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How to generate the barcode 128 in Qpixmap ?



  • Hi!
    How to generate the barcode 128 in Qpixmap ?


  • Lifetime Qt Champion

    Hi
    I would find a library to use - unless you are feeling ultra hardcore and want to make your own encoder.

    This one is pretty nice and supports Qt directly.
    https://github.com/ftylitak/qzxing

    Or you could take this and tweak it to do what you want
    https://github.com/fhunleth/code128
    Its raw c but should be easy to make it work with pixmap



  • I tried using a font to encode the barcode, with the phone unable to recognize it. Do you know how to fix it?



  • Found a class for encoding. Please help to use it
    .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;
    
        /* Code128 encoding of data
         *
         * Accepts characters in the basic ASCII set (ASCII values 32-126).
         * Maximum length is 100 characters, though I doubt any bar code
         * scanner will read that.
         *
         * Returns a list of bar widths. For example 2 3 1 4. This would mean
         * to draw a set of bars with widths 2, 3, 1 and 4. The odd numbered bars
         * are dark and the even numbered bars a light. 4 is the maximum width
         * returned.
         */
        static BarCode encode( const QString & data );
    
    };
    
    #endif // _PROMIXIS_CODE128_H
    

    .cpp

    /*
    
        Code128
    
        Code 128 is a very high-density barcode symbology. It is used
        for alphanumeric or numeric-only barcodes. This implementation
        can encode all 128 characters of ASCII. The implementation can
        switch between mode B and mode C to compress numbers.
    
        https://en.wikipedia.org/wiki/Code_128
    
    
        The MIT License (MIT)
    
        Copyright (c) 2013 Promixis, LLC
    
        Permission is hereby granted, free of charge, to any person obtaining a copy
        of this software and associated documentation files (the "Software"), to deal
        in the Software without restriction, including without limitation the rights
        to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        copies of the Software, and to permit persons to whom the Software is
        furnished to do so, subject to the following conditions:
    
        The above copyright notice and this permission notice shall be included in
        all copies or substantial portions of the Software.
    
        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
        AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        THE SOFTWARE.
    
    */
    
    #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_C )
                {
                    if ( mode == IDLE )
                    {
                        addSymbolCodeInt(SYM_StartC, symbols, checkSum);
                    }
                    else
                    {
                        addSymbolCodeInt(SYM_CodeC, symbols, checkSum);
                    }
                    mode = MODE_C;
                }
    
                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 )
                {
                    if ( mode == IDLE )
                    {
                        addSymbolCodeInt(SYM_StartB, symbols, checkSum);
                    }
                    else
                    {
                        addSymbolCodeInt(SYM_CodeB, symbols, checkSum);
                    }
                    mode = MODE_B;
                }
                addSymbolCodeChar( data.at(pos).toLatin1(), symbols, checkSum );
                pos++;
            }
        }
    
        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;
    }
    
    


  • This library not works https://github.com/ftylitak/qzxing, not work encoder.



  • @Mihaill QZXing encoder support only Qr Codes for now so it will not suit you.



  • Clearly. But maybe you know how to encode using a font?


  • Lifetime Qt Champion

    @Mihaill said in How to generate the barcode 128 in Qpixmap ?:

    _PROMIXIS_CODE128_H

    Hi
    There is an example included
    https://github.com/promixis/Code128/blob/master/src/mainwindow.cpp
    did you try it ?



  • @mrjj I tried. It draws on QGraphicsScene. I need a picture or text to print. I don't need the output on the screen.


  • Lifetime Qt Champion

    ok but you can render the scene to an image.

    QImage image(fn);
    QPainter painter(&image);
    painter.setRenderHint(QPainter::Antialiasing);
    scene.render(&painter);
    image.save("file_name.png")
    

    and you dont need to show the scene to user etc.



  • @mrjj It's dont works:

        QImage image;
        QPainter painter(&image);
        painter.setRenderHint(QPainter::Antialiasing);
        m_Scene.render(&painter);
    

    This works, but the first line is obtained more rest. I don't understand why. And there is a line on top. Please tell me how to remove it.

