How to generate the barcode 128 in Qpixmap ?

Mihaill

Hi!
How to generate the barcode 128 in Qpixmap ?

mrjj

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

Mihaill

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

Mihaill

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;
}

Mihaill

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

favoritas37

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

Mihaill

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

mrjj

@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 ?

Mihaill

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

mrjj

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.

Mihaill

@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();

Mihaill

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();

mrjj

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.

Mihaill

@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)

SGaist

Hi,

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

mrjj

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

Mihaill

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

Mihaill

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

mrjj

@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");

mrjj

@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.

Mihaill

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.

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

mrjj

@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

Mihaill

Thanks, now works fine

Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

How to generate the barcode 128 in Qpixmap ?