moving part while dragging, not only on mouseRelease

src/main/java/de/ph87/electro/CONFIG.java

@@ -11,16 +11,12 @@ public class CONFIG {
 
   public static final double MAX_RESISTANCE = 1 / NO_RESISTANCE;
 
-  public static boolean SHOW_WIRE_DETAILS = true;
-
-  public static boolean SHOW_NODE_VOLTAGES = false;
-
-  public static boolean SHOW_NODE_NAMES = false;
-
   public static final double VOLTAGE_HIGH_MIN = 0.1;
 
   public static final int RASTER = 200;
 
+  public static final int SUB_RASTER = RASTER / 5;
+
   public static final int P03 = (int) round(0.03 * RASTER);
 
   public static final int P05 = (int) round(0.05 * RASTER);
@@ -81,6 +77,12 @@ public class CONFIG {
 
   public static final BasicStroke SWITCH_STROKE = new BasicStroke(15);
 
+  public static boolean SHOW_WIRE_DETAILS = false;
+
+  public static boolean SHOW_NODE_VOLTAGES = false;
+
+  public static boolean SHOW_NODE_NAMES = false;
+
   public static Point ALIGN(final Point position) {
     return new Point(position.x / RASTER * RASTER, position.y / RASTER * RASTER);
   }

src/main/java/de/ph87/electro/Window.java

@@ -36,6 +36,11 @@ public class Window extends JFrame {
     setVisible(true);
   }
 
+  public static void main(String[] args) {
+    final Window window = new Window();
+    window.setCircuit(Demos.potiAndVoltmeter());
+  }
+
   public void setCircuit(final Circuit circuit) {
     circuitPanel.setCircuit(circuit);
   }
@@ -51,9 +56,4 @@ public class Window extends JFrame {
     setLocation(screenBounds.x, screenBounds.y);
   }
 
-  public static void main(String[] args) {
-    final Window window = new Window();
-    window.setCircuit(Demos.potiAndVoltmeter());
-  }
-
 }

src/main/java/de/ph87/electro/circuit/Circuit.java

@@ -9,38 +9,42 @@ import de.ph87.electro.circuit.wire.WireDto;
 import lombok.Getter;
 import lombok.NonNull;
 import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
 
 import java.awt.*;
 import java.io.File;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
-import java.util.ArrayList;
 import java.util.List;
-import java.util.Optional;
+import java.util.*;
 import java.util.stream.Stream;
 
 import static de.ph87.electro.CONFIG.ALIGN;
 
+@Slf4j
 public class Circuit {
 
-  @Getter
-  private final String created;
-
-  @Getter
-  private final List<Part> parts = new ArrayList<>();
-
-  private final List<Wire> wires = new ArrayList<>();
-
   @Setter
   @Getter
   private File file = null;
 
+  @NonNull
+  @Getter
+  private final String created;
+
+  @NonNull
+  @Getter
+  private final List<Part> parts = new ArrayList<>();
+
+  @NonNull
+  private final List<Wire> wires = new ArrayList<>();
+
   public Circuit() {
     this.created = ZonedDateTime.now().format(DateTimeFormatter.ISO_OFFSET_DATE_TIME);
   }
 
   @SuppressWarnings("unused")
-  public Circuit(final File file, final CircuitDto dto) {
+  public Circuit(@NonNull final File file, @NonNull final CircuitDto dto) {
     this.created = dto.getCreated();
     for (PartDto partDto : dto.getParts()) {
       final Part part = Part.fromDto(partDto);
@@ -54,13 +58,23 @@ public class Circuit {
     }
   }
 
-  public Wire connect(final Node a, final Node b) {
+  public void connect(@NonNull final Node a, @NonNull final Node b) {
+    if (a == b) {
+      log.warn("No Wire created: Nodes are identical: {}", a);
+      return;
+    }
+    final Optional<Wire> duplicate = a.getWires().stream().filter(w -> w.getOpposite(a) == b).findFirst();
+    if (duplicate.isPresent()) {
+      log.warn("No Wire created: Between these nodes, a wire already exists: {}", duplicate);
+      return;
+    }
     final Wire wire = new Wire(a, b);
     wires.add(wire);
-    return wire;
+    log.info("Wire CREATED: {}", wire);
+    evaluate();
   }
 
-  public void disconnect(final Wire wire) {
+  public void disconnect(@NonNull final Wire wire) {
     if (!wires.contains(wire)) {
       throw new RuntimeException();
     }
@@ -69,7 +83,7 @@ public class Circuit {
     wire.getB().getWires().remove(wire);
   }
 
-  public <T extends Part> T addPart(final T part) {
+  public <T extends Part> T addPart(@NonNull final T part) {
     if (parts.contains(part)) {
       throw new RuntimeException();
     }
@@ -78,7 +92,21 @@ public class Circuit {
     return part;
   }
 
-  public void removePart(final Part part) {
+  public void removePart(@NonNull final Part part) {
+    for (final Node node : part.getNodes()) {
+      Node origin = null;
+      Set<Node> destinations = new HashSet<>();
+      for (final Wire wire : node.getWires()) {
+        if (origin == null) {
+          origin = wire.getOpposite(node);
+        } else {
+          destinations.add(wire.getOpposite(node));
+        }
+      }
+      for (final Node destination : destinations) {
+        connect(origin, destination);
+      }
+    }
     if (parts.remove(part)) {
       part.getNodes().stream().flatMap(node -> node.getWires().stream()).toList().forEach(this::disconnect); // jep, first toList(), then forEach (due to concurrent modification)
     } else {
@@ -86,13 +114,13 @@ public class Circuit {
     }
   }
 
-  public void verifyFree(final Point position) {
+  public void verifyFree(@NonNull final Point position) {
     if (isOccupied(position)) {
       throw new RuntimeException();
     }
   }
 
-  public boolean isOccupied(final Point position) {
+  public boolean isOccupied(@NonNull final Point position) {
     final Point aligned = ALIGN(position);
     return parts.stream().anyMatch(part -> part.getPosition().equals(aligned));
   }
@@ -109,16 +137,15 @@ public class Circuit {
     return parts.size();
   }
 
-  public Optional<Part> findPartByPosition(final Point position) {
+  public Optional<Part> findPartByPosition(@NonNull final Point position) {
-    final Point aligned = ALIGN(position);
+    return streamParts().filter(p -> p.intersects(position)).findFirst();
-    return streamParts().filter(p -> p.getPosition().equals(aligned)).findFirst();
   }
 
