How to create customized barcode in qt c++?

Question

I'm using qt 5.15 i have to develop application for Code 128 barcode generator and now I want to reduce the barcode strips. How do I create customized barcode strips?

My code is below,

Code128.h

#ifndef _PROMIXIS_CODE128_H
#define _PROMIXIS_CODE128_H

#include <QString>
#include <QList>
#include <QStringList>

class Code128
{
    typedef char * Symbol;
    enum Symbols { SYM_CodeC=99, SYM_CodeB = 100, SYM_StartA=103, SYM_StartB, SYM_StartC, SYM_Stop, SYM_NA };
    static Code128::Symbol symbols[108];

    enum Mode { MODE_A, MODE_B, MODE_C, IDLE };
    static Symbol symbolCode(quint8 c );
    static void addSymbolCodeChar( char c, QStringList & symbols, int & checksum );
    static void addSymbolCodeInt(quint8 value, QStringList & symbols, int & checksum );
    static quint8 digitCount( const QString & data, int startPos );

public:

    typedef QList<quint8> BarCode;
    static BarCode encode( const QString & data );

};

#endif // _PROMIXIS_CODE128_H

Code128item.h

#ifndef CODE128ITEM_H
#define CODE128ITEM_H

#include <QGraphicsItem>
#include "code128.h"

class Code128Item : public QGraphicsItem
{
    bool m_TextVisible;
    float m_Width;
    float m_Height;
    QString m_Text;
    Code128::BarCode m_Code;
    int m_CodeLength;
    bool m_HighDPI;

public:
    Code128Item();
    void setText ( const QString & text );
    void setWidth( float width );
    void setHeight( float height );
    void setTextVisible( bool visible );
    void setHighDPI(bool highDPI);

    QRectF boundingRect() const;
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget * widget);
};
#endif // CODE128ITEM_H

code128.cpp

#include "code128.h"

Code128::Symbol Code128::symbols[108] = {

    "212222", "222122", "222221", "121223", "121322", "131222", "122213", "122312", "132212", "221213",
    "221312", "231212", "112232", "122132", "122231", "113222", "123122", "123221", "223211", "221132",
    "221231", "213212", "223112", "312131", "311222", "321122", "321221", "312212", "322112", "322211",
    "212123", "212321", "232121", "111323", "131123", "131321", "112313", "132113", "132311", "211313",
    "231113", "231311", "112133", "112331", "132131", "113123", "113321", "133121", "313121", "211331",
    "231131", "213113", "213311", "213131", "311123", "311321", "331121", "312113", "312311", "332111",
    "314111", "221411", "431111", "111224", "111422", "121124", "121421", "141122", "141221", "112214",
    "112412", "122114", "122411", "142112", "142211", "241211", "221114", "413111", "241112", "134111",
    "111242", "121142", "121241", "114212", "124112", "124211", "411212", "421112", "421211", "212141",
    "214121", "412121", "111143", "111341", "131141", "114113", "114311", "411113", "411311", "113141",
    "114131", "311141", "411131", "211412", "211214", "211232", "2331112", ""
};


Code128::Symbol Code128::symbolCode(quint8 c)
{
    if ( c > SYM_Stop )
    {
        return symbols[107];
    }

    return symbols[c];
}



void Code128::addSymbolCodeChar(char c, QStringList &symbols, int &checksum)
{
    // keep characters in valid range.
    if ( c < 32 )
    {
        c = 32;
    }
    if ( c > 126 )
    {
        c = 32;
    }
    quint8 value = (unsigned int)c - 32;
    Code128::Symbol symbol = symbolCode(value);
    symbols += symbol;
    checksum += value * ( symbols.count() == 1 ? 1 : symbols.count() - 1 );
}

void Code128::addSymbolCodeInt(quint8 value, QStringList &symbols, int &checksum)
{
    Code128::Symbol symbol = symbolCode(value);
    symbols += symbol;
    checksum += value * ( symbols.count() == 1 ? 1 : symbols.count() - 1 );
}

quint8 Code128::digitCount(const QString &data, int startPos)
{
    quint8 cnt = 0;

    for ( ;startPos < data.length();startPos++ )
    {
        if ( !data.at(startPos).isDigit() )
        {
            break;
        }
        cnt++;
    }

    cnt &= 0xfe; // only pairs please.
    return cnt;
}

Code128::BarCode Code128::encode(const QString &data)
{
    QStringList symbols;
    int checkSum = 0;

    if ( data.length() > 100 || data.length() == 0 )
    {
        return BarCode();
    }

    int pos = 0;

