Re: [swarm-hackers] fedora 11, tcl/tk 8.5: Some actual news!

[Paul Johnson]

OK, I made some progress on tcl/tk. I *believe* Swarm is not 
incompatible with tcl/tk 8.5. batch programs run fine. 

After a lot of random bumping around in the dark today, I found a bug
report (https://bugzilla.redhat.com/show_bug.cgi?id=504388) to indicate
that this crash

$ ./heatbugs
X Error of failed request:  BadMatch (invalid parameter attributes)
Major opcode of failed request:  151 (RENDER)
Minor opcode of failed request:  4 (RenderCreatePicture)
Serial number of failed request:  3758
Current serial number in output stream:  3764


is caused by a bug in tcl/tk 8.5 that is triggered by usage of 
Tk_DrawChars() in blt.  I gather that one of the significant 
improvements in tk 8.5 is support for xft fonts, and it turns out that 
the bug is caused by usage of xft fonts. 

That bug report is dated July 12, 2009, so I am encouraged to learn 
other people have found the same.

The workaround for now is to recompile tcl/tk with --disable-xft.  That 
makes the fonts uglier, but after that Swarm programs do not crash anymore!

There is an example tcl program in that note that can be used to test 
blt and tk.

It is simple. Put this in a file "blttest.tcl"

#! /usr/bin/wish
package require Tclx
package require BLT
namespace import blt::*
tabset .ts -side left -rotate 90 -activebackground green
.ts insert end .tstab -text "Test"
pack .ts


Then run "wish blttest.tcl" and if it crashes, you are using a system 
that has the bug.

I've had this "success" with swarm-2.2.5.

Right now, I'm uploading the RPMS I've built for tk and swarm. I rebuilt 
tcl, but I do not think it was strictly necessary.  But I'm uploading it 
anyway.  It may also be I need to upload blt in order for this to work 
on other systems, we will have to test.

http://pj.freefaculty.org/Swarm/Swarm-2.2X_F11

There you should find these files:

$ ls Swarm-2.2X_F11/ -la
total 19076
drwxrwxr-x  2 pauljohn32 pg512501    4096 2009-07-23 17:25 .
drwxr-xr-x 21 pauljohn32 pg512501    4096 2009-07-23 17:23 ..
-rw-r--r--  1 pauljohn32 pg512501 1051351 2009-07-23 17:24 
swarm-2.2.5-2F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 3449459 2009-07-23 17:24 
swarm-debuginfo-2.2.5-2F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501  532786 2009-07-23 17:24 
swarm-gcjswarm-2.2.5-2F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 1700573 2009-07-23 17:24 
swarm-jdk-2.2.5-2F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 1293736 2009-07-23 17:24 
swarm-static-2.2.5-2F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 2335448 2009-07-23 17:25 
tcl-8.5.6-7F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 2609968 2009-07-23 17:25 
tcl-debuginfo-8.5.6-7F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501  178332 2009-07-23 17:25 
tcl-devel-8.5.6-7F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 1598296 2009-07-23 17:25 
tk-8.5.6-5F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501 4160755 2009-07-23 17:25 
tk-debuginfo-8.5.6-5F11kups.i586.rpm
-rw-r--r--  1 pauljohn32 pg512501  543054 2009-07-23 17:25 
tk-devel-8.5.6-5F11kups.i586.rpm

If your swarm programs crash after installing these, it is *almost 
certainly* because the blt you have is not the same as the one that I 
have.   Here's what you need to do.  Keep the blt for tk8.5 provided 
with F11, but then you need to add a symbolic link.

Check this directory:

/usr/share/tcl8.5/blt2.4

see if you have a symbolic link from graph.tcl to bltGraph.tcl.  you 
probably do not, and you need one. So do

ln -sf /usr/share/tcl8.5/blt2.4/graph.tcl 
/usr/share/tcl8.5/blt2.4/bltGraph.tcl

I'll probably make a new blt RPM that does that automatically, as I have 
done in the past, for tcl/tk 8.4.

It appeared to me a few years ago that tcl/tk would completely die, but 
now it is pretty heavily used by some really cool projects, including 
Swarm and R, and thus I believe they will fix it and we will soon have 
anti-aliased fonts.

Apparently, this problem has been known since 2007, however, and that is 
a bit discouraging.  Joe English, one of the Tk maintainers, says this 
"The preferred solution is to not call Tk_DrawChars() on drawables of 
depth 1. This is preferable in any event, so that compositing will 
work."  (http://objectmix.com/tcl/303826-8-5b3-linked-against-x11.html) 
It could be that means they will refuse to fix Tk, and blt will have to 
change, in which case Swarm's usage may break. Oh, well. Details like 
that are above my level of understanding.



pj




--
Paul E. Johnson                       email: address@hidden
Professor, Political Science          http://pj.freefaculty.org
1541 Lilac Lane, Rm 504                              
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66044-3177           FAX: (785) 864-5700