-  public Optional<Node> findNodeByUuid(@NonNull final String nodeUuid) {
+  public Optional<? extends Node> findNodeByUuid(@NonNull final String nodeUuid) {
     return parts.stream().map(part -> part.findNodeByUuid(nodeUuid)).filter(Optional::isPresent).map(Optional::get).findFirst();
   }
 
-  public Optional<Wire> findWireByPosition(final Point position) {
+  public Optional<Wire> findWireByPosition(@NonNull final Point position) {
     return wires.stream().filter(wire -> wire.intersects(position)).findFirst();
   }
 

src/main/java/de/ph87/electro/circuit/CircuitPainter.java

@@ -69,7 +69,7 @@ public class CircuitPainter {
 
     for (Part part : circuit.getParts()) {
       for (final Node node : part.getNodes()) {
-        final Point absolute = node.getAbsolute();
+        final Point absolute = node.getPosition();
         if (SHOW_NODE_NAMES) {
           int offsetY = third;
           if (SHOW_NODE_VOLTAGES) {

src/main/java/de/ph87/electro/circuit/CircuitPanel.java

@@ -40,7 +40,7 @@ public class CircuitPanel extends JPanel {
   public void paint(final Graphics graphics) {
     final Graphics2D g = (Graphics2D) graphics;
     CircuitPainter.draw(g, circuit, getWidth(), getHeight());
-    mouseAdapter.drawHover(g);
+    mouseAdapter.drawHovers(g);
     mouseAdapter.drawDrag(g);
   }
 

src/main/java/de/ph87/electro/circuit/CircuitPanelDropTarget.java

@@ -22,12 +22,6 @@ public class CircuitPanelDropTarget extends AbstractDropTarget {
     final Point aligned = ALIGN(point);
     if (data.equals(Battery.class.getSimpleName())) {
       circuitPanel.getCircuit().addPart(new Battery(aligned));
-    } else if (data.equals(ConnectorCorner.class.getSimpleName())) {
-      circuitPanel.getCircuit().addPart(new ConnectorCorner(aligned));
-    } else if (data.equals(ConnectorEdge.class.getSimpleName())) {
-      circuitPanel.getCircuit().addPart(new ConnectorEdge(aligned));
-    } else if (data.equals(ConnectorMiddle.class.getSimpleName())) {
-      circuitPanel.getCircuit().addPart(new ConnectorMiddle(aligned));
     } else if (data.equals(Light.class.getSimpleName())) {
       circuitPanel.getCircuit().addPart(new Light(aligned));
     } else if (data.equals(Switch1x1.class.getSimpleName())) {

src/main/java/de/ph87/electro/circuit/CircuitPanelMouseAdapter.java

@@ -2,7 +2,9 @@ package de.ph87.electro.circuit;
 
 import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.part.node.Node;
+import de.ph87.electro.circuit.part.parts.ConnectorSub;
 import de.ph87.electro.circuit.wire.Wire;
+import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
 
 import java.awt.*;
@@ -25,66 +27,112 @@ class CircuitPanelMouseAdapter extends MouseAdapter {
 
   private Point dragging = null;
 
-  CircuitPanelMouseAdapter(final CircuitPanel circuitPanel) {
+  private Part part2 = null;
+
+  private Node node2 = null;
+
+  private Point draggingSub;
+
+  CircuitPanelMouseAdapter(@NonNull final CircuitPanel circuitPanel) {
     this.circuitPanel = circuitPanel;
     circuitPanel.addMouseListener(this);
     circuitPanel.addMouseMotionListener(this);
   }
 
-  @Override
+  /* HOVER ---------------------------------------------------------------------------------------- */
-  public void mouseClicked(final MouseEvent event) {
-    hoverUpdate(event);
 
-    if (wire != null) {
+  @Override
-      switch (event.getButton()) {
+  public void mouseMoved(@NonNull final MouseEvent event) {
-        case BUTTON3:
+    findHovers(event);
-          circuitPanel.getCircuit().disconnect(wire);
+    circuitPanel.repaint();
-          circuitPanel.getCircuit().evaluate();
+  }
-          wire = null;
+
-          break;
+  private void findHovers(@NonNull final MouseEvent event) {
+    final Point position = event.getPoint();
+    part = circuitPanel.getCircuit().findPartByPosition(position).orElse(null);
+    node = part != null ? part.findNodeByPosition(position).orElse(null) : null;
+    if (node != null) {
+      part = null;
+      if (wire != null) {
+        wire.setGhost(false);
       }
-    }
+      wire = null;
-
-    if (part != null) {
-      switch (event.getButton()) {
-        case BUTTON1:
-          part.action();
-          circuitPanel.getCircuit().evaluate();
-          break;
-        case BUTTON2:
-          part.rotate();
-          break;
-        case BUTTON3:
-          circuitPanel.getCircuit().removePart(part);
-          circuitPanel.getCircuit().evaluate();
-          part = null;
-          break;
-      }
-    }
-
-    circuitPanel.repaint();
-  }
-
-  @Override
-  public void mouseMoved(final MouseEvent event) {
-    hoverUpdate(event);
-    circuitPanel.repaint();
-  }
-
-  @Override
-  public void mouseDragged(final MouseEvent event) {
-    if (dragging == null) {
-      hoverUpdate(event);
-    }
-    dragging = event.getPoint();
-    circuitPanel.repaint();
-  }
-
-  @Override
-  public void mouseReleased(final MouseEvent event) {
-    if (dragging == null) {
       return;
     }
+    wire = circuitPanel.getCircuit().findWireByPosition(position).orElse(null);
+    if (wire != null) {
+      part = null;
+    }
+  }
+
+  public void drawHovers(@NonNull final Graphics2D g) {
+    drawPartHover(g);
+    drawNodeHover(g, node);
+    drawNodeHover(g, node2);
+    drawWireHover(g);
+  }
+
+  private void drawPartHover(@NonNull final Graphics2D g) {
+    if (part == null) {
+      return;
+    }
+
+    g.setColor(NODE_HOVER_BORDER_COLOR);
+    g.setStroke(HOVER_STROKE);
+    g.drawRect(part.getPosition().x, part.getPosition().y, RASTER, RASTER);
+  }
+
+  private void drawNodeHover(@NonNull final Graphics2D g, final Node n) {
+    if (n == null) {
+      return;
+    }
+
+    final Point absolute = n.getPosition();
+
+    g.setColor(n.getColor());
+    g.fillArc(absolute.x - NODE_RADIUS_HOVER, absolute.y - NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 0, 360);
+
+    g.setColor(NODE_HOVER_BORDER_COLOR);
+    g.setStroke(HOVER_STROKE);
+    g.drawArc(absolute.x - NODE_RADIUS_HOVER, absolute.y - NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 0, 360);
+  }
+
+  private void drawWireHover(@NonNull final Graphics2D g) {
+    if (wire == null || wire.isGhost()) {
+      return;
+    }
+
+    final Point aa = wire.getA().getPosition();
+    final Point bb = wire.getB().getPosition();
+
+    g.setColor(WIRE_HOVER_COLOR_BACK);
+    g.setStroke(WIRE_HOVER_STROKE_BACK);
+    g.drawLine(aa.x, aa.y, bb.x, bb.y);
+
+    g.setColor(wire.getA().getColor());
+    g.setStroke(WIRE_HOVER_STROKE);
+    g.drawLine(aa.x, aa.y, bb.x, bb.y);
+  }
+
+  /* DRAG ----------------------------------------------------------------------------------------- */
+
+  @Override
+  public void mouseDragged(@NonNull final MouseEvent event) {
+    if (dragging == null) {
+      findHovers(event);
+      if (wire != null) {
+        wire.setGhost(true);
+      }
+    } else {
+      part2 = circuitPanel.getCircuit().findPartByPosition(dragging).orElse(null);
+      node2 = part2 == null ? null : part2.findNodeByPosition(dragging).orElse(null);
+    }
+
+    dragging = event.getPoint();
+    draggingSub = new Point(
+      dragging.x / SUB_RASTER * SUB_RASTER,
+      dragging.y / SUB_RASTER * SUB_RASTER
+    );
 
