Add experimental Qt 6 support flags. (#7182)

* refactored gui_templates.h

* experimental qt6 support enabled

* replace qt5_wrap_ui with cmake_autouic

* Make the minimum code compile for Qt6

The following changes are applied to make the minimum build configuration compile:
*  Remove usage of a `QKeyEvent` constructor in `ColorChooser.h` by directly forwarding the original event.
* Change `QMap` to `QMulitMap` in several places in `ControlLayout.h` because that's what in fact is used.
* Change the parameter from `QEvent` to `QEnterEvent` in some `enterEvent` overrides.
* Add an include for `algorithm` in `MixHelpers.cpp`
* Fix a problem with string argument replacement in `embed.cpp`
* Introduce the usage of `QKeySequence` including the replacement of the `+` operator with the `|` operator.
* Add an include for `QActionGroup` in `ProjectNotes.cpp`.
* Use `QPalette::window` instead of `QPalette::background` in `ClipView.cpp`
* Use `qBound<panning_t>` instead of `qBound<int>` in `PianoRoll.cpp`. Add a cast.
* Replace the deprecated call to `QLayout::setMargin` with `QLayout::setContentsMargins`

Note: there are still lots of warnings when you compile this state with Qt6!

* Qt 5 support

* Fix Qt5 build for ControlLayout

Fix the Qt5 build for `ControlLayout` by intoducing typedefs depending on the Qt version and using these throughout `ControlLayout`.

* Prepare LadspaMatrixControlDialog for Qt6

Use `setContentsMargins` instead of `setMargin`.

* CMakeLists.txt adjustments for Qt6

Add the dependency to "Core5Compat" to the main CMakeLists.txt. It is needed so that we can use `QTextCodec` which is used by the Hydrogen importer plugin.

Adjust the CMakeLists.txt of the ZynAddSubFx plugin so that it also makes use of `QT_VERSION_MAJOR` and therefore builds under Qt5 and Qt6.

* force qt 5 on vst for now

* cleanup qt5compat finding code

* Fix build

Fix the build that failed after the merge of master. The data type that `QColor::getRgbF` uses has changed between Qt5 and Qt6. This is solved with a using because changing the type to `float` which is used by Qt6 did not work with Qt5 either.

* Fix warnings in AutomationClip.cpp

Fix warnings in `AutomationClip.cpp`. These have been warnings of the type:
"Warning: »QMap<int, lmms::AutomationNode>::const_iterator operator-(QMap<int, lmms::AutomationNode>::const_iterator, QMap<int, lmms::AutomationNode>::const_iterator::difference_type)« is deprecated: Use std::prev; QMap iterators are not random access [-Wdeprecated-declarations]

* Fix warning in AutomationClipView

Fix build warning about deprecated iterator operators in `AutomationClipView`.

* Fix deprecated usage of x() and y() methods

Fix the deprecated usage of the following methods:
* `QMouseEvent:x()`
* `QMouseEvent:y()`
* `QDropEvent:x()`
* `QDropEvent:y()`

This is done by adding two new helper methods names `position` to `DeprecationHelper.h` and using these methods in the event methods.

* Fix more iterator operator warnings

Fix more warnings about iterator operators by using `std::prev` and `std::next`.

* Fix QKeyCombination warning

Fix warnings about `QKeyCombination::operator+`.

* added minimum version check

Co-authored-by: Dalton Messmer <messmer.dalton@gmail.com>

* zyn build fix for msvc qt6

---------

Co-authored-by: Michael Gregorius <michael.gregorius.git@arcor.de>
Co-authored-by: Dalton Messmer <messmer.dalton@gmail.com>

CMakeLists.txt

@@ -103,6 +103,7 @@ option(WANT_DEBUG_TSAN	"Enable ThreadSanitizer" OFF)
 option(WANT_DEBUG_MSAN	"Enable MemorySanitizer" OFF)
 option(WANT_DEBUG_UBSAN	"Enable UndefinedBehaviorSanitizer" OFF)
 OPTION(BUNDLE_QT_TRANSLATIONS	"Install Qt translation files for LMMS" OFF)
+option(WANT_QT6 "Build with experimental Qt6 support" OFF)
 
