codeeditor.cpp

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#include <QPlainTextEdit>
#include <QPainter>
#include <QTextBlock>
 
#include "codeeditor_p.h"
 
 
CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
{
    lineNumberArea = new LineNumberArea(this);
 
    connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int))); // clazy:exclude=old-style-connect
    connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateLineNumberArea(QRect,int))); // clazy:exclude=old-style-connect
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine())); // clazy:exclude=old-style-connect
 
    QFont font(QStringLiteral("Monospace"));
    font.setStyleHint(QFont::TypeWriter);
    setFont(font);
 
    updateLineNumberAreaWidth(0);
    highlightCurrentLine();
}
 
 
 
int CodeEditor::lineNumberAreaWidth()
{
    int digits = 1;
    int max = qMax(1, blockCount());
    while (max >= 10) {
        max /= 10;
        ++digits;
    }
 
    const int space = 3 + (fontMetrics().horizontalAdvance(QLatin1Char('9')) * digits);
 
    return space;
}
 
 
 
void CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */)
{
    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}
 
 
 
void CodeEditor::updateLineNumberArea(QRect rect, int dy)
{
    if (dy)
        lineNumberArea->scroll(0, dy);
    else
        lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());
 
    if (rect.contains(viewport()->rect()))
        updateLineNumberAreaWidth(0);
}
 
 
 
void CodeEditor::resizeEvent(QResizeEvent *event)
{
    QPlainTextEdit::resizeEvent(event);
 
    const QRect cr = contentsRect();
    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
}
 
void CodeEditor::focusOutEvent(QFocusEvent *event)
{
    Q_UNUSED(event);
    Q_EMIT editingFinished(toPlainText());
}
 
void CodeEditor::highlightCurrentLine()
{
    QList<QTextEdit::ExtraSelection> extraSelections;
 
    if (!isReadOnly()) {
        QTextEdit::ExtraSelection selection;
 
        const 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::lineNumberAreaPaintEvent(QPaintEvent *event)
{
    QPainter painter(lineNumberArea);
    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();
 
    while (block.isValid() && top <= event->rect().bottom()) {
        if (block.isVisible() && bottom >= event->rect().top()) {
            const QString number = QString::number(blockNumber + 1);
            painter.setPen(Qt::black);
            painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
                            Qt::AlignRight, number);
        }
 
        block = block.next();
        top = bottom;
        bottom = top + (int) blockBoundingRect(block).height();
        ++blockNumber;
    }
}