'Annotation' of lines in a QTextEdit

[fullmetalcoder]

FMC: If you managed to insert a "margin widget" into a scroll area, could you please present a minimal code that accomplishes that? We might be going in circles here and I'm really interested in finding a solution.

Minimal? well... my code is not really minimal because the layout used has some complexities and I use a custom class, QPanel (inheriting from QWidget). As I don't feel like spending too much time on trimming down my code so I'll give you a layout-less sample... Fell free to ask for the layout code if you want something a little more flexible but then don't expect something that will work out of box...

So here comes the minimum (not very handy nor fully functionnal but works...) :

#include <QPainter>
#include <QPaintEvent>
 
#include <QTextEdit>
#include <QTextBlock>
#include <QTextLayout>
 
#include <QScrollBar>
#include <QApplication>
 
class SampleArea : public QTextEdit
{
	public:
		SampleArea(QWidget *p = 0)
		 : QTextEdit(p)
		{
			QString txt =  "eat me...\ndrink me...\n";
 
			for ( int i = 0; i < 8; ++i )
				txt += txt;
 
			document()->setPlainText(txt);
		}
 
		inline void setMargins(int l, int r, int t, int b)
		{ setViewportMargins(l, r, t, b); }
};
 
class SamplePanel : public QWidget
{
	public:
		SamplePanel(SampleArea *a)
		 : QWidget(a), m_area(a)
		{
			setFixedWidth(50);
			setFixedHeight(a->height());
 
			connect(a->verticalScrollBar()	, SIGNAL( valueChanged(int) ),
					this					, SLOT  ( update() ));
 
			a->setMargins(50, 0, 0, 0);
		}
 
	protected:
		virtual void paintEvent(QPaintEvent *e)
		{
			e->accept();
 
			QPainter p(this);
 
			int m_lineNumber = 1;
			const QFontMetrics fm = fontMetrics();
			const int ascent = fontMetrics().ascent() + 1;
			QTextBlock block = m_area->document()->begin();
			int contentsY = m_area->verticalScrollBar()->value();
			qreal pageBottom = contentsY + m_area->viewport()->height();
 
			for ( ; block.isValid(); block = block.next(), ++m_lineNumber )
			{
				QTextLayout* layout = block.layout();
				QPointF position = layout->position();
				const QRectF boundingRect = layout->boundingRect();
 
				if ( position.y() + boundingRect.height() < contentsY )
					continue;
 
				if ( position.y() > pageBottom )
					break;
 
				const QString txt = QString::number( m_lineNumber );
 
				p.drawText(width() - fm.width(txt) - 2, qRound(position.y()) - contentsY + ascent, txt);
			}
		}
 
	private:
		SampleArea *m_area;
};
 
int main (int argc, char **argv)
{
	QApplication app(argc, argv);
 
	SampleArea area;
	SamplePanel panel(&area);
 
	area.show();
 
	return app.exec();
}

#include <QPainter>
#include <QPaintEvent>

#include <QTextEdit>
#include <QTextBlock>
#include <QTextLayout>

#include <QScrollBar>
#include <QApplication>

class SampleArea : public QTextEdit
{
	public:
		SampleArea(QWidget *p = 0)
		 : QTextEdit(p)
		{
			QString txt =  "eat me...\ndrink me...\n";
			
			for ( int i = 0; i < 8; ++i )
				txt += txt;
			
			document()->setPlainText(txt);
		}
		
		inline void setMargins(int l, int r, int t, int b)
		{ setViewportMargins(l, r, t, b); }
};

class SamplePanel : public QWidget
{
	public:
		SamplePanel(SampleArea *a)
		 : QWidget(a), m_area(a)
		{
			setFixedWidth(50);
			setFixedHeight(a->height());
			
			connect(a->verticalScrollBar()	, SIGNAL( valueChanged(int) ),
					this					, SLOT  ( update() ));
			
			a->setMargins(50, 0, 0, 0);
		}
		
	protected:
		virtual void paintEvent(QPaintEvent *e)
		{
			e->accept();
			
			QPainter p(this);
			
			int m_lineNumber = 1;
			const QFontMetrics fm = fontMetrics();
			const int ascent = fontMetrics().ascent() + 1;
			QTextBlock block = m_area->document()->begin();
			int contentsY = m_area->verticalScrollBar()->value();
			qreal pageBottom = contentsY + m_area->viewport()->height();
			
			for ( ; block.isValid(); block = block.next(), ++m_lineNumber )
			{
				QTextLayout* layout = block.layout();
				QPointF position = layout->position();
				const QRectF boundingRect = layout->boundingRect();
				
				if ( position.y() + boundingRect.height() < contentsY )
					continue;
				
				if ( position.y() > pageBottom )
					break;
				
				const QString txt = QString::number( m_lineNumber );
		
				p.drawText(width() - fm.width(txt) - 2, qRound(position.y()) - contentsY + ascent, txt);
			}
		}
		
	private:
		SampleArea *m_area;
};

int main (int argc, char **argv)
{
	QApplication app(argc, argv);
	
	SampleArea area;
	SamplePanel panel(&area);
	
	area.show();
	
	return app.exec();
}

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[marcel]

Here's one. Just two buttons and a graphics view.

