UnifiedDiffEditor: Fix indent visualization

Add TextEditor::setVisualIndentOffset() protected helper.

Change-Id: I0755a732d07dec651c090dd6afd87d293453f0e1
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/diffeditor/unifieddiffeditorwidget.cpp

@@ -36,6 +36,8 @@ UnifiedDiffEditorWidget::UnifiedDiffEditorWidget(QWidget *parent)
     : SelectableTextEditorWidget("DiffEditor.UnifiedDiffEditor", parent)
     , m_controller(this)
 {
+    setVisualIndentOffset(1);
+
     connect(TextEditorSettings::instance(), &TextEditorSettings::fontSettingsChanged,
             this, &UnifiedDiffEditorWidget::setFontSettings);
     setFontSettings(TextEditorSettings::fontSettings());

src/plugins/texteditor/texteditor.cpp

@@ -810,6 +810,7 @@ public:
     using UndoMultiCursor = QList<UndoCursor>;
     QStack<UndoMultiCursor> m_undoCursorStack;
     QList<int> m_visualIndentCache;
+    int m_visualIndentOffset = 0;
 };
 
 class TextEditorWidgetFind : public BaseTextFind
@@ -1699,6 +1700,11 @@ QString TextEditorWidget::selectedText() const
     return d->m_cursors.selectedText();
 }
 
+void TextEditorWidget::setVisualIndentOffset(int offset)
+{
+    d->m_visualIndentOffset = qMax(0, offset);
+}
+
 void TextEditorWidgetPrivate::updateCannotDecodeInfo()
 {
     q->setReadOnly(m_document->hasDecodingError());
@@ -4388,7 +4394,7 @@ int TextEditorWidgetPrivate::indentDepthForBlock(const QTextBlock &block)
     const auto blockDepth = [&](const QTextBlock &block) {
         int depth = m_visualIndentCache.value(block.blockNumber(), -1);
         if (depth < 0) {
-            const QString text = block.text();
+            const QString text = block.text().mid(m_visualIndentOffset);
             depth = text.simplified().isEmpty() ? -1 : tabSettings.indentationColumn(text);
         }
         return depth;
@@ -4448,18 +4454,19 @@ void TextEditorWidgetPrivate::paintIndentDepth(PaintEventData &data,
         return;
 
     const TabSettings &tabSettings = m_document->tabSettings();
-    const qreal horizontalAdvance = QFontMetricsF(q->font()).horizontalAdvance(
-        QString(tabSettings.m_indentSize, QChar(' ')));
+    const qreal horizontalAdvance = QFontMetricsF(q->font()).horizontalAdvance(' ');
+    const qreal fullHorizontalAdvance = horizontalAdvance * tabSettings.m_indentSize;
 
     painter.save();
     painter.setPen(data.visualWhitespaceFormat.foreground().color());
 
     const QTextLine textLine = blockData.layout->lineAt(0);
     const QRectF rect = textLine.naturalTextRect();
-    qreal x = textLine.cursorToX(0) + data.offset.x() + qMax(0, q->cursorWidth() - 1);
+    qreal x = textLine.cursorToX(0) + data.offset.x() + qMax(0, q->cursorWidth() - 1)
+            + horizontalAdvance * m_visualIndentOffset;
     int paintColumn = 0;
 
-    const QString text = data.block.text();
+    const QString text = data.block.text().mid(m_visualIndentOffset);
     while (paintColumn < depth) {
         if (x >= 0) {
             int paintPosition = tabSettings.positionAtColumn(text, paintColumn);
@@ -4470,7 +4477,7 @@ void TextEditorWidgetPrivate::paintIndentDepth(PaintEventData &data,
             const QLineF line(top, bottom);
             painter.drawLine(line);
         }
-        x += horizontalAdvance;
+        x += fullHorizontalAdvance;
         paintColumn += tabSettings.m_indentSize;
     }
     painter.restore();

src/plugins/texteditor/texteditor.h

@@ -537,6 +537,8 @@ protected:
     virtual void finalizeInitializationAfterDuplication(TextEditorWidget *) {}
     static QTextCursor flippedCursor(const QTextCursor &cursor);
 
+    void setVisualIndentOffset(int offset);
+
 public:
     QString selectedText() const;