 
 IF(LMMS_BUILD_APPLE)
@@ -179,30 +180,59 @@ check_library_exists(rt shm_open "" LMMS_HAVE_LIBRT)
 
 LIST(APPEND CMAKE_PREFIX_PATH "${CMAKE_INSTALL_PREFIX}")
 
-FIND_PACKAGE(Qt5 5.9.0 COMPONENTS Core Gui Widgets Xml REQUIRED)
-FIND_PACKAGE(Qt5 COMPONENTS LinguistTools QUIET)
+IF(WANT_QT6)
+	MESSAGE("Building with Qt6 is experimental, not guaranteed to succeed")
+	SET(QT_VERSION_MAJOR 6)
+	SET(LMMS_QT_MIN_VERSION 6.0.0)
+	SET(WANT_VST OFF)
+	SET(STATUS_VST "VSTs not supported with Qt 6")
+	SET(STATUS_QT6 "ENABLED")
+ELSE()
+	SET(QT_VERSION_MAJOR 5)
+	SET(LMMS_QT_MIN_VERSION 5.9.0)
+	SET(STATUS_QT6 "NOT ENABLED")
+ENDIF()
+
+FIND_PACKAGE(Qt${QT_VERSION_MAJOR} ${LMMS_QT_MIN_VERSION} COMPONENTS Core Gui Widgets Xml REQUIRED)
+FIND_PACKAGE(Qt${QT_VERSION_MAJOR} COMPONENTS LinguistTools QUIET)
 
 INCLUDE_DIRECTORIES(
-	${Qt5Core_INCLUDE_DIRS}
-	${Qt5Gui_INCLUDE_DIRS}
-	${Qt5Widgets_INCLUDE_DIRS}
-	${Qt5Xml_INCLUDE_DIRS}
+	${Qt${QT_VERSION_MAJOR}Core_INCLUDE_DIRS}
+	${Qt${QT_VERSION_MAJOR}Gui_INCLUDE_DIRS}
+	${Qt${QT_VERSION_MAJOR}Widgets_INCLUDE_DIRS}
+	${Qt${QT_VERSION_MAJOR}Xml_INCLUDE_DIRS}
 )
 
 SET(QT_LIBRARIES
-	Qt5::Core
-	Qt5::Gui
-	Qt5::Widgets
-	Qt5::Xml
+	Qt${QT_VERSION_MAJOR}::Core
+	Qt${QT_VERSION_MAJOR}::Gui
+	Qt${QT_VERSION_MAJOR}::Widgets
+	Qt${QT_VERSION_MAJOR}::Xml
 )
 
+IF(WANT_QT6)
+    # Core5Compat is needed so that we get QTextCodec which is used by
+    # the Hydrogen importer plugin. 
+	# TODO : fix hydrogen importer plugin with qt6
+    # See: https://doc.qt.io/qt-6/qtcore5-index.html
+    FIND_PACKAGE(Qt6 COMPONENTS Core5Compat REQUIRED)
+    INCLUDE_DIRECTORIES(${Qt6Core5Compat_INCLUDE_DIRS})
+    SET(QT_LIBRARIES ${QT_LIBRARIES} Qt6::Core5Compat)
+ENDIF()
+
 IF(LMMS_BUILD_LINUX AND WANT_VST)
+	# Todo, enable qt6 for vst support
     FIND_PACKAGE(Qt5 COMPONENTS X11Extras REQUIRED)
     LIST(APPEND QT_LIBRARIES Qt5::X11Extras)
 ENDIF()
 
