Easy Beginner's Environment in QT Code

#include "binarynumber.h"
#include "settings.h"

BinaryNumber::BinaryNumber()
    : QWidget()
{
    width = 16;
    charSize = ebe["font_size"].toInt();
    highlightLow = -1;
    highlightHigh = -1;
    clear();
    underline = false;
    overline = false;
}

void BinaryNumber::clear()
{
    for (int i = 0; i < 80; i++) chars[i] = ' ';
}

void BinaryNumber::setUnderline()
{
    underline = true;
}

void BinaryNumber::setOverline()
{
    overline = true;
}

void BinaryNumber::setBits(int x, int w, int s)
{
    width = w;
    show = s >= 0 ? s : w;
    for (int bit = 0; bit <= w; bit++) {
        if (bit >= show) {
            chars[bit] = ' ';
        } else {
            chars[bit] = (x >> bit) & 1 ? '1' : '0';
        }
    }
}

void BinaryNumber::setBit(int x, int bit)
{
    chars[bit] = x & 1 ? '1' : '0';
}

void BinaryNumber::setNibbles(int x, int w, int s)
{
    int nibble;
    width = w;
    show = s >= 0 ? s : w;
    for (int bit = 0; bit <= w; bit++) {
        if (bit >= show) {
            chars[bit] = ' ';
        } else {
            nibble = (x >> (bit * 4)) & 0xf;
            chars[bit] = nibble > 9 ? 'A' + nibble - 10 : '0' + nibble;
        }
    }
}

void BinaryNumber::setText(QString s, int /* w */)
{
    int n = s.length();

    clear();
    for (int i = 0; i < n; i++) {
#if QT_VERSION >= 0x050000
        chars[n-i-1] = s[i].toLatin1();
#else
        chars[n - i - 1] = s[i].toAscii();
#endif
    }
}

QSize BinaryNumber::sizeHint() const
{
    int charSize = ebe["font_size"].toInt();
    return (QSize(charSize * width, underline ? charSize + 8 : charSize + 4));
}

void BinaryNumber::setHighlight(int l, int h)
{
    highlightLow = l;
    highlightHigh = h >= 0 ? h : l;
}

void BinaryNumber::paintEvent(QPaintEvent * /* event */)
{
    QString t;
    int x;
    int y;

    QPainter painter(this);
    //painter.setPen(pen);
    //painter.setBrush(brush);
    //painter.setRenderHint(QPainter::AntiAliasing,true);
    QFont font("courier");
    charSize = ebe["font_size"].toInt();
    font.setPixelSize(charSize + 3);
    font.setBold(true);
    painter.setFont(font);

    int height;
    height = underline ? charSize + 8 : charSize + 4;
    if (overline) height += 4;
    setFixedSize(charSize * width, height);
    y = 2 + charSize;
    if (overline) y = 5 + charSize;
    for (int i = 0; i <= width; i++) {
        t = QChar(chars[i]);
        x = charSize / 4 + charSize * (width - i - 1);
        if (i >= highlightLow && i <= highlightHigh) {
            painter.setPen(QColor("red"));
            painter.drawText(x, y, t);
            painter.setPen(QColor("black"));
        } else {
            painter.drawText(x, y, t);
        }
    }
    QPen pen(QColor("black"));
    pen.setWidth(2);
    painter.setPen(pen);
    if (underline) {
        y = charSize + 7;
        painter.drawLine((width - show) * charSize, y, width * charSize, y);
    }
    if (overline) {
        y = 3;
        painter.drawLine((width - show) * charSize, y, width * charSize, y);
    }
}