On Feb 4, 2013, at 12:48 PM, Alexander Hansen <alexanderk.han...@gmail.com> wrote:
> On 2/4/13 10:35 AM, Eigil Krogh Sorensen wrote: >> Hi >> >> I ask the questions below, because it took many hours to install >> Octave-Atlas on my MAC, so I would like to avoid as much installation time >> as possible. >> >> It seems GraphicsMagic be configured at installation with an "Optional >> Package/Option": "--with-quantum-depth", but >> >> 1) I don't know if the rest of the plot chain in Octave-Atlas can handle >> more bits per pixel > > That's a matter to discuss with the Octave developers on one of the > octave mailing lists. > >> 2) I don't know how to reinstall GraphicsMagick and Octave-Atlas with a >> new value of "--with-quantum-depth". > > > I believe you would just need to rebuild graphicsmagick, which should go > quickly. > > Can I use the description in >> http://finkers.wordpress.com/2009/07/24/creating-local-packages/ for that >> or are there smarter ways to do that? >> >> > > "--with-quantum-depth" is explicitly set to 16 in the ConfigureParams > field in graphicsmagick.info, so just try setting that to 32 instead. > > I'm not sure why it's set to 16, which is a good reason to keep cc'ing > the maintainer. The default quantum value for GraphicsMagick is 8 which is sufficient for most uses since most display devices only support 8 bits per pixel anyway. GraphicsMagick uses floating point math internally to avoid accuracy issues. The quantum value really only affects quantization noise in certain operations. I chose a quantum of 16 as a compromise to give better results for those that need it. The problem is that each higher quantum value makes GraphicsMagick run slower and doubles the amount of memory used. Using a quantum of 32 would significantly degrade performance for very little gain for most users. Upstream recommends 16 in most cases. If you know that you really need 32, follow Alexander's suggestion to set --with-quantum-depth to 32. Daniel ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Fink-users mailing list Fink-users@lists.sourceforge.net List archive: http://news.gmane.org/gmane.os.macosx.fink.user Subscription management: https://lists.sourceforge.net/lists/listinfo/fink-users
