Version 2 of MimeTexPreview
Updated 2007-05-14 15:22:21 by ak
FF 2007-05-13 I remember some people asked about displaying mathematical formula in Tcl. Some implemented typesetting-like systems in pure Tcl. Cause I don't like re-inventing the wheel I preferred using a well known working system, based on a well known typesetting language: TeX (more precisely, the math extensions).
Btw the TeX distribution can be quite huge, and sometimes troublesome to install on non-UNIX-like systems (see Windows).
Fortunately a nice small application here comes in help: mimetex.
mimetex is mainly used in the CGI form, e.g. wikis and forums, to display mathematical formulae (see Wikipedia for a live example). Anyway it can be compiled as a standalone executable, producing nice GIF (anti-aliased, if you want it) output.
The script below it is just an example on how to embed it for using into a canvas.
I addressed several problems, like working with live iostreams, base64 encoding, and without producing intermediate temporary files. Feel free to improve it (and post it here) if you like.
See also: Rendering mathematical formulae for an alternative example, not using TeX at all.
#!/bin/sh
# -*- tcl -*-
# The next line is executed by /bin/sh, but not tcl \
exec tclsh "$0" ${1+"$@"}
package require base64
set img {}
#set mimetex_bin "c:/mimetex/mt.exe"
set mimetex_bin "mimetex"
proc render e {
global img
.c delete eee
catch {image delete $img}
set p [open [list |$::mimetex_bin -d $e] r]
fconfigure $p -translation binary -encoding binary
set rawData [base64::encode [read $p]]
close $p
set img [image create photo -data $rawData]
.c create image 10 10 -image $img -tags eee -anchor nw
}
grid [canvas .c] -row 0 -columnspan 2 -sticky news
grid [entry .t -textvariable ee] -row 1 -column 0 -sticky we
grid [button .b -command {render $ee} -text Render] -row 1 -column 1
grid columnconfigure . 0 -weight 1
grid rowconfigure . 0 -weight 1
set ee "x_{1,2}=\\frac{-b \\pm \\sqrt{b^2 - 4ac}}{2a}"