    Mode mode = IDLE;

    while ( pos < data.length() )
    {
        quint8 dc = digitCount(data, pos);

        if ( dc >= 4 )
        {

            if ( mode != MODE_B )
            {
                addSymbolCodeInt(SYM_CodeB, symbols, checkSum);
                mode = MODE_B;
            }

            dc = dc>>1;
            for ( int i=0; i < dc; i++ )
            {
                QString v = data.mid(pos,2);
                int value = v.toInt();
                addSymbolCodeInt(value, symbols, checkSum);
                pos+=2;
            }
        }
        else
        {
            if ( mode != MODE_B )
            {
                addSymbolCodeInt(SYM_CodeB, symbols, checkSum);
                mode = MODE_B;
            }
            addSymbolCodeChar( data.at(pos).toLatin1(), symbols, checkSum );
            pos++;
        }
    }
    quint8 remainder = checkSum % 103;
    addSymbolCodeInt(remainder, symbols, checkSum);

  /*  quint8 remainder = checkSum % 103;
    addSymbolCodeInt(remainder, symbols, checkSum);
    addSymbolCodeInt(SYM_Stop, symbols, checkSum);*/

    QString code = symbols.join("");
    BarCode b;
    for(int i=0;i<code.length();i++)
    {
        QString v = code.at(i);
        b << v.toInt();
    }

    return b;
}

code128item.cpp

#include "code128item.h"

#include <QPainter>
#include "code128.h"

Code128Item::Code128Item() :
    m_TextVisible(true),
    m_Width(200),
    m_Height(80),
    m_CodeLength(0)
{
}

void Code128Item::setText(const QString &text)
{
    m_Code = Code128::encode(text);
    m_Text = text;

    m_CodeLength = 0;
    for (int i=0;i<m_Code.length();i++)
    {
        m_CodeLength+=m_Code[i];
    }
}

void Code128Item::setWidth(float width)
{
    m_Width = width;
}

void Code128Item::setHeight(float height)
{
    m_Height = height;
}

void Code128Item::setTextVisible(bool visible)
{
    m_TextVisible = visible;
}

void Code128Item::setHighDPI(bool highDPI)
{
    m_HighDPI = highDPI;
}

QRectF Code128Item::boundingRect() const
{
    return QRectF(0,0, m_Width, m_Height);
}

void Code128Item::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    float lineWidth = m_Width / m_CodeLength;


    /*
     * This code tries to fit the barcode right inside the width. If the code
     * is too long this means that the bar width goes below one pixel. Which in
     * turn means we get no barcode. On printers this is not a problem too fast
     * as they have 600 DPI usually. Screens with 96 DPI run out faster.
     *
     */

    if ( !m_HighDPI )
    {
        lineWidth = qRound(lineWidth);
        if ( lineWidth < 1 )
        {
            lineWidth = 1;
        }
    }


    float fontHeight = painter->fontMetrics().height();

    float left = 0;
    for (int i=0;i<m_Code.length();i++)
    {

        float width = m_Code[i] * lineWidth;

        if ( i % 2 == 0 )
        {
            QRectF bar(left, 0, width, m_Height - fontHeight );
            painter->fillRect(bar, Qt::SolidPattern);
        }

        left+= width;
    }

    if ( m_TextVisible )
    {
        QRectF box(0, m_Height - fontHeight , left, fontHeight);
        painter->drawText(box, m_Text, Qt::AlignHCenter | Qt::AlignVCenter);
    }
}

MainWindow.CPP

#include "mainwindow.h"
#include "ui_mainwindow.h"



MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->graphicsView->setScene(&m_Scene);

    m_Barcode = new Code128Item();
    m_Barcode->setWidth( 200 );
    m_Barcode->setHeight( 80 );
    m_Barcode->setPos(0,0);
    m_Barcode->setText("Welcome");
    m_Barcode->setHighDPI(true);
    m_Scene.addItem( m_Barcode );
    m_Scene.update();
    m_Barcode->update();
    ui->lineEdit->setText("Welcome");
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_lineEdit_textChanged(const QString &arg1)
{
    m_Barcode->setText(arg1);
    m_Barcode->update();
    m_Scene.update();
}

void MainWindow::on_actionExit_triggered()
{
    close();
}

The output image

I want this image format reduced barcode stripes

Please give me any suggession to make a customized barcode.

Thank you...