fix: resolve multi-line unindent issue with Shift+Tab

src/editor/dtextedit.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2011-2023 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2011 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -1602,30 +1602,51 @@ void TextEdit::unindentText()
 {
     qDebug() << "Unindenting text";
     QTextCursor cursor = this->textCursor();
-    cursor.movePosition(QTextCursor::StartOfBlock);
-    int pos = cursor.position();
-    cursor.setPosition(cursor.position() + 1, QTextCursor::KeepAnchor);
 
-    //the text in front of current line is '\t'.
-    if ("\t" == cursor.selectedText()) {
-        qDebug() << "Unindenting text with tab";
-        DeleteBackCommand *com = new DeleteBackCommand(cursor, this);
+    if (cursor.hasSelection()) {
+        qDebug() << "Unindenting text with selection";
+        //calculate the start postion and the end postion of current selection.
+        int pos1 = cursor.position();
+        int pos2 = cursor.anchor();
+        if (pos1 > pos2)
+            std::swap(pos1, pos2);
+
+        //calculate the start line and end line of current selection.
+        cursor.setPosition(pos1);
+        int line1 = cursor.blockNumber();
+        cursor.setPosition(pos2);
+        int line2 = cursor.blockNumber();
+
+        //do the unindent operation for multiple lines
+        auto com = new UnindentTextCommand(this, pos1, pos2, line1, line2, m_tabSpaceNumber);
         m_pUndoStack->push(com);
-    }
-    //the text in front of current line is ' '.
-    else if (" " == cursor.selectedText()) {
-        qDebug() << "Unindenting text with space";
-        int startpos = pos;
-        int cnt = 0;
-        // calculate the number of ' '.
-        while (document()->characterAt(pos) == ' ' && cnt < m_tabSpaceNumber) {
-            pos++;
-            cnt++;
+    } else {
+        //single line unindent (original behavior)
+        cursor.movePosition(QTextCursor::StartOfBlock);
+        int pos = cursor.position();
+        cursor.setPosition(cursor.position() + 1, QTextCursor::KeepAnchor);
+
+        //the text in front of current line is '\t'.
+        if ("\t" == cursor.selectedText()) {
+            qDebug() << "Unindenting text with tab";
+            DeleteBackCommand *com = new DeleteBackCommand(cursor, this);
+            m_pUndoStack->push(com);
+        }
+        //the text in front of current line is ' '.
+        else if (" " == cursor.selectedText()) {
+            qDebug() << "Unindenting text with space";
+            int startpos = pos;
+            int cnt = 0;
+            // calculate the number of ' '.
+            while (document()->characterAt(pos) == ' ' && cnt < m_tabSpaceNumber) {
+                pos++;
+                cnt++;
+            }
+            cursor.setPosition(startpos);
+            cursor.setPosition(pos, QTextCursor::KeepAnchor);
+            DeleteBackCommand *com = new DeleteBackCommand(cursor, this);
+            m_pUndoStack->push(com);
         }
-        cursor.setPosition(startpos);
-        cursor.setPosition(pos, QTextCursor::KeepAnchor);
-        DeleteBackCommand *com = new DeleteBackCommand(cursor, this);
-        m_pUndoStack->push(com);
     }
     qDebug() << "Unindenting text successfully";
 }

