BBitmapStream allows for the easy conversion of a translator bitmap, the default Translation Kit bitmap format, to a BBitmap. It's a very limited subclass of BPositionIO capable only of reading and writing translator bitmaps; performing i/o on the object with other types of data can yield strange results. The main attraction of the class is the DetachBitmap() method, which returns the contents of the object as a BBitmap.

Most of the time, you won't need to use BBitmapStream directly; BTranslationUtils contains the functionality required to load images from files, resources, or general BPositionIOs into BBitmaps.

The following snippet illustrates typical usage of BBitmapStream sans proper error checking:

BBitmap *FetchBitmap(char *filename)
{
    BFile file(filename, B_READ_ONLY);
    BTranslatorRoster *roster = BTranslatorRoster::Default();
    BBitmapStream stream;
    BBitmap *result = NULL;
    if (roster->Translate(&file, NULL, NULL, &stream,
        B_TRANSLATOR_BITMAP) < B_OK)
        return NULL;
    stream.DetachBitmap(&result);
    return result;
}

You can also initialize the class with a BBitmap and use it as input to BTranslatorRoster::Translate() to save it in a different format:

void StoreTranslatorBitmap(BBitmap *bitmap, char *filename,
                           uint32 type)
{
    BTranslatorRoster *roster = BTranslatorRoster::Default();
    BBitmapStream stream(bitmap); // init with contents of bitmap
    BFile file(filename, B_CREATE_FILE | B_WRITE_ONLY);

    roster->Translate(&stream, NULL, NULL, &file, type);
}