wie fügen Sie Zeilen-Nummern an : QTextEdit?

Ich weiß, dass Qt tutorial empfiehlt die Verwendung QPlainTextEdit für text-editor-Implementierungen, und dass die Frage (mit Ausnahme der im Titel genannten), der allgemeiner als der Umgang (absolut) mit einem QTextEdit widget, aber ich habe es geschafft, die Implementierung der Verhalten (Zeilennummern + aktuelle Zeilennummer markieren), und ich denke, das könnte hilfreich sein für einige Menschen (wie mich), die wirklich wollen, zu gehen zu halten mit der Rich Text widget und möchte über meine Umsetzung (die ist bei weitem nicht perfekt ist - Recht schnell codiert...).

LineNumberArea.h : (ähnlich wie "QPlainTextEdit" tutorial)

class LineNumberArea : public QWidget
{
    Q_OBJECT

public:
    LineNumberArea(QTextEdit *editor);

    QSize sizeHint() const;

protected:
    void paintEvent(QPaintEvent *event);

private:
    QTextEdit *codeEditor;
};

LineNumberArea.cpp : (ähnlich wie "QPlainTextEdit" tutorial)

LineNumberArea::LineNumberArea(QTextEdit *editor) : QWidget(editor) {
    codeEditor = editor;
}

QSize LineNumberArea::sizeHint() const {
    return QSize(((QTextEditHighlighter *)codeEditor)->lineNumberAreaWidth(), 0);
}

void LineNumberArea::paintEvent(QPaintEvent *event) {
    ((QTextEditHighlighter *)codeEditor)->lineNumberAreaPaintEvent(event);
}

>> qtextedithighlighter.h :

class QTextEditHighlighter : public QTextEdit
{
    Q_OBJECT

public:

    explicit QTextEditHighlighter(QWidget *parent = 0);

    int getFirstVisibleBlockId();
    void lineNumberAreaPaintEvent(QPaintEvent *event);
    int lineNumberAreaWidth();

signals:


public slots:

    void resizeEvent(QResizeEvent *e);

private slots:

    void updateLineNumberAreaWidth(int newBlockCount);
    void updateLineNumberArea(QRectF /*rect_f*/);
    void updateLineNumberArea(int /*slider_pos*/);
    void updateLineNumberArea();

private:

    QWidget *lineNumberArea;

};

>> qtextedithighlighter.cpp :

#include "qtextedithighlighter.h"

QTextEditHighlighter::QTextEditHighlighter(QWidget *parent) :
    QTextEdit(parent)
{
    //Line numbers
    lineNumberArea = new LineNumberArea(this);
    ///
    connect(this->document(), SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
    connect(this->verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(updateLineNumberArea/*_2*/(int)));
    connect(this, SIGNAL(textChanged()), this, SLOT(updateLineNumberArea()));
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(updateLineNumberArea()));
    ///
    updateLineNumberAreaWidth(0);
}

int QTextEditHighlighter::lineNumberAreaWidth()
{
    int digits = 1;
    int max = qMax(1, this->document()->blockCount());
    while (max >= 10) {
        max /= 10;
        ++digits;
    }

    int space = 13 +  fontMetrics().width(QLatin1Char('9')) * (digits);

    return space;
}

void QTextEditHighlighter::updateLineNumberAreaWidth(int /* newBlockCount */)
{
    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}


void QTextEditHighlighter::updateLineNumberArea(QRectF /*rect_f*/)
{
    QTextEditHighlighter::updateLineNumberArea();
}
void QTextEditHighlighter::updateLineNumberArea(int /*slider_pos*/)
{
    QTextEditHighlighter::updateLineNumberArea();
}
void QTextEditHighlighter::updateLineNumberArea()
{
    /*
     * When the signal is emitted, the sliderPosition has been adjusted according to the action,
     * but the value has not yet been propagated (meaning the valueChanged() signal was not yet emitted),
     * and the visual display has not been updated. In slots connected to this signal you can thus safely
     * adjust any action by calling setSliderPosition() yourself, based on both the action and the
     * slider's value.
     */
    //Make sure the sliderPosition triggers one last time the valueChanged() signal with the actual value !!!!
    this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition());

    //Since "QTextEdit" does not have an "updateRequest(...)" signal, we chose
    //to grab the imformations from "sliderPosition()" and "contentsRect()".
    //See the necessary connections used (Class constructor implementation part).

