Implement nearest item selection.

5 files changed, 141 insertions, 57 deletions

diff --git a/Editor.qml b/Editor.qml
index b05c3d9..b7aef56 100644
--- a/Editor.qml
+++ b/Editor.qml
@@ -47,20 +47,27 @@ Rectangle
 
 		onPositionChanged:
 		{
-			mousex = Math.round((mouse.x - canvas.x) / scalexy / snapgrid) * snapgrid - max - offset
-			mousey = max - Math.round((mouse.y - canvas.y) / scalexy / snapgrid) * snapgrid + offset
-
-			if ( mousex < -max)
-				mousex = -max
-			else if ( mousex > max )
-				mousex = max
-			if ( mousey < -max )
-				mousey = -max
-			else if ( mousey > max )
-				mousey = max
-
-			if ( down )
-				canvas.requestPaint()
+			if ( tool === Editor.Tool.Select )
+			{
+				mousex = Math.round((mouse.x - canvas.x) / scalexy) - max - offset
+				mousey = max - Math.round((mouse.y - canvas.y) / scalexy) + offset
+			}
+			else	// snap and clip
+			{
+				mousex = Math.round((mouse.x - canvas.x) / scalexy / snapgrid) * snapgrid - max - offset
+				mousey = max - Math.round((mouse.y - canvas.y) / scalexy / snapgrid) * snapgrid + offset
+				if ( mousex < -max)
+					mousex = -max
+				else if ( mousex > max )
+					mousex = max
+				if ( mousey < -max )
+					mousey = -max
+				else if ( mousey > max )
+					mousey = max
+
+				if ( down )
+					canvas.requestPaint()
+			}
 		}
 
 		onPressed:
@@ -82,7 +89,7 @@ Rectangle
 			{
 				endx = mousex
 				endy = mousey
-				if ( startx != endx && starty != endy )
+				if ( startx != endx || starty != endy )
 				{
 					if ( tool === Editor.Tool.Line )
 					{
diff --git a/symbol.cpp b/symbol.cpp
index f95ba71..ea24933 100644
--- a/symbol.cpp
+++ b/symbol.cpp
@@ -99,7 +99,7 @@ QString& SymEditSymbol::Save(QString& buffer) const
 			position = item.Value;
 			break;
 		}
-		case 'R':
+		case 'R':	// circle
 		{
 			if ( item.Point != position )
 				appendvalue(buffer.append('U'), item.Point, 2);
@@ -155,63 +155,99 @@ SymEditSymbol::Item& SymEditSymbol::AddItem(int operation, QPoint point, QString
 //! Remove item.
 /*!
 	\param index		Item index.
+	\return				True for success.
 */
-void SymEditSymbol::RemoveItem(int index)
+bool SymEditSymbol::RemoveItem(int index)
 {
 	if ( static_cast<size_t>(index) < Items.size() )
 	{
 		Items.erase(Items.begin() + index);
 		ActiveIndex = index - 1;
+		return true;
 	}
+	return false;
 }
 
-//
+//! Select item nearest to point.
+/*!
+	\param point		Point coordinates.
+	\return				Nearest item index.
+*/
 int SymEditSymbol::SelectItem(QPoint point) const
 {
 	ActiveIndex = -1;
 	int index = 0;
-	QPoint previous(0, 0);
 	double minimum = 100.0;
+
+	auto difference = [](const QPoint& start, const QPoint& end) { return QPoint(end.x() - start.x(), end.y() - start.y()); };
+	auto length = [](const QPoint& point) { return sqrt(point.x() * point.x() + point.y() * point.y()); };
+	auto scalar = [](const QPoint& start, const QPoint& end) { return static_cast<double>(start.x() * end.x() + start.y() * end.y()); };
+	auto cross = [](const QPoint& start, const QPoint& end) { return static_cast<double>(start.x() * end.y() - start.y() * end.x()); };
+	auto projection = [&](const QPoint& point, const QPoint& start, const QPoint& end)
+	{
+		QPoint line = difference(start, end);
+		return scalar(difference(start, point), line) / length(line);
+	};
+	auto check = [&](double distance)
+	{
+		if ( ActiveIndex < 0 || distance < minimum )
+		{
+			ActiveIndex = index;
+			minimum = distance;
+		}
+	};
+
+	auto distance = [&](const QPoint& point, const QPoint& start, const QPoint& end)
+	{
+		QPoint line = difference(start, end);
+		double len = length(line), a = projection(point, start, end);
+		if ( a > 0.0 && a < len )
+			check(fabs(cross(difference(start, point), line) / len));
+		check(length(difference(point, start)));
+		check(length(difference(point, end)));
+	};
+
 	for ( const auto& item : Items )
 	{
 		switch ( item.Operation )
 		{
 			case 'D':	// line
 			{
-				//##
+				distance(point, item.Point, item.Value);
 				break;
 			}
 			case 'B':	// rectangle
 			{
-				//##
+				distance(point, item.Point, QPoint(item.Point.x(), item.Value.y()));
+				distance(point, QPoint(item.Point.x(), item.Value.y()), item.Value);
+				distance(point, item.Value, QPoint(item.Value.x(), item.Point.y()));
+				distance(point, QPoint(item.Value.x(), item.Point.y()), item.Point);
 				break;
 			}
 			case 'R':	// circle
 			{
-				double dx = point.x() - previous.x();
-				double dy = point.y() - previous.y();
-				double distance = sqrt(dx * dx + dy * dy);
-				distance = abs(distance - item.Point.x());
-				if ( ActiveIndex < 0 || distance < minimum )
-				{
-					ActiveIndex = index;
-					minimum = distance;
-				}
+				check(fabs(length(difference(point, item.Point)) - item.Value.x()));
 				break;
 			}
 		}
 		++index;
 	}
-	return static_cast<int>(ActiveIndex);
+	return ActiveIndex;
 }
 
