Drag and drop from external applications v3

include/ClipView.h

@@ -35,6 +35,8 @@
 
 
 class QMenu;
+class QMimeData;
+
 
 namespace lmms
 {
@@ -178,8 +180,9 @@ public slots:
 
 	float pixelsPerBar();
 
-
+	//! Turn a selection of clips into a DataFile used for drag-and-drop or copy
 	DataFile createClipDataFiles(const QVector<ClipView *> & clips) const;
+	virtual QMimeData* createClipboardData();
 
 	virtual void paintTextLabel(QString const & text, QPainter & painter);
 

include/Clipboard.h

@@ -26,8 +26,10 @@
 #define LMMS_CLIPBOARD_H
 
 #include <QDomElement>
-#include <QMap>
+#include <QDropEvent>
+#include <QPixmap>
 
+#include "FileTypes.h"
 #include "lmms_export.h"
 
 class QMimeData;
@@ -38,10 +40,14 @@ namespace lmms::Clipboard
 	enum class MimeType
 	{
 		StringPair,
-		Default
+		// TODO rename Default to DataFile or something
+		// It is used as piano roll clipboard to hold DataFile XML
+		Default,
+		PlainText,
 	};
 
 	// Convenience Methods
+	void copyMimeData(QMimeData* m);
 	const QMimeData * getMimeData();
 	bool hasFormat( MimeType mT );
 
@@ -51,7 +57,10 @@ namespace lmms::Clipboard
 
 	// Helper methods for String Pair data
 	void copyStringPair( const QString & key, const QString & value );
+
+	//! deprecated - use MimeData::toStringPair instead
 	QString decodeKey( const QMimeData * mimeData );
+	//! deprecated - use MimeData::toStringPair instead
 	QString decodeValue( const QMimeData * mimeData );
 
 	inline const char * mimeType( MimeType type )
@@ -60,14 +69,50 @@ namespace lmms::Clipboard
 		{
 			case MimeType::StringPair:
 				return "application/x-lmms-stringpair";
-			break;
 			case MimeType::Default:
-			default:
 				return "application/x-lmms-clipboard";
-				break;
+			default:
+				return "text/plain";
 		}
 	}
 
 } // namespace lmms::Clipboard
 
+
+
+
+namespace lmms::MimeData
+{
+	//! Create a new QMimeData from a string pair
+	LMMS_EXPORT QMimeData* fromStringPair(const QString& key, const QString& value);
+
+	//! Extract string pair from QMimeData
+	LMMS_EXPORT std::pair<QString, QString> toStringPair(const QMimeData* md);
+
+} // namespace lmms::MimeData
+
+
+
+
+namespace lmms::DragAndDrop
+{
+	//! Start a QDrag from given widget, return mouse is released
+	LMMS_EXPORT void exec(QWidget* widget, QMimeData* md, const QPixmap& icon = {});
+
+	//! Start a QDrag containing a string pair
+	LMMS_EXPORT void execStringPairDrag(const QString& key, const QString& value, const QPixmap& icon, QWidget* widget);
+
+	//! Accept drag enter event if it contains a file of allowed type
+	LMMS_EXPORT bool acceptFile(QDragEnterEvent* dee, const std::initializer_list<FileType> allowedTypes);
+
+	//! Accept drag enter event if it contains a string pair of allowed type
+	LMMS_EXPORT bool acceptStringPair(QDragEnterEvent* dee, const std::initializer_list<QString> allowedKeys);
+
+	//! Get file path from drop event (empty if it doesn't match allowedType)
+	LMMS_EXPORT QString getFile(const QDropEvent* de, FileType allowedType);
+	LMMS_EXPORT std::pair<QString, FileType> getFileAndType(const QDropEvent* de);
+	LMMS_EXPORT std::pair<QString, QString> getFileAndExt(const QDropEvent* de);
+
+} // namespace lmms::DragAndDrop
+
 #endif // LMMS_CLIPBOARD_H

include/DataFile.h

@@ -30,6 +30,7 @@
 #include <QDomDocument>
 #include <vector>
 
+#include "FileTypes.h"
 #include "lmms_export.h"
 
 class QTextStream;
@@ -73,6 +74,12 @@ class LMMS_EXPORT DataFile : public QDomDocument
 