    QRect rect =  this->contentsRect();
    lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());
    updateLineNumberAreaWidth(0);
    //----------
    int dy = this->verticalScrollBar()->sliderPosition();
    if (dy > -1) {
        lineNumberArea->scroll(0, dy);
    }

    //Addjust slider to alway see the number of the currently being edited line...
    int first_block_id = getFirstVisibleBlockId();
    if (first_block_id == 0 || this->textCursor().block().blockNumber() == first_block_id-1)
        this->verticalScrollBar()->setSliderPosition(dy-this->document()->documentMargin());

//   //Snap to first line (TODO...)
//   if (first_block_id > 0)
//   {
//       int slider_pos = this->verticalScrollBar()->sliderPosition();
//       int prev_block_height = (int) this->document()->documentLayout()->blockBoundingRect(this->document()->findBlockByNumber(first_block_id-1)).height();
//       if (dy <= this->document()->documentMargin() + prev_block_height)
//           this->verticalScrollBar()->setSliderPosition(slider_pos - (this->document()->documentMargin() + prev_block_height));
//   }

}


void QTextEditHighlighter::resizeEvent(QResizeEvent *e)
{
    QTextEdit::resizeEvent(e);

    QRect cr = this->contentsRect();
    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
}


int QTextEditHighlighter::getFirstVisibleBlockId()
{
    //Detect the first block for which bounding rect - once translated 
    //in absolute coordinated - is contained by the editor's text area

    //Costly way of doing but since "blockBoundingGeometry(...)" doesn't 
    //exists for "QTextEdit"...

    QTextCursor curs = QTextCursor(this->document());
    curs.movePosition(QTextCursor::Start);
    for(int i=0; i < this->document()->blockCount(); ++i)
    {
        QTextBlock block = curs.block();

        QRect r1 = this->viewport()->geometry();
        QRect r2 = this->document()->documentLayout()->blockBoundingRect(block).translated(
                    this->viewport()->geometry().x(), this->viewport()->geometry().y() - (
                        this->verticalScrollBar()->sliderPosition()
                        ) ).toRect();

        if (r1.contains(r2, true)) { return i; }

        curs.movePosition(QTextCursor::NextBlock);
    }

    return 0;
}

void QTextEditHighlighter::lineNumberAreaPaintEvent(QPaintEvent *event)
{
    this->verticalScrollBar()->setSliderPosition(this->verticalScrollBar()->sliderPosition());

    QPainter painter(lineNumberArea);
    painter.fillRect(event->rect(), Qt::lightGray);
    int blockNumber = this->getFirstVisibleBlockId();

    QTextBlock block = this->document()->findBlockByNumber(blockNumber);
    QTextBlock prev_block = (blockNumber > 0) ? this->document()->findBlockByNumber(blockNumber-1) : block;
    int translate_y = (blockNumber > 0) ? -this->verticalScrollBar()->sliderPosition() : 0;

    int top = this->viewport()->geometry().top();

    //Adjust text position according to the previous "non entirely visible" block 
    //if applicable. Also takes in consideration the document's margin offset.
    int additional_margin;
    if (blockNumber == 0)
        //Simply adjust to document's margin
        additional_margin = (int) this->document()->documentMargin() -1 - this->verticalScrollBar()->sliderPosition();
    else
        //Getting the height of the visible part of the previous "non entirely visible" block
        additional_margin = (int) this->document()->documentLayout()->blockBoundingRect(prev_block)
                .translated(0, translate_y).intersect(this->viewport()->geometry()).height();

    //Shift the starting point
    top += additional_margin;

    int bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height();

    QColor col_1(90, 255, 30);      //Current line (custom green)
    QColor col_0(120, 120, 120);    //Other lines  (custom darkgrey)

    //Draw the numbers (displaying the current line number in green)
    while (block.isValid() && top <= event->rect().bottom()) {
        if (block.isVisible() && bottom >= event->rect().top()) {
            QString number = QString::number(blockNumber + 1);
            painter.setPen(QColor(120, 120, 120));
            painter.setPen((this->textCursor().blockNumber() == blockNumber) ? col_1 : col_0);
            painter.drawText(-5, top,
                             lineNumberArea->width(), fontMetrics().height(),
                             Qt::AlignRight, number);
        }

        block = block.next();
        top = bottom;
        bottom = top + (int) this->document()->documentLayout()->blockBoundingRect(block).height();
        ++blockNumber;
    }

}

Hoffe, dass dies helfen kann...

InformationsquelleAutor Gauthier Boaglio