Re: RFC: require librsvg to implement SVG image support

[Aaron Hill]

On 2023-01-09 11:12 am, Jean Abou Samra wrote:
> I'm not really sure how to get factual data about this (a straw poll
> on the user list?).
>
> In my experience, for things like logos, SVG is more common (there 
> *are*
> logos in PDF, they're just less common as far as I know, but again this 
> is
> only my experience).

Logos are probably most common on cover pages, but some of the folios in 
our choir's repository do start the music on the cover.  As such, 
publisher logos and other artwork sometimes appear on that first page 
along side notation.  The last page might also have non-musical 
graphics.

Of course, I have no idea what formats these houses use internally, but 
the art libraries that I have access to use EPS for the vector format.  
I suspect that SVG is just too "new" a format for these older resources. 
 (NOTE: One of the libraries I have also provides JPEGs but I find the 
DPI to be too low for any print use, and even screen use is not great.  
I wonder if PNG was too novel a format when this library was assembled.)

I have had some success with converting EPS to SVG (albeit with some 
manual correction for color spaces), so I would have no real objection 
with LilyPond moving towards SVG as its preferred vector-based image 
format.  What I would fight against is any form of rasterization.  When 
helping to prepare bulletins and inserts for my church, it is a real 
struggle getting our printer to produce high quality output.  Pure 
vector is the only way to have sharp, clear music notation.  Even very 
high DPI raster ends up slightly out of focus.  I suspect that somewhere 
in the software and hardware stacks, raster images are undergoing 
photographic manipulation/optimization.  That is, they expect raster to 
be a natural real-world image, so it can freely mess about with gamma 
correction and low-pass filtering.  Line artwork and music content does 
not fit this pattern, so it gets muddled.

So, my only comment on the specific libraries and technologies that we 
end up using is that there must exist a pure vector pipeline from input 
sources to output documents.  It is not burdensome for me to have to 
migrate my art assets to SVG.


-- Aaron Hill