Legacy ImageMagick Discussions Archive

The cost of the image brightness algorithm increases linearly with the area of the image:

• convert logo: -resize 100% logo.mpc
  time convert logo.mpc -modulate 50% null:
  0.060u 0.032s 0:00.09 100.0% 0+0k 0+0io 1pf+0w
  convert logo: -resize 200% logo.mpc
  time convert logo.mpc -modulate 50% null:
  0.212u 0.060s 0:00.26 103.8% 0+0k 0+0io 0pf+0w
  convert logo: -resize 400% logo.mpc
  time convert logo.mpc -modulate 50% null:
  0.816u 0.152s 0:00.98 97.9% 0+0k 0+0io 0pf+0w
  convert logo: -resize 800% logo.mpc
  time convert logo.mpc -modulate 50% null:
  3.300u 0.480s 0:03.95 95.6% 0+0k 0+0io 0pf+0w
  convert logo: -resize 1600% logo.mpc
  time convert logo.mpc -modulate 50% null:
  12.604u 2.336s 0:27.17 54.9% 0+0k 0+0io 49pf+0w

We're using ImageMagick 6.2.6-8 and we tried these commands under Windows XP:

• convert sp001.jpg -modulate 105% bright.jpg
  convert bright.jpg -modulate 105% bright.jpg
  convert bright.jpg -modulate 105% bright.jpg
  convert bright.jpg -modulate 105% bright.jpg
  ...

and each command completed in under a second.

Certainly testing the current release would be helpful since we have shown it works fine (no hanging when modulating).