update line number display in program view dick widget

program line delegate now has base line number, one digit pixel width,
and line number area width set up in the constructor; a new function to
calculate the line number area width when the line count changed, which
emits a signal that the program view needs updating when the width
changes; and paints the line number with a gray background in its own
rectangle

in main window, program line delegate and program view needed to be set
up before loading the program so that the program view has a change to
calculate the line number area width

main window now maintains the program line count and can update the
program line delegate when the line count changes; and processes the
signal from the program line delegate when it requests the program view
to be update

the edit box base line number constant was made public to be accessible
when the program line delegate is created

editbox.h

@@ -44,6 +44,10 @@ class EditBox : public QPlainTextEdit
 	int lineNumberWidgetWidth(void);
 	void lineNumberWidgetPaint(QPaintEvent *event);
 
+	enum {
+		BaseLineNumber = 0			// number of first line
+	};
+
 protected:
 	void keyPressEvent(QKeyEvent *event);
 	void resizeEvent(QResizeEvent *event);
@@ -63,10 +67,6 @@ private slots:
 private:
 	bool pasteSelection(const QPoint &pos = QPoint());
 
-	enum {
-		BaseLineNumber = 0			// number of first line
-	};
-
 	int m_lineModified;				// current line that has been modified
 	bool m_lineModifiedIsNew;		// modified line is a new line flag
 	QWidget *m_lineNumberWidget;	// widget to display line numbers

mainwindow.cpp

@@ -101,6 +101,18 @@ MainWindow::MainWindow(QWidget *parent) :
 	m_editBox->addActions(actions);
 	m_editBox->setContextMenuPolicy(Qt::ActionsContextMenu);
 
+	// setup program view and its program line delegate
+	m_programLineDelegate = new ProgramLineDelegate(EditBox::BaseLineNumber,
+		ui->programView->fontMetrics(), this);
+	ui->programView->setItemDelegate(m_programLineDelegate);
+	ui->programView->setModel(m_programModel);
+	ui->programView->setFont(m_editBox->font());
+	m_programLines = 0;  // FIXME temporary
+
+	// connect update requests to update program view
+	connect(m_programLineDelegate, SIGNAL(programViewUpdate()),
+		this, SLOT(programViewUpdate()));
+
 	// if a file name was specified on the command line
 	// then it overrides the restored program
 	if (!m_commandLine->fileName().isEmpty())
@@ -123,10 +135,6 @@ MainWindow::MainWindow(QWidget *parent) :
 		// TODO should an warning message be issued here?
 	}
 
-	m_programLineDelegate = new ProgramLineDelegate(this);
-	ui->programView->setItemDelegate(m_programLineDelegate);
-	ui->programView->setModel(m_programModel);
-	ui->programView->setFont(m_editBox->font());
 	m_guiActive = true;
 }
 
@@ -436,7 +444,7 @@ bool MainWindow::programSave(const QString &programPath)
 void MainWindow::programChanged(int lineNumber, int linesDeleted,
 	int linesInserted, QStringList lines)
 {
-	// FIXME for now just echo to the console
+	// FIXME this is temporary until program model functionality is expanded
 	int i;
 	int count = lines.count();
 	for (i = 0; i < count - linesInserted; i++)
@@ -457,6 +465,20 @@ void MainWindow::programChanged(int lineNumber, int linesDeleted,
 			m_programModel->setData(index, lines.at(i++));
 		}
 	}
+	if (m_programModel->rowCount() != m_programLines)
+	{
+		m_programLines = m_programModel->rowCount();
+		m_programLineDelegate->lineNumberWidthUpdate(m_programLines);
+	}
+}
+
+
+// function to force update of program view
+
+void MainWindow::programViewUpdate(void)
+{
+	// FIXME expanded program model functionality should handle this
+	ui->programView->update(ui->programView->rect());
 }
 
 

mainwindow.h

@@ -75,6 +75,7 @@ private slots:
 	void on_actionSelectAll_triggered(void);
 	void programChanged(int lineNumber, int linesDeleted, int linesInserted,
 		QStringList lines);
+	void programViewUpdate(void);
 
 private:
 	bool isOkToContinue(void);
@@ -98,6 +99,7 @@ private slots:
 	QString m_curDirectory;
 	QStringListModel *m_programModel;
 	ProgramLineDelegate *m_programLineDelegate;
+	int m_programLines;					// FIXME temporary
 
 };
 

programlinedelegate.cpp

@@ -26,15 +26,52 @@
 
 #include "programlinedelegate.h"
 
-ProgramLineDelegate::ProgramLineDelegate(QObject *parent) :
-	QItemDelegate(parent)
+ProgramLineDelegate::ProgramLineDelegate(int baseLineNumber,
+		const QFontMetrics &fontMetrics, QObject *parent) :
+	QItemDelegate(parent),
+    m_baseLineNumber(baseLineNumber),
+    m_digitWidth(fontMetrics.width(QLatin1Char('9'))),
+    m_lineNumberWidth(0)
 {
 }
 
+
+// function to update the width needed for the line number area
+
+void ProgramLineDelegate::lineNumberWidthUpdate(int newLineCount)
+{
+	int digits = 2;  // plus 2 * 0.5 spacing on either side
+	while (newLineCount > 10 - m_baseLineNumber)
+	{
+		newLineCount /= 10;
+		digits++;
+	}
+	int width = m_digitWidth * digits;
+	if (width != m_lineNumberWidth)
+	{
+		m_lineNumberWidth = width;
+		emit programViewUpdate();
+	}
+}
+
+
+// function that paints one program line to the program view list widget
+
 void ProgramLineDelegate::paint(QPainter *painter,
 	const QStyleOptionViewItem &option, const QModelIndex &index) const
 {
-	QString text = QString("%1: %2").arg(index.row())
-		.arg(index.model()->data(index, Qt::DisplayRole).toString());
-	painter->drawText(option.rect, text);
+	// draw line number with gray background
+	QRect rect = option.rect;
+	rect.setWidth(m_lineNumberWidth);
+	painter->fillRect(rect, Qt::lightGray);
+	rect.setLeft(rect.left() + m_digitWidth / 2);
+	rect.setWidth(m_lineNumberWidth - m_digitWidth);
+	QString text = QString("%1").arg(index.row() + m_baseLineNumber);
+	painter->drawText(rect, Qt::AlignRight, text);
+
+	// draw program line text
+	rect.setLeft(rect.left() + m_lineNumberWidth);
+	rect.setWidth(option.rect.width() - m_lineNumberWidth);
+	text = index.model()->data(index, Qt::DisplayRole).toString();
+	painter->drawText(rect, text);
 }

programlinedelegate.h

@@ -31,14 +31,21 @@ class ProgramLineDelegate : public QItemDelegate
 {
 	Q_OBJECT
 public:
-	explicit ProgramLineDelegate(QObject *parent = 0);
+	explicit ProgramLineDelegate(int baseLineNumber,
+		const QFontMetrics &fontMetrics, QObject *parent = 0);
+	void lineNumberWidthUpdate(int newLineCount);
 	void paint(QPainter *painter, const QStyleOptionViewItem &option,
 		const QModelIndex &index) const;
 
 signals:
+	void programViewUpdate(void);
 
 public slots:
 
+private:
+	int m_baseLineNumber;				// first line number
+	int m_digitWidth;					// pixel width of one digit
+	int m_lineNumberWidth;				// width of line number area
 };
 
 #endif // PROGRAMLINEDELEGATE_H