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