qt实现小票打印

1.需求

需要实现订单结算后的小票打印，要求能打印商品数据和结算数据及将小票号打印成条码，退货或查询时能通过扫描枪扫描条码快速查询到订单信息

2.解决

1.通过将数据转化为html后调用qt进行打印，打印机无法打印img标签中的条码

2.通过将数据转化为html，将条码直接绘制的方法实现了需求

3.代码

Barcode.h

// Barcode.h: interface for the CBarcode class.////  Copyright 2002 Neil Van Eps////////////////////////////////////////////////////////////////////////#ifndef BARCODE_H#define BARCODE_H#include <QString>#include <QPainter>// bblib.h//  must put build number define on third line#define BUILDNUM 7//////  Copyright 2002 Neil Van Eps//enum Symbology{    RATIONALCODABAR,    TRADITIONALCODABAR,    I2OF5,    CODE39,    COD128,    UPCEAN,    CODE93};#define     COLORWHITE  0x00FFFFFF#define     COLORBLACK  0x00000000class CBarcode  {public:    CBarcode();    void    LoadData(QString csMessage, const QString &strImagePath, double dNarrowBar, double dFinalHeight, int nStartingXPixel, int nStartingYPixel, double dRatio = 1.0);    virtual void DrawBitmap(QPainter *painter = nullptr) = 0;    //virtual void BitmapToClipboard() = 0;    virtual ~CBarcode();    long    GetBarcodePixelWidth();    long    GetBarcodePixelHeight();protected:    QString m_csMessage;    //HDC       m_hDC;         QString m_strImagePath;    long    m_nFinalBarcodePixelWidth;    long    m_nNarrowBarPixelWidth;    long    m_nPixelHeight;    long    m_nStartingXPixel;    long    m_nStartingYPixel;    long    m_nSymbology;    long    m_nWideBarPixelWidth;    virtual void DrawPattern(QString csPattern, QPainter *painter) = 0;};#endif // !defined(AFX_BARCODE_H__C5D7FCDA_5C8F_4244_AF95_33D6FA93F8EB__INCLUDED_)

Barcode.cpp

// Barcode.cpp: implementation of the CBarcode class.////  Copyright 2002 Neil Van Eps////////////////////////////////////////////////////////////////////////#include "Barcode.h"//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CBarcode::CBarcode(){}CBarcode::~CBarcode(){}////////////////////////////////////////////////////////////////////////////////////////  Name://      LoadData()////  Description://////  Arguments://////  Return://////  Called by:////////////////////////////////////////////////////////////////////////////////////////void CBarcode::LoadData(QString csMessage, const QString &strImagePath, double dNarrowBar, double dFinalHeight, int nStartingXPixel, int nStartingYPixel, double dRatio){    int     i, nXAxisDpi, nYAxisDpi, nTemp;    char    c;    // values that can be saved without translation    m_csMessage = csMessage;    m_nStartingXPixel = nStartingXPixel;//nStartingXPixel*10;    m_nStartingYPixel = nStartingYPixel;//nStartingYPixel*10;    //m_hDC = pDC;    m_strImagePath = strImagePath;    // load the final attributes that depend on the device context    m_nPixelHeight = (int)dFinalHeight;//(int)((10*dFinalHeight) + 0.5);    m_nNarrowBarPixelWidth = (int)(dNarrowBar + 0.5);    m_nWideBarPixelWidth = (int)(dRatio*m_nNarrowBarPixelWidth);    switch (m_nSymbology)    {    case CODE39:        // get final character width        //nTemp = m_csMessage.GetLength() + 2;        nTemp = m_csMessage.length() + 2;        // add message        m_nFinalBarcodePixelWidth = nTemp * ((3 * m_nWideBarPixelWidth) + (7 * m_nNarrowBarPixelWidth));        break;    case COD128:        // get final character width        //nTemp = m_csMessage.GetLength();        nTemp = m_csMessage.length();        m_nFinalBarcodePixelWidth = ((nTemp * 11) + 35)*m_nNarrowBarPixelWidth;        break;    case CODE93:        // get final character width        //nTemp = m_csMessage.GetLength();        nTemp = m_csMessage.length();        m_nFinalBarcodePixelWidth = (((nTemp + 4) * 9) + 1)*m_nNarrowBarPixelWidth;    case UPCEAN:    case TRADITIONALCODABAR:        break;    }    return;}long CBarcode::GetBarcodePixelHeight(){    return m_nPixelHeight;}long CBarcode::GetBarcodePixelWidth(){    return m_nFinalBarcodePixelWidth;}