-//
+//! Set active item index.
+/*!
+	\param index		Active item index.
+*/
 void SymEditSymbol::SetActiveIndex(int index)
 {
 	ActiveIndex = index;
 }
 
-//
+//! Get active item index.
+/*!
+	\return				Active item index.
+*/
 int SymEditSymbol::GetActiveIndex() const
 {
 	return static_cast<int>(ActiveIndex);
diff --git a/symbol.h b/symbol.h
index 2ee996c..7bd0237 100644
--- a/symbol.h
+++ b/symbol.h
@@ -34,7 +34,7 @@ public:
 	Item& AddItem(int operation, QPoint point, int value, int fill);
 	Item& AddItem(int operation, QPoint point, QPoint end, int fill);
 	Item& AddItem(int operation, QPoint point, QString text, int align);
-	void RemoveItem(int index);
+	bool RemoveItem(int index);
 
 	int SelectItem(QPoint point) const;
 	void SetActiveIndex(int index);
diff --git a/symedit.cpp b/symedit.cpp
index 1138d66..0c9d831 100644
--- a/symedit.cpp
+++ b/symedit.cpp
@@ -180,10 +180,17 @@ void SymEditManager::addTextItem(int operation, QPoint point, QString value, int
 }
 
 //! Remove active item.
-void SymEditManager::removeItem()
+/*!
+	\return				True for success.
+*/
+bool SymEditManager::removeItem()
 {
-	undosave();
-	Symbol.RemoveItem(Symbol.GetActiveIndex());
+	if ( Symbol.GetItemCount() )
+	{
+		undosave();
+		return Symbol.RemoveItem(Symbol.GetActiveIndex());
+	}
+	return false;
 }
 
 //! Get item count.
@@ -202,8 +209,12 @@ int SymEditManager::getItemCount() const
 */
 int SymEditManager::getItemOperation(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	return item.Operation;
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		return item.Operation;
+	}
+	return 0;
 }
 
 //! Get item position.
@@ -213,10 +224,14 @@ int SymEditManager::getItemOperation(int index) const
 */
 QPoint SymEditManager::getItemPosition(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	if ( item.Operation == 'B' )	// normalize to upper left
-		return QPoint(std::min(item.Value.x(), item.Point.x()), std::max(item.Value.y(), item.Point.y()));
-	return item.Point;
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		if ( item.Operation == 'B' )	// normalize to upper left
+			return QPoint(std::min(item.Value.x(), item.Point.x()), std::max(item.Value.y(), item.Point.y()));
+		return item.Point;
+	}
+	return QPoint(0, 0);
 }
 
 //! Get item int value.
@@ -226,8 +241,12 @@ QPoint SymEditManager::getItemPosition(int index) const
 */
 int SymEditManager::getItemValue(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	return item.Value.x();
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		return item.Value.x();
+	}
+	return 0;
 }
 
 //! Get item point value.
@@ -237,10 +256,14 @@ int SymEditManager::getItemValue(int index) const
 */
 QPoint SymEditManager::getItemPoint(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	if ( item.Operation == 'B' )	// normalize to lower right
-		return QPoint(std::max(item.Value.x(), item.Point.x()), std::min(item.Value.y(), item.Point.y()));
-	return item.Value;
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		if ( item.Operation == 'B' )	// normalize to lower right
+			return QPoint(std::max(item.Value.x(), item.Point.x()), std::min(item.Value.y(), item.Point.y()));
+		return item.Value;
+	}
+	return QPoint(0, 0);
 }
 
 //! Get item text value.
@@ -250,30 +273,48 @@ QPoint SymEditManager::getItemPoint(int index) const
 */
 QString SymEditManager::getItemText(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	return item.Text;
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		return item.Text;
+	}
+	return "";
 }
 
 //
 int SymEditManager::getItemFill(int index) const
 {
-	const auto& item = Symbol.GetItem(index);
-	return item.Fill;
+	if ( Symbol.GetItemCount() )
+	{
+		const auto& item = Symbol.GetItem(index);
+		return item.Fill;
+	}
+	return 0;
 }
 
-//
+//! Select item nearest to point.
+/*!
+	\param point		Point coordinates.
+	\return				Nearest item index.
+*/
 int SymEditManager::selectItem(QPoint point) const
 {
 	return Symbol.SelectItem(point);
 }
 
-//
+//! Set active item index.
+/*!
+	\param index		Active item index.
+*/
 void SymEditManager::setActiveIndex(int index)
 {
 	Symbol.SetActiveIndex(index);
 }
 
-//
+//! Get active item index.
+/*!
+	\return				Active item index.
+*/
 int SymEditManager::getActiveIndex() const
 {
 	return Symbol.GetActiveIndex();
diff --git a/symedit.h b/symedit.h
index f10a07a..ba6e822 100644
--- a/symedit.h
+++ b/symedit.h
@@ -69,7 +69,7 @@ public:
 	Q_INVOKABLE void addValueItem(int operation, QPoint point, int value, int fill);
 	Q_INVOKABLE void addPointItem(int operation, QPoint point, QPoint value, int fill);
 	Q_INVOKABLE void addTextItem(int operation, QPoint point, QString value, int align);
-	Q_INVOKABLE void removeItem();
+	Q_INVOKABLE bool removeItem();
 
 	Q_INVOKABLE int getItemCount() const;
 	Q_INVOKABLE int getItemOperation(int index) const;