Sequencer - Unified drag'n'drop handling

Until now the various types of drag'n'drop were handled separately and
could very possibly interfere with each other. This fixes the problem by
using a single variable for the current type (if any) of drag'n'drop

TODO

@@ -30,7 +30,6 @@ Sync / inputs:
 * Zoom level is mostly useless, fix it
 * Save/restore sets of tracks
 * Edition buttons in toolbar
-* Fix drag-and-drop
 * Moving tracks
 * Moving segments
 * Add curve display

ui-sequencer.cc

@@ -330,6 +330,16 @@ struct T_SyncViewImpl_
 		POINT_VALUE ,
 	};
 
+	// Type of drag-and-drop operation in progress
+	enum class E_DNDType {
+		NONE ,		// No drag'n'drop
+		CLICK ,		// Clicked in an area that will not
+				// cause drag'n'drop to happen
+		TIME ,		// Time being adjusted
+		ZOOM ,		// Zoom region being selected
+		POINT ,		// Point being moved
+	};
+
 	// Make sure all displayed inputs/overrides still exist
 	void checkTracks( ) noexcept;
 	// Make sure the currently selected track/segment/point is still valid
@@ -408,6 +418,7 @@ struct T_SyncViewImpl_
 
 	// Misc stuff
 	T_StringBuilder stringBuffer;	// XXX damn this shit to fucking hell
+	E_DNDType dnd{ E_DNDType::NONE };
 
 	// Computed metrics
 	bool checkLockMode{ false };
@@ -426,7 +437,6 @@ struct T_SyncViewImpl_
 	T_Array< T_TrackPointDisplay > dspPoints;
 
 	// Zoom area selection
-	bool zoomInProgress{ false };
 	float firstZoomPixel;
 	float curZoomPixel;
 
@@ -434,7 +444,6 @@ struct T_SyncViewImpl_
 	T_Optional< T_SyncTrackId > selId{ };
 	T_Optional< uint32_t > selSegment;
 	T_Optional< uint32_t > selPoint;
-	bool selPointDnD{ false };
 	float selPointDnDStart , selPointDnDCur;
 
 	// Original and copy of curve being modified
@@ -829,8 +838,11 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 		return;
 	}
 
-	if ( zoomInProgress && !io.MouseDown[ 1 ] ) {
+	if ( dnd == E_DNDType::ZOOM ) {
-		zoomInProgress = false;
+		if ( io.MouseDown[ 1 ] ) {
+			curZoomPixel = mPixels;
+			return;
+		}
 		checkLockMode = true;
 		const auto zMin{ std::min( firstZoomPixel , curZoomPixel ) } ,
 		      zMax{ std::max( firstZoomPixel , curZoomPixel ) } ,
@@ -846,16 +858,17 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 				zoomLevel = ( ppu - BarWidth ) / ( BarWidth - width / u ) + 1;
 			}
 		}
-	} else if ( zoomInProgress && io.MouseDown[ 1 ] ) {
+	} else if ( dnd == E_DNDType::POINT && handlePointDrag( mPixels , io.MouseDown[ 0 ] ) ) {
-		curZoomPixel = mPixels;
+		return;
+	} else if ( dnd == E_DNDType::CLICK && ( io.MouseDown[ 0 ] || io.MouseDown[ 1 ] ) ) {
+		return;
+	} else if ( dnd == E_DNDType::TIME && io.MouseDown[ 0 ] ) {
+		sync.setTime( mTime );
 		return;
 	}
 
-	if ( selPointDnD && handlePointDrag( mPixels , io.MouseDown[ 0 ] ) ) {
+	if ( dnd != E_DNDType::NONE && !( io.MouseDown[ 0 ] || io.MouseDown[ 1 ] ) ) {
-		return;
+		dnd = E_DNDType::NONE;
-	}
-
-	if ( !( io.MouseDown[ 0 ] || io.MouseDown[ 1 ] ) ) {
 		ClearActiveID( );
 		return;
 	}
@@ -864,10 +877,10 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 	if ( mp.type == E_MousePosType::NONE ) {
 		if ( io.MouseDown[ 0 ] ) {
 			sync.setTime( mTime );
-		}
+			dnd = E_DNDType::TIME;
-		if ( io.MouseDown[ 1 ] ) {
+		} else if ( io.MouseDown[ 1 ] ) {
 			firstZoomPixel = mPixels;
-			zoomInProgress = true;
+			dnd = E_DNDType::ZOOM;
 			curZoomPixel = mPixels;
 
 		}
@@ -878,6 +891,7 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 			selSegment = decltype( selSegment ){};
 			selPoint = decltype( selPoint ){};
 			sub = E_SubWindow::SW_TRACK;
+			dnd = E_DNDType::CLICK;
 		}
 	} else if ( mp.type == E_MousePosType::SEGMENT ) {
 		auto const& dSeg{ dspSegments[ mp.index ] };
@@ -887,6 +901,7 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 			selSegment = dSeg.seg;
 			selPoint = decltype( selPoint ){};
 			sub = E_SubWindow::SW_SEGMENT;
+			dnd = E_DNDType::CLICK;
 		}
 	} else if ( mp.type == E_MousePosType::POINT ) {
 		auto const& dPoint{ dspPoints[ mp.index ] };
@@ -896,8 +911,8 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 			selId = dTrack.id;
 			selSegment = dSeg.seg;
 			selPoint = dPoint.index;
-			selPointDnD = io.MouseDown[ 0 ] && dPoint.index != 0;
+			const bool pdnd{ io.MouseDown[ 0 ] && dPoint.index != 0 };
-			if ( selPointDnD ) {
+			if ( pdnd ) {
 				assert( selUpdate == E_ChangeType::NONE );
 				selPointDnDStart = selPointDnDCur = mPixels;
 				if ( selId->isOverride ) {
@@ -910,6 +925,9 @@ void T_SyncViewImpl_::sequencerWidget( ) noexcept
 					selUpdatingOriginals.add( *sync.getCurve( selId->id ) );
 				}
 				selUpdate = E_ChangeType::POINT_DND;
+				dnd = E_DNDType::POINT;
+			} else {
+				dnd = E_DNDType::CLICK;
 			}
 			sub = E_SubWindow::SW_POINT;
 		}
@@ -1013,7 +1031,7 @@ void T_SyncViewImpl_::sequencerBody(
 
 	dl->AddRectFilled( inner.Min , inner.Max , ColMain );
 	dl->AddRect( bb.Min , bb.Max , ColFrame );
-	if ( zoomInProgress ) {
+	if ( dnd == E_DNDType::ZOOM ) {
 		const float z0{ ImClamp( firstZoomPixel - startPixel + inner.Min.x , inner.Min.x , inner.Max.x ) } ,
 			      z1{ ImClamp( curZoomPixel - startPixel + bb.Min.x , inner.Min.x , inner.Max.x ) };
 		const float zMin{ std::min( z0 , z1 ) } , zMax{ std::max( z0 , z1 ) };
@@ -1430,7 +1448,6 @@ bool T_SyncViewImpl_::handlePointDrag(
 
 	assert( selUpdate == E_ChangeType::POINT_DND );
 	selUpdate = E_ChangeType::NONE;
-	selPointDnD = false;
 	if ( moved ) {
 		auto& undo{ dynamic_cast< T_UndoSyncChanges& >(
 				Common::Undo( ).add< T_UndoSyncChanges >( ) ) };