Refactor painting of editor gutter

pglab/codeeditor/CodeEditor.cpp

@@ -120,45 +120,17 @@ void CodeEditor::updateExtraSelections()
 	setExtraSelections(extraSelections);
 }
 
-void CodeEditor::gutterAreaPaintEvent(QPaintEvent *event)
+void CodeEditor::drawGutterErrorMarker(QPainter &painter, int top)
 {
-	QPainter painter(gutterArea);
-	painter.fillRect(event->rect(), Qt::lightGray);
-
-	QTextBlock block = firstVisibleBlock();
-	int blockNumber = block.blockNumber();
-	int top = (int) blockBoundingGeometry(block).translated(contentOffset()).top();
-	int bottom = top + (int) blockBoundingRect(block).height();
-
-	// We will now loop through all visible lines and paint the line numbers in the
-	// extra area for each line. Notice that in a plain text edit each line will
-	// consist of one QTextBlock; though, if line wrapping is enabled, a line may span
-	// several rows in the text edit's viewport.
-	//
-	// We get the top and bottom y-coordinate of the first text block, and adjust these
-	// values by the height of the current text block in each iteration in the loop.
-    while (block.isValid() && top <= event->rect().bottom())
-    {
-        if (block.isVisible() && bottom >= event->rect().top())
-        {
-			QString number = QString::number(blockNumber + 1);
-			painter.setPen(Qt::black);
-			painter.drawText(0, top, gutterArea->width(), fontMetrics().height(),
-							 Qt::AlignRight, number);
-
-            if (errorLines.count(blockNumber) > 0)
-            {
     int s = fontMetrics().height() - 8;
     painter.setBrush(QBrush(Qt::red));
     painter.drawEllipse(4, top + 4, s, s);
-			}
-		}
 
-		block = block.next();
+}
-		top = bottom;
+
-		bottom = top + (int) blockBoundingRect(block).height();
+bool CodeEditor::lineHasError(int blockNumber) const
-		++blockNumber;
+{
-	}
+    return errorLines.count(blockNumber) > 0;
 }
 
 void CodeEditor::keyPressEvent(QKeyEvent *e)
@@ -194,6 +166,8 @@ void CodeEditor::keyPressEvent(QKeyEvent *e)
 	QPlainTextEdit::keyPressEvent(e);
 }
 
+
+
 bool CodeEditor::indentSelection(bool indent)
 {
 	auto cursor = textCursor();
@@ -222,14 +196,29 @@ bool CodeEditor::indentSelection(bool indent)
     {
 		cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
         if (indent)
-        {
+            insertIndentation(cursor);
+        else
+            removeIndentation(cursor);
+		cursor.movePosition(QTextCursor::NextBlock, QTextCursor::MoveAnchor);
+	}
+	cursor.endEditBlock();
+
+    makeSelection(cursor, first_pos, end_block);
+
+	setTextCursor(cursor);
+	return true;
+}
+
+void CodeEditor::insertIndentation(QTextCursor &cursor)
+{
     if (m_useTab)
         cursor.insertText("\t");
     else
         cursor.insertText(QString(m_tabSize, ' '));
-		}
+}
-        else
+
-        {
+void CodeEditor::removeIndentation(QTextCursor &cursor)
+{
     // remove tab if there is a tab
     cursor.movePosition(QTextCursor::EndOfLine, QTextCursor::KeepAnchor);
     const QString text = cursor.selectedText();
@@ -252,20 +241,17 @@ bool CodeEditor::indentSelection(bool indent)
     for (int i = 0; i < index; ++i)
         cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor);
     cursor.removeSelectedText();
-		}
-		cursor.movePosition(QTextCursor::NextBlock, QTextCursor::MoveAnchor);
-	}
-	cursor.endEditBlock();
 
+}
+
+void CodeEditor::makeSelection(QTextCursor &cursor, int first_pos, int end_block)
+{
     cursor.setPosition(first_pos, QTextCursor::MoveAnchor);
     cursor.movePosition(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
     while(cursor.block().blockNumber() < end_block)
         cursor.movePosition(QTextCursor::NextBlock, QTextCursor::KeepAnchor);
 
     cursor.movePosition(QTextCursor::EndOfBlock, QTextCursor::KeepAnchor);
-
-	setTextCursor(cursor);
-	return true;
 }
 
 void CodeEditor::setFont(const QFont &f)

pglab/codeeditor/CodeEditor.h

@@ -13,7 +13,6 @@ class CodeEditor : public QPlainTextEdit
 public:
 	explicit CodeEditor(QWidget *parent = nullptr);
 
-	void gutterAreaPaintEvent(QPaintEvent *event);
 	int gutterAreaWidth();
 
 	void addErrorMarker(int position, int length);
@@ -47,9 +46,16 @@ private:
 	int m_tabSize = 0;  // tabSize in characters
 	bool m_useTab = false;
 
+    bool lineHasError(int blockNumber) const;
     void updateExtraSelections();
 	bool indentSelection(bool indent);
+    void drawGutterErrorMarker(QPainter &painter, int top);
 
+    void insertIndentation(QTextCursor &cursor);
+    void removeIndentation(QTextCursor &cursor);
+    void makeSelection(QTextCursor &cursor, int first_pos, int end_block);
+
+    friend class GutterPainter;
 };
 
