l3color named color support and spotcolors in LuaLaTeX (#494)

* fontspec support for extended luaotfload color feature

* Adjust testfiles

* check for xcolor and l3color names

* update docu

* update colour-basic test

* correction if opacity is set with hex and key

* testfiles for opacity, color model, spotcolor

* document color changes

CHANGES.md

@@ -10,6 +10,8 @@ Change history
   * Support variable fonts under LuaLaTeX.
   * Skip scanning for filenames when loading fonts by name on LuaLaTeX.
   * Allow restricting filename lookup to kpathsea lookups using `KpseOnly`.
+  * added support for named colors from l3color 
+  * support with lualatex spotcolors and cmyk colors in the pdf. 
 
 
 ## v2.8a (2022/01/15)

fontspec-code-internal.dtx

@@ -371,7 +371,8 @@
 
     \str_if_eq:eeF { \l_@@_hexcol_tl \l_@@_opacity_tl }
                      { \c_@@_hexcol_tl \c_@@_opacity_tl }
-      { \@@_update_featstr:n { color = \l_@@_hexcol_tl\l_@@_opacity_tl } }
+%<XE>       { \@@_update_featstr:n { color = \l_@@_hexcol_tl\l_@@_opacity_tl } }
+%<LU>       { \@@_update_featstr:n { color = {\l_@@_hexcol_tl\l_@@_opacity_tl} } }
   }
 %    \end{macrocode}
 % \end{macro}

fontspec-code-keyval.dtx

@@ -697,26 +697,61 @@
 %    \end{macrocode}
 %
 % \paragraph{Color}
-% Hooks into pkg{xcolor}, which names its colours \texttt{\char`\\color@<name>}.
+% Test first if the color is a named l3color, then if it is a color from
+% \pkg{xcolor}, which names its colours \texttt{\char`\\color@<name>}.
+% If this fails the argument is assumed to be a hex color.
+%
 %    \begin{macrocode}
 \@@_keys_define_code:nnn {fontspec} {Color}
   {
-    \cs_if_exist:cTF { \token_to_str:N \color@ #1 }
+%<*XE>
+    \color_if_exist:nTF {#1}
       {
-        \convertcolorspec{named}{#1}{HTML}\l_@@_hexcol_tl
+        \color_export:nnN {#1} {HTML}\l_@@_hexcol_tl
       }
       {
-        \int_compare:nTF { \tl_count:n {#1} == 6 }
-          { \tl_set:Nn \l_@@_hexcol_tl {#1} }
+        \cs_if_exist:cTF { \token_to_str:N \color@ #1 }        
+          {
+            \convertcolorspec{named}{#1}{HTML}\l_@@_hexcol_tl
+          }
           {
-            \int_compare:nTF { \tl_count:n {#1} == 8 }
-              { \fontspec_parse_colour:viii #1 }
+            \int_compare:nTF { \tl_count:n {#1} == 6 }
+              { \tl_set:Nn \l_@@_hexcol_tl {#1} }
               {
-                \bool_if:NF \l_@@_firsttime_bool
-                  { \@@_warning:nx {bad-colour} {#1} }
+                \int_compare:nTF { \tl_count:n {#1} == 8 }
+                  { \fontspec_parse_colour:viii #1 }
+                  {
+                    \bool_if:NF \l_@@_firsttime_bool
+                      { \@@_warning:nx {bad-colour} {#1} }
+                  }
               }
           }
       }
+%</XE>
+%<*LU>
+    \color_if_exist:nTF {#1}
+      {
+        \tl_set:Nn \l_@@_hexcol_tl {#1}
+      }
+      {
+        \cs_if_exist:cTF { \token_to_str:N \color@ #1 }        
+          {
+            \convertcolorspec{named}{#1}{HTML}\l_@@_hexcol_tl
+          }
+          {
+            \int_compare:nTF { \tl_count:n {#1} == 6 }
+              { \tl_set:Nn \l_@@_hexcol_tl {#1} }
+              {
+                \int_compare:nTF { \tl_count:n {#1} == 8 }
+                  { \fontspec_parse_colour:viii #1 }
+                  {
+                    \bool_if:NF \l_@@_firsttime_bool
+                      { \@@_warning:nx {bad-colour} {#1} }
+                  }
+              }
+          }
+      }      
+%</LU>
   }
 %    \end{macrocode}
 %
@@ -745,6 +780,7 @@
       }
     \tl_set:Nx \l_@@_opacity_tl
       {
+%<LU>      ,
         \int_compare:nT { \l_@@_tmp_int <= "F } {0} % zero pad
         \int_to_hex:n { \l_@@_tmp_int }
       }