 	QString nameWithExtension( const QString& fn ) const;
 
+	//! Return preferred file extension for type
+	static QString extension(Type type);
+
+	//! List all DataFile file extensions (used to build FileTypes database)
+	static std::vector<std::pair<FileType, QString>> allSupportedFileTypes();
+
 	void write( QTextStream& strm );
 	bool writeFile(const QString& fn, bool withResources = false);
 	bool copyResources(const QString& resourcesDir); //!< Copies resources to the resourcesDir and changes the DataFile to use local paths to them

include/FileBrowser.h

@@ -33,6 +33,7 @@
 
 #include <QTreeWidget>
 
+#include "FileTypes.h"
 #include "SideBarWidget.h"
 #include "lmmsconfig.h"
 
@@ -255,30 +256,6 @@ class Directory : public QTreeWidgetItem
 class FileItem : public QTreeWidgetItem
 {
 public:
-	enum class FileType
-	{
-		Project,
-		Preset,
-		Sample,
-		SoundFont,
-		Patch,
-		Midi,
-		VstPlugin,
-		Unknown
-	} ;
-
-	enum class FileHandling
-	{
-		NotSupported,
-		LoadAsProject,
-		LoadAsPreset,
-		LoadByPlugin,
-		ImportAsProject
-	} ;
-
-
-	FileItem( QTreeWidget * parent, const QString & name,
-							const QString & path );
 	FileItem( const QString & name, const QString & path );
 
 	QString fullName() const
@@ -291,29 +268,23 @@ class FileItem : public QTreeWidgetItem
 		return( m_type );
 	}
 
-	inline FileHandling handling() const
-	{
-		return( m_handling );
-	}
-
+	//! True if the file can be used to create a new instrument track
 	inline bool isTrack() const
 	{
-		return m_handling == FileHandling::LoadAsPreset || m_handling == FileHandling::LoadByPlugin;
+		return m_type == FileType::InstrumentPreset
+			|| m_type == FileType::InstrumentAsset
+			|| m_type == FileType::Sample;
 	}
 
 	QString extension();
 	static QString extension( const QString & file );
 	static QString defaultFilters();
 
+	void startFileDrag(QWidget* dragSource);
 
 private:
-	void initPixmaps();
-	void determineFileType();
-
 	QString m_path;
 	FileType m_type;
-	FileHandling m_handling;
-
 } ;
 
 

include/FileTypes.h

@@ -0,0 +1,64 @@
+/*
+ * FileTypes.h
+ *
+ * Copyright (c) 2025 allejok96 <gmail>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ */
+
+#ifndef LMMS_FILE_TYPES_H
+#define LMMS_FILE_TYPES_H
+
+#include <QString>
+
+#include "lmms_export.h"
+
+namespace lmms
+{
+
+class DataFile;
+
+enum class FileType
+{
+	Unknown,
+	ImportableProject, //!< any file that can be imported by some import filter
+	InstrumentAsset, //!< any file that can be loaded by some instrument plugin
+	InstrumentPreset, //!< DataFile of Instrument
+	MidiClipData, //!< DataFile of MidiClip
+	Project,
+	ProjectTemplate,
+	Sample, //! any audio file supported by SampleDecoder
+};
+
+
+namespace FileTypes
+{
+	//! Create a filter string to be used in file dialogs
+	LMMS_EXPORT QString compileFilter(const std::initializer_list<FileType> fileTypes = {}, const QString& label = {});
+
+	//! Return a FileType for the given file extension
+	LMMS_EXPORT FileType find(const QString& ext);
+
+	//! Return an icon name for the given file extension
+	LMMS_EXPORT std::string iconName(const QString& ext);
+
+} // namespace FileTypes
+
+} // namespace lmms
+
+#endif // LMMS_FILE_TYPES_H

