From 381b74f837c565e35b6c1037262b76241d98ee07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6ren=20Weber?= <mail@soeren-weber.de>
Date: Thu, 9 Feb 2023 00:53:11 +0100
Subject: [PATCH] i18n: add RTL support for nav bar and child items #470

---
 .../content/basics/migration/_index.en.md     |  6 ++
 layouts/partials/header.html                  | 14 ++--
 static/css/ie.css                             | 14 ++++
 static/css/theme.css                          | 27 +++++++-
 static/js/theme.js                            | 69 ++++++++++++-------
 5 files changed, 98 insertions(+), 32 deletions(-)

diff --git a/exampleSite/content/basics/migration/_index.en.md b/exampleSite/content/basics/migration/_index.en.md
index b349615156..26b8b6ed91 100644
--- a/exampleSite/content/basics/migration/_index.en.md
+++ b/exampleSite/content/basics/migration/_index.en.md
@@ -18,6 +18,12 @@ This document shows you what's new in the latest release. For a detailed list of
 
 ---
 
+## 5.12.0 (not yet released)
+
+- {{% badge style="info" icon="plus-circle" title=" " %}}New{{% /badge %}} Support for languages that are written right to left (like Arabic) is expanded to the top navigation bar. This feature is not available in Internet Explorer 11.
+
+---
+
 ## 5.11.0 (2023-02-07)
 
 - {{% badge style="note" title=" " %}}Change{{% /badge %}} The theme removed the popular [jQuery](https://jquery.com) library from its distribution.
diff --git a/layouts/partials/header.html b/layouts/partials/header.html
index b02d0c55d1..8faf1cef0f 100644
--- a/layouts/partials/header.html
+++ b/layouts/partials/header.html
@@ -56,7 +56,7 @@
     <div id="body" class="default-animation">
       <div id="sidebar-overlay"></div>
       <div id="toc-overlay"></div>
-      <nav id="topbar" class="highlightable" dir="ltr">
+      <nav id="topbar" class="highlightable">
         <div>
         {{- $File := .File }}
         {{- $Site := .Site }}
@@ -67,12 +67,18 @@
           {{- if $parent }}
             {{- $ispublished = gt (int (len $parent.Permalink)) 0 }}
           {{- end }}
+          {{- $startarrow := "&#129104;" }}
+          {{- $endarrow := "&#129106;" }}
+          {{- if eq (T "Reading-direction" | default "ltr") "rtl" }}
+            {{- $startarrow = "&#129106;" }}
+            {{- $endarrow = "&#129104;" }}
+          {{- end }}
           <div class="navigation">
           {{- if or (ne $outputFormat "html") (not (and $ispublished ($.Scratch.Get "relearnNextPage"))) }}
             <span class="nav nav-next topbar-link"><i class="fa fa-chevron-right fa-fw"></i></span>
           {{- else }}
             {{- with ($.Scratch.Get "relearnNextPage") }}
-            <a class="nav nav-next topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} (&#129106;)"><i class="fas fa-chevron-right fa-fw"></i></a>
+            <a class="nav nav-next topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} ({{ $endarrow | safeHTML }})"><i class="fas fa-chevron-right fa-fw"></i></a>
             {{- end }}
           {{- end }}
           </div>
@@ -81,11 +87,11 @@
             <span class="nav nav-prev topbar-link"><i class="fa fa-chevron-left fa-fw"></i></span>
           {{- else if or (ne $outputFormat "html") (eq .Page.Kind "taxonomy") (eq .Page.Kind "term") (not (and $ispublished ($.Scratch.Get "relearnPrevPage"))) }}
             {{- with .Site.Home }}
-            <a class="nav nav-prev topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} (&#129104;)"><i class="fas fa-chevron-left fa-fw"></i></a>
+            <a class="nav nav-prev topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} ({{ $startarrow | safeHTML }})"><i class="fas fa-chevron-left fa-fw"></i></a>
             {{- end }}
           {{- else }}
             {{- with ($.Scratch.Get "relearnPrevPage") }}
-            <a class="nav nav-prev topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} (&#129104;)"><i class="fas fa-chevron-left fa-fw"></i></a>
+            <a class="nav nav-prev topbar-link" href="{{ partial "relLangPrettyUglyURL.hugo" (dict "to" .) }}" title="{{.Title}} ({{ $startarrow | safeHTML }})"><i class="fas fa-chevron-left fa-fw"></i></a>
             {{- end}}
           {{- end}}
           </div>
diff --git a/static/css/ie.css b/static/css/ie.css
index a8d4b40ea7..72cd64fcc0 100644
--- a/static/css/ie.css
+++ b/static/css/ie.css
@@ -1,5 +1,19 @@
 @media all and (-ms-high-contrast:none) {
 	/* turn off LTR support as it is dependend on CSS properties that aren't supported by IE11 */
+	html[dir="rtl"] #body #breadcrumbs {
+		float: left;
+	}
+	html[dir="rtl"] .navigation,
+	html[dir="rtl"] #top-print-link,
+	html[dir="rtl"] #top-github-link {
+		float: right;
+	}
+	html[dir="rtl"] .nav i{
+		transform: scaleX(1);
+	}
+	html[dir="rtl"] .progress {
+        left: 4.25rem;
+    }
 	article,
 	.toc-wrapper,
 	.tags {
diff --git a/static/css/theme.css b/static/css/theme.css
index 6a3659fb4d..9386c6c857 100644
--- a/static/css/theme.css
+++ b/static/css/theme.css
@@ -843,6 +843,11 @@ td {
     display: block;
     float: right;
 }
+html[dir="rtl"] .navigation,
+html[dir="rtl"] #top-print-link,
+html[dir="rtl"] #top-github-link {
+    float: left;
+}
 
