[MLPost] Curly brances

[MLPost] Curly brances

[Alexandre Pilkiewicz]

Dear list

I'm sorry if that's the wrong list, but mlpost doesn't seem to have
it's own list.

I'm starting to use (quite happily!) MLPost for some drawing, and it
works perfectly. But now I'm trying some more advance things, and I'm
stuck:

I would like to draw variable size curly braces, pretty much like
\underbrace would do in LaTeX. More specifically, I want to draw 16
boxes horizontally alligned (representing 16 bits of a VM
instruction), and "select" (by a curly brace) say the 4 first and say
it's the opcode, and then the 12 next and say it's the argument.

How could I do that?

Thanks in advance.

Alexandre Pilkiewicz

Re: [Caml-list] [MLPost] Curly brances

[Johannes Kanig]

Hi,

On Fri, Mar 5, 2010 at 5:51 PM, Alexandre Pilkiewicz
<alexandre.pilkiewicz@polytechnique.org> wrote:
> I'm sorry if that's the wrong list, but mlpost doesn't seem to have
> it's own list.

You can either use the mlpost-users list on mlpost's ocamlforge site -
it hasn't seen much use yet, but this shouldn't hold you off - or
simply send an email to one of the developers.

> I would like to draw variable size curly braces,

Unfortunately, this is trickier than one might think. TeX itself makes
use of some special characters in the font to do it. However, there
still are several possibilities.

The first is to simply scale the "{" character to the right size,
using either Picture.tex or Box.tex and the corresponding xscale /
yscale functions. However, it's difficult to get it right, it never
has quite the right proportions, and rarely looks good.

The second option is to obtain the intended size (using Box.height /
Box.width etc.), get a float value of this size using the
Concrete.float_of_num function and generate the curly brace using the
corresponding latex macro.

The third option would be to use the same trick as latex does
(aligning several characters of the font) in mlpost, but off the top
of my head I couldn't do it right now.

We really should put such a function in the interface ...

Johannes

-- 
Johannes Kanig
johannes.kanig@lri.fr

Re: [Caml-list] [MLPost] Curly brances

[Alexandre Pilkiewicz]

Hi

Thanks for the answer

2010/3/6 Johannes Kanig <johannes.kanig@gmail.com>:
> The second option is to obtain the intended size (using Box.height /
> Box.width etc.), get a float value of this size using the
> Concrete.float_of_num function and generate the curly brace using the
> corresponding latex macro.

I'm trying that one and it seems pretty good, except that my mlpost
(compiled from godi) does not support Concrete. Is it because I'm on a
mac, or for something else ? Also, it's version 0.7.1, which is not up
to date (but I don't like to install caml software by hand when it is
in godi).

I can already do my drawing since I know the size of my object, so thank you!

Alexnadre

Re: [Caml-list] [MLPost] Curly brances

[Johannes Kanig]

On Sat, Mar 6, 2010 at 12:45 PM, Alexandre Pilkiewicz
<alexandre.pilkiewicz@polytechnique.org> wrote:
> my mlpost
> (compiled from godi) does not support Concrete.

Normally the GODI package should support everything. The output of the
./configure script (at the beginning of the GODI output) prints if it
uses the cairo backend (in the 0.7.x versions, Concrete is still part
of the cairo backend; this will be better in 0.8). You need bitstring
and the cairo-bindings for this, but the GODI package has the right
dependencies.

Johannes

-- 
Johannes Kanig
johannes.kanig@lri.fr