Move guts of wordwrap expression function to QgsStringUtils::wordWrap

To allow use outside of expressions

python/core/auto_generated/qgsstringutils.sip.in

@@ -260,6 +260,20 @@ links.
 :return: string with inserted links
 
 .. versionadded:: 3.0
+%End
+
+    static QString wordWrap( const QString &string, int length, bool useMaxLineLength = true, const QString &customDelimiter = QString() );
+%Docstring
+Automatically wraps a \string by inserting new line characters at appropriate locations in the string.
+
+The ``length`` argument specifies either the minimum or maximum length of lines desired, depending
+on whether ``useMaxLineLength`` is true. If ``useMaxLineLength`` is true, then the string will be wrapped
+so that each line ideally will not exceed ``length`` of characters. If ``useMaxLineLength`` is false, then
+the string will be wrapped so that each line will ideally exceed ``length`` of characters.
+
+A custom delimiter can be specified to use instead of space characters.
+
+.. versionadded:: 3.4
 %End
 };
 

src/core/expression/qgsexpressionfunction.cpp

@@ -1014,73 +1014,9 @@ static QVariant fcnWordwrap( const QVariantList &values, const QgsExpressionCont
     QString str = QgsExpressionUtils::getStringValue( values.at( 0 ), parent );
     qlonglong wrap = QgsExpressionUtils::getIntValue( values.at( 1 ), parent );
 
-    if ( !str.isEmpty() && wrap != 0 )
-    {
-      QString newstr;
-      QRegExp rx;
-      QString customdelimiter = QgsExpressionUtils::getStringValue( values.at( 2 ), parent );
-      int delimiterlength;
-
-      if ( customdelimiter.length() > 0 )
-      {
-        rx.setPatternSyntax( QRegExp::FixedString );
-        rx.setPattern( customdelimiter );
-        delimiterlength = customdelimiter.length();
-      }
-      else
-      {
-        // \x200B is a ZERO-WIDTH SPACE, needed for worwrap to support a number of complex scripts (Indic, Arabic, etc.)
-        rx.setPattern( QStringLiteral( "[\\s\\x200B]" ) );
-        delimiterlength = 1;
-      }
-
+    QString customdelimiter = QgsExpressionUtils::getStringValue( values.at( 2 ), parent );
 
-      QStringList lines = str.split( '\n' );
-      int strlength, strcurrent, strhit, lasthit;
-
-      for ( int i = 0; i < lines.size(); i++ )
-      {
-        strlength = lines[i].length();
-        strcurrent = 0;
-        strhit = 0;
-        lasthit = 0;
-
-        while ( strcurrent < strlength )
-        {
-          // positive wrap value = desired maximum line width to wrap
-          // negative wrap value = desired minimum line width before wrap
-          if ( wrap > 0 )
-          {
-            //first try to locate delimiter backwards
-            strhit = lines[i].lastIndexOf( rx, strcurrent + wrap );
-            if ( strhit == lasthit || strhit == -1 )
-            {
-              //if no new backward delimiter found, try to locate forward
-              strhit = lines[i].indexOf( rx, strcurrent + std::labs( wrap ) );
-            }
-            lasthit = strhit;
-          }
-          else
-          {
-            strhit = lines[i].indexOf( rx, strcurrent + std::labs( wrap ) );
-          }
-          if ( strhit > -1 )
-          {
-            newstr.append( lines[i].midRef( strcurrent, strhit - strcurrent ) );
-            newstr.append( '\n' );
-            strcurrent = strhit + delimiterlength;
-          }
-          else
-          {
-            newstr.append( lines[i].midRef( strcurrent ) );
-            strcurrent = strlength;
-          }
-        }
-        if ( i < lines.size() - 1 ) newstr.append( '\n' );
-      }
-
-      return QVariant( newstr );
-    }
+    return QgsStringUtils::wordWrap( str, static_cast< int >( wrap ), wrap > 0, customdelimiter );
   }
 
   return QVariant();

src/core/qgsstringutils.cpp

@@ -442,6 +442,76 @@ QString QgsStringUtils::insertLinks( const QString &string, bool *foundLinks )
   return converted;
 }
 
