Hi Jules, I added your function with some changes (e.g. rename functions and use auto-generated haskell function instead of hardcode function) in the darcs repositoy.
http://www.mail-archive.com/[EMAIL PROTECTED]/msg00304.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg00322.html Please check these functions. If there is a bug in these functions, please send us tiny example. Because I want to fix that before wxhaskell 0.11 release when these functions have bug. Best regards, On Sat, 29 Mar 2008 20:04:55 +0900, Jules Bean <[EMAIL PROTECTED]> wrote: > So, I have successfully added some of the missing bindings that I needed. > > The code is so short that I embed it in this email. I'd be interested > to hear any comments on the way I did this, and what you would want to > change before committing it to wxhaskell. > > 1) Loading images from in-memory blocks > > Stub C++ file to bind to the appropriate wxImage constructor: > > #include "wx/wx.h" > #include "wx/image.h" > #include "wx/mstream.h" > > extern "C" > { > void * wxImage_CreateFromFileInMemory(void* data,int length,int type) { > wxMemoryInputStream in(data,length); > return (void*) new wxImage(in,type); > } > } > > You can compile this with "g++ -c `wx-config --cppflags` cstub.cpp" > > Then a haskell stub file to wrap a Ptr version of this and two > bytestring versions: > > {-# OPTIONS -fglasgow-exts #-} > module ImageExtras where > > import qualified Data.ByteString.Lazy as LB > import qualified Data.ByteString as B > import Foreign > import Foreign.C > import Graphics.UI.WXCore.WxcTypes > import Graphics.UI.WXCore.WxcClassTypes > > imageCreateFromPtrFile :: Ptr b -> Int -> Int -> IO (Image ()) > imageCreateFromPtrFile ptr len typ > = withManagedObjectResult $ > wxImage_CreateFromFileInMemory ptr (fromIntegral len) (fromIntegral > typ) > foreign import ccall "wxImage_CreateFromFileInMemory" > wxImage_CreateFromFileInMemory :: Ptr b -> CInt -> CInt -> IO (Ptr > (TImage ())) > imageCreateFromLBytestringFile :: LB.ByteString -> Int -> IO (Image ()) > imageCreateFromLBytestringFile bs typ > = withArray (LB.unpack bs) $ \ptr -> > imageCreateFromPtrFile ptr (fromIntegral $ LB.length bs) typ > > imageCreateFromBytestringFile :: B.ByteString -> Int -> IO (Image ()) > imageCreateFromBytestringFile bs typ > = withArray (B.unpack bs) $ \ptr -> > imageCreateFromPtrFile ptr (B.length bs) typ > > I'm not sure if you can make these a bit more efficient by attacking > the underlying bytestring rep, but I didn't try. > > It works, anyhow. I am able to load images from bytestreams (as it > happens, the cover art from an M4A file). The magic invocation to get > ghc to link it correctly seems to be: > > ghc --make main.hs cstub.o -lstdc++ `wx-config --libs` -optl -fexceptions > > 2) GetOption / SetOption for Images > > Slightly more fiddly. The C++ stub looks like this: > > #include "wx/wx.h" > #include "wx/image.h" > > extern "C" > { > void wxImage_SetOption(void *_obj, void* key,void *value) { > ((wxImage*)_obj)->SetOption((wxChar*)key,(wxChar*)value); > } > wxString* wxImage_GetOption(void *_obj, void* key) { > return new wxString(((wxImage*)_obj)->GetOption((wxChar*)key)); > } > } > > (it took me quite a while to understand why casting to wxChar* works > when the underlying type is WxString&; there is an implicit conversion > because of a constructor) > > The haskell stub is this: > > {-# OPTIONS -fglasgow-exts #-} > module ImageOptions where > > import Graphics.UI.WXCore.WxcTypes > import Graphics.UI.WXCore.WxcClassTypes > > imageSetOption :: Image a -> String -> String -> IO () > imageSetOption _obj key value = > withObjectRef "imageSetOption" _obj $ \cobj -> > withCWString key $ \cstr_key -> > withCWString value $ \cstr_value -> > wxImage_SetOption cobj cstr_key cstr_value > foreign import ccall "wxImage_SetOption" wxImage_SetOption :: > Ptr (TImage a) -> CWString -> CWString -> IO () > > imageGetOption :: Image a -> String -> IO String > imageGetOption _obj key = > withManagedStringResult $ > withObjectRef "imageGetOption" _obj $ \cobj -> > withCWString key $ \cstr_key -> > wxImage_GetOption cobj cstr_key > foreign import ccall "wxImage_GetOption" wxImage_GetOption :: > Ptr (TImage a) -> CWString -> IO (Ptr (TWxString ())) > > > 3) Points of confusion: > > For return types of type String, looking at the examples in elj*.cpp, > why does it sometimes use copyStrToBuf to unpack the WxString on the > C++ side in combination with withWStringResult on the haskell side, > and other times just pass back the a freshly allocated WxString* from > C++ in combination with withManagedStringResult? > > For arguments of object types, why do some bindings use withObjectPtr > and some use withObjectRef? > > What's the EXWXEXPORT() macro for? It didn't seem very useful to me... -- shelarcy <shelarcy hotmail.co.jp> http://page.freett.com/shelarcy/ ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ wxhaskell-users mailing list wxhaskell-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wxhaskell-users