     if (part != null) {
       final Point aligned = ALIGN(event.getPoint());
@@ -96,80 +144,184 @@ class CircuitPanelMouseAdapter extends MouseAdapter {
       }
     }
 
+
+    circuitPanel.repaint();
+  }
+
+  @Override
+  public void mouseReleased(@NonNull final MouseEvent event) {
+    if (dragging == null) {
+      return;
+    }
+
     if (node != null) {
       final Node source = node;
-      hoverUpdate(event);
+      findHovers(event);
       if (node != null) {
-        final Wire wire = circuitPanel.getCircuit().connect(source, node);
+        circuitPanel.getCircuit().connect(source, node);
-        log.info("Wire CREATED: {}", wire);
         circuitPanel.getCircuit().evaluate();
       } else {
         log.info("No Wire created: No destination node found!");
       }
     }
 
+    if (wire != null) {
+      wireBend();
+    }
+
+    terminateMouseAction();
+  }
+
+  private void wireBend() {
+    if (node2 != null) {
+      wireBendToExistingNode();
+    } else {
+      wireBendToNewConnector();
+    }
+  }
+
+  private void wireBendToExistingNode() {
+    if (wire == null) {
+      throw new RuntimeException();
+    }
+    if (node2 == wire.getA() || node2 == wire.getB()) {
+      log.info("Wire-bending-destination node is already part of that wire: wire={}, node={}", wire, node2);
+      return;
+    }
+    connectIntermediate(node2);
+  }
+
+  private void wireBendToNewConnector() {
+    final ConnectorSub newConnector = circuitPanel.getCircuit().addPart(new ConnectorSub(draggingSub));
+    connectIntermediate(newConnector.getNode());
+  }
+
+  private void connectIntermediate(@NonNull final Node intermediate) {
+    circuitPanel.getCircuit().connect(wire.getA(), intermediate);
+    circuitPanel.getCircuit().connect(intermediate, wire.getB());
+    circuitPanel.getCircuit().disconnect(wire);
+    circuitPanel.getCircuit().evaluate();
+  }
+
+  public void drawDrag(@NonNull final Graphics2D g) {
+    drawPartDrag(g);
+    drawNodeDrag(g);
+    drawWireDrag(g);
+  }
+
+  private void drawWireDrag(@NonNull final Graphics2D g) {
+    if (dragging == null || wire == null) {
+      return;
+    }
+
+    final Point vertex;
+    if (part2 != null) {
+      if (node2 == null) {
+        // hovering part, but not a node
+        vertex = dragging;
+      } else {
+        // hovering existing node
+        vertex = node2.getPosition();
+      }
+    } else {
+      // hovering free space (will create a new connector in sub-raster)
+      g.setColor(PART_HOVER_COLOR);
+      g.fillRect(draggingSub.x, draggingSub.y, SUB_RASTER, SUB_RASTER);
+      vertex = new Point(
+        draggingSub.x + SUB_RASTER / 2,
+        draggingSub.y + SUB_RASTER / 2
+      );
+    }
+
+    // wire
+    g.setColor(wire.getA().getColor());
+    g.setStroke(WIRE_STROKE);
+    g.drawLine(wire.getA().getPosition().x, wire.getA().getPosition().y, vertex.x, vertex.y);
+    g.drawLine(vertex.x, vertex.y, wire.getB().getPosition().x, wire.getB().getPosition().y);
+  }
+
+  private void drawNodeDrag(@NonNull final Graphics2D g) {
+    if (dragging == null || node == null) {
+      return;
+    }
+    g.setColor(node.getColor());
+    g.setStroke(WIRE_STROKE);
+    final Point absolute = node.getPosition();
+    g.drawLine(absolute.x, absolute.y, dragging.x, dragging.y);
+  }
+
+  private void drawPartDrag(@NonNull final Graphics2D g) {
+    if (dragging == null || part == null) {
+      return;
+    }
+    g.setColor(PART_HOVER_COLOR);
+    g.fillRect(dragging.x - P50, dragging.y - P50, RASTER, RASTER);
+  }
+
+  /* CLICK ---------------------------------------------------------------------------------------- */
+
+  @Override
+  public void mouseClicked(@NonNull final MouseEvent event) {
+    findHovers(event);
+    if (mouseClickedAction(event)) {
+      terminateMouseAction();
+    }
+  }
+
+  private boolean mouseClickedAction(@NonNull final MouseEvent event) {
+    if (node != null && node.getPart() instanceof ConnectorSub) {
+      switch (event.getButton()) {
+        case BUTTON3:
+          circuitPanel.getCircuit().removePart(node.getPart());
+          circuitPanel.getCircuit().evaluate();
+          return true;
+      }
+    }
+    if (wire != null) {
+      switch (event.getButton()) {
+        case BUTTON3:
+          circuitPanel.getCircuit().disconnect(wire);
+          circuitPanel.getCircuit().evaluate();
+          return true;
+      }
+    }
+    if (part != null) {
+      switch (event.getButton()) {
+        case BUTTON1:
+          part.action();
+          circuitPanel.getCircuit().evaluate();
+          return true;
+        case BUTTON2:
+          part.rotate();
+          return true;
+        case BUTTON3:
+          circuitPanel.getCircuit().removePart(part);
+          circuitPanel.getCircuit().evaluate();
+          part = null;
+          return true;
+      }
+    }
+    return false;
+  }
+
+  /* COMMON --------------------------------------------------------------------------------------- */
+
+  private void terminateMouseAction() {
+    if (wire != null) {
+      wire.setGhost(false);
+    }
+
+    part = null;
+    node = null;
+    wire = null;
+
+    part2 = null;
+    node2 = null;
+
     dragging = null;
+    draggingSub = null;
+
     circuitPanel.repaint();
   }
 