fontspec-code-vars.dtx

@@ -299,7 +299,8 @@
 %
 %    \begin{macrocode}
 \tl_const:Nn \c_@@_hexcol_tl {000000}
-\tl_const:Nn \c_@@_opacity_tl {FF~}
+%<XE> \tl_const:Nn \c_@@_opacity_tl {FF~}
+%<LU> \tl_const:Nn \c_@@_opacity_tl {}
 \tl_const:Nn \c_@@_postadjust_tl { \l_@@_wordspace_adjust_tl \l_@@_punctspace_adjust_tl }
 %    \end{macrocode}
 %

fontspec-doc-featset.tex

@@ -330,7 +330,7 @@ \subsection{Colour}
 (For example, if you set the colour in a \verb|\setmainfont| command, \verb|\color{...}| and related commands, including hyperlink colouring, will no longer have any effect on text in this font.)
 Therefore, \pkg{fontspec}'s colour commands are best used to set explicit colours in specific situations, and the \pkg{xcolor} package is recommended for more general colour functionality.
 
-The colour is defined as a triplet of two-digit Hex RGB
+The colour can be defined as a triplet of two-digit Hex RGB
 values, with optionally another value for the transparency (where
 |00| is completely transparent and |FF| is opaque.)
 \begin{Lexample}{color}{Selecting colour with transparency.}
@@ -341,8 +341,6 @@ \subsection{Colour}
   {\addfontfeature{Color=DDBB2299}P}\kern-0.5ex
   {\addfontfeature{Color=00BB3399}R}
 \end{Lexample}
-Transparency is supported by \LuaLaTeX; \XeLaTeX\ with the \texttt{xdvipdfmx} driver
-does not support this feature.
 
 If you load the \pkg{xcolor} package, you may use any named colour instead
 of writing the colours in hexadecimal.
@@ -353,17 +351,61 @@ \subsection{Colour}
  \definecolor{Foo}{rgb}{0.3,0.4,0.5}
  \fontspec[Color=Foo]{Verdana} ...
 \end{Verbatim}
-The \pkg{color} package is \emph{not} supported; use \pkg{xcolor} instead.
 
-You may specify the transparency with a named colour using the \feat{Opacity}
-feature which takes an decimal from zero to one corresponding to
-transparent to opaque respectively:
+You may also use named colours defined with the color commands of the L3 
+programming layer:
+\begin{Verbatim}
+ \ExplSyntaxOn
+ \color_set:nnn{Foo}{rgb}{0.3,0.4,0.5}
+\ExplSyntaxOff
+ ...
+ \fontspec[Color=Foo]{Verdana} ...
+\end{Verbatim}
+
+Color expressions (\verb+red!50!blue+) are not supported. The \pkg{color} 
+package is \emph{not} supported neither. 
+
+The code will at first test for color names of the L3 layer, then for xcolor 
+names and at last try to use the argument as a hexadecimal value.
+
+You may specify the transparency with a named colour using the \feat{Opacity} 
+feature which takes an decimal from zero to one corresponding to transparent 
+to opaque respectively: 
 \begin{Verbatim}
  \fontspec[Color=red,Opacity=0.7]{Verdana} ...
 \end{Verbatim}
 It is still possible to specify a colour in six-char hexadecimal form
 while defining opacity in this way, if you like.
 