 #endif // CODEEDITOR_H

pglab/codeeditor/EditorGutter.cpp

@@ -1,5 +1,6 @@
 #include "EditorGutter.h"
 #include "CodeEditor.h"
+#include "GutterPainter.h"
 
 EditorGutter::EditorGutter(CodeEditor *editor)
 	: QWidget(editor)
@@ -13,5 +14,6 @@ QSize EditorGutter::sizeHint() const
 
 void EditorGutter::paintEvent(QPaintEvent *event)
 {
-	codeEditor->gutterAreaPaintEvent(event);
+    GutterPainter gutterpainter(codeEditor, event);
+    gutterpainter.Paint();
 }

pglab/codeeditor/GutterPainter.cpp

@@ -0,0 +1,69 @@
+#include "GutterPainter.h"
+#include "CodeEditor.h"
+
+
+GutterPainter::GutterPainter(CodeEditor *editor, QPaintEvent *event)
+    : editor(editor)
+    , painter(editor->gutterArea)
+    , event(event)
+    , fontMetrics(editor->fontMetrics())
+{}
+
+void GutterPainter::Paint()
+{
+    painter.fillRect(event->rect(), Qt::lightGray);
+
+    LoopState loopState(editor);
+    // We will now loop through all visible lines and paint the line numbers in the
+    // extra area for each line. Notice that in a plain text edit each line will
+    // consist of one QTextBlock; though, if line wrapping is enabled, a line may span
+    // several rows in the text edit's viewport.
+    //
+    // We get the top and bottom y-coordinate of the first text block, and adjust these
+    // values by the height of the current text block in each iteration in the loop.
+    while (loopState.block.isValid() && loopState.top <= event->rect().bottom())
+    {
+        if (loopState.block.isVisible() && loopState.bottom >= event->rect().top())
+        {
+            drawLineNumber(loopState);
+            if (editor->lineHasError(loopState.blockNumber()))
+                drawGutterErrorMarker(loopState);
+        }
+
+        loopState.advanceToNextLine();
+    }
+}
+
+void GutterPainter::drawLineNumber(const LoopState &loopState)
+{
+    QString number = QString::number(loopState.blockNumber() + 1);
+    painter.setPen(Qt::black);
+    painter.drawText(0, loopState.top, editor->gutterArea->width(), fontMetrics.height(),
+                     Qt::AlignRight, number);
+}
+
+void GutterPainter::drawGutterErrorMarker(const LoopState &loopState)
+{
+    int s = fontMetrics.height() - 8;
+    painter.setBrush(QBrush(Qt::red));
+    painter.drawEllipse(4, loopState.top + 4, s, s);
+}
+
+GutterPainter::LoopState::LoopState(CodeEditor *editor)
+    : editor(editor)
+    , block(editor->firstVisibleBlock())
+    , top((int) editor->blockBoundingGeometry(block).translated(editor->contentOffset()).top())
+    , bottom(top + (int) editor->blockBoundingRect(block).height())
+{}
+
+int GutterPainter::LoopState::blockNumber() const
+{
+    return block.blockNumber();
+}
+
+void GutterPainter::LoopState::advanceToNextLine()
+{
+    block = block.next();
+    top = bottom;
+    bottom = top + (int) editor->blockBoundingRect(block).height();
+}

pglab/codeeditor/GutterPainter.h

@@ -0,0 +1,38 @@
+#include <QPainter>
+#include <QTextBlock>
+
+#pragma once
+
+class CodeEditor;
+class QPaintEvent;
+
+class GutterPainter
+{
+public:
+    GutterPainter(CodeEditor *editor, QPaintEvent *event);
+
+    void Paint();
+private:
+    CodeEditor *editor;
+    QPainter painter;
+    QPaintEvent *event;
+    QFontMetrics fontMetrics;
+
+    // Loop state
+    struct LoopState {
+        CodeEditor *editor;
+        QTextBlock block;
+        int top;
+        int bottom;
+
+        LoopState(CodeEditor *editor);
+
+        int blockNumber() const;
+
+        void advanceToNextLine();
+    };
+
+    void drawLineNumber(const LoopState &loopState);
+
+    void drawGutterErrorMarker(const LoopState &loopState);
+};

pglab/crud/CrudTab.cpp

@@ -70,7 +70,7 @@ void CrudTab::on_actionRemove_rows_triggered()
 {
 	std::set<IntegerRange<int>> row_ranges;
     auto selection = m_SortFilterProxy->mapSelectionToSource(ui->tableView->selectionModel()->selection());
-	for (auto range : selection) {
+    for (auto& range : selection) {
 		row_ranges.emplace(range.top(), range.height());
 	}
 	std::set<IntegerRange<int>> merged_ranges;

pglab/pglab.pro

@@ -45,6 +45,7 @@ SOURCES += main.cpp\
     catalog/widgets/ColumnPage.cpp \
     catalog/widgets/DependantsPage.cpp \
     catalog/widgets/TriggerPage.cpp \
+    codeeditor/GutterPainter.cpp \
     crud/CrudModel.cpp \
     crud/CrudTab.cpp \
     querytool/QueryExplainModel.cpp \
@@ -119,6 +120,7 @@ HEADERS  += \
     catalog/widgets/ColumnPage.h \
     catalog/widgets/DependantsPage.h \
     catalog/widgets/TriggerPage.h \
+    codeeditor/GutterPainter.h \
     crud/CrudModel.h \
     crud/CrudTab.h \
     querytool/QueryExplainModel.h \