Thank you very much! Your information was spot on. Kind of like priming the pump for me.
On Sat, Mar 21, 2009 at 12:52 AM, Sherlock, Ric <[email protected]>wrote: > > From: Jonathan Lettvin > > > > It is not clear that 'image3' is cross platform like 'platimg'. > > If switching to platimg is preferable, please show conversion from RGB > > plane to R G B planes. > > Hi Jonathon, > image3 is crossplatform - it installs & uses a library of image functions > to work with images - libimage3.dll, libimage3.so or libimage3.dylib > depending on OS. > > platimg is also crossplatform but uses image manipulation frameworks native > on each platform. > > load 'media/image3 media/platimg' > fn1=: jpath '~addons/image3/hy_fly_di.png' > img1=: read_image fn1 NB. read image using image3 > img2=: readimg fn1 NB. read same image using platimg > img2 -: img1 > 0 > $img1 > 880 880 3 NB. R G B planes > $img2 > 880 880 NB. RGB plane > > If you decide to use platimg it contains a utility to convert from R G B > planes to RGB plane - you want to do the reverse > > img2 -: rgbmat_pplatimg_ img1 > 1 > > rgbmat_pplatimg_ > 3 : 0 > 'empty data' assert 0<#y > 'rank error' assert 3>:#$y > while. 2 > #$y do. y=. ,:y end. > if. 3=#$y do. > assert 3 e. $y > y=. 256#.(|:~ (i.3) A.~ _1 + 2 ^ 2 - 3 i.~$) y > end. > y bOR 24 bSH 16bff NB. opacity > ) > > The key line that does the conversion is: > y=. 256#.(|:~ (i.3) A.~ _1 + 2 ^ 2 - 3 i.~$) y > > You need to work out how to do the reverse. > > The following is the same expression using explicit (rather than tacit) > notation which you may find easier to understand. > $ 256#. img1 |:~ 0 1 2 A.~ _1 + 2 ^ 2 - 3 i.~ $img1 > 880 880 > > It might be worth checking out #: > > Hope that is of some use: > Regards, > Ric > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- This e-mail is from Jonathan D. Lettvin, and may contain information that is confidential or privileged. If you are not the intended recipient, do not read, copy or distribute the e-mail or any attachments. Instead, please notify the sender and delete the e-mail and any attachments. Thank you. Jonathan D. Lettvin ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