 .nav,
 .print-link,
@@ -851,6 +856,9 @@ td {
     padding-left: 1rem;
     padding-right: 1rem;
 }
+html[dir="rtl"] .nav i{
+    transform: scaleX(-1);
+}
 span.nav i{
     color: rgba( 134, 134, 134, .333 );
 }
@@ -887,6 +895,9 @@ span.nav i{
     white-space: nowrap;
     width: calc(100% - 5*3.25rem);
 }
+html[dir="rtl"] #body #breadcrumbs {
+    float: right;
+}
 @media screen and (max-width: 47.938em) {
     #body #breadcrumbs {
         text-overflow: unset;
@@ -897,16 +908,24 @@ span.nav i{
     display: none;
 }
 .progress {
-    left: 1rem;
     top: 1rem;
 }
+html[dir="ltr"] .progress {
+    left: 1rem;
+}
+html[dir="rtl"] .progress {
+    right: 1rem;
+}
 @media screen and (max-width: 47.938em) {
     .mobile-support #sidebar-toggle-span {
         display: inline;
     }
-    .progress {
+    html[dir="ltr"] .progress {
         left: 4.25rem;
     }
+    html[dir="rtl"] .progress {
+        right: 4.25rem;
+    }
 }
 
 #body #breadcrumbs .links {
@@ -1750,3 +1769,7 @@ article ul li input[type="checkbox"]:checked::before {
     overflow: auto;
     padding: min(2vh, 2vw);
 }
+
+#TableOfContents{
+    min-width: 1px;
+}
\ No newline at end of file
diff --git a/static/js/theme.js b/static/js/theme.js
index 8756863c02..460890565a 100644
--- a/static/js/theme.js
+++ b/static/js/theme.js
@@ -11,6 +11,20 @@ else{
 }
 var isPrint = document.querySelector( 'body' ).classList.contains( 'print' );
 
+var isRtl = document.querySelector( 'html' ).getAttribute( 'dir' ) == 'rtl';
+var dir_padding_start = 'padding-left';
+var dir_padding_end = 'padding-right';
+var dir_key_start = 37;
+var dir_key_end = 39;
+var dir_scroll = 1;
+if( isRtl && !isIE ){
+    dir_padding_start = 'padding-right';
+    dir_padding_end = 'padding-left';
+    dir_key_start = 39;
+    dir_key_end = 37;
+    dir_scroll = -1;
+}
+
 var touchsupport = ('ontouchstart' in window) || (navigator.maxTouchPoints > 0) || (navigator.msMaxTouchPoints > 0)
 
 var formelements = 'button, datalist, fieldset, input, label, legend, meter, optgroup, option, output, progress, select, textarea';
@@ -26,7 +40,7 @@ var pst;
 var elc = document.querySelector('#body-inner');
 
 function documentFocus(){
-    document.querySelector( '#body-inner' ).focus();
+    elc.focus();
     psc && psc.scrollbarY.focus();
 }
 