The cpp:

#include "scrollarea.h"
#include <QGraphicsView>
#include <QWidget>
#include <QPushButton>
#include <QScrollBar>
 
#define DEFAULT_MARGIN 30
 
scroller::scroller(QWidget* parent/* =null */)
:QGraphicsView(parent)
{
    mLeftWidget = NULL;
    mTopWidget = NULL;
 
    setScene(new QGraphicsScene(this));
    scene()->setSceneRect(QRectF(0, 0, 3000.0f, 3000.0f)); //just for scrolling purposes
 
    QScrollBar* hbar = verticalScrollBar();
    QScrollBar* vbar = horizontalScrollBar();
    connect(hbar, SIGNAL(valueChanged(int)), this, SLOT(adjustMarginWidgets()));
    connect(vbar, SIGNAL(valueChanged(int)), this, SLOT(adjustMarginWidgets()));
    setViewportMargins(DEFAULT_MARGIN, DEFAULT_MARGIN, 0, 0 );
    createMarginWidgets();
}
 
scroller::~scroller()
{
 
}
 
void scroller::createMarginWidgets()
{
    mLeftWidget = new QPushButton("L", this);
    mTopWidget = new QPushButton("T", this);
 
    adjustMarginWidgets();
}
 
void scroller::adjustMarginWidgets()
{
    QRect viewportRect = viewport()->geometry();
    QRect lrect = QRect(viewportRect.topLeft(), viewportRect.bottomLeft());
    lrect.adjust(-DEFAULT_MARGIN, 0, 0, 0);
    mLeftWidget->setGeometry(lrect);
 
    QRect trect = QRect(viewportRect.topLeft(), viewportRect.topRight());
    trect.adjust(0, -DEFAULT_MARGIN, 0, 0);
    mTopWidget->setGeometry(trect);
}
 
void scroller::createCornerWidget()
{
 
}
 
void scroller::resizeEvent(QResizeEvent *e)
{
    QGraphicsView::resizeEvent(e);
    adjustMarginWidgets();
}

#include "scrollarea.h"
#include <QGraphicsView>
#include <QWidget>
#include <QPushButton>
#include <QScrollBar>

#define DEFAULT_MARGIN 30

scroller::scroller(QWidget* parent/* =null */)
:QGraphicsView(parent)
{
    mLeftWidget = NULL;
    mTopWidget = NULL;
    
    setScene(new QGraphicsScene(this));
    scene()->setSceneRect(QRectF(0, 0, 3000.0f, 3000.0f)); //just for scrolling purposes

    QScrollBar* hbar = verticalScrollBar();
    QScrollBar* vbar = horizontalScrollBar();
    connect(hbar, SIGNAL(valueChanged(int)), this, SLOT(adjustMarginWidgets()));
    connect(vbar, SIGNAL(valueChanged(int)), this, SLOT(adjustMarginWidgets()));
    setViewportMargins(DEFAULT_MARGIN, DEFAULT_MARGIN, 0, 0 );
    createMarginWidgets();
}

scroller::~scroller()
{

}

void scroller::createMarginWidgets()
{
    mLeftWidget = new QPushButton("L", this);
    mTopWidget = new QPushButton("T", this);
    
    adjustMarginWidgets();
}

void scroller::adjustMarginWidgets()
{
    QRect viewportRect = viewport()->geometry();
    QRect lrect = QRect(viewportRect.topLeft(), viewportRect.bottomLeft());
    lrect.adjust(-DEFAULT_MARGIN, 0, 0, 0);
    mLeftWidget->setGeometry(lrect);

    QRect trect = QRect(viewportRect.topLeft(), viewportRect.topRight());
    trect.adjust(0, -DEFAULT_MARGIN, 0, 0);
    mTopWidget->setGeometry(trect);
}

void scroller::createCornerWidget()
{
    
}

void scroller::resizeEvent(QResizeEvent *e)
{
    QGraphicsView::resizeEvent(e);
    adjustMarginWidgets();
}

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The header:

#pragma once
 
#include <QGraphicsView>
 
class QWidget;
class QPushButton;
 
class scroller : public QGraphicsView
{
    Q_OBJECT
public:
    scroller(QWidget* = NULL);
    ~scroller();
 
protected:
    virtual void resizeEvent(QResizeEvent *);
 
private slots:
    void adjustMarginWidgets();
 
private:
    void createMarginWidgets();
    void createCornerWidget();
    QPushButton *mLeftWidget;
    QPushButton    *mTopWidget;
};

#pragma once

#include <QGraphicsView>

class QWidget;
class QPushButton;

class scroller : public QGraphicsView
{
    Q_OBJECT
public:
    scroller(QWidget* = NULL);
    ~scroller();

protected:
    virtual void resizeEvent(QResizeEvent *);

private slots:
    void adjustMarginWidgets();

private:
    void createMarginWidgets();
    void createCornerWidget();
    QPushButton *mLeftWidget;
    QPushButton    *mTopWidget;
};

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You can just set this as the central widget in a main window, or whatever.

Regards