Code de la classe fenetrePerso.cpp

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

QPushButton *bouton;

fenetrePerso::fenetrePerso() : QWidget() {
    setFixedSize(200, 100);

    m_slider = new QSlider(Qt::Horizontal, this);
    m_slider->setGeometry(10, 60, 150, 20);
    QObject::connect(m_slider, SIGNAL(valueChanged(int)), this, SLOT(changerTaille(int)));
}
void fenetrePerso::changerTaille(int hauteur) {
    setFixedSize(200, hauteur);
}