Code39.h

// Code39.h: interface for the CCode39 class.////  Copyright 2002 Neil Van Eps////////////////////////////////////////////////////////////////////////#ifndef CODE39_H#define CODE39_H#include "Barcode.h"class CCode39 : public CBarcode  {public:    //void BitmapToClipboard();    void DrawBitmap(QPainter *painter = nullptr);    CCode39();    virtual ~CCode39();private:    void    DrawPattern(QString csPattern, QPainter *painter);    QString RetrievePattern(char c);};#endif // !defined(AFX_CODE39_H__6FE17747_EADF_4E89_9DCF_7688B04897BC__INCLUDED_)

Code39.cpp

// Code39.cpp: implementation of the CCode39 class.////  Copyright 2002 Neil Van Eps////////////////////////////////////////////////////////////////////////#include "Code39.h"#include <QPainter>#include <QImage>#include <QPen>#include <QChar>//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CCode39::CCode39(){    // code 39    m_nSymbology = CODE39;}CCode39::~CCode39(){}////////////////////////////////////////////////////////////////////////////////////////  Name://      DrawBitmap()////  Description://      draws a barcode using the previously loaded data////  Arguments://      none////  Return://      void////  Called by://      public class interface////////////////////////////////////////////////////////////////////////////////////////这里有一个问题 我怎么搞到图片大小呢void CCode39::DrawBitmap(QPainter *painter){    int     i;    QString csCurrentPattern;    DrawPattern(RetrievePattern('*'), painter);    // draw each character in the message    for (i=0;i<m_csMessage.length();i++)        DrawPattern(RetrievePattern(m_csMessage.at(i).toLatin1()), painter);    // draw stop character, also an asterisk    DrawPattern(RetrievePattern('*'), painter);    return;}////////////////////////////////////////////////////////////////////////////////////////  Name://      DrawPattern()////  Description://      draws the passed character pattern at the end of the barcode////  Arguments://      CString     csPattern   -   the bar pattern to draw////  Return://      void////  Called by://      CRationalCodabar::DrawBitmap()//////////////////////////////////////////////////////////////////////////////////////void CCode39::DrawPattern( QString csPattern ,QPainter *painter){    int         i, nXPixel, nYPixel, nTempWidth;    QPen penbar = QPen(Qt::black);    penbar.setWidth(1);    penbar.setStyle(Qt::SolidLine);    QPen penspace = QPen(Qt::white);    penspace.setWidth(1);    penspace.setStyle(Qt::SolidLine);    painter->setRenderHint(QPainter::Antialiasing, true);    // initialize X pixel value    nXPixel = m_nStartingXPixel;    for (i = 0; i < csPattern.length(); i++)    {        // decide if narrow or wide bar        if (csPattern.at(i) == L'n')            nTempWidth = m_nNarrowBarPixelWidth;        else            nTempWidth = m_nWideBarPixelWidth;        // X value for loop        for (nXPixel = m_nStartingXPixel; nXPixel < m_nStartingXPixel + nTempWidth; nXPixel++)        {            if (i % 2 == 0)                painter->setPen(penbar);            else                painter->setPen(penspace);            painter->drawLine(nXPixel, m_nStartingYPixel, nXPixel, m_nStartingYPixel + m_nPixelHeight);        }        // advance the starting position        m_nStartingXPixel += nTempWidth;    }    //    //oDC.SelectObject(hPenOld);    //::DeleteObject(hPenBar);    //::DeleteObject(hPenSpace);    // detach from the device context    //oDC.Detach();    return;}////////////////////////////////////////////////////////////////////////////////////////  Name://      RetrievePattern()////  Description://      retrieves the bar pattern for a given character////  Arguments://      char    cInputCharacter -   the input character to get the bar pattern for////  Return://      CString -   the bar pattern for the input character////  Called by://      CRationalCodabar::DrawBitmap()//////////////////////////////////////////////////////////////////////////////////////QString CCode39::RetrievePattern(char c){    QString csCharPattern;    switch (c)    {        case '1':            csCharPattern = "wnnwnnnnwn";            break;        case '2':            csCharPattern = "nnwwnnnnwn";            break;        case '3':            csCharPattern = "wnwwnnnnnn";            break;        case '4':            csCharPattern = "nnnwwnnnwn";            break;        case '5':            csCharPattern = "wnnwwnnnnn";            break;        case '6':            csCharPattern = "nnwwwnnnnn";            break;        case '7':            csCharPattern = "nnnwnnwnwn";            break;        case '8':            csCharPattern = "wnnwnnwnnn";            break;        case '9':            csCharPattern = "nnwwnnwnnn";            break;        case '0':            csCharPattern = "nnnwwnwnnn";            break;        case 'A':            csCharPattern = "wnnnnwnnwn";            break;        case 'B':            csCharPattern = "nnwnnwnnwn";            break;        case 'C':            csCharPattern = "wnwnnwnnnn";            break;        case 'D':            csCharPattern = "nnnnwwnnwn";            break;        case 'E':            csCharPattern = "wnnnwwnnnn";            break;        case 'F':            csCharPattern = "nnwnwwnnnn";            break;        case 'G':            csCharPattern = "nnnnnwwnwn";            break;        case 'H':            csCharPattern = "wnnnnwwnnn";            break;        case 'I':            csCharPattern = "nnwnnwwnnn";            break;        case 'J':            csCharPattern = "nnnnwwwnnn";            break;        case 'K':            csCharPattern = "wnnnnnnwwn";            break;        case 'L':            csCharPattern = "nnwnnnnwwn";            break;        case 'M':            csCharPattern = "wnwnnnnwnn";            break;        case 'N':            csCharPattern = "nnnnwnnwwn";            break;        case 'O':            csCharPattern = "wnnnwnnwnn";            break;        case 'P':            csCharPattern = "nnwnwnnwnn";            break;        case 'Q':            csCharPattern = "nnnnnnwwwn";            break;        case 'R':            csCharPattern = "wnnnnnwwnn";            break;        case 'S':            csCharPattern = "nnwnnnwwnn";            break;        case 'T':            csCharPattern = "nnnnwnwwnn";            break;        case 'U':            csCharPattern = "wwnnnnnnwn";            break;        case 'V':            csCharPattern = "nwwnnnnnwn";            break;        case 'W':            csCharPattern = "wwwnnnnnnn";            break;        case 'X':            csCharPattern = "nwnnwnnnwn";            break;        case 'Y':            csCharPattern = "wwnnwnnnnn";            break;        case 'Z':            csCharPattern = "nwwnwnnnnn";            break;        case '-':            csCharPattern = "nwnnnnwnwn";            break;        case '.':            csCharPattern = "wwnnnnwnnn";            break;        case ' ':            csCharPattern = "nwwnnnwnnn";            break;        case '*':            csCharPattern = "nwnnwnwnnn";            break;        case '$':            csCharPattern = "nwnwnwnnnn";            break;        case '/':            csCharPattern = "nwnwnnnwnn";            break;        case '+':            csCharPattern = "nwnnnwnwnn";            break;        case '%':            csCharPattern = "nnnwnwnwnn";            break;    }    return csCharPattern;}////////////////////////////////////////////////////////////////////////////////////////  Name://      BitmapToClipboard()////  Description://      puts the specified bitmap on the clipboard////  Arguments://      none////  Return://      void////  Called by://      public class interface - called by users of the class//////////////////////////////////////////////////////////////////////////////////////#if 0void CCode39::BitmapToClipboard(){    CDC                 memDC;    CBitmap             oBitmap;    memDC.CreateCompatibleDC(NULL);    m_hDC = memDC.GetSafeHdc();    // create compatible, correctly sized bitmap    oBitmap.CreateCompatibleBitmap(&memDC,m_nFinalBarcodePixelWidth,m_nPixelHeight);    // select our bitmap into the device context    CBitmap * oldbm = memDC.SelectObject(&oBitmap);    // turn area white - stock black bitmap is selected    memDC.BitBlt(0,0,m_nFinalBarcodePixelWidth,m_nPixelHeight,NULL,0,0,WHITENESS);    // draw bitmap into memory device context    DrawBitmap();    // put bitmap on clipboard    ::OpenClipboard(NULL);    ::EmptyClipboard();    ::SetClipboardData(CF_BITMAP, oBitmap.m_hObject);    ::CloseClipboard();    //  deselect object out of device context    memDC.SelectObject(oldbm);    // make sure bitmap not deleted with CBitmap object         oBitmap.Detach();    return;}#endif

mytest.cpp中的调用

QPrintDialog dialog(&m_printer, this);if (dialog.exec() == QDialog::Accepted){    QPainter painter(&m_printer);    CCode39 mycode;    mycode.LoadData(QString("ST-1435887826818763"), QString("pos.jpg"), 1, 30, 5, 5, 3.0);    mycode.DrawBitmap(&painter);}

4.参考

Barcode.h Barcode.cpp Code39.h Code39.cpp是codeproject上的代码用mfc写的 我改动了下