DrawPathTool: Highlight object that is going to be followed

In complex map situations it is unclear which object will be followed
when the user uses the Shift modifier key to follow lines or area object
boundaries. This change makes the object selection more obvious.

As part of the job we are hardening and making more use of
finishFollowing() that removes the highlight renderables for us.

Co-authored-by: Matthias Kuehlewein <[email protected]>

src/tools/draw_path_tool.cpp

@@ -51,6 +51,7 @@
 #include "core/path_coord.h"
 #include "core/virtual_coord_vector.h"
 #include "core/virtual_path.h"
+#include "core/symbols/combined_symbol.h"
 #include "core/symbols/line_symbol.h"
 #include "core/symbols/symbol.h"
 #include "core/objects/object.h"
@@ -64,6 +65,8 @@
 #include "util/util.h"
 #include "undo/object_undo.h"
 
+#include <core/symbols/point_symbol.h>
+
 
 namespace OpenOrienteering {
 
@@ -73,9 +76,38 @@ DrawPathTool::DrawPathTool(MapEditorController* editor, QAction* tool_action, bo
 , angle_helper(new ConstrainAngleToolHelper())
 , azimuth_helper(new AzimuthInfoHelper(cur_map_widget, active_color))
 , snap_helper(new SnappingToolHelper(this))
+, covering_white_dot(std::make_unique<LineSymbol>())
+, covering_red_dot(std::make_unique<LineSymbol>())
+, follow_highlight_symbol(std::make_unique<CombinedSymbol>())
 , follow_helper(new FollowPathToolHelper())
 , allow_closing_paths(allow_closing_paths)
 {
+	auto const dot_distance = 500;
+
+	covering_red_dot->setSegmentLength(dot_distance);
+	covering_red_dot->setMidSymbolsPerSpot(1);
+	auto* red_dot = new PointSymbol(); // yeah, we are leaking objects here and below -> FIXME
+	auto* red_color = new MapColor(MapColor::CoveringRed);
+	red_dot->setInnerColor(red_color);
+	red_dot->setInnerRadius(150);
+	covering_red_dot->setMidSymbol(red_dot);
+
+	// We cannot use the outer width dot parameter due to the scaling hack for
+	// helper colors (PainterConfig::activate() / if (color_priority < 0 &&
+	// color_priority != MapColor::Registration) ...). So we combine two dotted
+	// lines to get the red dots with white outline.	        
+	covering_white_dot->setSegmentLength(dot_distance);
+	covering_white_dot->setMidSymbolsPerSpot(1);
+	auto* white_dot = new PointSymbol();
+	auto* white_color = new MapColor(MapColor::CoveringWhite);
+	white_dot->setInnerColor(white_color);
+	white_dot->setInnerRadius(180);
+	covering_white_dot->setMidSymbol(white_dot);
+
+	follow_highlight_symbol->setNumParts(2);
+	follow_highlight_symbol->setPart(0, covering_white_dot.get(), false);
+	follow_highlight_symbol->setPart(1, covering_red_dot.get(), false);
+
 	angle_helper->setActive(false);
 	connect(angle_helper.get(), &ConstrainAngleToolHelper::displayChanged, this, &DrawPathTool::updateDirtyRect);
 
@@ -884,7 +916,7 @@ void DrawPathTool::finishDrawing()
 	}
 
 	dragging = false;
-	following = false;
+	finishFollowing();
 	setEditingInProgress(false);
 	if (!ctrl_pressed)
 		angle_helper->setActive(false);
@@ -900,7 +932,7 @@ void DrawPathTool::finishDrawing()
 void DrawPathTool::abortDrawing()
 {
 	dragging = false;
-	following = false;
+	finishFollowing();
 	setEditingInProgress(false);
 	if (!ctrl_pressed)
 		angle_helper->setActive(false);
@@ -938,7 +970,10 @@ void DrawPathTool::updateDirtyRect()
 	}
 	if (shift_pressed || (!editingInProgress() && ctrl_pressed))
 		snap_helper->includeDirtyRect(rect);
+
 	includePreviewRects(rect);
+	if (followed_path)
+		rectInclude(rect, followed_path->getExtent());
 
 	if (is_helper_tool)
 		emit dirtyRectChanged(rect);
@@ -1056,6 +1091,15 @@ void DrawPathTool::startFollowing(SnappingToolHelperSnapInfo& snap_info, const M
 	previous_point_is_curve_point = false;
 	updatePreviewPath();
 	follow_start_index = preview_path->getCoordinateCount() - 1;
+
+	const auto* followed_object = follow_helper->followedObject();
+	const auto& part = followed_object->parts()[follow_helper->partIndex()];
+	followed_path = std::make_unique<PathObject>(follow_highlight_symbol.get());
+	for (auto i = part.first_index; i <= part.last_index; ++i)
+		followed_path->addCoordinate(followed_object->getCoordinate(i));
+	followed_path->update();
+	renderables->insertRenderablesOfObject(followed_path.get());
+	updateDirtyRect();
 }
 
 void DrawPathTool::updateFollowing()
@@ -1090,17 +1134,23 @@ void DrawPathTool::finishFollowing()
 {
 	following = false;
 
-	auto last = preview_path->getCoordinateCount() - 1;
+	renderables->removeRenderablesOfObject(followed_path.get(), false);
+	followed_path.reset();
 
-	previous_point_is_curve_point = (last >= 3 && preview_path->getCoordinate(last - 3).isCurveStart());
-	if (previous_point_is_curve_point)
+	if (preview_path)
 	{
-		const MapCoord first = preview_path->getCoordinate(last - 1);
-		const MapCoord second = preview_path->getCoordinate(last);
+		auto last = preview_path->getCoordinateCount() - 1;
 
-		previous_point_direction = -atan2(second.x() - first.x(), first.y() - second.y());
-		previous_pos_map = MapCoordF(second);
-		previous_drag_map = MapCoordF(2*second.x() - first.x(), 2*second.y() +  - first.y());
+		previous_point_is_curve_point = (last >= 3 && preview_path->getCoordinate(last - 3).isCurveStart());
+		if (previous_point_is_curve_point)
+		{
+			const MapCoord first = preview_path->getCoordinate(last - 1);
+			const MapCoord second = preview_path->getCoordinate(last);
+
+			previous_point_direction = -atan2(second.x() - first.x(), first.y() - second.y());
+			previous_pos_map = MapCoordF(second);
+			previous_drag_map = MapCoordF(2*second.x() - first.x(), 2*second.y() +  - first.y());
+		}
 	}
 
 	updateAngleHelper();

src/tools/draw_path_tool.h

@@ -152,6 +152,10 @@ protected slots:
 	std::unique_ptr<SnappingToolHelper> snap_helper;
 
 	PathObject* append_to_object;
+	std::unique_ptr<PathObject> followed_path;
+	std::unique_ptr<LineSymbol> covering_white_dot;
+	std::unique_ptr<LineSymbol> covering_red_dot;
+	std::unique_ptr<CombinedSymbol> follow_highlight_symbol;
 
 	std::unique_ptr<FollowPathToolHelper> follow_helper;
 	MapCoordVector::size_type follow_start_index;