Unix print dialog: Properly initialize duplex

In case the user has explicitly selected a value for the
duplex mode in the print dialog before, select this one when
another printer is selected and the newly selected printer
supports it.

Otherwise, always set to the default value of the respective
device that was selected.

This way, default values that the user (or admin) has set for
a CUPS printer (or printer instance) are honored, but an explicit
user choice made in the dialog takes precedence.

Previously, the duplex values was always reset to "None"
every time the printer was changed.

Change-Id: Id9683a05b10cf7a4b842f8b6c8452e80cdc6ff91
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

1 files changed, 26 insertions, 5 deletions

diff --git a/src/printsupport/dialogs/qprintdialog_unix.cpp b/src/printsupport/dialogs/qprintdialog_unix.cpp
index ebf63ea568..5c87af0f35 100644
--- a/src/printsupport/dialogs/qprintdialog_unix.cpp
+++ b/src/printsupport/dialogs/qprintdialog_unix.cpp
@@ -249,6 +249,10 @@ public:
     QDialogButtonBox *buttons;
     QPushButton *collapseButton;
     QPrinter::OutputFormat printerOutputFormat;
+private:
+    void setExplicitDuplexMode(QPrint::DuplexMode duplexMode);
+    // duplex mode explicitly set by user, QPrint::DuplexAuto otherwise
+    QPrint::DuplexMode explicitDuplexMode;
 };
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -588,7 +592,8 @@ bool QPrintPropertiesDialog::anyAdvancedOptionConflict() const
 
 */
 QPrintDialogPrivate::QPrintDialogPrivate()
-    : top(nullptr), bottom(nullptr), buttons(nullptr), collapseButton(nullptr)
+    : top(nullptr), bottom(nullptr), buttons(nullptr), collapseButton(nullptr),
+      explicitDuplexMode(QPrint::DuplexAuto)
 {
     initResources();
 }
@@ -650,6 +655,10 @@ void QPrintDialogPrivate::init()
 
     QObject::connect(collapseButton, SIGNAL(released()), q, SLOT(_q_collapseOrExpandDialog()));
 
+    QObject::connect(options.noDuplex, &QAbstractButton::clicked, q, [this] { setExplicitDuplexMode(QPrint::DuplexNone); });
+    QObject::connect(options.duplexLong, &QAbstractButton::clicked, q, [this] { setExplicitDuplexMode(QPrint::DuplexLongSide); });
+    QObject::connect(options.duplexShort, &QAbstractButton::clicked, q, [this] { setExplicitDuplexMode(QPrint::DuplexShortSide); });
+
 #if QT_CONFIG(cups)
     QObject::connect(options.noDuplex, &QAbstractButton::toggled, q, [this] { updatePpdDuplexOption(options.noDuplex); });
     QObject::connect(options.duplexLong, &QAbstractButton::toggled, q, [this] { updatePpdDuplexOption(options.duplexLong); });
@@ -674,13 +683,20 @@ void QPrintDialogPrivate::selectPrinter(const QPrinter::OutputFormat outputForma
         else
             options.grayscale->setChecked(true);
 
-        switch (p->duplex()) {
-        case QPrinter::DuplexNone:
+        // keep duplex value explicitly set by user, if any, and selected printer supports it;
+        // use device default otherwise
+        QPrint::DuplexMode duplex;
+        if (explicitDuplexMode != QPrint::DuplexAuto && supportedDuplexMode.contains(explicitDuplexMode))
+            duplex = explicitDuplexMode;
+        else
+            duplex = top->d->m_currentPrintDevice.defaultDuplexMode();
+        switch (duplex) {
+        case QPrint::DuplexNone:
             options.noDuplex->setChecked(true); break;
-        case QPrinter::DuplexLongSide:
+        case QPrint::DuplexLongSide:
         case QPrinter::DuplexAuto:
             options.duplexLong->setChecked(true); break;
-        case QPrinter::DuplexShortSide:
+        case QPrint::DuplexShortSide:
             options.duplexShort->setChecked(true); break;
         }
         options.copies->setValue(p->copyCount());
@@ -795,6 +811,11 @@ void QPrintDialogPrivate::updatePpdDuplexOption(QRadioButton *radio)
 
 #endif
 
+void QPrintDialogPrivate::setExplicitDuplexMode(const QPrint::DuplexMode duplexMode)
+{
+    explicitDuplexMode = duplexMode;
+}
+
 void QPrintDialogPrivate::setupPrinter()
 {
     // First setup the requested OutputFormat, Printer and Page Size first