Conventions

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

#include <QStyleOption>
#include <QPainter>
#include <QPaintEvent>
#include <QMouseEvent>
#include <QResizeEvent>
#include "canvas.h"

Canvas::Canvas(QWidget *parent) :
  QWidget(parent)
{
}

void Canvas::paintEvent(QPaintEvent *e)
{
  QPainter painter(this);

  QStyleOption opt;
  opt.initFrom(this);
  this->style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);

  painter.drawImage(e->rect().topLeft(), image);
}

void Canvas::updateImage()
{
  QPainter painter(&image);
  painter.setPen(QColor(Qt::black));
  painter.setRenderHint(QPainter::Antialiasing);
  painter.drawPolyline(m_points.data(), m_points.count());
  this->update();
}

void Canvas::mousePressEvent(QMouseEvent *e)
{
  m_points.clear();
  m_points.append(e->localPos());
  updateImage();
}

void Canvas::mouseMoveEvent(QMouseEvent *e)
{
  m_points.append(e->localPos());
  updateImage();
}

void Canvas::mouseReleaseEvent(QMouseEvent *e)
{
  m_points.append(e->localPos());
  updateImage();
}

void Canvas::resizeEvent(QResizeEvent *e)
{
  QImage newImage(e->size(), QImage::Format_RGB32);
  newImage.fill(Qt::white);
  QPainter painter(&newImage);
  painter.drawImage(0, 0, image);
  image = newImage;
  QWidget::resizeEvent(e);
}

..\..\bin\binarycreator.exe -c config\config.xml -p packages internationalization_installer.exe