kali@tut.fi (Salo Juha) (07/25/89)
Hello Xperts,
I noted in O'Reilly's Xlib book that there should be a newsgroup or
mailing list for X users interested in image processing called ximage.
However, I can't find it from the netnews list supplied at our domain.
So, how can I access the 'ximage' group?
Please e-mail answers to
kali@tut.fi
thanks in advance
--
\ J.Salo / Tampere University on Technology, FINLAND
>8-)= _ kali@tut.fi, kali@tut.uucp, kali@tut.eunet
/cheung@marble.sw.mcc.com (Po Cheung) (10/26/89)
To invert an XImage, I can think of creating a pixmap of same size and depth, copying the image (with XPutImage and GXcopyInverted) into the pixmap, and retrieving the image back from the pixmap (XGetImage). Is this the right way? Does it mean all graphics operations on images have to go through a pixmap? Thanks.
madd@world.std.com (jim frost) (10/27/89)
In article <3048@marble.sw.mcc.com> cheung@marble.sw.mcc.com (Po Cheung) writes: |To invert an XImage, I can think of creating a pixmap of same size and |depth, copying the image (with XPutImage and GXcopyInverted) into the |pixmap, and retrieving the image back from the pixmap (XGetImage). | |Is this the right way? Does it mean all graphics operations on images |have to go through a pixmap? No, you can do each of them yourself in the client with either GetPixel/PutPixel or your own (presumably much faster) functions. I did the latter when creating my xloadimage program, mostly because X supports very few image manipulations (which is as it should be, I think). The only problem with creating your own images manipulation routines is that XImages might be in many different bit and byte orders. I get around this by using my own image format and setting up the XImage to match (which works very well). It's probably best to think of X as a display server and not an image manipulation utility; it's good at displaying images but most of the trivial image manipulation functions that it provides are really best used as graphical operations with draw commands (eg GXcopyinverted might be used to invert a menu option). jim frost software tool & die "The World" Public Access Unix for the '90s madd@std.com +1 617-739-WRLD 24hrs {3,12,24}00bps
rws@EXPO.LCS.MIT.EDU (Bob Scheifler) (10/28/89)
To invert an XImage, I can think of creating a pixmap of same size and
depth, copying the image (with XPutImage and GXcopyInverted) into the
pixmap, and retrieving the image back from the pixmap (XGetImage).
That's a possible way, but probably not the fastest (although it depends
a lot on the size of the image, and the relative performance of the client,
the server, and the network connection). You can simply use XGetPixel and
XPutPixel and do it all on the client side. The GetPixel/PutPixel code is
rather slow in R3, but this will be fixed in R4.kek@DINORAH.WUSTL.EDU (10/30/89)
eb, susan, ijadi