Reversing bits in a byte

[Robert Flintham]

Further to my earlier reply to Dave:

I'd like to either display the image in a GUI, or save it in a format that can be opened easily in Windows (like a PNG or a 24-bit BMP).

I know the dimensions as it's coming from the header of a DICOM file.  I'm trying to analyse DICOM images where an 'overlay' image is stored as a bitmap in the header information.  So the bitmap data is one DICOM tag (6000,3000) and the height and width of the overlay are in two other tags (6000,0010) and (6000,0011).

All the best,
Rob

Robert Flintham
Trainee Clinical Scientist - MRI

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Email:       Robert.Flintham at uhb.nhs.uk
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-----Original Message-----
From: Tim Chase [mailto:python.list at tim.thechases.com] 
Sent: 12 March 2013 13:21
To: Robert Flintham
Cc: 'python-list at python.org'
Subject: Re: Reversing bits in a byte

On 2013-03-11 15:32, Robert Flintham wrote:
> I have a 'bytes' object which contains a simple bitmap image (i.e.
> 1 bit per pixel).  I can't work out how I would go about displaying 
> this image.  Does anyone have any thoughts?

You'd need to detail
- how you want to display it (console, GUI, web page)
- how you know what the dimensions are
- the bit order

It could be something as simple as

  HEIGHT = 40
  some_bytes = file('data.bin').read()
  WIDTH = len(some_bytes) // HEIGHT
  for i, byte in enumerate(some_bytes):
    if i and i % WIDTH == 0:
      print # a new line
    for bit in range(8):
      if byte & (1 << bit):
        print '*',
      else:
        print ' ',


-tkc

> DISCLAIMER:
[trim a paragraph of useless junk]
Please remove these disclaimers if at all possible.  You're posting to a public forum, which pretty much waives all credibility to the disclaimer (not that they've held much legal standing in any argument I've heard).






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