cups: Clear cups options at the start of QPrintPropertiesDialog::setupPrinter

For some reason the cups options are kept globally instead of per printer at QCupsPrintEnginePrivate
so when setting the printer options on accepting the print dialog, we first need to clear them
and then call the other functions that set them, otherwise, we will "reuse" cups option set on
the previous print.

How to reproduce:
 * Open print dialog, set some advanced option to a non default value, easiest one is print in grayscale
 * Print
 * Check it prints in grayscale
 * Open print dialog, check the advanced options are all on default values
 * Print
 * Check it incorrectly prints in grayscale

Change-Id: I59aacaf30db844ad40887d6b771f9354557852b6
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

2 files changed, 6 insertions, 0 deletions

diff --git a/src/printsupport/kernel/qcups.cpp b/src/printsupport/kernel/qcups.cpp
index be170ed619..7e8e1707b2 100644
--- a/src/printsupport/kernel/qcups.cpp
+++ b/src/printsupport/kernel/qcups.cpp
@@ -77,6 +77,11 @@ void QCUPSSupport::clearCupsOption(QPrinter *printer, const QString &option)
     }
 }
 
+void QCUPSSupport::clearCupsOptions(QPrinter *printer)
+{
+    setCupsOptions(printer, QStringList());
+}
+
 static inline QString jobHoldToString(const QCUPSSupport::JobHoldUntil jobHold, const QTime holdUntilTime)
 {
     switch (jobHold) {
diff --git a/src/printsupport/kernel/qcups_p.h b/src/printsupport/kernel/qcups_p.h
index da2b087d5b..9a71483bb9 100644
--- a/src/printsupport/kernel/qcups_p.h
+++ b/src/printsupport/kernel/qcups_p.h
@@ -132,6 +132,7 @@ public:
 
     static void setCupsOption(QPrinter *printer, const QString &option, const QString &value);
     static void clearCupsOption(QPrinter *printer, const QString &option);
+    static void clearCupsOptions(QPrinter *printer);
 
     static void setJobHold(QPrinter *printer, const JobHoldUntil jobHold = NoHold, const QTime &holdUntilTime = QTime());
     static void setJobBilling(QPrinter *printer, const QString &jobBilling = QString());