src/editor/indenttextcommond.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2022 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2022 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -86,3 +86,129 @@ void IndentTextCommand::undo()
     }
     qDebug() << "IndentTextCommand undo exit";
 }
+
+UnindentTextCommand::UnindentTextCommand(TextEdit* edit,int startpos,int endpos,int startline,int endline,int tabSpaceNumber):
+    m_edit(edit),
+    m_startpos(startpos),
+    m_endpos(endpos),
+    m_startline(startline),
+    m_endline(endline),
+    m_tabSpaceNumber(tabSpaceNumber)
+{
+    qDebug() << "UnindentTextCommand created - startpos:" << startpos
+             << "endpos:" << endpos << "lines:" << startline << "-" << endline
+             << "hasSelection:" << m_edit->textCursor().hasSelection();
+    m_hasselected = m_edit->textCursor().hasSelection();
+    m_removedChars.resize(endline - startline + 1);
+}
+
+UnindentTextCommand::~UnindentTextCommand()
+{
+    qDebug() << "UnindentTextCommand destroyed";
+}
+
+void UnindentTextCommand::redo()
+{
+    qInfo() << "UnindentTextCommand redo - removing indents from lines:"
+            << m_startline << "-" << m_endline;
+    auto cursor = m_edit->textCursor();
+
+    //remove indentation from multiple lines.
+    cursor.setPosition(m_startpos);
+    int totalRemoved = 0;
+
+    for(int i=m_startline;i<=m_endline;i++){
+        cursor.movePosition(QTextCursor::StartOfBlock);
+        int lineStart = cursor.position();
+        int removed = 0;
+
+        //check if line starts with tab
+        if(m_edit->document()->characterAt(lineStart) == '\t'){
+            cursor.deleteChar();
+            removed = 1;
+        }
+        //check if line starts with spaces
+        else if(m_edit->document()->characterAt(lineStart) == ' '){
+            int cnt = 0;
+            int pos = lineStart;
+            while(m_edit->document()->characterAt(pos) == ' ' && cnt < m_tabSpaceNumber){
+                pos++;
+                cnt++;
+            }
+            if(cnt > 0){
+                cursor.setPosition(lineStart);
+                cursor.setPosition(pos, QTextCursor::KeepAnchor);
+                cursor.removeSelectedText();
+                removed = cnt;
+            }
+        }
+
+        m_removedChars[i - m_startline] = removed;
+        totalRemoved += removed;
+        cursor.movePosition(QTextCursor::NextBlock);
+    }
+
+    //reset selection.
+    if(m_hasselected){
+        qDebug() << "UnindentTextCommand redo, m_hasselected, totalRemoved:" << totalRemoved;
+        if(m_startline == m_endline){
+            qDebug() << "UnindentTextCommand redo, m_startline == m_endline";
+            int newStartPos = m_startpos - m_removedChars[0];
+            if(newStartPos < 0) newStartPos = 0;
+            cursor.setPosition(newStartPos);
+            cursor.movePosition(QTextCursor::StartOfBlock);
+            cursor.movePosition(QTextCursor::EndOfBlock,QTextCursor::KeepAnchor);
+            m_edit->setTextCursor(cursor);
+        }
+        else{
+            qDebug() << "UnindentTextCommand redo, m_startline != m_endline";
+            int firstLineRemoved = m_removedChars[0];
+            int newStartPos = m_startpos - firstLineRemoved;
+            int newEndPos = m_endpos - totalRemoved;
+
+            //ensure positions are valid
+            if(newStartPos < 0) newStartPos = 0;
+            if(newEndPos < newStartPos) newEndPos = newStartPos;
+
+            cursor.setPosition(newStartPos);
+            cursor.setPosition(newEndPos, QTextCursor::KeepAnchor);
+            m_edit->setTextCursor(cursor);
+        }
+    }
+    qDebug() << "UnindentTextCommand redo exit";
+}
+
+void UnindentTextCommand::undo()
+{
+    qInfo() << "UnindentTextCommand undo - restoring indents to lines:"
+            << m_startline << "-" << m_endline;
+    auto cursor = m_edit->textCursor();
+
+    //restore indentation to multiple lines.
+    cursor.setPosition(m_startpos);
+    for(int i=m_startline;i<=m_endline;i++){
+        qDebug() << "UnindentTextCommand undo, i:" << i;
+        cursor.movePosition(QTextCursor::StartOfBlock);
+        int removed = m_removedChars[i - m_startline];
+
+        if(removed == 1){
+            //restore tab
+            cursor.insertText("\t");
+        }
+        else if(removed > 1){
+            //restore spaces
+            cursor.insertText(QString(removed, ' '));
+        }
+
+        cursor.movePosition(QTextCursor::NextBlock);
+    }
+
+    //reset selection
+    if(m_hasselected){
+        qDebug() << "UnindentTextCommand undo, m_hasselected";
+        cursor.setPosition(m_startpos);
+        cursor.setPosition(m_endpos, QTextCursor::KeepAnchor);
+        m_edit->setTextCursor(cursor);
+    }
+    qDebug() << "UnindentTextCommand undo exit";
+}

src/editor/indenttextcommond.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2022 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2022 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -35,4 +35,32 @@ class IndentTextCommand:public QUndoCommand
 
 };
 
+//unindent text in front of multiple lines
+class UnindentTextCommand:public QUndoCommand
+{
+public:
+    UnindentTextCommand(TextEdit* edit,int startpos,int endpos,int startline,int endline,int tabSpaceNumber);
+    virtual ~UnindentTextCommand();
+
+    virtual void redo();
+    virtual void undo();
+
+private:
+
+    TextEdit* m_edit=nullptr;
+    //the start postion of selected text.
+    int m_startpos=0;
+    //the end postion of selected text.
+    int m_endpos=0;
+    //the start line of selected text.
+    int m_startline=0;
+    //the end line of selected text.
+    int m_endline=0;
+    bool m_hasselected=false;
+    int m_tabSpaceNumber=4;
+    //store the number of characters removed from each line
+    QVector<int> m_removedChars;
+
+};
+
 #endif // IndentTextCommand_H