-  private void hoverUpdate(final MouseEvent event) {
-    final Point position = event.getPoint();
-    part = circuitPanel.getCircuit().findPartByPosition(position).orElse(null);
-    node = part != null ? part.findNodeByPosition(position).orElse(null) : null;
-    if (node != null) {
-      part = null;
-      wire = null;
-      return;
-    }
-    wire = circuitPanel.getCircuit().findWireByPosition(position).orElse(null);
-    if (wire != null) {
-      part = null;
-    }
-  }
-
-  public void drawHover(final Graphics2D g) {
-    if (part != null) {
-      g.setColor(NODE_HOVER_BORDER_COLOR);
-      g.setStroke(HOVER_STROKE);
-      g.drawRect(part.getPosition().x, part.getPosition().y, RASTER, RASTER);
-    }
-    if (node != null) {
-      final Point absolute = node.getAbsolute();
-
-      g.setColor(node.getColor());
-      g.fillArc(absolute.x - NODE_RADIUS_HOVER, absolute.y - NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 0, 360);
-
-      g.setColor(NODE_HOVER_BORDER_COLOR);
-      g.setStroke(HOVER_STROKE);
-      g.drawArc(absolute.x - NODE_RADIUS_HOVER, absolute.y - NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 2 * NODE_RADIUS_HOVER, 0, 360);
-    }
-    if (wire != null) {
-      final Point aa = wire.getA().getAbsolute();
-      final Point bb = wire.getB().getAbsolute();
-
-      g.setColor(WIRE_HOVER_COLOR_BACK);
-      g.setStroke(WIRE_HOVER_STROKE_BACK);
-      g.drawLine(aa.x, aa.y, bb.x, bb.y);
-
-      g.setColor(wire.getA().getColor());
-      g.setStroke(WIRE_HOVER_STROKE);
-      g.drawLine(aa.x, aa.y, bb.x, bb.y);
-    }
-  }
-
-  public void drawDrag(final Graphics2D g) {
-    if (dragging != null) {
-      if (part != null) {
-        g.setColor(PART_HOVER_COLOR);
-        g.fillRect(dragging.x - P50, dragging.y - P50, RASTER, RASTER);
-      }
-      if (node != null) {
-        g.setColor(node.getColor());
-        g.setStroke(WIRE_STROKE);
-        final Point absolute = node.getAbsolute();
-        g.drawLine(absolute.x, absolute.y, dragging.x, dragging.y);
-      }
-    }
-  }
-
 }

src/main/java/de/ph87/electro/circuit/calculation/Calculation.java

@@ -12,10 +12,7 @@ import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.math3.linear.*;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 
 import static java.lang.Math.max;
 
@@ -35,20 +32,6 @@ public class Calculation {
 
   private RealVector potentials = null;
 
-  public static List<Calculation> calculate(final Circuit circuit) {
-    final List<Calculation> calculations = new ArrayList<>();
-    final List<Battery> batteries = new ArrayList<>(circuit.streamParts().flatMap(Battery::filterCast).toList());
-    while (!batteries.isEmpty()) {
-      final Battery pivot = batteries.removeFirst();
-      final Set<Node> connectedNodes = new HashSet<>();
-      pivot.getPlus().collectConnectedNodes(connectedNodes);
-      pivot.getMinus().collectConnectedNodes(connectedNodes);
-      connectedNodes.stream().map(Node::getOwner).flatMap(Battery::filterCast).forEach(batteries::remove);
-      calculations.add(new Calculation(connectedNodes, pivot));
-    }
-    return calculations;
-  }
-
   public Calculation(final int numNodes) {
     matrix = new Array2DRowRealMatrix(numNodes, numNodes);
     currents = new ArrayRealVector(numNodes);
@@ -56,7 +39,9 @@ public class Calculation {
 
   private Calculation(final Set<Node> connectedNodes, final Battery pivot) {
     for (final Node node : connectedNodes) {
-      parts.add(node.getOwner());
+      if (node instanceof final Node partNode) {
+        parts.add(partNode.getPart());
+      }
       if (!nodes.contains(node) && node != pivot.getMinus()) {
         // pivot.minus is GND and cannot be part of the matrix (linear dependency)
         this.nodes.add(node);
@@ -71,6 +56,20 @@ public class Calculation {
     toSchematic();
   }
 
+  public static List<Calculation> calculate(final Circuit circuit) {
+    final List<Calculation> calculations = new ArrayList<>();
+    final List<Battery> batteries = new ArrayList<>(circuit.streamParts().flatMap(Battery::filterCast).toList());
+    while (!batteries.isEmpty()) {
+      final Battery pivot = batteries.removeFirst();
+      final Set<Node> connectedNodes = new HashSet<>();
+      pivot.getPlus().collectConnectedNodes(connectedNodes);
+      pivot.getMinus().collectConnectedNodes(connectedNodes);
+      connectedNodes.stream().map(Node::getPart).flatMap(Battery::filterCast).forEach(batteries::remove);
+      calculations.add(new Calculation(connectedNodes, pivot));
+    }
+    return calculations;
+  }
+
   private void fromSchematic() {
     wires.forEach(
       wire -> addResistor(wire.getA(), wire.getB(), CONFIG.NO_RESISTANCE)
@@ -191,12 +190,12 @@ public class Calculation {
   @Getter
   private static final class Format {
 
+    private final String format;
+
     private int integer;
 
     private int decimal;
 
-    private final String format;
-
     public Format(final RealMatrix matrix) {
       for (int r = 0; r < matrix.getRowDimension(); r++) {
         for (int c = 0; c < matrix.getColumnDimension(); c++) {

src/main/java/de/ph87/electro/circuit/part/Part.java

@@ -14,92 +14,121 @@ import java.awt.geom.Point2D;
 import java.util.List;
 import java.util.*;
 
-import static de.ph87.electro.CONFIG.*;
+import static de.ph87.electro.CONFIG.P50;
+import static de.ph87.electro.CONFIG.PART_BACK_COLOR;
 import static java.lang.Math.round;
 
