diff -r 36ea1a8aee33 -r 8305e2f968fb src/ui/canvas.h
--- a/src/ui/canvas.h	Sat Mar 05 13:32:58 2022 +0200
+++ b/src/ui/canvas.h	Sat Mar 05 13:38:22 2022 +0200
@@ -21,6 +21,7 @@
 	void addToSelection(ldraw::id_t id);
 	void setOverpaintCallback(OverpaintCallback fn);
 	void drawWorldPoint(QPainter* painter, const glm::vec3& worldPoint) const;
+	void drawWorldPolyline(QPainter* painter, const std::vector<glm::vec3>& points);
 	void drawWorldPolygon(QPainter* painter, const std::vector<glm::vec3>& points);
 	const std::optional<glm::vec3>& getWorldPosition() const;
 	void adjustGridToView();
@@ -42,6 +43,7 @@
 	void setGridMatrix(const glm::mat4 &newMatrix);
 	glm::vec3 cameraVector() const;
 	bool isGridPerpendicularToScreen(float threshold) const;
+	QVector<QPointF> convertWorldPointsToScreenPoints(const std::vector<glm::vec3>& worldPoints);
 	std::optional<GridProgram> gridProgram;
 	std::optional<AxesProgram> axesProgram;
 	std::optional<VertexProgram> vertexProgram;