[Microbit-Python] What to do about display and images?

[Larry Hastings]

So, the ur-operation of all bitmap operations is the "bit blit", as 
evinced by this Win32 API, unchanged from Win16:

    BOOL BitBlt(
       _In_ HDC   hdcDest,
       _In_int    nXDest,
       _In_int    nYDest,
       _In_int    nWidth,
       _In_int    nHeight,
       _In_ HDC   hdcSrc,
       _In_int    nXSrc,
       _In_int    nYSrc,
       _In_ DWORD dwRop
    );


    https://msdn.microsoft.com/en-us/library/windows/desktop/dd183370(v=vs.85).aspx


If you have BitBlt you can do anything.  You can construct any other 
operation you need.

An "HDC" is a Handle to a Device Context, which we can think of here as 
a bitmap.  So this function copies the bits from one bitmap to another.  
It takes the X and Y of where to copy from on the source, the width and 
height of the area we want copied, the X and Y of where we want to copy 
/to/ on the destination, and the "raster operation" which is the 
approach to take when copying.  There are seventeen (!) possible raster 
ops with BitBlt() but you only ever use a few.


In theory I'd be interested in things like "scale" and "brighten", but 
in practice a 5x5 screen is so low-resolution I'll never scale anything, 
and there are only about four brightness levels (including "off"), so 
it's hard to get excited about those operations.  I suppose you could 
still add these operations but I would put them off until last.

I'd be happy to take a crack at designing the API /I'd/ want to use.  
All I need to know for now is: does MicroPython support a) positional 
parameters with defaults, b) name-only parameters with defaults?


//arry/
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