iOS: Enable the Qt Print Support module

The print support module was disabled for the initial port of Qt
for iOS due to the lack of a native print backend and native
print dialogs, as we have on macOS.

However, even lacking these we should be able to offer the print
to PDF feature, with widget based print dialogs. We can do so
by opting in to the generic Unix print dialogs and backends,
as these do not have a hard dependency on CUPS.

Longer term we should adopt UIPrintInteractionController,
UIPrinterPickerController, and UIPrinter, but that's a bigger
task.

[ChangeLog[iOS] The Qt Print Support module is now enabled,
allowing printing to PDF. Printing to system provided printers
are not yet supported.

Fixes: QTBUG-125581
Change-Id: I5bc143e47c7277b3cea52760672ac4d0c8a7a898
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

src/printsupport/CMakeLists.txt

@@ -179,7 +179,7 @@ qt_internal_extend_target(PrintSupport CONDITION QT_FEATURE_printdialog AND WIN3
         dialogs/qprintdialog_win.cpp
 )
 
-qt_internal_extend_target(PrintSupport CONDITION QT_FEATURE_printdialog AND UNIX AND NOT APPLE
+qt_internal_extend_target(PrintSupport CONDITION QT_FEATURE_printdialog AND UNIX AND NOT MACOS
     SOURCES
         dialogs/qpagesetupdialog_unix.cpp dialogs/qpagesetupdialog_unix_p.h
         dialogs/qprintdialog_unix.cpp

src/printsupport/configure.cmake

@@ -40,7 +40,7 @@ qt_feature("printer" PUBLIC
     SECTION "Painting"
     LABEL "QPrinter"
     PURPOSE "Provides a printer backend of QPainter."
-    CONDITION NOT UIKIT AND QT_FEATURE_picture AND QT_FEATURE_temporaryfile AND QT_FEATURE_pdf
+    CONDITION QT_FEATURE_picture AND QT_FEATURE_temporaryfile AND QT_FEATURE_pdf
 )
 qt_feature_definition("printer" "QT_NO_PRINTER" NEGATE VALUE "1")
 qt_feature("printpreviewwidget" PUBLIC

src/printsupport/dialogs/qpagesetupdialog.cpp

@@ -100,7 +100,7 @@ void QPageSetupDialog::open(QObject *receiver, const char *member)
     QDialog::open();
 }
 
-#if defined(Q_OS_MAC) || defined(Q_OS_WIN)
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN)
 /*! \fn void QPageSetupDialog::setVisible(bool visible)
     \reimp
 */

src/printsupport/dialogs/qpagesetupdialog.h

@@ -25,7 +25,7 @@ public:
     explicit QPageSetupDialog(QWidget *parent = nullptr);
     ~QPageSetupDialog();
 
-#if defined(Q_OS_MAC) || defined(Q_OS_WIN) || defined(Q_QDOC)
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN) || defined(Q_QDOC)
     void setVisible(bool visible) override;
 #endif
     int exec() override;

src/printsupport/dialogs/qprintdialog.h

@@ -28,7 +28,7 @@ public:
     ~QPrintDialog();
 
     int exec() override;
-#if defined (Q_OS_UNIX) && !defined(Q_OS_MAC)
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MACOS)
     virtual void accept() override;
 #endif
     void done(int result) override;
@@ -55,7 +55,7 @@ Q_SIGNALS:
     void accepted(QPrinter *printer);
 
 private:
-#if defined (Q_OS_UNIX) && !defined(Q_OS_MAC)
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MACOS)
     Q_PRIVATE_SLOT(d_func(), void _q_togglePageSetCombo(bool))
     Q_PRIVATE_SLOT(d_func(), void _q_collapseOrExpandDialog())
 #if QT_CONFIG(messagebox)

src/printsupport/dialogs/qprintpreviewdialog.cpp

@@ -250,7 +250,7 @@ void QPrintPreviewDialogPrivate::init(QPrinter *_printer)
     QWidget *pageEdit = new QWidget(toolbar);
     QVBoxLayout *vboxLayout = new QVBoxLayout;
     vboxLayout->setContentsMargins(0, 0, 0, 0);
-#ifdef Q_OS_MAC
+#ifdef Q_OS_MACOS
     // We query the widgets about their size and then we fix the size.
     // This should do the trick for the laying out part...
     QSize pageNumEditSize, pageNumLabelSize;
@@ -260,7 +260,7 @@ void QPrintPreviewDialogPrivate::init(QPrinter *_printer)
     pageNumLabel->resize(pageNumLabelSize);
 #endif
     QFormLayout *formLayout = new QFormLayout;
-#ifdef Q_OS_MAC
+#ifdef Q_OS_MACOS
     // We have to change the growth policy in Mac.
     formLayout->setFieldGrowthPolicy(QFormLayout::AllNonFixedFieldsGrow);
 #endif
@@ -310,7 +310,7 @@ void QPrintPreviewDialogPrivate::init(QPrinter *_printer)
     q->setWindowTitle(caption);
 
     if (!printer->isValid()
-#if defined(Q_OS_WIN) || defined(Q_OS_MAC)
+#if defined(Q_OS_WIN) || defined(Q_OS_APPLE)
         || printer->outputFormat() != QPrinter::NativeFormat
 #endif
         )
@@ -539,7 +539,7 @@ void QPrintPreviewDialogPrivate::_q_print()
 {
     Q_Q(QPrintPreviewDialog);
 
-#if defined(Q_OS_WIN) || defined(Q_OS_MAC)
+#if defined(Q_OS_WIN) || defined(Q_OS_APPLE)
     if (printer->outputFormat() != QPrinter::NativeFormat) {
         QString title = QCoreApplication::translate("QPrintPreviewDialog", "Export to PDF");
         QString suffix = ".pdf"_L1;

src/printsupport/widgets/qprintpreviewwidget.cpp

@@ -111,7 +111,7 @@ public:
     GraphicsView(QWidget* parent = nullptr)
         : QGraphicsView(parent)
     {
-#ifdef Q_OS_MAC
+#ifdef Q_OS_APPLE
         setFrameStyle(QFrame::NoFrame);
 #endif
     }