[PyQt] writing to a QImage buffer

[Florian Bruhin]

* James Conger <jlconger at yahoo.com> [2014-11-12 17:00:01 -0800]:
> QImage.scanLine() returns a sip void * pointer to a memory block containing one row of the image. For performance reasons I would like to write pixel RGB data directly to that buffer from within my Python code. How do you convert the void * pointer to a r/w object such as a Python array? 
> 
> Many thanks.

See
http://pyqt.sourceforge.net/Docs/PyQt5/gotchas.html#support-for-void

    A sip.voidptr may also be given a size (ie. the size of the block
    of memory that is pointed to) by calling its setsize() method. If
    it has a size then it is also able to support Python’s buffer
    protocol and behaves like a Python memoryview object so that the
    block of memory can be treated as a mutable list of bytes.

Florian

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