@@ -45,13 +59,13 @@ function scrollbarWidth(){
 
 var scrollbarSize = scrollbarWidth();
 function adjustContentWidth(){
-    var left = parseFloat( getComputedStyle( elc ).getPropertyValue( 'padding-left' ) );
-    var right = left;
+    var start = parseFloat( getComputedStyle( elc ).getPropertyValue( dir_padding_start ) );
+    var end = start;
     if( elc.scrollHeight > elc.clientHeight ){
-        // if we have a scrollbar reduce the right margin by the scrollbar width
-        right = Math.max( 0, left - scrollbarSize );
+        // if we have a scrollbar reduce the end margin by the scrollbar width
+        end = Math.max( 0, start - scrollbarSize );
     }
-    elc.style[ 'padding-right' ] = '' + right + 'px';
+    elc.style[ dir_padding_end ] = '' + end + 'px';
 }
 
 function switchTab(tabGroup, tabId) {
@@ -416,41 +430,41 @@ function initArrowNav(){
     // avoid prev/next navigation if we are not at the start/end of the
     // horizontal area
     var el = document.querySelector('#body-inner');
-    var scrollLeft = 0;
-    var scrollRight = 0;
+    var scrollStart = 0;
+    var scrollEnd = 0;
     document.addEventListener('keydown', function(event){
         if( !event.shiftKey && !event.ctrlKey && !event.altKey && !event.metaKey ){
-            if( event.which == '37' ){
-                if( !scrollLeft && +el.scrollLeft.toFixed() <= 0 ){
+            if( event.which == dir_key_start ){
+                if( !scrollStart && +el.scrollLeft.toFixed()*dir_scroll <= 0 ){
                     prev && prev.click();
                 }
-                else if( scrollLeft != -1 ){
-                    clearTimeout( scrollLeft );
+                else if( scrollStart != -1 ){
+                    clearTimeout( scrollStart );
                 }
-                scrollLeft = -1;
+                scrollStart = -1;
             }
-            if( event.which == '39' ){
-                if( !scrollRight && +el.scrollLeft.toFixed() + +el.clientWidth.toFixed() >= +el.scrollWidth.toFixed() ){
+            if( event.which == dir_key_end ){
+                if( !scrollEnd && +el.scrollLeft.toFixed()*dir_scroll + +el.clientWidth.toFixed() >= +el.scrollWidth.toFixed() ){
                     next && next.click();
                 }
-                else if( scrollRight != -1 ){
-                    clearTimeout( scrollRight );
+                else if( scrollEnd != -1 ){
+                    clearTimeout( scrollEnd );
                 }
-                scrollRight = -1;
+                scrollEnd = -1;
             }
         }
     });
     document.addEventListener('keyup', function(event){
         if( !event.shiftKey && !event.ctrlKey && !event.altKey && !event.metaKey ){
-            if( event.which == '37' ){
+            if( event.which == dir_key_start ){
                 // check for false indication if keyup is delayed after navigation
-                if( scrollLeft == -1 ){
-                    scrollLeft = setTimeout( function(){ scrollLeft = 0; }, 300 );
+                if( scrollStart == -1 ){
+                    scrollStart = setTimeout( function(){ scrollStart = 0; }, 300 );
                 }
             }
-            if( event.which == '39' ){
-                if( scrollRight == -1 ){
-                    scrollRight = setTimeout( function(){ scrollRight = 0; }, 300 );
+            if( event.which == dir_key_end ){
+                if( scrollEnd == -1 ){
+                    scrollEnd = setTimeout( function(){ scrollEnd = 0; }, 300 );
                 }
             }
         }
@@ -459,7 +473,7 @@ function initArrowNav(){
     // avoid keyboard navigation for input fields
     document.querySelectorAll( formelements ).forEach( function( e ){
         e.addEventListener( 'keydown', function( event ){
-            if( event.which == 37 || event.which == 39 ){
+            if( event.which == dir_key_start || event.which == dir_key_end ){
                 event.stopPropagation();
             }
         });
@@ -545,8 +559,11 @@ function initMenuScrollbar(){
             psm && psm.update();
         });
     });
+    // bugfix for PS in RTL mode: the initial scrollbar position is off;
+    // calling update() once, fixes this
+    pst && setTimeout( function(){ pst.update(); }, 0 );
 
-    // finally, we want to adjust the contents right padding if there is a scrollbar visible
+    // finally, we want to adjust the contents end padding if there is a scrollbar visible
     window.addEventListener('resize', adjustContentWidth );
     adjustContentWidth();
 }