 @Getter
 @ToString(onlyExplicitlyIncluded = true)
 public abstract class Part {
 
+  @NonNull
   @ToString.Include
   private final String uuid;
 
+  @NonNull
+  private final List<Node> nodes = new ArrayList<>();
+
+  @NonNull
+  protected Orientation orientation = Orientation.R0;
+
+  @NonNull
   @Setter
   @ToString.Include
   private String name;
 
+  @NonNull
   private Point position;
 
-  protected Orientation orientation = Orientation.R0;
-
-  private final List<Node> nodes = new ArrayList<>();
-
   @NonNull
-  private AffineTransform transform;
+  private AffineTransform transform = new AffineTransform();
 
-  protected Part(final String name, final Point position) {
+  protected Part(@NonNull final String name, @NonNull final Point position) {
     this.uuid = UUID.randomUUID().toString();
     this.name = name;
     this.position = position;
-    this.transform = newTransform();
+    updateTransform();
   }
 
-  protected Part(final PartDto dto) {
+  protected Part(@NonNull final PartDto dto) {
     this.uuid = dto.getUuid();
     this.name = dto.getName();
     this.orientation = dto.getOrientation();
     this.position = dto.getPosition();
-    this.transform = newTransform();
+    updateTransform();
   }
 
-  private AffineTransform newTransform() {
+  @NonNull
-    final AffineTransform transform = new AffineTransform();
+  public static Part fromDto(@NonNull final PartDto abstractDto) {
-    transform.translate(position.x, position.y);
+    return switch (abstractDto) {
-    transform.rotate(orientation.getRadians(), P50, P50);
+      case final BatteryDto dto -> new Battery(dto);
-    return transform;
+      case final LightDto dto -> new Light(dto);
+      case final ConnectorSubDto dto -> new ConnectorSub(dto);
+      case final Switch1x1Dto dto -> new Switch1x1(dto);
+      case final Switch1x2Dto dto -> new Switch1x2(dto);
+      case final SwitchCrossDto dto -> new SwitchCross(dto);
+      case final PotiDto dto -> new Poti(dto);
+      case final VoltmeterDto dto -> new Voltmeter(dto);
+      case null, default -> throw new RuntimeException();
+    };
   }
 
-  public Point transform(final Point point) {
+  @NonNull
-    final Point2D result = transform.transform(point, new Point2D.Double());
+  public abstract Point getSize();
-    return new Point((int) round(result.getX()), (int) round(result.getY()));
-  }
 
-  protected Node addNode(final String name, final int x, final int y) {
+  public void setPosition(@NonNull final Point position) {
-    return addNode(new Node(this, name, new Point(x, y)));
-  }
-
-  protected Node addNode(final NodeDto dto, final int x, final int y) {
-    return addNode(new Node(this, dto, new Point(x, y)));
-  }
-
-  private Node addNode(final Node node) {
-    nodes.add(node);
-    return node;
-  }
-
-  public void setPosition(final Point position) {
     this.position = position;
-    this.transform = newTransform();
+    updateTransform();
   }
 
   public void rotate() {
     this.orientation = orientation.clockwise();
-    this.transform = newTransform();
+    updateTransform();
   }
 
-  public final void draw(final Graphics2D g) {
+  @NonNull
+  private void updateTransform() {
+    transform = new AffineTransform();
+    transform.translate(position.x, position.y);
+    transform.rotate(orientation.getRadians(), P50, P50);
+    nodes.forEach(Node::positionChanged);
+  }
+
+  @NonNull
+  public Point transform(@NonNull final Point point) {
+    final Point2D result = transform.transform(point, new Point2D.Double());
+    return new Point((int) round(result.getX()), (int) round(result.getY()));
+  }
+
+  @NonNull
+  protected Node addNode(@NonNull final String name, final int x, final int y) {
+    return addNode(new Node(this, name, new Point(x, y)));
+  }
+
+  @NonNull
+  protected Node addNode(@NonNull final NodeDto dto, final int x, final int y) {
+    return addNode(new Node(this, dto, new Point(x, y)));
+  }
+
+  @NonNull
+  private Node addNode(@NonNull final Node node) {
+    nodes.add(node);
+    return node;
+  }
+
+  public final void draw(@NonNull final Graphics2D g) {
     g.setColor(PART_BACK_COLOR);
-    g.fillRect(0, 0, RASTER, RASTER);
+    g.fillRect(0, 0, getSize().x, getSize().y);
     _render(g);
     nodes.forEach(node -> node.draw(g));
     _labels(g);
   }
 
-  protected void _render(final Graphics2D g) {
+  protected void _render(@NonNull final Graphics2D g) {
     // -
   }
 
-  protected void _labels(final Graphics2D g) {
+  protected void _labels(@NonNull final Graphics2D g) {
     // -
   }
 
@@ -111,32 +140,24 @@ public abstract class Part {
     // -
   }
 
+  @NonNull
   public List<InnerConnection> getInnerConnections() {
     return Collections.emptyList();
   }
 
-  public Optional<Node> findNodeByUuid(final String nodeUuid) {
+  @NonNull
+  public Optional<Node> findNodeByUuid(@NonNull final String nodeUuid) {
     return nodes.stream().filter(node -> node.getUuid().equals(nodeUuid)).findFirst();
   }
 
-  public Optional<Node> findNodeByPosition(final Point position) {
+  @NonNull
+  public Optional<Node> findNodeByPosition(@NonNull final Point position) {
     return nodes.stream().filter(node -> node.intersects(position)).findFirst();
   }
 
-  public static Part fromDto(final PartDto abstractDto) {
+  public boolean intersects(@NonNull final Point point) {
-    return switch (abstractDto) {
+    return this.position.x <= point.x && point.x < this.position.x + this.getSize().x
-      case final BatteryDto dto -> new Battery(dto);
+      && this.position.y <= point.y && point.y < this.position.y + this.getSize().y;
-      case final ConnectorCornerDto dto -> new ConnectorCorner(dto);
-      case final ConnectorEdgeDto dto -> new ConnectorEdge(dto);
-      case final ConnectorMiddleDto dto -> new ConnectorMiddle(dto);
-      case final LightDto dto -> new Light(dto);
-      case final Switch1x1Dto dto -> new Switch1x1(dto);
-      case final Switch1x2Dto dto -> new Switch1x2(dto);
-      case final SwitchCrossDto dto -> new SwitchCross(dto);
-      case final PotiDto dto -> new Poti(dto);
-      case final VoltmeterDto dto -> new Voltmeter(dto);
-      case null, default -> throw new RuntimeException();
-    };
   }
 
