[racket] Snips displaying pdfs

Hm. What I meant was, is there a way to do that without
rasterization? I intended to use this for rendering posters,
where a 3MB 2000dpi image is less desirable than a few
line-drawing commands. It would be lovely to be able to rotate
and scale PDFs with slidehsow/pict without converting them to
bitmaps first, but doing so in a portable way.

Maybe it's best to provide both ways? Making a pdf-page->bitmap%
function with the kosher bitmap% get-handle way, and a
render-pdf-to-dc! function. I'll investigate this.

8 hours ago, Jens Axel Søgaard wrote:
> 2012/5/8 Michael W <mwilber at uccs.edu>:
> > Sure, but I mean, is there a better way to get at a dc<%>'s cairo
> > context than (require racket/draw/private/local) ? From what I
> > understand, those areas aren't meant to be used by third-party
> > libraries, and definitely not by planet packages. Not all dc<%>s
> > are even backed by cairo contexts...
> 
> I believe you want get-handle. It will give you the surface of a bitmap,
> and you can then get a context.
> 
> (let* ([bitmap    (make-bitmap WIDTH HEIGHT)]  ; works
>        [filename
> "/Users/soegaard/Dropbox/GitHub/this-and-that/racket-poppler/bla.pdf"]
>        [document  (poppler_document_new_from_file (string-append
> "file:" filename) #f #f)]
>        [page      (poppler_document_get_page document 0)]
>        [surface   (send bitmap get-handle)]
>        [context   (cairo_create surface)])
>   (cairo_scale context 2.0 2.0)
>   (poppler_page_render page context)
>   (make-object image-snip% bitmap))
> 
> This example is from
> 
> https://github.com/soegaard/this-and-that/blob/master/racket-poppler/racket-poppler.rkt
> 
> /Jens Axel
> 
> >
> > 16 minutes ago, Eli Barzilay wrote:
> >> Three hours ago, Michael W wrote:
> >> >
> >> > I'm not rasterizing to a bitmap% or anything like that. Instead,
> >> > I'm asking poppler to draw directly to the dc<%>'s cairo context
> >> > (Eli and Matthew are probably cringing), which means that you can
> >> > render to arbitrary dc<%> objects at the cost of being much more
> >> > hacky than your version.
> >>
> >> I don't know about "hacky" -- it just sounds like it'll invoke the
> >> library for every redraw, which would be overall slower than going
> >> through a bitmap that saves the results.
> >>
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