PushButton的简单封装，主要是背景图像自适应button大小和文字显示,该如何处理

#pragma once
#include <QPushButton>
#include <QImage>
#include <QPixmap>
#include <QSize>
#include <QIcon>
#include <QPaintEvent>
#include <QPainter>
#include <QColor>
class IButton :
    public QPushButton
{
    Q_OBJECT
public:
    IButton(QWidget * parent = 0);
    ~IButton(void);
    void setBlack(QString & name);
    void wordshow(QString &show_word);
    void set_font_size();
public:
    QString word_;
protected:
    QImage *image_;
    QIcon *icon_;
    QPixmap *pixmap_;
protected:
    void paintEvent( QPaintEvent * event );
};

#include "IButton.h"

IButton::IButton(QWidget * parent)
    :QPushButton(parent)
{
    int h;
    QPalette palette_;// = palette();
    palette_ = palette();
    
    QFont font_ = font();
    
    image_ = new QImage();
    pixmap_ = new QPixmap();
    icon_ = new QIcon();
    word_.clear();
    h = size().width()>size().height()?size().height():size().width();
    font_.setPointSize(h-h/3);
    setFont(font_);
    palette_.setColor(QPalette::Active,QPalette::ButtonText,QColor(255,255,255));
    setPalette(palette_);
    setFocusPolicy(Qt::NoFocus);    
}

IButton::~IButton(void)
{
    delete []image_;
    delete []pixmap_;
    delete icon_;
}
void IButton::setBlack(QString & name)
{
    image_->load(name);
    QSize s = size();//the button you would to set the back;
    QImage i2 = image_->scaled(s);//adapt the size of button;
    *pixmap_ = QPixmap::fromImage(i2);//this is the static function
    setIcon(QIcon(*pixmap_));
    setIconSize(s);
}
void IButton::paintEvent(QPaintEvent * event)
{
    QPushButton::paintEvent(event) ;
    QPainter painter(this) ; 
    if (!word_.isEmpty())
    {
        painter.drawText(rect(),Qt::AlignCenter,word_);
    }    
    
    
    event->accept();
    return ;
}
void IButton::wordshow(QString &show_word)
{
    word_ = show_word;
}
void IButton::set_font_size()
{

}