 }

src/main/java/de/ph87/electro/circuit/part/PartDto.java

@@ -32,10 +32,8 @@ public abstract class PartDto {
   public static PartDto of(final Part abstractPart) {
     return switch (abstractPart) {
       case final Battery part -> new BatteryDto(part);
-      case final ConnectorCorner part -> new ConnectorCornerDto(part);
-      case final ConnectorEdge part -> new ConnectorEdgeDto(part);
-      case final ConnectorMiddle part -> new ConnectorMiddleDto(part);
       case final Light part -> new LightDto(part);
+      case final ConnectorSub part -> new ConnectorSubDto(part);
       case final Switch1x1 part -> new Switch1x1Dto(part);
       case final Switch1x2 part -> new Switch1x2Dto(part);
       case final SwitchCross part -> new SwitchCrossDto(part);

src/main/java/de/ph87/electro/circuit/part/node/Node.java

@@ -3,6 +3,7 @@ package de.ph87.electro.circuit.part.node;
 import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.wire.Wire;
 import lombok.Getter;
+import lombok.NonNull;
 import lombok.ToString;
 
 import java.awt.*;
@@ -17,50 +18,67 @@ import static de.ph87.electro.CONFIG.*;
 @ToString(onlyExplicitlyIncluded = true)
 public class Node {
 
+  @NonNull
   @ToString.Include
   private final String uuid;
 
-  private final Part owner;
+  @NonNull
-
   @ToString.Include
   private final String name;
 
+  @NonNull
+  private final Part part;
+
+  @NonNull
   private final Point inside;
 
+  @NonNull
   private final Set<Wire> wires = new HashSet<>();
 
+  @NonNull
+  protected Point position;
+
+  @NonNull
   @ToString.Include
   private double voltage = Double.NaN;
 
+  @NonNull
   private Color color = VOLTAGE_UNKNOWN_COLOR;
 
+  public Node(@NonNull final Part part, @NonNull final String name, @NonNull final Point inside) {
+    this.part = part;
+    this.inside = inside;
+    this.uuid = UUID.randomUUID().toString();
+    this.name = name;
+    this.position = part.transform(inside);
+  }
+
+  public Node(@NonNull final Part part, @NonNull final NodeDto dto, @NonNull final Point inside) {
+    this.uuid = dto.getUuid();
+    this.name = dto.getName();
+    this.part = part;
+    this.inside = inside;
+    this.position = part.transform(inside);
+  }
+
+  @NonNull
   @ToString.Include
   @SuppressWarnings("unused") // lombok toString
   public List<String> destinations() {
     return wires.stream().map(wire -> wire.getOpposite(this)).map(Node::getUuid).toList();
   }
 
-  public Node(final Part owner, final String name, final Point inside) {
-    this.owner = owner;
-    this.uuid = UUID.randomUUID().toString();
-    this.name = name;
-    this.inside = inside;
-  }
-
-  public Node(final Part owner, final NodeDto dto, final Point inside) {
-    this.owner = owner;
-    this.uuid = dto.getUuid();
-    this.name = dto.getName();
-    this.inside = inside;
-  }
-
   public void setVoltage(final double voltage) {
     this.voltage = voltage;
     this.color = Double.isNaN(voltage) ? VOLTAGE_UNKNOWN_COLOR : ((voltage >= VOLTAGE_HIGH_MIN) ? VOLTAGE_HIGH_COLOR : VOLTAGE_LOW_COLOR);
   }
 
-  public void draw(final Graphics2D g) {
+  public void positionChanged() {
-    g.setColor(color);
+    position = part.transform(inside);
+  }
+
+  public void draw(@NonNull final Graphics2D g) {
+    g.setColor(getColor());
     g.fillArc(inside.x - NODE_RADIUS, inside.y - NODE_RADIUS, 2 * NODE_RADIUS, 2 * NODE_RADIUS, 0, 360);
 
     g.setColor(Color.BLACK);
@@ -68,21 +86,17 @@ public class Node {
     g.drawArc(inside.x - NODE_RADIUS, inside.y - NODE_RADIUS, 2 * NODE_RADIUS, 2 * NODE_RADIUS, 0, 360);
   }
 
-  public boolean intersects(final Point position) {
+  public boolean intersects(@NonNull final Point position) {
-    return getAbsolute().distance(position) <= NODE_RADIUS_HOVER;
+    return this.position.distance(position) <= NODE_RADIUS_HOVER;
   }
 
-  public void collectConnectedNodes(final Set<Node> connected) {
+  public void collectConnectedNodes(@NonNull final Set<Node> connected) {
     if (connected.contains(this)) {
       return;
     }
     connected.add(this);
     wires.forEach(wire -> wire.getOpposite(this).collectConnectedNodes(connected));
-    owner.getInnerConnections().stream().flatMap(innerConnection -> innerConnection.filter(this)).forEach(opposite -> opposite.collectConnectedNodes(connected));
+    part.getInnerConnections().stream().flatMap(innerConnection -> innerConnection.filter(this)).forEach(opposite -> opposite.collectConnectedNodes(connected));
-  }
-
-  public Point getAbsolute() {
-    return owner.transform(inside);
   }
 
 }

src/main/java/de/ph87/electro/circuit/part/parts/Battery.java

@@ -29,6 +29,8 @@ public class Battery extends Part {
 
   private static final int PLUS_H = (int) round(0.6 * RASTER);
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node minus;
 
   private final Node plus;

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorCorner.java

@@ -1,33 +0,0 @@
-package de.ph87.electro.circuit.part.parts;
-
-import de.ph87.electro.circuit.part.Part;
-import de.ph87.electro.circuit.part.node.Node;
-import lombok.Getter;
-import lombok.ToString;
-
-import java.awt.*;
-
-import static de.ph87.electro.CONFIG.P10;
-import static de.ph87.electro.CONFIG.P90;
-
-@Getter
-@ToString(callSuper = true)
-public class ConnectorCorner extends Part {
-
-  private final Node j0;
-
-  private final Node j1;
-
-  public ConnectorCorner(final Point position) {
-    super("", position);
-    j0 = addNode("J0", P10, P10);
-    j1 = addNode("J1", P90, P90);
-  }
-
-  public ConnectorCorner(final ConnectorCornerDto dto) {
-    super(dto);
-    j0 = addNode(dto.getJ0(), P10, P10);
-    j1 = addNode(dto.getJ1(), P90, P90);
-  }
-
-}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorCornerDto.java