        QRectF r =m_Barcode->boundingRect();
        QPixmap pixmap(r.width(), r.height());
        pixmap.fill(QColor(0, 0, 0, 0));
        QPainter painter(&pixmap);
        //painter.setBrush(QBrush(QColor(0, 0, 0, 0)));
        painter.drawRect(r);
        m_Scene.render(&painter);
        //m_Scene.r
        //m_Scene.render(&painter, QRectF(), m_Barcode->sceneBoundingRect());
        painter.end();
    

    2.png



  • It's work, but the barcode is not placed all and therefore not read the picture. How do I know the size of the barcode?

        m_Barcode = new Code128Item();
            m_Barcode->setWidth( 200 );
            m_Barcode->setHeight( 80 );
            m_Barcode->setPos(0,0);
            m_Barcode->setText("Promixis");
            m_Scene.addItem( m_Barcode );
            m_Scene.update();
            m_Barcode->update();
        
        //    QRectF r =m_Barcode->boundingRect();
        //    QPixmap pixmap(r.width(), r.height());
            QPixmap pixmap(m_Barcode->boundingRect().width(), 80);
            pixmap.fill(QColor(0, 0, 0, 0));
            QPainter painter(&pixmap);
            //painter.setBrush(QBrush(QColor(0, 0, 0, 0)));
            //painter.drawRect(r);
            m_Scene.render(&painter);
            //m_Scene.r
            //m_Scene.render(&painter, QRectF(), m_Barcode->sceneBoundingRect());
            painter.end();
    

  • Lifetime Qt Champion

    Hi
    Im not sure what
    ' but the barcode is not placed all and therefore not read the picture'
    means ?

    The rendered image is cut off ?

    Anyway, did check out
    void Code128Item::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
    in code128item.cpp

    It seems it would be easy to make a version that would just draw to an image as you want.
    Its not really tied to QGraphicsScene and would work in a normal paintEvent.



  • @mrjj Yes, the rendered image is clipped.

    If you do so, the image is also cropped. Need as the otherwise set width QPixamp.

        QPixmap pixmap(m_Barcode->boundingRect().width(), 80);
        pixmap.fill(QColor(0, 0, 0, 0));
        QPainter painter(&pixmap);
        //painter.setBrush(QBrush(QColor(0, 0, 0, 0)));
        //painter.drawRect(r);
    //    m_Scene.render(&painter);
    //    //m_Scene.render(&painter, QRectF(), m_Barcode->sceneBoundingRect());
    //    painter.end();
    
        QWidget widget;
        QStyleOptionGraphicsItem styleOptionGraphicsItem ;
        m_Barcode->paint(&painter, &styleOptionGraphicsItem, &widget); //(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
    

  • Lifetime Qt Champion

    Hi,

    Take the code inside that method and apply it on a QImage.


  • Lifetime Qt Champion

    Hi
    It turns out its not even using the other parameters (QStyleOptionGraphicsItem , widget) so you can directly just call it to paint on pixmap.

       QPixmap pix(200, 80); // match the actual values if u change them
        QPainter paint(&pix);
        pix.fill( Qt::white );
        m_Barcode->paint(&paint,nullptr, nullptr);
        pix.save("e:/test.png");
    

    and get a perfect sized image.

    alt text



  • @mrjj Strange, but I have such code clips picture.2.png



  • The program or draws normally, or increases in 1,25 depending on the text. Why so?


  • Lifetime Qt Champion

    @Mihaill
    Very strange. it works flawless here.
    You have the default sizes ?

       m_Barcode = new Code128Item();
        m_Barcode->setWidth( 200 );
        m_Barcode->setHeight( 80 );
        m_Barcode->setPos(0,0);
        m_Barcode->setText("Promixis");
    
        QPixmap pix(200, 80); // MUST match the setWidth, setHeight
        QPainter paint(&pix);
        pix.fill( Qt::white );
        m_Barcode->paint(&paint,nullptr, nullptr);
        pix.save("e:/test.png");
    

  • Lifetime Qt Champion

    @Mihaill said in How to generate the barcode 128 in Qpixmap ?:

    the program or draws normally, or increases in 1,25 depending on the text. Why so?

    I dont know what this means ?

    The images becomes bigger with bigger text ?
    That is normal for barcode 128.
    The data limit is normally 48 chars but its not hard limit and it will expand the barcode to the point where its too wide for pratical use.



  • I understand that the number of sticks is changing. But the pixel size of the image changes by 1.25 times or 1. And the picture is cropped and the barcode is not correct.
    2.png

    2.png
    Here 2 pictures of the same size, but one the size of the shaded zone higher in 1,25. Why so?


  • Lifetime Qt Champion

    @Mihaill
    Hi
    the programmer made it so, it seems.

    void Code128Item::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
    {
        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;
            }
        }
    
    

    so it tries to fit in area and might alter the lineWidth. and hence the barcode has a different size.

    try
    m_Barcode->setHighDPI(true);

    alt text



  • Thanks, now works fine


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