MathGroup Archive 2001

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Re: Faster rotate bitmap

  • To: mathgroup at
  • Subject: [mg29168] Re: [mg29115] Faster rotate bitmap
  • From: Simon Chandler <simon_chandler at>
  • Date: Fri, 1 Jun 2001 04:15:29 -0400 (EDT)
  • References: <9ektan$> <>
  • Sender: owner-wri-mathgroup at


In reply to my question about FASTER rotation of bitmap images you posted a routine "RasterRotate".

Am I doing something wrong?  As far as I can tell your function is 35x SLOWER than the compiled function "RotateArrayC4" which I included with my original posting. Also, your function seems to be very memory hungry, so for images of the size I said I was using (1280 x 960 pixels) my computer has real problems. Finally, the "holes" that appear in your rotated image are not acceptable to the subsequent processing I need to perform on the rotated image.

So I repeat my questions to the MathGroup:

   Q2: Do you think that my method (see below) can be made 10x faster
       by improving the code?

   Q3: Will I have to resort to a Mathlinked low-level program to achieve the
       10x speed increase I'm looking for?



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