Re: Improvements to Postscript backend (patches included)

[Han-Wen Nienhuys]

David Feuer wrote:
> I sent this some hours ago, but haven't seen it yet.  Is the mailing list
> broken, or just really slow?

The list is a bit slow, and I have been away.

> Original message:
>
> I made some changes to the Postscript backend, making the output more readable
> (especially for text), around 10% shorter, and, at least in theory, also faster
> to interpret.  These changes are just a start, but I hope they help.  I'd like
> to know if it might be possible to make the backend work at a slightly higher
> level, which should allow much smaller files (e.g., Postscript could easily
> understand the concept of "filled dotted quarter note in current note font with
> upward stem 3 staff spaces long").

That's very unlikely. The internal representation is not strictly 
hierarchical, so it's difficult to group different objects (eg. note and 
stem) so they will be output together, and still be sure that all of 
them are processed.

> I'm not a master of diff, so let me know if the following aren't done right.
> Diffs (made with -u) against the 2.8.0 source:

I'm missing a Changelog entry.

> --- ../Installation
> Programs/lilypond-2.8.0-src/lilypond-2.8.0/scm/framework-ps.scm     2006-03-20
> 19:45:18.000000000 -0500
> +++ framework-ps.scm    2006-03-25 18:25:43.875475200 -0500
> @@ -42,8 +42,10 @@
>    (define font-list (ly:paper-fonts paper))
>    (define (define-font command fontname scaling)
>      (string-append
> -     "/" command " { /" fontname " findfont "
> -     (ly:number->string scaling) " output-scale div scalefont } bind def\n"))
> +      "/" command " { /" fontname " " (ly:number->string scaling) "
> output-scale div selectfont } bind def\n"))
> +;    (string-append
> +;     "/" command " { /" fontname " findfont "
> +;     (ly:number->string scaling) " output-scale div scalefont } bind def\n"))

Hi,

thanks for you patch.  CAn you have a second look; there are some style 
issues,




> +/printletter {
> +       currentpoint
> +       3 2 roll
> +       glyphshow
> +       moveto
> +} bind def
>  
> +/printglyphs {
> +       -1 1
> +       {
> +               3 mul -3 roll
> +               printletter
> +               rmoveto
> +       }for
> +}bind def

can you add some comment explaining in more detail that this is for 
kerning?   Also, can you follow the naming convention, which is 
word_word iso. wordword for PS files.

(I'd like to change this to word-word, some time)


> +(define (round2 num)
> +  (/ (round (* 100 num)) 100))
> +
> +(define (round4 num)
> +  (/ (round (* 10000 num)) 10000))
> +
> +(define (str4 num)
> +  (format #f "~f" (round4 num)))

can you rename this to something more comprehensible?



> +;;  s/\.\([0-9]\{-}\)0* /\1 /g
> +

?

>    (format #f "gsave 
> -  /~a ~a ~a output-scale div scalefont setfont\n~a grestore"
> +  /~a ~a output-scale div selectfont\n~a grestore"
>           postscript-font-name
> -         (if cid?
> -             " /CIDFont findresource "
> -             " findfont")

I don't understand this? How are CID resources supposed to be loaded now?


>  (define (named-glyph font glyph)
>    (string-append 
> -   (ps-font-command font) " setfont " 
> +   (ps-font-command font) " " 
>     "/" glyph " glyphshow "))

While you're at it, I think it would improve readability of the SCM file 
when you try to replace string-append in cases like these.


--

Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen

LilyPond Software Design
 -- Code for Music Notation
http://www.lilypond-design.com