-# Resolve Qt5::qmake to full path for use in packaging scripts
-GET_TARGET_PROPERTY(QT_QMAKE_EXECUTABLE "${Qt5Core_QMAKE_EXECUTABLE}" IMPORTED_LOCATION)
+# Resolve qmake to full path for use in packaging scripts
+IF(WANT_QT6)
+	FIND_PROGRAM(QT_QMAKE_EXECUTABLE NAME qmake.exe
+		PATHS "${CMAKE_PREFIX_PATH}/bin" /opt/Qt6/bin) # TODO: add more paths here
+ELSE()
+	GET_TARGET_PROPERTY(QT_QMAKE_EXECUTABLE "${Qt5Core_QMAKE_EXECUTABLE}" IMPORTED_LOCATION)
+ENDIF()
 
 # Find the location of Qt translation files
 execute_process(COMMAND ${QT_QMAKE_EXECUTABLE} -query QT_INSTALL_TRANSLATIONS
@@ -215,8 +245,8 @@ IF(EXISTS "${QT_TRANSLATIONS_DIR}")
 	ADD_DEFINITIONS("-DQT_TRANSLATIONS_DIR=\"${QT_TRANSLATIONS_DIR}\"")
 ENDIF()
 
-FIND_PACKAGE(Qt5Test)
-SET(QT_QTTEST_LIBRARY Qt5::Test)
+FIND_PACKAGE(Qt${QT_VERSION_MAJOR}Test)
+SET(QT_QTTEST_LIBRARY Qt${QT_VERSION_MAJOR}::Test)
 
 # check for libsndfile
 FIND_PACKAGE(SndFile REQUIRED)
@@ -890,6 +920,7 @@ MESSAGE(
 "* Debug using ThreadSanitizer       : ${STATUS_DEBUG_TSAN}\n"
 "* Debug using MemorySanitizer       : ${STATUS_DEBUG_MSAN}\n"
 "* Debug using UBSanitizer           : ${STATUS_DEBUG_UBSAN}\n"
+"* Experimental Qt6 support          : ${STATUS_QT6}\n"
 )
 
 MESSAGE(

cmake/install/CMakeLists.txt

@@ -1,6 +1,6 @@
 SET(PLUGIN_FILES "")
 IF(LMMS_BUILD_WIN32)
-	INSTALL(FILES $<TARGET_FILE:Qt5::QWindowsIntegrationPlugin> DESTINATION platforms)
+	INSTALL(FILES $<TARGET_FILE:Qt${QT_VERSION_MAJOR}::QWindowsIntegrationPlugin> DESTINATION platforms)
 ENDIF()
 
 IF(LMMS_BUILD_WIN32 OR LMMS_INSTALL_DEPENDENCIES)

cmake/modules/BuildPlugin.cmake

@@ -30,8 +30,13 @@ MACRO(BUILD_PLUGIN PLUGIN_NAME)
 		ADD_GEN_QRC(RCC_OUT "${PLUGIN_NAME}.qrc" PREFIX artwork/${PLUGIN_NAME} ${PLUGIN_EMBEDDED_RESOURCES})
 	ENDIF(ER_LEN)
 
-	QT5_WRAP_CPP(plugin_MOC_out ${PLUGIN_MOCFILES})
-	QT5_WRAP_UI(plugin_UIC_out ${PLUGIN_UICFILES})
+	IF(WANT_QT6)
+		QT6_WRAP_CPP(plugin_MOC_out ${PLUGIN_MOCFILES})
+		QT6_WRAP_UI(plugin_UIC_out ${PLUGIN_UICFILES})
+	ELSE()
+		QT5_WRAP_CPP(plugin_MOC_out ${PLUGIN_MOCFILES})
+		QT5_WRAP_UI(plugin_UIC_out ${PLUGIN_UICFILES})
+	ENDIF()
 
 	FOREACH(f ${PLUGIN_SOURCES})
 		ADD_FILE_DEPENDENCIES(${f} ${RCC_OUT} ${plugin_UIC_out})
@@ -56,7 +61,7 @@ MACRO(BUILD_PLUGIN PLUGIN_NAME)
 
 	ADD_LIBRARY(${PLUGIN_NAME} ${PLUGIN_LINK} ${PLUGIN_SOURCES} ${plugin_MOC_out} ${RCC_OUT})
 
