[Enhancement] Add '-dcrop' option to ps and svg backends

Issue 5165

This change allows the output of scores in the format provided by the '-dpreview' option but including all systems, not just the first.

This would allow for easier SVG use in HTML, without the need for cropping snippets. Further, SVG is an HTML standard, and its vector nature makes its use unparalleled for the web. This change would allow SVG use in 'lilypond-book' in the future.

[pkx166h, 2017-07-27 07:21:12]

Please note that *i* did the commit message - trying to interpret what Etienne
is trying to achieve, so if this is completely non-sensical, blame me not him :)

Etienne knows this is a first 'draft' and sent me an email to say so, any
guidance would be appreciated:

---

From: Étienne Beaulé <beauleetienne0@gmail.com>
To: James <pkx@gnu.org>
Subject: Re: [Feature Request]: More flexible SVG snippet cropping
Date: Wed, 26 Jul 2017 20:24:41 -0300

I tried making a simple patch, but doesn't work. It's attached. I wouldn't
know how, but if something like the "stack-stencils Y DOWN 0.0" section
from the output-preview-framework could be passed from output-framework to
dump-page and there's a if statement for svg-begin for the -dcrop option.
Guidance?

All the best
Étienne

[pkx166h, 2017-08-01 08:13:37]

I am going to leave this on review for this countdown only that the submitter
(not me) had doubts about this patch and was looking for any guidance (it does
pass all the tests BTW).

[Carl, 2017-08-01 12:22:03]

I have listed some specific changes that must be made (move to the proper
alphabetical order)  and raised questions about how the code works with an
apparently misspelled argument.  I believe both of those need to be fixed before
pushing the patch.

I would also like to see crop apply to at least the pdf backend in addition to
svg, if it's not too much work.

https://codereview.appspot.com/326960043/diff/1/Documentation/usage/running.i...
File Documentation/usage/running.itely (right):

https://codereview.appspot.com/326960043/diff/1/Documentation/usage/running.i...
Documentation/usage/running.itely:683: @tab Match the size of the normal output
to the typeset image for SVGs.
This should be placed in alphabetical order (about line 532)

I would prefer to see the description be something like

Match the size of the normal output to the typeset image (currently only
implemented for svg backend).

Actually, I'd even more prefer to have the crop function work on the pdf backend
as well as the svg backend.  Have you investigated whether your code could work
on PDF as well?

Also, the placement of crop in this file causes reading problems, because it's
placed in the middle of preview, and the text below says "This option is
supported by all backends", which applies to preview, but not to crop.

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm
File scm/framework-svg.scm (right):

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm#newcode173
scm/framework-svg.scm:173: (define (dump-page-crop paper filename page
page-number page-count stensil)
Hmm -- the argument here is spelled "stensil"

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm#newcode178
scm/framework-svg.scm:178: (x-extent (ly:stencil-extent stencil X))
But here it is spelled "stencil"

How does this work?  Perhaps the stencil argument is unnecessary and not doing
anything here?  I'm confused.

https://codereview.appspot.com/326960043/diff/1/scm/lily.scm
File scm/lily.scm (right):

https://codereview.appspot.com/326960043/diff/1/scm/lily.scm#newcode341
scm/lily.scm:341: (crop
This should be put in the proper alphabetical order (up at line 231), rather
than placed under preview

[Carl, 2017-08-01 12:25:09]

Oh, now I read the first message and see that the code doesn't work.

My first attempt at getting the code to work would be to change "stensil" to
"stencil" and see if that fixed things.

[Ebe123, 2017-08-04 02:52:25]

In PS2, an implementation of the '-dcrop' argument was added to the 'ps'
backend. My implementation has also been revamped to *work* and be more elegant.
Letting James upload the patchset.

https://codereview.appspot.com/326960043/diff/1/Documentation/usage/running.i...
File Documentation/usage/running.itely (right):

https://codereview.appspot.com/326960043/diff/1/Documentation/usage/running.i...
Documentation/usage/running.itely:683: @tab Match the size of the normal output
to the typeset image for SVGs.
On 2017/08/01 12:22:02, Carl wrote:
> This should be placed in alphabetical order (about line 532)
> 
> I would prefer to see the description be something like
> 
> Match the size of the normal output to the typeset image (currently only
> implemented for svg backend).
> 
> Actually, I'd even more prefer to have the crop function work on the pdf
backend
> as well as the svg backend.  Have you investigated whether your code could
work
> on PDF as well?
> 
> Also, the placement of crop in this file causes reading problems, because it's
> placed in the middle of preview, and the text below says "This option is
> supported by all backends", which applies to preview, but not to crop.

Done.

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm
File scm/framework-svg.scm (right):

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm#newcode173
scm/framework-svg.scm:173: (define (dump-page-crop paper filename page
page-number page-count stensil)
On 2017/08/01 12:22:02, Carl wrote:
> Hmm -- the argument here is spelled "stensil"

Acknowledged.

https://codereview.appspot.com/326960043/diff/1/scm/framework-svg.scm#newcode178
scm/framework-svg.scm:178: (x-extent (ly:stencil-extent stencil X))
On 2017/08/01 12:22:02, Carl wrote:
> But here it is spelled "stencil"
> 
> How does this work?  Perhaps the stencil argument is unnecessary and not doing
> anything here?  I'm confused.

Function removed in PS2.

https://codereview.appspot.com/326960043/diff/1/scm/lily.scm
File scm/lily.scm (right):

https://codereview.appspot.com/326960043/diff/1/scm/lily.scm#newcode341
scm/lily.scm:341: (crop
On 2017/08/01 12:22:02, Carl wrote:
> This should be put in the proper alphabetical order (up at line 231), rather
> than placed under preview

Done.

[pkx166h, 2017-08-04 09:32:10]

Implementation '-dcrop' argument was added to 'ps'

[Ebe123, 2017-08-04 14:39:38]

Add '-dcrop' option to ps and svg backends

This change allows the output of scores in the format provided by the
'-dpreview' option but including all systems, not just the first.

This would allow for easier SVG use in HTML, without the need for cropping
snippets. Further, SVG is an HTML standard, and its vector nature makes its use
unparalleled for the web. This change would allow SVG use in 'lilypond-book' in
the future.

-----

This patch: https://gerrit.wikimedia.org/r/#/c/370209/ will make use of this
change.

[pkx166h, 2017-08-11 13:08:18]

One thing I think we need is an entry in the changes.tely for this new feature.

Also now that you have tracker access (and because I cannot reassign this
Rietveld issue to someone), could you Etienne create a new Rietveld issue for
the tracker (which is now assigned to you) when you make the edit to the
changes.tely? 

Then we can discard this one.