+\subsubsection{Color models}
+
+With \XeTeX\ color are always written in the rgb color model into the PDF. 
+When using \LuaTeX, colors with the commands of the L3 layer can be written 
+as rgb or cmyk or as spot color depending on their definition and of the 
+value of the variable \verb+\l_color_fixed_model_tl+. 
+
+\subsubsection{Spot colors} 
+With \LuaTeX\ it is possible to use spot colors. This requires the use of the 
+PDF management:
+\begin{Verbatim}
+\DocumentMetadata{}
+\documentclass{article}
+\usepackage{fontspec}
+\ExplSyntaxOn
+ \color_model_new:nnn { sepblue } { Separation }
+    {
+      name = PANTONE~3005~U ,
+      alternative-model = cmyk ,
+      alternative-values = {1, 0.56, 0,0},
+    }
+ \color_set:nnn{spotblue}{sepblue}{1}
+\ExplSyntaxOff
+...
+\fontspec[Color=spotblue]{texgyreheros}
+\end{Verbatim}
+
+
+
 \subsection{Scale}
 
 \cmdbox{

testfiles/aff-group.luatex.tlg

@@ -6,13 +6,13 @@ TU/texgyretermes-regular.otf(0)/m/n:
   [texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;
 Adding a colour:
 TU/texgyretermes-regular.otf(1)/m/n:
-  "[texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA00AAFF ;"
+  [texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA00AA};
 Back to normalfont:
 TU/texgyretermes-regular.otf(0)/m/n:
   [texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;
 Open group and add a different colour:
 TU/texgyretermes-regular.otf(2)/m/n:
-  "[texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color=00AAAAFF ;"
+  [texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color={00AAAA};
 End the group:
 TU/texgyretermes-regular.otf(0)/m/n:
   [texgyretermes-regular.otf]:mode=node;script=latn;language=dflt;+tlig;
@@ -21,17 +21,17 @@ The following demonstrates strange behaviour to be wary of.
 TU/texgyrepagella-regular.otf(0)/m/n:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;
 TU/texgyrepagella-regular.otf(0)/m/n:
-  "[texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA00AAFF ;"
+  [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA00AA};
 TU/texgyrepagella-regular.otf(0)/m/n:
-  "[texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA00AAFF ;"
+  [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA00AA};
 ============================================================
 And check NFSSFamily use inside a group.
 Reload another font:
 TU/texgyreheros-regular.otf(0)/m/n:
   [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;+tlig;
 Open group and add a different colour, without changing family:
 TU/texgyreheros-regular.otf(0)/m/n:
-  "[texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color=00AAAAFF ;"
+  [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;+tlig;color={00AAAA};
 End the group:
 TU/texgyreheros-regular.otf(0)/m/n:
   [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;+tlig;

testfiles/aff-italic-only.luatex.tlg

@@ -6,9 +6,9 @@ TU/texgyrepagella(0)/m/n:
 TU/texgyrepagella(0)/m/sc:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;
 TU/texgyrepagella(0)/m/it:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA0000};
 TU/texgyrepagella(0)/m/scit:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;color={AA0000};
 TU/texgyrepagella(0)/b/n:
   [texgyrepagella-bold.otf]:mode=node;script=latn;language=dflt;+tlig;
 TU/texgyrepagella(0)/b/sc:
@@ -23,9 +23,9 @@ TU/texgyrepagella(1)/m/n:
 TU/texgyrepagella(1)/m/sc:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;+smcp;
 TU/texgyrepagella(1)/m/it:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;color={AA0000};
 TU/texgyrepagella(1)/m/scit:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;+smcp;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;+smcp;color={AA0000};
 TU/texgyrepagella(1)/b/n:
   [texgyrepagella-bold.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;
 TU/texgyrepagella(1)/b/sc:
@@ -40,9 +40,9 @@ TU/texgyrepagella(2)/m/n:
 TU/texgyrepagella(2)/m/sc:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;
 TU/texgyrepagella(2)/m/it:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;color={AA0000};
 TU/texgyrepagella(2)/m/scit:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;+smcp;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+onum;+smcp;color={AA0000};
 TU/texgyrepagella(2)/b/n:
   [texgyrepagella-bold.otf]:mode=node;script=latn;language=dflt;+tlig;
 TU/texgyrepagella(2)/b/sc:

