Support CSS text-decoration-color in underlines, overlines, strikethrough

Also add a feature to the textedit example to set this value.

[ChangeLog][QtGui][CSS] The CSS text-decoration-color attribute is now
supported in rich text spans with underlines, overlines and strikethrough.

Fixes: QTBUG-82114
Task-number: QTBUG-39617
Change-Id: I0065cb5431833da55b0f503ce7ff2b83b74b718a
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

5 files changed, 13 insertions, 4 deletions

diff --git a/src/gui/text/qcssparser.cpp b/src/gui/text/qcssparser.cpp
index 46ed67ea7d..4cc310c7e7 100644
--- a/src/gui/text/qcssparser.cpp
+++ b/src/gui/text/qcssparser.cpp
@@ -166,6 +166,7 @@ static const QCssKnownValue properties[NumProperties - 1] = {
     { "subcontrol-position", QtPosition },
     { "text-align", TextAlignment },
     { "text-decoration", TextDecoration },
+    { "text-decoration-color", TextDecorationColor },
     { "text-indent", TextIndent },
     { "text-transform", TextTransform },
     { "text-underline-style", TextUnderlineStyle },
diff --git a/src/gui/text/qcssparser_p.h b/src/gui/text/qcssparser_p.h
index 1ccfc45d21..56af5c8bb2 100644
--- a/src/gui/text/qcssparser_p.h
+++ b/src/gui/text/qcssparser_p.h
@@ -201,6 +201,7 @@ enum Property {
     QtIcon,
     LetterSpacing,
     WordSpacing,
+    TextDecorationColor,
     NumProperties
 };
 
diff --git a/src/gui/text/qtextdocument.cpp b/src/gui/text/qtextdocument.cpp
index 2c0c3582ed..d3bec57bd4 100644
--- a/src/gui/text/qtextdocument.cpp
+++ b/src/gui/text/qtextdocument.cpp
@@ -2560,6 +2560,11 @@ bool QTextHtmlExporter::emitCharFormatStyle(const QTextCharFormat &format)
         if (!atLeastOneDecorationSet)
             html += QLatin1String("none");
         html += QLatin1Char(';');
+        if (format.hasProperty(QTextFormat::TextUnderlineColor)) {
+            html += QLatin1String(" text-decoration-color:");
+            html += colorValue(format.underlineColor());
+            html += QLatin1Char(';');
+        }
         attributesEmitted = true;
     } else {
         html.chop(decorationTag.size());
diff --git a/src/gui/text/qtextformat.cpp b/src/gui/text/qtextformat.cpp
index 44986c337c..80c7845410 100644
--- a/src/gui/text/qtextformat.cpp
+++ b/src/gui/text/qtextformat.cpp
@@ -642,7 +642,7 @@ Q_GUI_EXPORT QDataStream &operator>>(QDataStream &stream, QTextFormat &fmt)
     \omitvalue FirstFontProperty
     \omitvalue LastFontProperty
 
-    \value TextUnderlineColor
+    \value TextUnderlineColor      Specifies the color to draw underlines, overlines and strikeouts.
     \value TextVerticalAlignment
     \value TextOutline
     \value TextUnderlineStyle
@@ -1984,8 +1984,8 @@ QStringList QTextCharFormat::anchorNames() const
 /*!
     \fn void QTextCharFormat::setUnderlineColor(const QColor &color)
 
-    Sets the underline color used for the characters with this format to
-    the \a color specified.
+    Sets the color used to draw underlines, overlines and strikeouts on the
+    characters with this format to the \a color specified.
 
     \sa underlineColor()
 */
@@ -1993,7 +1993,8 @@ QStringList QTextCharFormat::anchorNames() const
 /*!
     \fn QColor QTextCharFormat::underlineColor() const
 
-    Returns the color used to underline the characters with this format.
+    Returns the color used to draw underlines, overlines and strikeouts
+    on the characters with this format.
 
     \sa setUnderlineColor()
 */
diff --git a/src/gui/text/qtexthtmlparser.cpp b/src/gui/text/qtexthtmlparser.cpp
index a242d5e645..3ad0938268 100644
--- a/src/gui/text/qtexthtmlparser.cpp
+++ b/src/gui/text/qtexthtmlparser.cpp
@@ -1346,6 +1346,7 @@ void QTextHtmlParserNode::applyCssDeclarations(const QList<QCss::Declaration> &d
             default: break;
             }
             break;
+        case QCss::TextDecorationColor: charFormat.setUnderlineColor(decl.colorValue()); break;
         case QCss::ListStyleType:
         case QCss::ListStyle:
             setListStyle(decl.d->values);