BLT graph widget 
Author Message
 BLT graph widget

I need a good 2D graph widget to complete my current project. The
BLT graph widget is very good, but it's a Tcl-Tk widget.
The Canvas widget just doesn't cut it. I need professional looking
graphs.

I've seen a number of postings requesting info about porting the
BLT graph widget into pTk, but I haven't seen any postive responses
to these requests.

So, I'm trying to port this beast into pTk.

I've made some headway by cutting outting things that don't pertain
directly to the graph widget, such as
   - the BLT vector action-oriented programming concepts
     (nice idea, but I don't have the time to touch it), and
   - the initialization operations that make BLT a tangled mess
     (perl clases provide a much cleaner initialization scheme)

The major difficulties arise from the fact that the Tcl 'C'
library provides more-or-less direct access to many Tcl functions,
bu the perl 'C' library does not (hence my previous post).
The BLT widget programmers made extensive use of Tcl's library
functions.

Some Tcl library routines be converted to other similar routines without
too much harm: Tcl_ExprDouble maps nicely to Tcl_GetDouble,
particularly since perl is smarter about passing arguments.
However, no substitute appears to exist for other routines, such as
Tcl_SplitString and Tcl_String_Match (not even in the perl API).

Another problem area arises in the use of Tcl_Eval and its kin.
What's being evaluated is a Tcl script, not a perl script. I've
built some additional 'glue' to overcome these as I proceed. For
example, "info exists ?varname?' translates nicely into 'C' function.
But again, if the Tcl function being accessed has no direct
libpTk.a / libperl.a equivalent, I'm stuck (at least for a few hours).

Any helpful hints would be appreciated, either regarding using perl
built-in functions from 'C', or porting Tcl-Tk widgets to perl
in general.

P.S.  If someone has already ported the BLT graph widget into
pTk, tell me, please. I'll cease and desist,and do so gladly.

Thanks,
Dave Hammen



Sun, 27 Dec 1998 03:00:00 GMT  
 BLT graph widget


Quote:
>I need a good 2D graph widget to complete my current project. The
>BLT graph widget is very good, but it's a Tcl-Tk widget.

I liked Stephen Lidie's plop - still available from:

  http://orwant.www.media.mit.edu/tpj/programs/Vol_1_Issue_1_Tk/plop

Quote:
>The Canvas widget just doesn't cut it. I need professional looking
>graphs.

huh?

Quote:
>I've seen a number of postings requesting info about porting the
>BLT graph widget into pTk, but I haven't seen any postive responses
>to these requests.

>So, I'm trying to port this beast into pTk.

>I've made some headway by cutting outting things that don't pertain
>directly to the graph widget, such as
>   - the BLT vector action-oriented programming concepts
>     (nice idea, but I don't have the time to touch it), and

You ain't seen nothin yet - see the pgplot home page in Australia.
See also the perlovl man page.

Quote:
>   - the initialization operations that make BLT a tangled mess
>     (perl clases provide a much cleaner initialization scheme)

>The major difficulties arise from the fact that the Tcl 'C'
>library provides more-or-less direct access to many Tcl functions,
>bu the perl 'C' library does not (hence my previous post).
>The BLT widget programmers made extensive use of Tcl's library
>functions.

>Some Tcl library routines be converted to other similar routines without
>too much harm: Tcl_ExprDouble maps nicely to Tcl_GetDouble,
>particularly since perl is smarter about passing arguments.
>However, no substitute appears to exist for other routines, such as
>Tcl_SplitString and Tcl_String_Match (not even in the perl API).

>Another problem area arises in the use of Tcl_Eval and its kin.
>What's being evaluated is a Tcl script, not a perl script. I've
>built some additional 'glue' to overcome these as I proceed. For
>example, "info exists ?varname?' translates nicely into 'C' function.
>But again, if the Tcl function being accessed has no direct
>libpTk.a / libperl.a equivalent, I'm stuck (at least for a few hours).

>Any helpful hints would be appreciated, either regarding using perl
>built-in functions from 'C', or porting Tcl-Tk widgets to perl
>in general.

>P.S.  If someone has already ported the BLT graph widget into
>pTk, tell me, please. I'll cease and desist,and do so gladly.

Not that I have heard of. Sounds like your making some headway and I would
encourage you to continue :-)

Quote:
>Thanks,
>Dave Hammen


Peter Prymmer



Tue, 29 Dec 1998 03:00:00 GMT  
 
 [ 2 post ] 

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