+QString QgsStringUtils::wordWrap( const QString &string, const int length, const bool useMaxLineLength, const QString &customDelimiter )
+{
+  if ( string.isEmpty() || length == 0 )
+    return string;
+
+  QString newstr;
+  QRegExp rx;
+  int delimiterLength = 0;
+
+  if ( !customDelimiter.isEmpty() )
+  {
+    rx.setPatternSyntax( QRegExp::FixedString );
+    rx.setPattern( customDelimiter );
+    delimiterLength = customDelimiter.length();
+  }
+  else
+  {
+    // \x200B is a ZERO-WIDTH SPACE, needed for worwrap to support a number of complex scripts (Indic, Arabic, etc.)
+    rx.setPattern( QStringLiteral( "[\\s\\x200B]" ) );
+    delimiterLength = 1;
+  }
+
+  const QStringList lines = string.split( '\n' );
+  int strLength, strCurrent, strHit, lastHit;
+
+  for ( int i = 0; i < lines.size(); i++ )
+  {
+    strLength = lines.at( i ).length();
+    strCurrent = 0;
+    strHit = 0;
+    lastHit = 0;
+
+    while ( strCurrent < strLength )
+    {
+      // positive wrap value = desired maximum line width to wrap
+      // negative wrap value = desired minimum line width before wrap
+      if ( useMaxLineLength )
+      {
+        //first try to locate delimiter backwards
+        strHit = lines.at( i ).lastIndexOf( rx, strCurrent + length );
+        if ( strHit == lastHit || strHit == -1 )
+        {
+          //if no new backward delimiter found, try to locate forward
+          strHit = lines.at( i ).indexOf( rx, strCurrent + std::abs( length ) );
+        }
+        lastHit = strHit;
+      }
+      else
+      {
+        strHit = lines.at( i ).indexOf( rx, strCurrent + std::abs( length ) );
+      }
+      if ( strHit > -1 )
+      {
+        newstr.append( lines.at( i ).midRef( strCurrent, strHit - strCurrent ) );
+        newstr.append( '\n' );
+        strCurrent = strHit + delimiterLength;
+      }
+      else
+      {
+        newstr.append( lines.at( i ).midRef( strCurrent ) );
+        strCurrent = strLength;
+      }
+    }
+    if ( i < lines.size() - 1 )
+      newstr.append( '\n' );
+  }
+
+  return newstr;
+}
+
 QgsStringReplacement::QgsStringReplacement( const QString &match, const QString &replacement, bool caseSensitive, bool wholeWordOnly )
   : mMatch( match )
   , mReplacement( replacement )

src/core/qgsstringutils.h

@@ -260,6 +260,20 @@ class CORE_EXPORT QgsStringUtils
      * \since QGIS 3.0
      */
     static QString insertLinks( const QString &string, bool *foundLinks = nullptr );
+
+    /**
+     * Automatically wraps a \string by inserting new line characters at appropriate locations in the string.
+     *
+     * The \a length argument specifies either the minimum or maximum length of lines desired, depending
+     * on whether \a useMaxLineLength is true. If \a useMaxLineLength is true, then the string will be wrapped
+     * so that each line ideally will not exceed \a length of characters. If \a useMaxLineLength is false, then
+     * the string will be wrapped so that each line will ideally exceed \a length of characters.
+     *
+     * A custom delimiter can be specified to use instead of space characters.
+     *
+     * \since QGIS 3.4
+     */
+    static QString wordWrap( const QString &string, int length, bool useMaxLineLength = true, const QString &customDelimiter = QString() );
 };
 
 #endif //QGSSTRINGUTILS_H

tests/src/core/testqgsstringutils.cpp

@@ -38,6 +38,8 @@ class TestQgsStringUtils : public QObject
     void titleCase();
     void ampersandEncode_data();
     void ampersandEncode();
+    void wordWrap_data();
+    void wordWrap();
 
 };
 
@@ -206,6 +208,35 @@ void TestQgsStringUtils::ampersandEncode()
 
 }
 
+void TestQgsStringUtils::wordWrap_data()
+{
+  QTest::addColumn<QString>( "input" );
+  QTest::addColumn<int>( "length" );
+  QTest::addColumn<bool>( "isMax" );
+  QTest::addColumn<QString>( "delimiter" );
+  QTest::addColumn<QString>( "expected" );
+
+  QTest::newRow( "wordwrap" ) << "university of qgis" << 13 << true << QString() << "university of\nqgis";
+  QTest::newRow( "optional parameters unspecified" ) << "test string" << 5 << true << QString() << "test\nstring";
+  QTest::newRow( "wordwrap with delim" ) << "university of qgis" << 13 << true << QStringLiteral( " " ) << "university of\nqgis";
+  QTest::newRow( "wordwrap min" ) << "university of qgis" << 3 << false << QStringLiteral( " " ) << "university\nof qgis";
+  QTest::newRow( "wordwrap min with delim" ) << "university of qgis" << 3 << false << QStringLiteral( " " ) << "university\nof qgis";
+  QTest::newRow( "wordwrap on multi line" ) << "university of qgis\nsupports many multiline" << 5 << false << QStringLiteral( " " ) << "university\nof qgis\nsupports\nmany multiline";
+  QTest::newRow( "wordwrap on zero-space width" ) << QStringLiteral( "test%1zero-width space" ).arg( QChar( 8203 ) ) << 4 << false << QString() << "test\nzero-width\nspace";
+  QTest::newRow( "optional parameters specified" ) << "testxstring" << 5 << true << "x" << "test\nstring";
+}
+
+void TestQgsStringUtils::wordWrap()
+{
+  QFETCH( QString, input );
+  QFETCH( int, length );
+  QFETCH( bool, isMax );
+  QFETCH( QString, delimiter );
+  QFETCH( QString, expected );
+
+  QCOMPARE( QgsStringUtils::wordWrap( input, length, isMax, delimiter ), expected );
+}
+
 
 QGSTEST_MAIN( TestQgsStringUtils )
 #include "testqgsstringutils.moc"