@@ -1,23 +0,0 @@
-package de.ph87.electro.circuit.part.parts;
-
-import de.ph87.electro.circuit.part.PartDto;
-import de.ph87.electro.circuit.part.node.NodeDto;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
-import lombok.ToString;
-
-@Getter
-@ToString
-@NoArgsConstructor
-public class ConnectorCornerDto extends PartDto {
-
-  private NodeDto j0;
-
-  private NodeDto j1;
-
-  public ConnectorCornerDto(final ConnectorCorner part) {
-    j0 = new NodeDto(part.getJ0());
-    j1 = new NodeDto(part.getJ1());
-  }
-
-}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorEdge.java

@@ -1,33 +0,0 @@
-package de.ph87.electro.circuit.part.parts;
-
-import de.ph87.electro.circuit.part.Part;
-import de.ph87.electro.circuit.part.node.Node;
-import lombok.Getter;
-import lombok.ToString;
-
-import java.awt.*;
-
-import static de.ph87.electro.CONFIG.P10;
-import static de.ph87.electro.CONFIG.P50;
-
-@Getter
-@ToString(callSuper = true)
-public class ConnectorEdge extends Part {
-
-  private final Node j0;
-
-  private final Node j1;
-
-  public ConnectorEdge(final Point position) {
-    super("", position);
-    j0 = addNode("J0", P10, P50);
-    j1 = addNode("J1", P50, P10);
-  }
-
-  public ConnectorEdge(final ConnectorEdgeDto dto) {
-    super(dto);
-    j0 = addNode(dto.getJ0(), P10, P50);
-    j1 = addNode(dto.getJ1(), P50, P10);
-  }
-
-}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorEdgeDto.java

@@ -1,23 +0,0 @@
-package de.ph87.electro.circuit.part.parts;
-
-import de.ph87.electro.circuit.part.PartDto;
-import de.ph87.electro.circuit.part.node.NodeDto;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
-import lombok.ToString;
-
-@Getter
-@ToString
-@NoArgsConstructor
-public class ConnectorEdgeDto extends PartDto {
-
-  private NodeDto j0;
-
-  private NodeDto j1;
-
-  public ConnectorEdgeDto(final ConnectorEdge part) {
-    j0 = new NodeDto(part.getJ0());
-    j1 = new NodeDto(part.getJ1());
-  }
-
-}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorMiddle.java

@@ -1,28 +0,0 @@
-package de.ph87.electro.circuit.part.parts;
-
-import de.ph87.electro.circuit.part.Part;
-import de.ph87.electro.circuit.part.node.Node;
-import lombok.Getter;
-import lombok.ToString;
-
-import java.awt.*;
-
-import static de.ph87.electro.CONFIG.P50;
-
-@Getter
-@ToString(callSuper = true)
-public class ConnectorMiddle extends Part {
-
-  private final Node node;
-
-  public ConnectorMiddle(final Point position) {
-    super("", position);
-    node = addNode("J", P50, P50);
-  }
-
-  public ConnectorMiddle(final ConnectorMiddleDto dto) {
-    super(dto);
-    node = addNode(dto.getNode(), P50, P50);
-  }
-
-}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorSub.java

@@ -0,0 +1,30 @@
+package de.ph87.electro.circuit.part.parts;
+
+import de.ph87.electro.circuit.part.Part;
+import de.ph87.electro.circuit.part.node.Node;
+import lombok.Getter;
+import lombok.ToString;
+
+import java.awt.*;
+
+import static de.ph87.electro.CONFIG.SUB_RASTER;
+
+@Getter
+@ToString(callSuper = true)
+public class ConnectorSub extends Part {
+
+  private final Node node;
+
+  private final Point size = new Point(SUB_RASTER, SUB_RASTER);
+
+  public ConnectorSub(final Point position) {
+    super("", position);
+    node = addNode("", SUB_RASTER / 2, SUB_RASTER / 2);
+  }
+
+  public ConnectorSub(final ConnectorSubDto dto) {
+    super(dto);
+    node = addNode(dto.getNode(), SUB_RASTER / 2, SUB_RASTER / 2);
+  }
+
+}

src/main/java/de/ph87/electro/circuit/part/parts/ConnectorSubDto.java

@@ -9,11 +9,11 @@ import lombok.ToString;
 @Getter
 @ToString
 @NoArgsConstructor
-public class ConnectorMiddleDto extends PartDto {
+public class ConnectorSubDto extends PartDto {
 
   private NodeDto node;
 
-  public ConnectorMiddleDto(final ConnectorMiddle part) {
+  public ConnectorSubDto(final ConnectorSub part) {
     node = new NodeDto(part.getNode());
   }
 

src/main/java/de/ph87/electro/circuit/part/parts/Light.java

@@ -20,22 +20,12 @@ import static java.lang.Math.round;
 @ToString(callSuper = true)
 public class Light extends Part {
 
-  private static final Color COLOR_DEFECT = new Color(255, 0, 234);
-
-  private static final int MINUS_W = (int) round(0.1 * RASTER);
-
-  private static final int MINUS_H = (int) round(0.3 * RASTER);
-
-  private static final int GAP = (int) round(0.05 * RASTER);
-
-  private static final int PLUS_W = (int) round(0.02 * RASTER);
-
-  private static final int PLUS_H = (int) round(0.6 * RASTER);
-
   private static final int BULB_RADIUS = (int) round(0.25 * RASTER);
 
   private static final Color BULB_OFF_COLOR = Color.DARK_GRAY;
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node a;
 
   private final Node b;

src/main/java/de/ph87/electro/circuit/part/parts/Poti.java

@@ -4,6 +4,7 @@ import de.ph87.electro.circuit.part.InnerConnection;
 import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.part.node.Node;
 import lombok.Getter;
+import lombok.NonNull;
 import lombok.Setter;
 import lombok.ToString;
 
@@ -18,25 +19,30 @@ import static java.lang.Math.max;
 @ToString(callSuper = true)
 public class Poti extends Part {
 
+  @NonNull
   private final Node common;
 
+  @NonNull
   private final Node middle;
 
+  @NonNull
   private final Node end;
 
+  private final Point size = new Point(RASTER, RASTER);
+
   @Setter
   private double resistance = 10;
 
   private double ratio = 0.0;
 
-  public Poti(final Point position) {
+  public Poti(@NonNull final Point position) {
     super("Poti", position);
     common = addNode("C", P10, P50);
     middle = addNode("M", P50, P10);
     end = addNode("E", P90, P50);
   }
 
-  public Poti(final PotiDto dto) {
+  public Poti(@NonNull final PotiDto dto) {
     super(dto);
     common = addNode(dto.getCommon().getName(), P10, P50);
     middle = addNode(dto.getMiddle().getName(), P50, P10);
@@ -53,7 +59,7 @@ public class Poti extends Part {
   }
 
