codeeditor.cpp Example File

widgets/codeeditor/codeeditor.cpp
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#include <QtWidgets> #include "codeeditor.h" CodeEditor::CodeEditor(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 CodeEditor::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 CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */) { setViewportMargins(lineNumberAreaWidth(), 0, 0, 0); } void CodeEditor::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 CodeEditor::resizeEvent(QResizeEvent *e) { QPlainTextEdit::resizeEvent(e); QRect cr = contentsRect(); lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height())); } void CodeEditor::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 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()) { 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; } }