2017-04-20 62 views
0

我想呈現每個單獨的頁面中的qwidgets並將其保存爲pdf格式。我試着使用QPainter,QPrinter來並試圖呈現在論壇上建議:http://doc.qt.io/qt-4.8/printing.html#printing-widgets如何使用Qpainter將多個qwidgets打印到不同頁面中的pdf中?

這是我的示例代碼:

QPainter painter; 
painter.begin(&printer); 
for(int page = 0;page<no_of_pages;page++) 
{ 
double xscale = printer.pageRect().width()/double(MyWidget[page]->width()); 
double yscale = printer.pageRect().height()/double(MyWidget[page]->height()); 
double scale = qMin(xscale, yscale); 
painter.translate(printer.paperRect().x() + printer.pageRect().width()/2, 
printer.paperRect().y() + printer.pageRect().height()/2); 
painter.scale(scale, scale); 
painter.translate(-MyWidget[page]->width()/2, -MyWidget[page]->height()/2); 
MyWidget[page]->render(&painter); 
if(page!=(no_of_pages-1)) 
    printer.newPage(); 
} 
painter.end(); 

當我執行上面的代碼,與在網頁的確切數量生成的PDF但只打印第一頁。當我檢查應用程序的輸出控制檯,以下消息打印:

QPainter::begin: Paint device returned engine == 0, type: 2 
QPainter::setRenderHint: Painter must be active to set rendering hints 
QPainter::setWorldTransform: Painter not active 
QWidget::render: Cannot render with an inactive painter 
QPainter::end: Painter not active, aborted 

我試着google一下這些消息,但他們都不是相關的渲染qwidgets。任何幫助表示讚賞。謝謝。

回答

1

問題不在於它不會在下一頁上打印,但比例不正確,您必須在每次迭代結束時重置所有轉換(使用resetTransform())。我更願意將小部件保存在QList <QWidget *>中。

QList <QWidget *> widgets; 
widgets.append({some widget}); 
[...] 

QPrinter printer; 
printer.setOutputFormat(QPrinter::PdfFormat); 
printer.setOutputFileName("printer.pdf"); 

QPainter painter; 

if (! painter.begin(&printer)) { // failed to open file 
    qWarning("failed to open file, is it writable?"); 
} 

for(auto widget: w){ 
    if(widget){ 
     if(widget->width() > 0 && widget->height() >0){ 

      qreal xscale = 0.9*printer.pageRect().width()/qreal(widget->width()); 
      qreal yscale = 0.9*printer.pageRect().height()/qreal(widget->height()); 

      qreal scale = qMin(xscale, yscale); 

      painter.translate(printer.paperRect().x() + printer.pageRect().width()/2, 
           printer.paperRect().y() + printer.pageRect().height()/2); 

      painter.scale(scale, scale); 
      painter.translate(-width()/2, -height()/2); 
      widget->render(&painter); 
      painter.resetTransform(); 
      if(widget != widgets.last()) 
       printer.newPage(); 
     } 
    } 

} 
painter.end(); 

觀察:設置,使得圖像顯示在一個更愉快的方式0.9的因素。

+0

它工作。你救了我的一天,非常感謝你。接受你的答案。 – Pramod