Added a gutter and currentline highlighting to the SQL editor.

Currently gutter only shows linenumbers. Code is mostly from http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html

There is a little bit included in this commit from a first try to make toobars adept to the current tab.

Code #2

pglab/CodeEditor.cpp

@@ -0,0 +1,112 @@
+#include "CodeEditor.h"
+#include "EditorGutter.h"
+#include <QPainter>
+#include <QTextBlock>
+//
+// Adapted from codeeditor example
+// http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html
+//
+// Used term gutter as I want to expand it to do other things to like error
+// position marking.
+//
+
+CodeEditor::CodeEditor(QWidget *parent)
+	: QPlainTextEdit(parent)
+	, gutterArea(new EditorGutter(this))
+{
+	connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateGutterAreaWidth(int)));
+	connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateGutterArea(QRect,int)));
+	connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));
+
+	updateGutterAreaWidth(0);
+	highlightCurrentLine();
+}
+
+int CodeEditor::gutterAreaWidth()
+{
+	int digits = 1;
+	int max = qMax(1, blockCount());
+	while (max >= 10) {
+		max /= 10;
+		++digits;
+	}
+
+	int space = 3 + fontMetrics().width(QLatin1Char('9')) * digits;
+
+	return space;
+}
+
+void CodeEditor::updateGutterAreaWidth(int /* newBlockCount */)
+{
+	setViewportMargins(gutterAreaWidth(), 0, 0, 0);
+}
+
+void CodeEditor::updateGutterArea(const QRect &rect, int dy)
+{
+	if (dy)
+		gutterArea->scroll(0, dy);
+	else
+		gutterArea->update(0, rect.y(), gutterArea->width(), rect.height());
+
+	if (rect.contains(viewport()->rect()))
+		updateGutterAreaWidth(0);
+}
+
+void CodeEditor::resizeEvent(QResizeEvent *e)
+{
+	QPlainTextEdit::resizeEvent(e);
+
+	QRect cr = contentsRect();
+	gutterArea->setGeometry(QRect(cr.left(), cr.top(), gutterAreaWidth(), cr.height()));
+}
+
+void CodeEditor::highlightCurrentLine()
+{
+	QList<QTextEdit::ExtraSelection> extraSelections;
+
+	if (!isReadOnly()) {
+		QTextEdit::ExtraSelection selection;
+
+		QColor lineColor = QColor(Qt::yellow).lighter(160);
+
+		selection.format.setBackground(lineColor);
+		selection.format.setProperty(QTextFormat::FullWidthSelection, true);
+		selection.cursor = textCursor();
+		selection.cursor.clearSelection();
+		extraSelections.append(selection);
+	}
+
+	setExtraSelections(extraSelections);
+}
+
+void CodeEditor::gutterAreaPaintEvent(QPaintEvent *event)
+{
+	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);
+		}
+
+		block = block.next();
+		top = bottom;
+		bottom = top + (int) blockBoundingRect(block).height();
+		++blockNumber;
+	}
+}