-	target_link_libraries("${PLUGIN_NAME}" lmms Qt5::Widgets Qt5::Xml)
+	target_link_libraries("${PLUGIN_NAME}" lmms Qt${QT_VERSION_MAJOR}::Widgets Qt${QT_VERSION_MAJOR}::Xml)
 
 	INSTALL(TARGETS ${PLUGIN_NAME}
 		LIBRARY DESTINATION "${PLUGIN_DIR}"

cmake/modules/GenQrc.cmake

@@ -58,7 +58,7 @@ function(add_gen_qrc RCC_OUT QRC_NAME)
 	# generators. See issue #6177.
 	add_custom_command(
 		OUTPUT "${CPP_FILE}"
-		COMMAND Qt5::rcc
+		COMMAND Qt${QT_VERSION_MAJOR}::rcc
 			--name "${RESOURCE_NAME}"
 			--output "${CPP_FILE}"
 			"${QRC_FILE}"

data/locale/CMakeLists.txt

@@ -1,5 +1,5 @@
-SET(QT_LUPDATE_EXECUTABLE "${Qt5_LUPDATE_EXECUTABLE}")
-SET(QT_LRELEASE_EXECUTABLE "${Qt5_LRELEASE_EXECUTABLE}")
+SET(QT_LUPDATE_EXECUTABLE "${Qt${QT_VERSION_MAJOR}_LUPDATE_EXECUTABLE}")
+SET(QT_LRELEASE_EXECUTABLE "${Qt${QT_VERSION_MAJOR}_LRELEASE_EXECUTABLE}")
 
 IF(QT_LUPDATE_EXECUTABLE STREQUAL "")
 	EXECUTE_PROCESS(COMMAND "lupdate" "-help" RESULT_VARIABLE LUPDATE_FALLBACK OUTPUT_QUIET)

include/ColorChooser.h

@@ -55,8 +55,7 @@ class ColorChooser : public QColorDialog
 	//! Forward key events to the parent to prevent stuck notes when the dialog gets focus
 	void keyReleaseEvent(QKeyEvent *event) override
 	{
-		QKeyEvent ke(*event);
-		QApplication::sendEvent(parentWidget(), &ke);
+		QApplication::sendEvent(parentWidget(), event);
 	}
 private:
 	//! Copy the current QColorDialog palette into an array

include/ColorHelper.h

@@ -34,16 +34,22 @@ class ColorHelper
 public:
 	static QColor interpolateInRgb(const QColor& a, const QColor& b, float t)
 	{
-		qreal ar, ag, ab, aa;
+		#if (QT_VERSION > QT_VERSION_CHECK(6, 0, 0))
+		using colorType = float;
+		#else
+		using colorType = qreal;
+		#endif
+
+		colorType ar, ag, ab, aa;
 		a.getRgbF(&ar, &ag, &ab, &aa);
 
-		qreal br, bg, bb, ba;
+		colorType br, bg, bb, ba;
 		b.getRgbF(&br, &bg, &bb, &ba);
 
-		const float interH = lerp(ar, br, t);
-		const float interS = lerp(ag, bg, t);
-		const float interV = lerp(ab, bb, t);
-		const float interA = lerp(aa, ba, t);
+		const colorType interH = lerp(ar, br, t);
+		const colorType interS = lerp(ag, bg, t);
+		const colorType interV = lerp(ab, bb, t);
+		const colorType interA = lerp(aa, ba, t);
 
 		return QColor::fromRgbF(interH, interS, interV, interA);
 	}

include/ControlLayout.h

@@ -98,6 +98,14 @@ class ControlLayout : public QLayout
 {
 	Q_OBJECT
 
+#if (QT_VERSION > QT_VERSION_CHECK(6, 0, 0))
+	using ControlLayoutMap = QMultiMap<QString, QLayoutItem *>;
+	using ControlLayoutMapIterator = QMultiMapIterator<QString, QLayoutItem *>;
+#else
+	using ControlLayoutMap = QMap<QString, QLayoutItem*>;
+	using ControlLayoutMapIterator = QMapIterator<QString, QLayoutItem*>;
+#endif
+
 public:
 	explicit ControlLayout(QWidget *parent,
 		int margin = -1, int hSpacing = -1, int vSpacing = -1);
@@ -126,9 +134,9 @@ private slots:
 private:
 	int doLayout(const QRect &rect, bool testOnly) const;
 	int smartSpacing(QStyle::PixelMetric pm) const;
-	QMap<QString, QLayoutItem *>::const_iterator pairAt(int index) const;
+	ControlLayoutMap::const_iterator pairAt(int index) const;
 