testfiles/aff-sc-repeated.luatex.tlg

@@ -6,9 +6,9 @@ TU/texgyrepagella(0)/m/n:
 TU/texgyrepagella(0)/m/sc:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;
 TU/texgyrepagella(0)/m/it:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA0000};
 TU/texgyrepagella(0)/m/scit:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;color={AA0000};
 TU/texgyrepagella(0)/b/n:
   [texgyrepagella-bold.otf]:mode=node;script=latn;language=dflt;+tlig;
 TU/texgyrepagella(0)/b/sc:
@@ -23,9 +23,9 @@ TU/texgyrepagella(1)/m/n:
 TU/texgyrepagella(1)/m/sc:
   [texgyrepagella-regular.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;+onum;
 TU/texgyrepagella(1)/m/it:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;color={AA0000};
 TU/texgyrepagella(1)/m/scit:
-  "[texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;+pnum;color=AA0000FF ;"
+  [texgyrepagella-italic.otf]:mode=node;script=latn;language=dflt;+tlig;+smcp;+pnum;color={AA0000};
 TU/texgyrepagella(1)/b/n:
   [texgyrepagella-bold.otf]:mode=node;script=latn;language=dflt;+tlig;
 TU/texgyrepagella(1)/b/sc:

testfiles/colour-basic.luatex.tlg

@@ -4,12 +4,15 @@ Loading xcolor...
 ...done
 Loading a font with hex colour:
 TU/texgyreheros-regular.otf(0)/m/n:
-  "[texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color=5500FFFF ;"
-Loading a font by name (xcolor):
+  [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color={5500FF};
+Loading a font by name (l3color+xcolor):
 TU/texgyreheros-regular.otf(1)/m/n:
-  "[texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color=FF0000FF ;"
+  [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color={red};
 Defining a new xcolor colour and using it:
 TU/texgyreheros-regular.otf(2)/m/n:
-  "[texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color=4D6680FF ;"
+  [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color={4D6680};
+Defining a new l3color colour and using it:
+TU/texgyreheros-regular.otf(3)/m/n:
+  [texgyreheros-regular.otf]:mode=node;script=latn;language=dflt;color={Bar};
 ***************
 Compilation 1 of test file completed with exit status 0

testfiles/colour-basic.lvt

@@ -9,11 +9,17 @@
 \MSG{Loading a font with hex colour:}
 {\fontspec[Color=5500FF]{texgyreheros-regular.otf}\CURRNFSS}
 
-\MSG{Loading a font by name (xcolor):}
+\MSG{Loading a font by name (l3color+xcolor):}
 {\fontspec[Color=red]{texgyreheros-regular.otf}\CURRNFSS}
 
 \MSG{Defining a new xcolor colour and using it:}
 \definecolor{Foo}{rgb}{0.3,0.4,0.5}
 {\fontspec[Color=Foo]{texgyreheros-regular.otf}\CURRNFSS}
 
-\end{document}
+\MSG{Defining a new l3color colour and using it:}
+\ExplSyntaxOn
+\color_set:nnn{Bar}{rgb}{0.5,0.4,0.3}
+\ExplSyntaxOff
+{\fontspec[Color=Bar]{texgyreheros-regular.otf}\CURRNFSS}
+
+\end{document}

testfiles/colour-basic.tlg

@@ -5,11 +5,14 @@ Loading xcolor...
 Loading a font with hex colour:
 TU/texgyreheros-regular.otf(0)/m/n:
   "[texgyreheros-regular.otf]/OT:script=latn;language=dflt;color=5500FFFF ;" at 10.0pt
-Loading a font by name (xcolor):
+Loading a font by name (l3color+xcolor):
 TU/texgyreheros-regular.otf(1)/m/n:
   "[texgyreheros-regular.otf]/OT:script=latn;language=dflt;color=FF0000FF ;" at 10.0pt
 Defining a new xcolor colour and using it:
 TU/texgyreheros-regular.otf(2)/m/n:
   "[texgyreheros-regular.otf]/OT:script=latn;language=dflt;color=4D6680FF ;" at 10.0pt
+Defining a new l3color colour and using it:
+TU/texgyreheros-regular.otf(3)/m/n:
+  "[texgyreheros-regular.otf]/OT:script=latn;language=dflt;color=80664CFF ;" at 10.0pt
 ***************
 Compilation 1 of test file completed with exit status 0