From 38d0934e3668d02bfe5bf84444d8ac19ae4e7c30 Mon Sep 17 00:00:00 2001
From: Vincenzo Mantova <xworld21@users.sf.net>
Date: Fri, 3 Jan 2025 19:58:08 +0000
Subject: [PATCH] reimplement \llap, \rlap using CSS float

---
 lib/LaTeXML/Engine/plain.pool.ltxml           |  5 +-
 lib/LaTeXML/resources/CSS/LaTeXML.css         |  6 +++
 .../resources/XSLT/LaTeXML-inline-xhtml.xsl   | 51 +++++++++++++------
 t/alignment/halignatt.xml                     |  2 +-
 t/ams/mathtools.xml                           |  6 +--
 t/structure/plainsample.xml                   |  2 +-
 6 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/lib/LaTeXML/Engine/plain.pool.ltxml b/lib/LaTeXML/Engine/plain.pool.ltxml
index afa62213cc..2a9044e48c 100644
--- a/lib/LaTeXML/Engine/plain.pool.ltxml
+++ b/lib/LaTeXML/Engine/plain.pool.ltxml
@@ -536,9 +536,8 @@ DefConstructor('\ltx@centerline{}', sub {
   alias   => '\centerline',
   bounded => 1);
 
-# These should be 0 width, but perhaps also shifted?
-DefMacro('\llap{}', '\hbox to 0pt{\hss#1}');
-DefMacro('\rlap{}', '\hbox to 0pt{#1\hss}');
+DefMacro('\llap{}', '\hbox{\@ADDCLASS{ltx_llap}#1}');
+DefMacro('\rlap{}', '\hbox{\@ADDCLASS{ltx_rlap}#1}');
 
 DefMacroI('\m@th', undef, '\mathsurround=0pt ');
 
diff --git a/lib/LaTeXML/resources/CSS/LaTeXML.css b/lib/LaTeXML/resources/CSS/LaTeXML.css
index b954b01b1a..4998d0e9d6 100644
--- a/lib/LaTeXML/resources/CSS/LaTeXML.css
+++ b/lib/LaTeXML/resources/CSS/LaTeXML.css
@@ -510,3 +510,9 @@ cite                 { font-style: normal; }
 
 .ltx_overlay {position:relative; }
 .ltx_overlay > span:nth-child(2) {position:absolute; left:0; }
+
+/* \llap, \rlap */
+.ltx__lap_container {
+  display:inline-block; vertical-align:bottom;  width:0pt; white-space:nowrap; /* width 0pt causes extreme wrapping otherwise */ }
+.ltx__lap_container>.ltx_llap { float:right; }
+.ltx__lap_container>.ltx_rlap { float:left; }
diff --git a/lib/LaTeXML/resources/XSLT/LaTeXML-inline-xhtml.xsl b/lib/LaTeXML/resources/XSLT/LaTeXML-inline-xhtml.xsl
index 122c5a3ab5..295c0b118c 100644
--- a/lib/LaTeXML/resources/XSLT/LaTeXML-inline-xhtml.xsl
+++ b/lib/LaTeXML/resources/XSLT/LaTeXML-inline-xhtml.xsl
@@ -33,22 +33,41 @@
   <xsl:preserve-space elements="ltx:text"/>
   <xsl:template match="ltx:text">
     <xsl:param name="context"/>
-    <xsl:element name="span" namespace="{$html_ns}">
-      <xsl:variable name="innercontext" select="'inline'"/><!-- override -->
-      <xsl:call-template name="add_id"/>
-      <xsl:call-template name="add_attributes">
-        <xsl:with-param name="extra_classes" select="f:if(@width,'ltx_inline-block','')"/>
-      </xsl:call-template>
-      <xsl:apply-templates select="." mode="begin">
-        <xsl:with-param name="context" select="$innercontext"/>
-      </xsl:apply-templates>
-      <xsl:apply-templates>
-        <xsl:with-param name="context" select="$innercontext"/>
-      </xsl:apply-templates>
-      <xsl:apply-templates select="." mode="end">
-        <xsl:with-param name="context" select="$innercontext"/>
-      </xsl:apply-templates>
-    </xsl:element>
+    <xsl:variable name="content">
+      <xsl:element name="span" namespace="{$html_ns}">
+        <xsl:variable name="innercontext" select="'inline'"/><!-- override -->
+        <xsl:call-template name="add_id"/>
+        <xsl:call-template name="add_attributes">
+          <xsl:with-param name="extra_classes" select="f:if(@width,'ltx_inline-block','')"/>
+        </xsl:call-template>
+        <xsl:apply-templates select="." mode="begin">
+          <xsl:with-param name="context" select="$innercontext"/>
+        </xsl:apply-templates>
+        <xsl:apply-templates>
+          <xsl:with-param name="context" select="$innercontext"/>
+        </xsl:apply-templates>
+        <xsl:apply-templates select="." mode="end">
+          <xsl:with-param name="context" select="$innercontext"/>
+        </xsl:apply-templates>
+      </xsl:element>
+    </xsl:variable>
+    <xsl:choose>
+      <xsl:when test="contains(concat(' ',@class,' '),' ltx_llap ')">
+        <xsl:element name="span" namespace="{$html_ns}">
+          <xsl:attribute name="class">ltx__lap_container</xsl:attribute>
+          <xsl:copy-of select="$content" />
+      </xsl:element>
+      </xsl:when>
+      <xsl:when test="contains(concat(' ',@class,' '),' ltx_rlap ')">
+        <xsl:element name="span" namespace="{$html_ns}">
+          <xsl:attribute name="class">ltx__lap_container</xsl:attribute>
+          <xsl:copy-of select="$content" />
+        </xsl:element>
+      </xsl:when>
+      <xsl:otherwise>
+        <xsl:copy-of select="$content" />
+      </xsl:otherwise>
+    </xsl:choose>
   </xsl:template>
 
