a

% The code in this file is based on <https://tex.stackexchange.com/a/349521/303>.
% ----

\RequirePackage{etoolbox}
\RequirePackage{iftex}

% Check if we are generating a PDF using XeTeX.
\ifboolexpr{test {\ifnumgreater{\value{pdftype}}{0}} and bool {XeTeX}}{
	\RequirePackage{atbegshi}
}{}

\makeatletter
\ifboolexpr{test {\ifnumequal{\value{pdftype}}{2}} and test {\ifnumequal{\value{colormode}}{1}}}{
	% This is a hack to get hyperref to make RGB-like links annotated with a C mark to instead be annotated with a K mark, in order to work in PDF/A with the CMYK colour profile.
	\patchcmd{\hyper@linkfile}{/C[}{/K[}{}{}
	\patchcmd{\hyper@linkurl}{/C[}{/K[}{}{}
	\patchcmd{\find@pdflink}{/C[}{/K[}{}{}
	\patchcmd{\hyper@linkstart}{/C[}{/K[}{}{}
}{}
\makeatother

% Check if PDF type is PDF/X.
\ifnumequal{\value{pdftype}}{1}{
	% ---- This code was derived from <http://tex.stackexchange.com/a/248911>.

	% 72.27 pt is 72 bp, 800/803. (See <http://tex.stackexchange.com/a/113513>)
	% Note: size in bp = (size in mm * 72) / 25.4.
	\makeatletter
	\edef\pwbp{\strip@pt\dimexpr0.996264009963\paperwidth\relax} % paper width in bp (PS points)
	\edef\phbp{\strip@pt\dimexpr0.996264009963\paperheight\relax} % paper height in bp (PS points)
	\makeatother

	\edef\calcpdfpageattr{
		/TrimBox [0 0 \pwbp\space\phbp]
	}

	% ----

	\hypersetup{
		pdfstartpage = {}, % Disable for PDF/X compliance.
	}

	\ifxetex
		% We are using XeTeX.

		\makeatletter

		\AtBeginShipout{ % hook that gets executed for every page
			\special{pdf: put @thispage
				<< \expandafter\calcpdfpageattr >>
			}
		}
		\special{pdf: put @thispage
			<< \expandafter\calcpdfpageattr >>
		}
		\special{pdf:docinfo
			<<
				/GTS_PDFXVersion (PDF/X-1:2001)
				/GTS_PDFXConformance (PDF/X-1a:2001)
				/Trapped/False
			>>
		}

		\ifnumequal{\value{iccinsert}}{1}{
			% Embed CMYK ICC profile from pdfx package.
			\special{pdf:fstream @cmykdata (FOGRA39L_coated.icc)
				<<
					/N 4^^J/Alternate/DeviceCMYK
				>>
			}
			\special{pdf:put @catalog
				<<
					/OutputIntents [
						<<
							/Type /OutputIntent
							/S /GTS_PDFX
							/DestOutputProfile @cmykdata
							/OutputConditionIdentifier (Coated FOGRA39)
							/Info (FOGRA39L)
							/RegistryName (http://www.color.org/)
						>>
					]
				>>
			}
		}{
			% Do not embed CMYK ICC profile from pdfx package.
			\special{pdf:put @catalog
				<<
					/OutputIntents [
						<<
							/Type /OutputIntent
							/S /GTS_PDFX
							/OutputConditionIdentifier (custom)
							/Info (none)
							/RegistryName (http://www.color.org/)
						>>
					]
				>>
			}
		}

		\makeatother
	\else
		% We are using pdfTeX or LuaTeX.