-	QMultiMap<QString, QLayoutItem *> m_itemMap;
+	ControlLayoutMap m_itemMap;
 	int m_hSpace;
 	int m_vSpace;
 	// relevant dimension is width, as later, heightForWidth() will be called

include/DeprecationHelper.h

@@ -64,6 +64,36 @@ inline QPoint position(QWheelEvent *wheelEvent)
 #endif
 }
 
+/**
+ * @brief position is a backwards-compatible adapter for
+ * QMouseEvent::position and pos functions.
+ * @param me
+ * @return the position of the mouse event
+ */
+inline QPoint position(QMouseEvent* me)
+{
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+	return me->position().toPoint();
+#else
+	return me->pos();
+#endif
+}
+
+/**
+ * @brief position is a backwards-compatible adapter for
+ * QDropEvent::position and pos functions.
+ * @param me
+ * @return the position of the drop event
+ */
+inline QPoint position(QDropEvent* de)
+{
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+	return de->position().toPoint();
+#else
+	return de->pos();
+#endif
+}
+
 } // namespace lmms
 
 #endif // LMMS_DEPRECATIONHELPER_H

include/FloatModelEditorBase.h

@@ -81,7 +81,12 @@ class LMMS_EXPORT FloatModelEditorBase : public QWidget, public FloatModelView
 	void paintEvent(QPaintEvent * me) override;
 	void wheelEvent(QWheelEvent * me) override;
 
+	// Todo : cleanup once we drop QT5 support
+	#if (QT_VERSION > QT_VERSION_CHECK(6, 0, 0))
+	void enterEvent(QEnterEvent *event) override;
+	#else
 	void enterEvent(QEvent *event) override;
+	#endif
 	void leaveEvent(QEvent *event) override;
 
 	virtual float getValue(const QPoint & p);

include/PluginBrowser.h

@@ -66,7 +66,12 @@ class PluginDescWidget : public QWidget
 	void openInNewInstrumentTrack(QString value);
 
 protected:
-	void enterEvent( QEvent * _e ) override;
+	// Todo : cleanup once QT 5 support is dropped
+	#if (QT_VERSION > QT_VERSION_CHECK(6, 0, 0))
+	void enterEvent( QEnterEvent * _e) override;
+	#else
+	void enterEvent(QEvent* _e) override;
+	#endif
 	void leaveEvent( QEvent * _e ) override;
 	void mousePressEvent( QMouseEvent * _me ) override;
 	void paintEvent( QPaintEvent * _pe ) override;

plugins/AudioFileProcessor/AudioFileProcessorWaveView.cpp

@@ -25,6 +25,7 @@
 #include "AudioFileProcessorWaveView.h"
 
 #include "ConfigManager.h"
+#include "DeprecationHelper.h"
 #include "gui_templates.h"
 #include "SampleWaveform.h"
 
@@ -113,10 +114,12 @@ void AudioFileProcessorWaveView::leaveEvent(QEvent * e)
 
 void AudioFileProcessorWaveView::mousePressEvent(QMouseEvent * me)
 {
+	const auto pos = position(me);
+
 	m_isDragging = true;
 	m_draggingLastPoint = me->pos();
 
-	const int x = me->x();
+	const int x = pos.x();
 
 	const int start_dist =		qAbs(m_startFrameX - x);
 	const int end_dist = 		qAbs(m_endFrameX - x);
@@ -154,7 +157,9 @@ void AudioFileProcessorWaveView::mouseMoveEvent(QMouseEvent * me)
 		return;
 	}
 
