Add rudimentary PDF/A-2b support

Redo merge request !32 (closed) using the pdfx package and avoid command line hassle using \pdfcreationdate.

RGB logo images are from !32 (closed), unknown to me how these are created.

liuthesis.cls

@@ -308,7 +308,7 @@
 \RequirePackage{pbox}
 \RequirePackage{ifthen}
 \RequirePackage{geometry}
-%%%%%%%%%% PDF/A support
+%%%%%%%%%% PDF/A and PDF/X support
 % https://tex.stackexchange.com/questions/474197/pdfx-incomplete-cidset-in-some-fonts/474336#474336
 \ifluatex
 \pdfvariable omitcidset=1
@@ -316,14 +316,14 @@
 \RequirePackage[pdfa,pdfusetitle,bookmarks=false]{hyperref} %bookmarks are incompatible with PDF/X<6
 \RequirePackage{hyperxmp}[2020/06/15]
 \RequirePackage{cmap}
-
+\RequirePackage{colorprofiles}
 \ifxetex
   \def\OBJ@CMYK{@colorprofile}%
-  \immediate\special{pdf:fstream \OBJ@CMYK (FOGRA39L_coated.icc) <</N 4>>}%
+  \immediate\special{pdf:fstream \OBJ@CMYK (\colorpro@cmyk@profile) <</N 4>>}%
   \def\pdfcatalog#1{\special{pdf:put @catalog <<#1>>}}
   \def\pdfpageattr#1{\special{pdf:put @thispage <<#1>>}}
 \else
-  \immediate\pdfobj stream attr{/N 4} file {FOGRA39L_coated.icc}%
+  \immediate\pdfobj stream attr{/N 4} file {\colorpro@cmyk@profile}%
   \edef\OBJ@CMYK{\the\pdflastobj\space 0 R}%
 \fi
 \pdfcatalog{%
@@ -331,38 +331,34 @@
     /Type /OutputIntent
     /S/GTS_PDFA1
     /DestOutputProfile \OBJ@CMYK
-    /OutputConditionIdentifier (Coated FOGRA39)
+    /OutputConditionIdentifier (\colorpro@cmyk@intent)
     /Info(FOGRA39L)
-    /OutputCondition(Offset printing, according to ISO 12647-2:2004/Amd 1, OFCOM, paper type 1 or 2 = coated art, 115 g/m2, tone value increase curves A (CMY) and B (K))
-    /RegistryName(http://www.fogra.org)
+    /OutputCondition(\colorpro@cmyk@identifier)
+    /RegistryName(\colorpro@cmyk@registry)
   >>
   <<
     /Type /OutputIntent
     /S/GTS_PDFX
     /DestOutputProfile \OBJ@CMYK
-    /OutputConditionIdentifier (Coated FOGRA39)
+    /OutputConditionIdentifier (\colorpro@cmyk@intent)
     /Info(FOGRA39L)
-    /OutputCondition(Offset printing, according to ISO 12647-2:2004/Amd 1, OFCOM, paper type 1 or 2 = coated art, 115 g/m2, tone value increase curves A (CMY) and B (K))
-    /RegistryName(http://www.fogra.org)
+    /OutputCondition(\colorpro@cmyk@identifier)
+    /RegistryName(\colorpro@cmyk@registry)
   >> ]
 }
-
 % Bugfix of hyperref to produce CMYK links
 \let\HyColor@HyperrefBorderColor\HyColor@XZeroOneThreeFour
-
-%we need to tell PDF/X the final format of the paper. This needs adjustment if you want graphics on the page border, called bleeding
+% Tell PDF/X the final format of the paper
 \@tempdima=0.99626400996264009962\paperwidth
 \edef\boxwd{\strip@pt\@tempdima}
 \@tempdima=0.99626400996264009962\paperheight
 \edef\boxht{\strip@pt\@tempdima}
-
 \edef\next{%
   \protect\pdfpageattr{
     /TrimBox[0.0 0.0 \boxwd\space \boxht]
   }%
 }
 \next
-
 \hypersetup{%
     pdfdisplaydoctitle=true,
     pdftrapped=False,
@@ -371,8 +367,7 @@
     pdfuapart=1,
     pdfxstandard={PDF/X-4},
 }
-
-%%%%%%%%%% end PDF/A support
+%%%%%%%%%% end PDF/A and PDF/X support
 \RequirePackage{amssymb}
 \RequirePackage{amsmath}
 \RequirePackage{etoolbox}