		\expandafter\pdfpageattr\expandafter{\calcpdfpageattr}

		\ifnumequal{\value{iccinsert}}{1}{
			% Embed CMYK ICC profile from pdfx package.
			\immediate\pdfobj stream attr{/N 4^^J/Alternate/DeviceCMYK} file{FOGRA39L_coated.icc}
			\pdfcatalog{
				/OutputIntents [
					<<
						/Type /OutputIntent
						/S /GTS_PDFX
						/DestOutputProfile \the\pdflastobj\space 0 R
						/OutputConditionIdentifier (Coated FOGRA39)
						/Info (FOGRA39L)
						/RegistryName (http://www.color.org/)
					>>
				]
			}
		}{
			% Do not embed CMYK ICC profile from pdfx package.
			\pdfcatalog{
				/OutputIntents [
					<<
						/Type /OutputIntent
						/S /GTS_PDFX
						/OutputConditionIdentifier (custom)
						/Info (none)
						/RegistryName (http://www.color.org/)
					>>
				]
			}
		}
	\fi

	% Remove all links and annotations for PDF/X compliance.
	% Note: the `NoHyper` environment does not deactivate the creation of bookmarks, the inclusion of document information, etc. (See <http://tex.stackexchange.com/a/300675> for more information.)
	\NoHyper

	% Set PDF/X standard via hyperxmp.
	\hypersetup{
		pdfxstandard = {\pdfxstandard},
	}
}{}

% Check if PDF type is PDF/A.
\ifnumequal{\value{pdftype}}{2}{
	\ifxetex
		% We are using XeTeX.

		% Check if colour mode is CMYK.
		\ifnumequal{\value{colormode}}{1}{
			% Embed CMYK ICC profile from pdfx package.
			\special{pdf:fstream @cmykdata (FOGRA39L_coated.icc)
				<<
					/N 4
				>>
			}
			\special{pdf:put @catalog
				<<
					/OutputIntents [
						<<
							/Type /OutputIntent
							/S /GTS_PDFA1
							/DestOutputProfile @cmykdata
							/OutputConditionIdentifier (Coated FOGRA39)
							/Info (FOGRA39 (ISO Coated v2 300\% (ECI)))
							/RegistryName (http://www.argyllcms.com/)
						>>
					]
				>>
			}
		}{
			\makeatletter
			\special{pdf:fstream @srgbdata (sRGB.icc)
				<<
					/N 3^^J/Alternate/DeviceRGB
				>>
			}
			\special{pdf:put @catalog
				<<
					/OutputIntents [
						<<
							/Type /OutputIntent
							/S /GTS_PDFA1
							/DestOutputProfile @srgbdata
							/OutputConditionIdentifier (sRGB IEC61966-2.1)
							/Info (sRGB IEC61966 v2.1)
							/RegistryName (http://www.color.org/)
						>>
					]
				>>
			}
			\makeatother
		}
	\else
		% We are using pdfTeX or LuaTeX.

		% Check if colour mode is CMYK.
		\ifnumequal{\value{colormode}}{1}{
			% Embed CMYK ICC profile from pdfx package.
			\immediate\pdfobj stream attr{/N 4} file{FOGRA39L_coated.icc}
			\pdfcatalog{
				/OutputIntents [
					<<
						/Type /OutputIntent
						/S /GTS_PDFA1
						/DestOutputProfile \the\pdflastobj\space 0 R
						/OutputConditionIdentifier (Coated FOGRA39)
						/Info (FOGRA39 (ISO Coated v2 300\% (ECI)))
						/RegistryName (http://www.argyllcms.com/)
					>>
				]
			}
		}{
			\immediate\pdfobj stream attr{/N 3^^J/Alternate/DeviceRGB} file{sRGB.icc}
			\pdfcatalog{
				/OutputIntents [
					<<
						/Type /OutputIntent
						/S /GTS_PDFA1
						/DestOutputProfile \the\pdflastobj\space 0 R
						/OutputConditionIdentifier (sRGB IEC61966-2.1)
						/Info (sRGB IEC61966 v2.1)
						/RegistryName (http://www.color.org/)
					>>
				]
			}
		}
	\fi

	% Set PDF/A part and conformance via hyperxmp.
	\hypersetup{
		pdfapart = {\pdfapart},
		pdfaconformance = {\pdfaconformance},
	}
}{}