QLabel实现柱状条(整理)

之前的实现有一点不让我满意, 就是无法根据layout自动变化大小, 在写UI时需要迁就该Label大小, 不太方便.
整理后的柱状条主要通过在paintEvent中修正QLabel大小解决不能放入layout的问题
不太会解释, 主要还是来看代码吧

pillarbox.h

/**
 *=====================================================================
*    Copyright (c) Power Star, Inc.  All rights reserved.
 *---------------------------------------------------------------------
 *    File Name: pillarbox.h
 *
 *    Description:
 *        draw pillar with rectangle background
 *
 *    History:
 *        2012.04.22    ryan.wang    Initial version
 *
 *=====================================================================
**/
#ifndef _pillarbox_h_
#define _pillarbox_h_
#include <QWidget>
#include <QLabel>
#include <QEvent>
#include <QPaintEvent>

class PillarBox : public QWidget
{
    Q_OBJECT
public:
    PillarBox( QWidget *parent );
    ~PillarBox();

    void resizePillar( int width=0,int height=0 );
    void changePartsDivided( int parts );
    void updatepillar( int val, QColor clr=Qt::green );

protected:
    virtual void paintEvent(QPaintEvent* event);    // 这是重载QWidget的方法

private:
    void setfgcolor( QColor clr );
    void initialize();

    QLabel *labbg;
    QLabel *labfg;
    int parts_divided;
    int m_value;
};

#endif /* _pillarbox_h_ */

pillarbox.cpp

/**
 *=====================================================================
*    Copyright (c) Power Star, Inc.  All rights reserved.
 *---------------------------------------------------------------------
 *    File Name: pillarbox.cpp
 *
 *    Description:
 *        draw pillar with rectangle background
 *
 *    History:
 *        2012.04.22    ryan.wang    Initial version
 *
 *=====================================================================
**/
#ifndef _pillarbox_cpp_
#define _pillarbox_cpp_
#include "pillarbox.h"
#include <QDebug>

//构造函数
PillarBox::PillarBox( QWidget *parent ): QWidget(parent)
{
    m_value = 0;
    initialize();
}

//虚构函数
PillarBox::~PillarBox()
{
    if ( labbg )
        delete labbg;
    if ( labfg )
        delete labfg;
}

//初始化，创建两个label
void PillarBox::initialize()
{
    labbg = NULL;
    labfg = NULL;

    //label background, that with frame box
    labbg = new QLabel(this);

    labbg->setAlignment( Qt::AlignHCenter|Qt::AlignTop );
    labbg->setFrameShape( QFrame::Box );

    //label foreground, that without frame box but with color filled
    labfg = new QLabel(this);
    labfg->setAutoFillBackground( true );

    //default, the pillar be divided into 100 parts
    parts_divided = 100;

    //default, set the pillar width with 20 pixels
    resizePillar(20);

    //default, set the pillar color with Qt::green
    setfgcolor( Qt::green );
}

//改变柱状条尺寸，即改变labbg尺寸
void PillarBox::resizePillar( int width,int height )
{
    if( 0 != width )
        labbg->setFixedWidth(width);

    if( 0 != height )
        labbg->setFixedHeight( height );

    updatepillar(m_value);
}

void PillarBox::changePartsDivided( int parts )
{
    parts_divided = parts;
}
void PillarBox::updatepillar( int val, QColor clr )
{
    int new_y,new_h; //new height & y_position for labfg
    int height,width;

    if( val > parts_divided )
        val = parts_divided;

    m_value = val;

    //if( this->width() > labbg->sizeHint().width() )
    //    width = labbg->sizeHint().width();
    //else
        width = this->width()-1;

    //if( this->height() > labbg->sizeHint().height() )
    //            height = labbg->sizeHint().height();
    //    else
    height = this->height();
    //labbg->setGeometry(QRect(0,0,this->width(),this->height()));
    labbg->resize( width, height );

    if( val )
        labbg->setText(QString::number(val));
    else
        labbg->setText(QString(""));

    new_h = val*height/parts_divided;
    new_y = height - new_h;
    labfg->setGeometry( QRect(1,new_y,width-2,new_h-1) );

    //qDebug() << "pillarbox size:";
    //qDebug() << "    this:" << this->width() << "," << this->height();
    //qDebug() << "    bg hint" << labbg->sizeHint().width() << labbg->sizeHint().height();
    //qDebug() << "    fg cur:" << width << height;
    setfgcolor( clr );

}

void PillarBox::setfgcolor( QColor clr )
{
    QPalette palette;
    //QColor clr = Qt::green;

    palette = labfg->palette();
    // clr = QColor::fromRgb(240,240,240);//QColorDialog::getColor(Qt::green, this);
    palette.setColor(labfg->backgroundRole(), clr);
    palette.setColor(labfg->foregroundRole(), clr);
    labfg->setPalette(palette);
}

void PillarBox::paintEvent(QPaintEvent* event)
{
    //qDebug() << "paintEvent" << event->rect();
    resizePillar(event->rect().width(),event->rect().height());
}


#endif /* _pillarbox_cpp_ */