README needs reorganization/transference to doco repository

[dwarring]

This was created before https://github.com/pdf-raku/pdf-raku.github.io can into existence and has continued to grow and become a defacto documentation point for the rest of the tool-chain.

Initial problem is that it's in the wrong place. At some point the bulk of it should be moved to the doco repository and the README slimmed down to refer to it.

[hectormonacci]

The code example just after https://github.com/pdf-raku/PDF-API6/blob/master/README.md#to-xobject is intended to show how to copy and transform pages from $old to $pdf, but it fails to use $old after opening it.

I tried changing my PDF::XObject $xo = $pdf.page(2).to-xobject; to my PDF::XObject $xo = $old.page(2).to-xobject; but after this change the example won't run under rakudo v2022.06.

[dwarring]

@hectormonacci I fixed the to-xobject example as above. I was able to run it on 2020.06. What issues are you having?

[hectormonacci]

Thank you. Here's more info:

raku -v:
Welcome to Rakudo™ v2022.06.
Implementing the Raku® Programming Language v6.d.
Built on MoarVM version 2022.06.

raku sample.raku (contains the example with minimal adaptations, and is applied to a valid v1.5 PDF input file):

indirect reference without associated reader: 3 0 R
in method deref at /usr/lib/raku/site/sources/3BAE5B323236C0357B33115CDCDF3E54C11BBF2F (PDF::COS::Tie) line 252
in method AT-KEY at /usr/lib/raku/site/sources/4643BF545A394ED914BE56449B35DE1B11718B4C (PDF::COS::Tie::Hash) line 73
in method AT-KEY at /usr/lib/raku/site/sources/4643BF545A394ED914BE56449B35DE1B11718B4C (PDF::COS::Tie::Hash) line 71
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 27
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method ref-count at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 20
in method body at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 67
in method ast at /usr/lib/raku/site/sources/C3530A88CEE9B5F532C720CDF215667E67FE53CA (PDF::IO::Serializer) line 259
in method ast at /usr/lib/raku/site/sources/7418831955D69E9D1DF9DB769436C4CEFCD8A0C7 (PDF) line 191
in method ast-writer at /usr/lib/raku/site/sources/7418831955D69E9D1DF9DB769436C4CEFCD8A0C7 (PDF) line 196
in method save-as at /usr/lib/raku/site/sources/7418831955D69E9D1DF9DB769436C4CEFCD8A0C7 (PDF) line 232
in method save-as at /usr/lib/raku/site/sources/F51B91A5DBC668E9092938CAB20E1AD2D8E61375 (PDF::Class) line 57
in block <unit> at sample.raku line 45

[dwarring]

That's on line 45, but my code sample only has 19 lines. Can you please show the actual code? It would also be helpful to attach a sample PDF, if you are able.

[hectormonacci]

Sure thing!

1. My code:

#!/usr/bin/env raku

# use PDF::API6;
# use PDF::Page;
# use PDF::XObject;
# use PDF::Content;
# use PDF::Content::Page :PageSizes;

# my PDF::API6 $old .= open('1842-gogol-capote.pdf');
# my PDF::API6 $pdf .= new;
# my PDF::Page $page = $pdf.add-page();
# my PDF::Content $gfx = $page.gfx;

# # Import Page 2 from the old PDF
# my PDF::XObject $xo = $pdf.page(1).to-xobject;

# # Add it to the new PDF's first page at 1/2 scale
# my $width = $xo.width / 2;
# my $bottom = 5;
# my $left = 10;
# $gfx.do($xo, :position[$bottom, $left], :$width);

# $pdf.media-box = A4;
# $pdf.save-as('1842-gogol-capote-raku.pdf');


use PDF::API6;
use PDF::Page;
use PDF::XObject;
use PDF::Content;
my PDF::API6 $old .= open('1842-gogol-capote.pdf');
my PDF::API6 $pdf .= new;
my PDF::Page $page = $pdf.add-page;
my PDF::Content $gfx = $page.gfx;

# Import first page from the old PDF
my PDF::XObject $xo = $old.page(1).to-xobject;

# Add it to the new PDF's first page at 1/2 scale
my $width = $xo.width / 2;
my $bottom = 5;
my $left = 10;
$gfx.do($xo, :position[$bottom, $left], :$width);

$pdf.save-as('new.pdf');

2. The PDF file to be used as source:

1842-gogol-capote.pdf

[dwarring]

Thanks, I can replicate the issue.

That is very close to the example, apologies.

I'm thinking it must be somehow PDF-specific. Will investigate.

[dwarring]

I fixed a bug in PDF::Content::Page which implements the to-xobject method, which wasn't building the xobjects's resources correctly.

@hectormonacci could you please upgrade to PDF::Content 0.6.6 and try again.

[hectormonacci]

Great job @dwarring ! I upgraded to PDF::Content 0.6.6 and now it works. Thanks a lot!

[hectormonacci]

By the way, I think another change would be needed on the same example.

:position[$bottom, $left]

should be changed to:

:position[$left, $bottom]