editor.cpp

#include "editor.h"
#include "linenumberarea.h"
#include <QPainter>
#include <QTextBlock>

Editor::Editor(QWidget *parent) : QPlainTextEdit(parent) {

    lineNumberArea = new LineNumberArea(this);
    fontSize = 14;

    connect(this, &Editor::blockCountChanged, this, &Editor::updateLineNumberAreaWidth);
    connect(this, &Editor::updateRequest, this, &Editor::updateLineNumberArea);
    connect(this, &Editor::cursorPositionChanged, this, &Editor::highlightCurrentLine);

    updateLineNumberAreaWidth(0);
    highlightCurrentLine();
}

int Editor::lineNumberAreaWidth() {

    int digits = 5;
    /*int max = qMax(1, blockCount());
    while (max >= 10) {
        max /= 10;
        ++digits;
    }*/

    int space = 3 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * digits;

    return space;
}

void Editor::updateLineNumberAreaWidth(int /* newBlockCount */) {

    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}

void Editor::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 Editor::resizeEvent(QResizeEvent *e) {

    QPlainTextEdit::resizeEvent(e);

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

void Editor::lineNumberAreaPaintEvent(QPaintEvent *event) {

    QPainter painter(lineNumberArea);
    painter.fillRect(event->rect(), QColor(39,40,42));

    QTextBlock block = firstVisibleBlock();
    int blockNumber = block.blockNumber();
    int top = qRound(blockBoundingGeometry(block).translated(contentOffset()).top());
    int bottom = top + qRound(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(QColor(197,197,197));
            painter.setFont(QFont("roboto", fontSize));
            painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
                             Qt::AlignCenter, number);
        }

        block = block.next();
        top = bottom;
        bottom = top + qRound(blockBoundingRect(block).height());
        ++blockNumber;
    }
}

void Editor::highlightCurrentLine() {
    QList<QTextEdit::ExtraSelection> extraSelections;

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

        QColor lineColor = QColor(39,40,42).lighter(130);

        selection.format.setBackground(lineColor);
        selection.format.setProperty(QTextFormat::FullWidthSelection, true);
        selection.cursor = textCursor();
        selection.cursor.clearSelection();
        extraSelections.append(selection);
    }

    setExtraSelections(extraSelections);
}

void Editor::setFontSize(int fontSize) {
    this->fontSize = fontSize;
    QFont font = this->font();
    font.setPointSize(this->fontSize);
    this->setFont(font);
}

int Editor::getFontSize() {
    return this->fontSize;
}