Doc: Added info on QWidget::render to printing docs

    Task-number: QTBUG-2210
    Reviewed-by: David Boddie

2 files changed, 65 insertions, 0 deletions

diff --git a/doc/src/painting-and-printing/printing.qdoc b/doc/src/painting-and-printing/printing.qdoc
index 62c8192..97cd92f 100644
--- a/doc/src/painting-and-printing/printing.qdoc
+++ b/doc/src/painting-and-printing/printing.qdoc
@@ -136,6 +136,17 @@
   used is constructed using the form of the constructor that accepts a
   QPaintDevice argument.
 
+  \section1 Printing Widgets
+
+  To print a widget, you can use the QWidget::render() function. As mentioned,
+  the printer's resolution is usually higher than the screen resolution, so you
+  will have to scale the painter. You may also want to position the widget on the
+  page. The following code sample shows how this may look.
+
+  \snippet doc/src/snippets/widgetprinting.cpp 0
+
+  This will center the widget on the page and scale it so that it fits the page.
+
   \section1 Printing from Complex Widgets
 
   Certain widgets, such as QTextEdit and QGraphicsView, display rich content
diff --git a/doc/src/snippets/widgetprinting.cpp b/doc/src/snippets/widgetprinting.cpp
new file mode 100644
index 0000000..b3d5b7c
--- /dev/null
+++ b/doc/src/snippets/widgetprinting.cpp
@@ -0,0 +1,54 @@
+
+#include <QtGui>
+
+class Window : public QWidget
+{
+    Q_OBJECT
+
+public:
+    Window() {
+        myWidget = new QPushButton("Print Me");
+        connect(myWidget, SIGNAL(clicked()), this, SLOT(print()));
+
+        QVBoxLayout *layout = new QVBoxLayout;
+        layout->addWidget(myWidget);
+        setLayout(layout);
+    }
+
+private slots:
+    void print() {
+        QPrinter printer(QPrinter::HighResolution);
+        
+        printer.setOutputFileName("test.pdf");
+
+//! [0]
+        QPainter painter;
+        painter.begin(&printer);
+        double xscale = printer.pageRect().width()/double(myWidget->width());
+        double yscale = printer.pageRect().height()/double(myWidget->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(-width()/2, -height()/2);
+
+        myWidget->render(&painter);
+//! [0]
+    }
+
+private:
+    QPushButton *myWidget;
+};
+
+int main(int argv, char **args)
+{
+    QApplication app(argv, args);
+
+    Window window;
+    window.show();
+
+    return app.exec();
+}
+
+#include "main.moc"
+