   <!-- Special case: all OTHER attributes have to be outside the "hidden"
diff --git a/t/alignment/halignatt.xml b/t/alignment/halignatt.xml
index 63ca62606f..0f3092becd 100644
--- a/t/alignment/halignatt.xml
+++ b/t/alignment/halignatt.xml
@@ -50,7 +50,7 @@
         <td border="l t" class="ltx_nopad_l ltx_nopad_r"/>
         <td align="right" border="r t">6</td>
         <td align="center" border="r t">51–59</td>
-        <td align="right" border="r t">.95<text width="0.0pt">*</text></td>
+        <td align="right" border="r t">.95<text class="ltx_rlap" width="0.0pt">*</text></td>
       </tr>
       <tr>
         <td align="left" border="t" class="ltx_nopad_l ltx_nopad_r" colspan="4">* (first quarter only)</td>
diff --git a/t/ams/mathtools.xml b/t/ams/mathtools.xml
index 0d49e03bfe..36b204e921 100644
--- a/t/ams/mathtools.xml
+++ b/t/ams/mathtools.xml
@@ -7120,7 +7120,7 @@ Then a switch of tag forms.</p>
     <title><tag close=" ">11</tag>Stepped lines</title>
     <para xml:id="S11.p1">
       <equation xml:id="S11.Ex81">
-        <Math class="ltx_math_unparsed" mode="display" tex="\begin{gathered}x=1,\quad x+1=2\\&#10;y=2\end{gathered}" text="[1∗  ]@x@=@1@,@quad@x@+@1@=@2@[ over]@[2∗  ]@y@=@2@[ over]" xml:id="S11.Ex81.m1">
+        <Math class="ltx_math_unparsed" mode="display" tex="\begin{gathered}x=1,\quad x+1=2\\&#10;y=2\end{gathered}" text="[​1∗  ]@x@=@1@,@quad@x@+@1@=@2@[ over]@[​2∗  ]@y@=@2@[ over]" xml:id="S11.Ex81.m1">
           <XMath>
             <XMDual>
               <XMWrap rule="Anything,">
@@ -7150,7 +7150,7 @@ Then a switch of tag forms.</p>
                         <XMTok meaning="equals" role="RELOP" xml:id="S11.Ex81.m1.3">=</XMTok>
                         <XMApp>
                           <XMTok meaning="times" role="MULOP">⁢</XMTok>
-                          <XMText xml:id="S11.Ex81.m1.1"><text width="0.0pt">1</text><Math mode="inline" tex="*" text="*" xml:id="S11.Ex81.m1.m1">
+                          <XMText xml:id="S11.Ex81.m1.1"><text class="ltx_llap" width="0.0pt">​<text class="ltx_llap_content">1</text></text><Math mode="inline" tex="*" text="*" xml:id="S11.Ex81.m1.m1">
                               <XMath>
                                 <XMTok meaning="times" role="MULOP">∗</XMTok>
                               </XMath>
@@ -7182,7 +7182,7 @@ Then a switch of tag forms.</p>
                       <XMTok meaning="equals" role="RELOP" xml:id="S11.Ex81.m1.14">=</XMTok>
                       <XMApp>
                         <XMTok meaning="times" role="MULOP">⁢</XMTok>
-                        <XMText xml:id="S11.Ex81.m1.12"><text width="0.0pt">2</text><Math mode="inline" tex="*" text="*" xml:id="S11.Ex81.m1.m2">
+                        <XMText xml:id="S11.Ex81.m1.12"><text class="ltx_llap" width="0.0pt">​<text class="ltx_llap_content">2</text></text><Math mode="inline" tex="*" text="*" xml:id="S11.Ex81.m1.m2">
                             <XMath>
                               <XMTok meaning="times" role="MULOP">∗</XMTok>
                             </XMath>
diff --git a/t/structure/plainsample.xml b/t/structure/plainsample.xml
index f05d63c4ed..b25e270c5f 100644
--- a/t/structure/plainsample.xml
+++ b/t/structure/plainsample.xml
@@ -80,7 +80,7 @@ finish the remaining cases.</p>
                       <XMTok role="CLOSE" stretchy="false">)</XMTok>
                     </XMWrap>
                   </XMDual>
-                  <XMText width="0.0pt">Draft</XMText>
+                  <XMText class="ltx_rlap" width="0.0pt">Draft</XMText>
                 </XMApp>
               </XMath>
             </Math></tag>