codeeditor.cc

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  #include <QtWidgets>


#include "codeeditor.hh"


CodeEditorWidget::CodeEditorWidget(QWidget *parent) : QPlainTextEdit(parent) {
  lineNumberArea = new LineNumberArea(this);

  connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
  connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateLineNumberArea(QRect,int)));
  connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));

  updateLineNumberAreaWidth(0);
  highlightCurrentLine();
}



int CodeEditorWidget::lineNumberAreaWidth() {

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



void CodeEditorWidget::updateLineNumberArea(const 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 CodeEditorWidget::resizeEvent(QResizeEvent *e) {
  QPlainTextEdit::resizeEvent(e);

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



void CodeEditorWidget::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 CodeEditorWidget::highLightErrorLine(int _line) {
  QList<QTextEdit::ExtraSelection> extraSelections;

  if (!isReadOnly()) {
    QTextEdit::ExtraSelection selection;

    QColor lineColor = QColor(Qt::red).lighter(160);

    selection.format.setBackground(lineColor);
    selection.format.setProperty(QTextFormat::FullWidthSelection, true);
    selection.cursor = QTextCursor(document());
    selection.cursor.movePosition ( QTextCursor::Down, QTextCursor::MoveAnchor, _line - 1 );
    selection.cursor.clearSelection();
    extraSelections.append(selection);
  }

  setExtraSelections(extraSelections);
}


void CodeEditorWidget::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()) {
      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;
  }

}