Qt学习之路之图像打印

拼搏现实的明天。 2022-08-06 06:10 157阅读 0赞

**首先，设置工程文件：QT += printsupport**

**打印图像实际实在一个QPaintDevice中画图。打印创建QPrinter对象进行画图，QPrinter本质上也是一个绘图设备QPaintDevice。**

**~~~~~上代码~~~~**

**pic\_widget.h**

#ifndef PICWIDGET_H
    #define PICWIDGET_H
    
    #include <QPainter>
    #include <QWidget>
    #include <QPushButton>
    #include <QPrintDialog>
    #include <QPrinter>
    #include <QPainter>
    #include <QRect>
    #include <QImage>
    
    class PicWidget : public QWidget
    {
    	Q_OBJECT
    public:
    	explicit PicWidget(QWidget *parent = 0);
    
    	public slots:
    		void slotPrintPic();
    private:
    	QPushButton *pintPicBtn;
    	QImage img;
    };
    
    #endif	//--PICWIDGET_H

**pic\_widget.cpp**

#include "pic_widget.h"
    
    PicWidget::PicWidget(QWidget *parent /*= 0*/) : QWidget(parent)
    {
    	//---按钮
    	pintPicBtn = new QPushButton("print", this);
    	pintPicBtn->setGeometry(70, 40, 50, 30);
    	connect(pintPicBtn, SIGNAL(clicked()), this, SLOT(slotPrintPic()));
    
    	//--导入图片
    	img.load(":/1");
    
    	//---窗口属性
    	resize(200, 100);
    }
    
    //---按钮槽函数
    void PicWidget::slotPrintPic()
    {
    	QPrinter printer;		//---构建新对象
    	QPrintDialog printDlg(&printer, this);
    	if (printDlg.exec())			// 用于判断用户是否点击“打印”按钮
    	{
    		QPainter painter(&printer);
    		QRect rect = painter.viewport();	//---获取Qpainter对象的矩形区域
    		QSize size = img.size();			//--获取图片的大小
    		size.scale(rect.size(), Qt :: KeepAspectRatio);		//----按照图形比例大小重新设置视口矩形区域
    
    		//---打印图片
    		painter.setViewport(rect.x(), rect.y(), size.width(), size.height());
    		painter.setWindow(img.rect());
    		painter.drawImage(0, 0, img);
    	}
    }

**main.cpp**

#include <QtWidgets/QApplication>
    #include "pic_widget.h"
    
    
    int main(int argc, char *argv[])
    {
    	QApplication a(argc, argv);
    
    	PicWidget win;
    	win.show();
    	
    	return a.exec();
    }

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