基于Qt的收银点餐系统之小票打印（二）

本篇给出基于QPrinter+QPainter的小票打印代码。

一、说明

类ReceiptPainter继承了QPainter，专门用于打印小票，在方法doCustomerPrint()中进行打印。
其成员变量OrderDetailBean* orderDetail 是订单的详细信息。包含有：
时间、编号、总价、收款、找零，以及订单中每样商品的详细信息：名称、数量、单价
main函数中的调用代码：

QString targetPrinterName = "XX打印机";QPrinterInfo targetPrinter = QPrinterInfo::printerInfo(targetPrinterName);QPrinter printer(targetPrinter);ReceiptPainter rPainter(&printer,orderDetailItem,shopName);

在使用QPrinter+QPainter进行小票打印中，打印内容以及排版在QPainter中进行设置。由下面代码将看出，与其说QPainter是对文字进行了排版，还不如说是QPainter对“矩形”进行了排版，然后才在各个矩形中填上了文字。这主要是由QPainter绘制文字的方式决定的。

QPainter::drawText ( const QRectF &rectangle,  const QString & text )

参考文章：http://www.qter.org/portal.php?mod=view&aid=40

二、代码

ReceiptPainter.h

#ifndef RECEIPTPAINTER_H#define RECEIPTPAINTER_H#include <QPaintEvent>#include <QtPrintSupport/QPrinter>#include <QtPrintSupport/QPrintDialog>#include <QPainter>#include <QWidget>#include <QList>#include <QString>#include <QChar>#include <QVector>#include "orderdetailbean.h"#include "ordergoodsbean.h"class ReceiptPainter : public QPainter{public:    ReceiptPainter(QPrinter*,OrderDetailBean*,QString);    ~ReceiptPainter();    void doCustomerPrint();    QString getSeperator(double);private:    //下面的数字单位是 像素    // 字体大小    enum {FONT_SIZE_NORMAL = 10,FONT_SIZE_MIDDLE = 12,FONT_SIZE_BIG = 20};  //正常、中等、大    //预留尺寸    enum {TOTAL_LENGTH = 140,GOODS_LENGTH = 40,GOODS_NUM_LENGTH = 40}; //小票每一行的可以打印的位数、商品名称的预留长度、商品数量的预留长度    OrderDetailBean* orderDetail;  //订单的详细信息：时间、编号、总价、收款、找零，以及订单中每样商品的详细信息：名称、数量、单价    QString shopName;};#endif // RECEIPTPAINTER_H