-	const int step = me->x() - m_draggingLastPoint.x();
+	const auto pos = position(me);
+
+	const int step = pos.x() - m_draggingLastPoint.x();
 	switch(m_draggingType)
 	{
 		case DraggingType::SampleStart:
@@ -168,14 +173,14 @@ void AudioFileProcessorWaveView::mouseMoveEvent(QMouseEvent * me)
 			break;
 		case DraggingType::Wave:
 		default:
-			if (qAbs(me->y() - m_draggingLastPoint.y())
-				< 2 * qAbs(me->x() - m_draggingLastPoint.x()))
+			if (qAbs(pos.y() - m_draggingLastPoint.y())
+				< 2 * qAbs(pos.x() - m_draggingLastPoint.x()))
 			{
 				slide(step);
 			}
 			else
 			{
-				zoom(me->y() < m_draggingLastPoint.y());
+				zoom(pos.y() < m_draggingLastPoint.y());
 			}
 	}
 
@@ -474,11 +479,13 @@ void AudioFileProcessorWaveView::reverse()
 
 void AudioFileProcessorWaveView::updateCursor(QMouseEvent * me)
 {
+	const auto pos = position(me);
+
 	bool const waveIsDragged = m_isDragging && (m_draggingType == DraggingType::Wave);
 	bool const pointerCloseToStartEndOrLoop = (me != nullptr) &&
-			(isCloseTo(me->x(), m_startFrameX) ||
-			  isCloseTo(me->x(), m_endFrameX) ||
-			  isCloseTo(me->x(), m_loopFrameX));
+			(isCloseTo(pos.x(), m_startFrameX) ||
+			  isCloseTo(pos.x(), m_endFrameX) ||
+			  isCloseTo(pos.x(), m_loopFrameX));
 
 	if (!m_isDragging && pointerCloseToStartEndOrLoop)
 		setCursor(Qt::SizeHorCursor);

plugins/Delay/DelayControlsDialog.cpp

@@ -25,6 +25,7 @@
 #include "AutomatableModel.h"
 #include "DelayControlsDialog.h"
 #include "DelayControls.h"
+#include "DeprecationHelper.h"
 #include "embed.h"
 #include "TempoSyncKnob.h"
 #include "../Eq/EqFader.h"
@@ -139,18 +140,20 @@ void XyPad::mouseReleaseEvent(QMouseEvent *event)
 
 void XyPad::mouseMoveEvent(QMouseEvent *event)
 {
-	if( m_acceptInput && (event->x() >= 0) && ( event->x() < width() )
-			&& ( event->y() >= 0) && ( event->y() < height() ) )
+	const auto pos = position(event);
+
+	if( m_acceptInput && (pos.x() >= 0) && ( pos.x() < width() )
+			&& ( pos.y() >= 0) && ( pos.y() < height() ) )
 	{
 		//set xmodel
 		float xRange = m_xModel->maxValue() - m_xModel->minValue();
 		float xInc = xRange / width();
-		m_xModel->setValue( m_xModel->minValue() + ( event->x() * xInc ) );
+		m_xModel->setValue( m_xModel->minValue() + ( pos.x() * xInc ) );
 
 		//set ymodel
 		float yRange = m_yModel->maxValue() - m_yModel->minValue();
 		float yInc = yRange / height();
-		m_yModel->setValue( m_yModel->minValue() + ( event->y() * yInc ) );
+		m_yModel->setValue( m_yModel->minValue() + ( pos.y() * yInc ) );
 	}
 }
 

plugins/LadspaEffect/LadspaMatrixControlDialog.cpp

@@ -182,7 +182,7 @@ QWidget * LadspaMatrixControlDialog::createMatrixWidget()
 {
 	QWidget *widget = new QWidget(this);
 	QGridLayout *gridLayout = new QGridLayout(widget);
-	gridLayout->setMargin(0);
+	gridLayout->setContentsMargins(0, 0, 0, 0);
 	widget->setLayout(gridLayout);
 
 	arrangeControls(widget, gridLayout);