[wxPython-users] speed up display of image data from 3rd party C++ extension

[Christopher Barker]

F. Oliver Gathmann wrote:
>>> directly using code similar to the recently added BitmapFromBuffer

> Yes, that's what I have in mind - create a wx.Bitmap in my C++ extension
> and pass it to my wxPython GUI for display.

In that case, you don't need wx.BitmapFromBuffer -- you need whatever 
the C++ call is for setting the data in a wxBitmap.

> I was thinking of using the buffer interface, but that would still
> involve *two* copies of the image data - one from my C++ image class
> into the buffer (the in-memory layout is different from what wx expects)
> and one from the buffer into the new wx.Bitmap object.

No, it wouldn't. That's the whole point of the buffer interface, when 
you create a Bitmap from a buffer, it uses the buffer data directly, it 
does not make a copy.

I was suggesting that approach, as it removes the need to have an wx 
code in your extension -- that's nice, as you don't have to make sure 
you're linked against the same version of wx.

> Yes, I have done that already (and since you can specify strides in
> numpy arrays, you don't have to copy any data at all), but that does not
> solve the problem of getting the image data to the screen in the most
> efficient manner.

True, though we're all hoping that the numpy-style nd-array will become 
a standard, and then we can make sure that wxPython functions like 
wx.BitmapFromBuffer understand it.

-Chris

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