data on-demand; in this case
<A HREF="wx35.htm#wxbitmapdataobjectwritebitmap">WriteBitmap</A> must be called from
within th overriding WriteData() method.<P>
<HR>
<A NAME="wxbitmapdataobjectwritebitmap"></A>
<H3>wxBitmapDataObject::WriteBitmap</H3>
<P>
<B>void</B> <B>WriteBitmap</B>(<B>const wxBitmap& </B><I>bitmap</I><B>void</B><I>*dest</I> ) <B>const</B><P>
Writes the the bitmap <I>bitmap</I> to <I>dest</I>. This method must be called
from <A HREF="wx35.htm#wxbitmapdataobjectwritedata">WriteData</A>.<P>
</BODY></HTML>
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