Re: [Denemo-devel] Denemo Breakthrough

[Richard Shann]

On Sun, 2011-07-24 at 15:08 +0000, Ralf Mattes wrote:
> 
> Hello,
> 
> sorry if I seem to just complain,
Not at all, I very much appreciate finding out how scheme/C should work
together

>  but that's an extremely ugly interface.
> You're introducing an ad-hoc markup language
however, this is going a bit far, asking the scripters to put the
parameters to the cairo_show_text() onto successive lines is no sort of
language at all; you cannot change font or size or anything within the
string you are printing. Curiously, cairo_show_text() is described by
the cairo folk as a "toy" interface, but it may be the right thing to
use here, as we are not seriously interested in text (kerning,
justification, spell-checking ...)

>  without need - have a look at
> Gtk's (Pango's, to be more specific) markup language [1]. 
> May I suggest a more "scheme-ish" way: 
> 
>  d-DirectivePut-standalone-graphic tag <spec>
> 
>  Where spec is either a string (backward-comaptible) or a list of the
>  form (<type> &rest ...)  where type is a keyword and the rest args
>  specify type specific information. A few examples:
> 
>   (d-DirectivePut-standalone-graphic tag (:graphic :file
> "/home/wallace/cheese.svg"))

Did you mean 'graphic 'file etc here?

>  
>   (d-DirectivePut-standalone-graphic tag (:glyph "MUSICAL SYMBOL
> DOUBLE FLAT" :font "Lucida Bright"))

Did you have some sort of lookup for "MUSICAL SYMBOL DOUBLE FLAT" to
find what utf8 value this was? I am not sure if there is stuff for that
available.
As always, the bottom line is having the manpower - I am confident now
about iterating through a scheme list in C (thanks to earlier comments
by you), but testing symbols like 'glyph would take me some research (in
fact I haven't really got a solid model in my head for symbols and the
strings that are used to name them ...). Well, the very bottom line is
that scheme objects carry their type with them, so we can always add
extra parameter types to d-DirectivePut-standalone-graphic, for instance
if we found we needed to use several fonts in one display string.

Thanks for your comments

Richard