Print: display an error message if no printers are found

When pressing Print or Preview from the PrintDialog, we need
to first check if there are printers installed. If not
we abort and show an error message.

This is needed because if no printers are installed,
things like the reported page height could be zero and
the profile and table print code in PrintLayout will
break.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

2 files changed, 21 insertions, 0 deletions

diff --git a/qt-ui/printdialog.cpp b/qt-ui/printdialog.cpp
index d1553aeea..472b7d942 100644
--- a/qt-ui/printdialog.cpp
+++ b/qt-ui/printdialog.cpp
@@ -11,6 +11,8 @@
 #include <QPrintPreviewDialog>
 #include <QPrintDialog>
 #include <QShortcut>
+#include <QPrinterInfo>
+#include <QMessageBox>
 
 PrintDialog::PrintDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(parent, f)
 {
@@ -65,8 +67,24 @@ PrintDialog::PrintDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(parent, f
 	connect(quit, SIGNAL(activated()), parent, SLOT(close()));
 }
 
+bool PrintDialog::checkForAvailablePrinters(void)
+{
+	QList<QPrinterInfo> list = QPrinterInfo::availablePrinters();
+	if (!list.length()) {
+		QMessageBox msgBox;
+		msgBox.setIcon(QMessageBox::Critical);
+		msgBox.setText(tr("Subsurface cannot find installed printers on this system!"));
+		msgBox.setWindowIcon(QIcon(":subsurface-icon"));
+		msgBox.exec();
+		return false;
+	}
+	return true;
+}
+
 void PrintDialog::previewClicked(void)
 {
+	if (!checkForAvailablePrinters())
+		return;
 	QPrintPreviewDialog previewDialog(&printer, this);
 	connect(&previewDialog, SIGNAL(paintRequested(QPrinter *)), this, SLOT(onPaintRequested(QPrinter *)));
 	previewDialog.exec();
@@ -74,6 +92,8 @@ void PrintDialog::previewClicked(void)
 
 void PrintDialog::printClicked(void)
 {
+	if (!checkForAvailablePrinters())
+		return;
 	QPrintDialog printDialog(&printer, this);
 	if (printDialog.exec() == QDialog::Accepted){
 		printLayout->print();
diff --git a/qt-ui/printdialog.h b/qt-ui/printdialog.h
index 32069a278..b29021838 100644
--- a/qt-ui/printdialog.h
+++ b/qt-ui/printdialog.h
@@ -18,6 +18,7 @@ public:
 	explicit PrintDialog(QWidget *parent = 0, Qt::WindowFlags f = 0);
 
 private:
+	bool checkForAvailablePrinters(void);
 	PrintOptions *optionsWidget;
 	PrintLayout *printLayout;
 	QProgressBar *progressBar;