Add wxBitmap::NewFromPNGData() for creating bitmaps from PNG data.

This simple function can be used to create a wxBitmap from the raw image data
in PNG format. It is just a thin wrapper around wxImage load functions under
almost all platforms but has two advantages:

1. It can be implemented natively for some platforms (currently only OS X).
2. It can be used in a single expression as it doesn't require creating a
   temporary wxMemoryInputStream and this will be required by wxBITMAP_PNG()
   macro that will be added soon.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72476 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/bmpbase.cpp

@@ -23,6 +23,12 @@
     #include "wx/image.h"
 #endif // WX_PRECOMP
 
+#if wxUSE_IMAGE && wxUSE_LIBPNG && wxUSE_STREAMS
+    #define wxHAS_PNG_LOAD
+
+    #include "wx/mstream.h"
+#endif
+
 // ----------------------------------------------------------------------------
 // wxVariant support
 // ----------------------------------------------------------------------------
@@ -37,6 +43,31 @@ IMPLEMENT_VARIANT_OBJECT_EXPORTED_SHALLOWCMP(wxIcon,WXDLLEXPORT)
 //WX_IMPLEMENT_ANY_VALUE_TYPE(wxAnyValueTypeImpl<wxIcon>)
 #endif
 
+// ----------------------------------------------------------------------------
+// wxBitmapHelpers
+// ----------------------------------------------------------------------------
+
+// wxOSX has a native version and doesn't use this one.
+
+#ifndef __WXOSX__
+
+/* static */
+wxBitmap wxBitmapHelpers::NewFromPNGData(const void* data, size_t size)
+{
+    wxBitmap bitmap;
+
+#ifdef wxHAS_PNG_LOAD
+    wxMemoryInputStream is(data, size);
+    wxImage image(is, wxBITMAP_TYPE_PNG);
+    if ( image.IsOk() )
+        bitmap = wxBitmap(image);
+#endif // wxHAS_PNG_LOAD
+
+    return bitmap;
+}
+
+#endif // !__WXOSX__
+
 // ----------------------------------------------------------------------------
 // wxBitmapBase
 // ----------------------------------------------------------------------------