ReceiptPainter.cpp

#include "receiptpainter.h"#include <QByteArray>#include <QTextCodec>#include <QDebug>#include <QRect>#include <QPen>#include <QBrush>#include <QFont>ReceiptPainter::ReceiptPainter(QPrinter* printer,OrderDetailBean* od,QString sn):QPainter(printer){    orderDetail = od;    shopName = sn;    doCustomerPrint();}QString ReceiptPainter::getSeperator(double width){    int per = 12;  //360pt可以打30个*    int cnt = width / per;    QString sep;    for(int i = 0; i < cnt; i++) sep.append("* ");    return sep;}void ReceiptPainter::doCustomerPrint(){    double rt = 0.38;    QFont font1("宋体",FONT_SIZE_NORMAL,QFont::Bold);    QFont font2("宋体",FONT_SIZE_NORMAL);    QFont font3("宋体",FONT_SIZE_NORMAL,QFont::Bold);    QFont font4("宋体",FONT_SIZE_MIDDLE);    int xx1 = 50 * rt;    int xx2 = 410 * rt;    int xx3 = 545 * rt;    //w1 w2 w3 分别是品名、数目、单价的所在栏占的宽度    int w1 = 360 * rt;      int w2 = 135 * rt;    int w3 = 150 * rt;    //h1 h2 分别适用于两种字体大小    int h1 = 48 * rt;    int h2 = 35 * rt;    int h3 = 60 * rt;    QString seperator = getSeperator(w1+w2+w3);    //打印店名    QRect rect(xx1,0,w1+w2+w3,h1);    this->setFont(font1);    this->drawText(rect,Qt::AlignCenter,shopName);    //打印订单号和时间    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    this->setFont(font2);    this->drawText(rect,"时间："+orderDetail->getTime());    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    this->drawText(rect,"堂食: "+ QString::number(orderDetail->getSerialNo()));    //分隔符    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    this->drawText(rect,seperator);    //品名                数量 单价    this->setFont(font3);    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    rect.setX(xx1);    rect.setWidth(w1);    this->drawText(rect,Qt::AlignLeft,"品名");    rect.setX(xx2);    rect.setWidth(w2);    this->drawText(rect,Qt::AlignLeft,"数量");    rect.setX(xx3);    rect.setWidth(w3);    this->drawText(rect,Qt::AlignLeft,"单价");    //打印商品    this->setFont(font2);    QList<OrderGoodsBean*> goodsList = orderDetail->getOrderGoodsList();    OrderGoodsBean* orderGoodsItem = new OrderGoodsBean();    for (int i = 0; i < goodsList.size(); i++) {        orderGoodsItem = goodsList.at(i);        QString nname = orderGoodsItem->getName();        QString num = QString::number(orderGoodsItem->getAmount(),'g',10);        QString price = QString::number(orderGoodsItem->getPrice(),'g',10);        rect.setY(rect.y()+rect.height());        rect.setHeight(h2);        rect.setX(xx1);        rect.setWidth(w1);        this->drawText(rect,Qt::AlignLeft,nname);        rect.setX(xx2);        rect.setWidth(w2);        this->drawText(rect,Qt::AlignLeft,num);        rect.setX(xx3);        rect.setWidth(w3);        this->drawText(rect,Qt::AlignLeft,"￥" + price);    }    //分隔符    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    rect.setX(xx1);    rect.setWidth(w1+w2+w3);    this->drawText(rect,seperator);    //打印总价、付款、找零信息    QString tp = QString::number(orderDetail->getTotalPrice(),'g',10);    QString pm = QString::number(orderDetail->getPaidMoney(),'g',10);    QString cg = QString::number(orderDetail->getChange(),'g',10);    this->setFont(font4);    rect.setY(rect.y()+rect.height());    rect.setHeight(h1);    rect.setX(xx1);    rect.setWidth(w1+w2);    this->drawText(rect,Qt::AlignLeft,"共计：");    rect.setX(xx3);    rect.setWidth(w3);    this->drawText(rect,Qt::AlignLeft,tp);    rect.setY(rect.y()+rect.height());    rect.setHeight(h1);    rect.setX(xx1);    rect.setWidth(w1+w2);    this->drawText(rect,Qt::AlignLeft,"已收款：");    rect.setX(xx3);    rect.setWidth(w3);    this->drawText(rect,Qt::AlignLeft,pm);    rect.setY(rect.y()+rect.height());    rect.setHeight(h1);    rect.setX(xx1);    rect.setWidth(w1+w2);    this->drawText(rect,Qt::AlignLeft,"找零：");    rect.setX(xx3);    rect.setWidth(w3);    this->drawText(rect,Qt::AlignLeft,cg);    //分隔符    this->setFont(font2);    rect.setY(rect.y()+rect.height());    rect.setHeight(h2);    rect.setX(xx1);    rect.setWidth(w1+w2+w3);    this->drawText(rect,seperator);}ReceiptPainter::~ReceiptPainter(){}

参考文章：

Qt中的打印操作：http://blog.csdn.net/amnes1a/article/details/70597506
QT的打印基础： http://blog.csdn.net/yavobo/article/details/5643441
QT打印过程：http://m.blog.csdn.net/qqbitqqbit/article/details/17722507
Qt学习之路(24): QPainter： http://devbean.blog.51cto.com/448512/235332/
Qt5之2D绘图（三）绘制文字：http://www.qter.org/portal.php?mod=view&aid=40