include/Plugin.h

@@ -97,11 +97,23 @@ class LMMS_EXPORT Plugin : public Model, public JournallingObject
 		int version;
 		Type type;
 		const PixmapLoader * logo;
-		const char * supportedFileTypes; //!< csv list of extensions
+
+		struct FileTypeInfo
+		{
+			QString ext;
+			std::string iconName = {};
+			bool enablePreview = true;
+		};
+
+		const std::vector<FileTypeInfo> supportedFileTypes;
 
 		inline bool supportsFileType( const QString& extension ) const
 		{
-			return QString( supportedFileTypes ).split( QChar( ',' ) ).contains( extension );
+			for (const auto& fileTypeInfo : supportedFileTypes)
+			{
+				if (fileTypeInfo.ext == extension) { return true; }
+			}
+			return false;
 		}
 
 		/**
@@ -124,7 +136,7 @@ class LMMS_EXPORT Plugin : public Model, public JournallingObject
 				its sub plugin (using the attributes).
 				When keys are saved, those attributes are
 				written to XML in order to find the right sub
-				plugin when realoading.
+				plugin when reloading.
 
 				@note Any data that is not required to reference
 					the right Plugin or sub plugin should

include/PluginFactory.h

@@ -79,6 +79,8 @@ class LMMS_EXPORT PluginFactory
 
 	/// Returns a list of all found plugins' PluginFactory::PluginInfo objects.
 	const PluginInfoList& pluginInfos() const;
+	/// Returns a list of all file extensions supported by any plugin
+	QStringList allSupportedExtensions();
 	/// Returns a plugin that support the given file extension
 	PluginInfoAndKey pluginSupportingExtension(const QString& ext);
 

include/PluginView.h

@@ -25,8 +25,11 @@
 #ifndef LMMS_GUI_PLUGIN_VIEW_H
 #define LMMS_GUI_PLUGIN_VIEW_H
 
+#include <QDragEnterEvent>
+#include <QDropEvent>
 #include <QWidget>
 
+#include "Clipboard.h"
 #include "ModelView.h"
 #include "Plugin.h"
 
@@ -42,6 +45,28 @@ class LMMS_EXPORT PluginView : public QWidget, public ModelView
 	}
 
 	virtual bool isResizable() const { return false; }
+
+protected:
+	void dragEnterEvent(QDragEnterEvent* dee) override
+	{
+		const auto [path, ext] = DragAndDrop::getFileAndExt(dee);
+
+		if (castModel<Plugin>()->descriptor()->supportsFileType(ext))
+		{
+			dee->acceptProposedAction();
+		}
+	}
+
+	void dropEvent(QDropEvent* de) override
+	{
+		const auto [path, ext] = DragAndDrop::getFileAndExt(de);
+
+		if (castModel<Plugin>()->descriptor()->supportsFileType(ext))
+		{
+			castModel<Plugin>()->loadFile(path);
+			de->accept();
+		}
+	}
 };
 
 } // namespace lmms::gui

include/SampleClipView.h

@@ -62,6 +62,7 @@ public slots:
 	void mouseDoubleClickEvent( QMouseEvent * ) override;
 	void paintEvent( QPaintEvent * ) override;
 
+	QMimeData* createClipboardData() override;
 
 private:
 	SampleClip * m_clip;

include/SampleDecoder.h

@@ -30,6 +30,7 @@
 #include <string>
 #include <vector>
 
+#include "lmms_export.h"
 #include "SampleFrame.h"
 
 namespace lmms {
@@ -49,7 +50,7 @@ class SampleDecoder
 	};
 
 	static auto decode(const QString& audioFile) -> std::optional<Result>;
-	static auto supportedAudioTypes() -> const std::vector<AudioType>&;
+	LMMS_EXPORT static auto supportedAudioTypes() -> const std::vector<AudioType>&;
 };
 } // namespace lmms