Add wxPNGHandler to interface.

interface/wx/imagpng.h

@@ -0,0 +1,49 @@
+///////////////////////////////////////////////////////////////////////////// 
+// Name:        imagpng.h 
+// Purpose:     interface of wxPNGHandler 
+// Author:      Samuel Dunn 
+// Licence:     wxWindows licence 
+//////////////////////////////////////////////////////////////////////////// 
+
+#define wxIMAGE_OPTION_PNG_FORMAT                   wxT("PngFormat")
+#define wxIMAGE_OPTION_PNG_BITDEPTH                 wxT("PngBitDepth")
+#define wxIMAGE_OPTION_PNG_FILTER                   wxT("PngF")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_LEVEL        wxT("PngZL")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_MEM_LEVEL    wxT("PngZM")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_STRATEGY     wxT("PngZS")
+#define wxIMAGE_OPTION_PNG_COMPRESSION_BUFFER_SIZE  wxT("PngZB")
+
+
+enum
+{
+    wxPNG_TYPE_COLOUR = 0,
+    wxPNG_TYPE_GREY = 2,
+    wxPNG_TYPE_GREY_RED = 3,
+    wxPNG_TYPE_PALETTE = 4
+};
+
+/**
+    @class wxPNGHandler
+
+    This is the image handler for the PNG format.
+
+    @library{core}
+    @category{gdi}
+
+    @see wxImage, wxImageHandler, wxInitAllImageHandlers()
+*/
+class wxPNGHandler : public wxImageHandler
+{
+public:
+    /**
+    Default constructor for wxPNGHandler
+    */
+    wxPNGHandler();
+
+    // let parent class's documentation through.
+    virtual bool LoadFile( wxImage *image, wxInputStream& stream, bool verbose=true, int index=-1 );
+    virtual bool SaveFile( wxImage *image, wxOutputStream& stream, bool verbose=true );
+
+protected:
+    virtual bool DoCanRead( wxInputStream& stream );
+};