--- /dev/null
+#include <QtWidgets>
+
+#include "codeeditor.h"
+
+extern bool usingDarkTheme;
+
+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().horizontalAdvance(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;
+ if (usingDarkTheme)
+ lineColor = QColor(Qt::darkGray).darker(150);
+ else
+ 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);
+ if (usingDarkTheme)
+ painter.fillRect(event->rect(), QColor(Qt::darkGray).darker(150));
+ else
+ 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();
+
+ QColor penColor;
+ if (usingDarkTheme)
+ penColor = Qt::lightGray;
+ else
+ penColor = Qt::black;
+
+ while (block.isValid() && top <= event->rect().bottom()) {
+ if (block.isVisible() && bottom >= event->rect().top()) {
+ QString number = QString::number(blockNumber + 1);
+ painter.setPen(penColor);
+ painter.drawText(0, top, lineNumberArea->width(),
+ fontMetrics().height(), Qt::AlignRight, number);
+ }
+
+ block = block.next();
+ top = bottom;
+ bottom = top + (int)blockBoundingRect(block).height();
+ ++blockNumber;
+ }
+}