   @Override
-  protected void _labels(final Graphics2D g) {
+  protected void _labels(@NonNull final Graphics2D g) {
     drawText(g, LABEL_FONT, "%3.0f%%".formatted(ratio * 100), P50, P50, Color.BLACK, orientation);
   }
 

src/main/java/de/ph87/electro/circuit/part/parts/Switch1x1.java

@@ -18,6 +18,8 @@ public class Switch1x1 extends Part {
 
   private static final Point END = new Point(P90, P25);
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node common;
 
   private final Node output;
@@ -49,8 +51,7 @@ public class Switch1x1 extends Part {
   @Override
   protected void _render(final Graphics2D g) {
     if (!state) {
-      final Point end = getOrientation().rotate(END);
+      drawLine(g, common, END, common.getColor(), SWITCH_STROKE);
-      drawLine(g, common.getAbsolute(), end, common.getColor(), SWITCH_STROKE);
     } else {
       drawLine(g, common, output, common.getColor(), SWITCH_STROKE);
     }

src/main/java/de/ph87/electro/circuit/part/parts/Switch1x2.java

@@ -16,6 +16,8 @@ import static de.ph87.electro.circuit.CircuitPainter.drawLine;
 @ToString(callSuper = true)
 public class Switch1x2 extends Part {
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node common;
 
   private final Node output0;

src/main/java/de/ph87/electro/circuit/part/parts/SwitchCross.java

@@ -16,6 +16,8 @@ import static de.ph87.electro.circuit.CircuitPainter.drawLine;
 @ToString(callSuper = true)
 public class SwitchCross extends Part {
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node common0;
 
   private final Node common1;

src/main/java/de/ph87/electro/circuit/part/parts/Voltmeter.java

@@ -4,6 +4,7 @@ import de.ph87.electro.circuit.part.InnerConnection;
 import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.part.PartDto;
 import de.ph87.electro.circuit.part.node.Node;
+import de.ph87.electro.common.RotationMatrix;
 import lombok.Getter;
 import lombok.Setter;
 import org.apache.commons.math3.linear.ArrayRealVector;
@@ -29,10 +30,14 @@ public class Voltmeter extends Part {
 
   private static final double DEGREES_RANGE = 90;
 
+  private final Point size = new Point(RASTER, RASTER);
+
   private final Node a;
 
   private final Node b;
 
+  double x = 0;
+
   @Setter
   private double min = -3;
 
@@ -55,7 +60,9 @@ public class Voltmeter extends Part {
     postCalculate(); // TODO remove
   }
 
-  double x = 0;
+  public static Point P(final RealVector anchor) {
+    return new Point((int) round(anchor.getEntry(0)), (int) round(anchor.getEntry(1)));
+  }
 
   @Override
   public void _render(final Graphics2D g) {
@@ -74,10 +81,6 @@ public class Voltmeter extends Part {
     drawCircle(g, P(ANCHOR), P03, 0, 360, null, null, Color.black);
   }
 
-  public static Point P(final RealVector anchor) {
-    return new Point((int) round(anchor.getEntry(0)), (int) round(anchor.getEntry(1)));
-  }
-
   private double getVoltage() {
     return !Double.isNaN(b.getVoltage()) && !Double.isNaN(a.getVoltage()) ? b.getVoltage() - a.getVoltage() : 0.0;
   }

src/main/java/de/ph87/electro/circuit/wire/Wire.java

@@ -12,20 +12,22 @@ import java.awt.geom.Rectangle2D;
 import static de.ph87.electro.CONFIG.*;
 import static java.lang.Math.*;
 
+@Getter
 @ToString
 public class Wire {
 
-  @Getter
   @NonNull
   private final Node a;
 
-  @Getter
   @NonNull
   private final Node b;
 
   @Setter
   private double current = Double.NaN;
 
+  @Setter
+  private boolean ghost = false;
+
   public Wire(@NonNull final Node a, @NonNull final Node b) {
     this.a = a;
     this.b = b;
@@ -34,7 +36,7 @@ public class Wire {
   }
 
   public boolean intersects(final Point position) {
-    return distanceToLine(position, a.getAbsolute(), b.getAbsolute());
+    return distanceToLine(position, a.getPosition(), b.getPosition());
   }
 
   public boolean distanceToLine(final Point point, final Point lineStart, final Point lineEnd) {
@@ -68,9 +70,11 @@ public class Wire {
   }
 
   public void draw(final Graphics2D g) {
-    g.setColor(a.getColor());
+    final Color color = ghost ? new Color(a.getColor().getRed(), a.getColor().getGreen(), a.getColor().getBlue(), 64) : a.getColor();
+
+    g.setColor(color);
     g.setStroke(WIRE_STROKE);
-    g.drawLine(a.getAbsolute().x, a.getAbsolute().y, b.getAbsolute().x, b.getAbsolute().y);
+    g.drawLine(a.getPosition().x, a.getPosition().y, b.getPosition().x, b.getPosition().y);
 
     if (SHOW_WIRE_DETAILS) {
       drawValues(g, "%.2f A".formatted(abs(current)), -0.5);
@@ -81,8 +85,8 @@ public class Wire {
   private void drawValues(final Graphics2D g, final String string, final double offset) {
     g.setFont(LABEL_FONT);
     final Rectangle2D bounds = g.getFontMetrics().getStringBounds(string, g);
-    final Point aa = a.getAbsolute();
+    final Point aa = a.getPosition();
-    final Point bb = b.getAbsolute();
+    final Point bb = b.getPosition();
 
     final int mx = (aa.x + bb.x) / 2;
     final int my = (aa.y + bb.y) / 2;

src/main/java/de/ph87/electro/common/RotationMatrix.java

@@ -1,4 +1,4 @@
-package de.ph87.electro.circuit.part.parts;
+package de.ph87.electro.common;
 
 import org.apache.commons.math3.linear.Array2DRowRealMatrix;
 import org.apache.commons.math3.linear.RealMatrix;

src/main/java/de/ph87/electro/sidebar/Sidebar.java

@@ -23,9 +23,6 @@ public class Sidebar extends JPanel {
 
     final Point ZERO = new Point();
     addPart(new Battery(ZERO));
-    addPart(new ConnectorCorner(ZERO));
-    addPart(new ConnectorEdge(ZERO));
-    addPart(new ConnectorMiddle(ZERO));
     addPart(new Light(ZERO));
     addPart(new Switch1x1(ZERO));
     addPart(new Switch1x2(ZERO));

src/test/java/de/ph87/electro/circuit/CalculationServiceTest.java

@@ -30,7 +30,8 @@ class CalculationServiceTest {
           log.info("  \"%s\" = %.2f V".formatted(node.getName(), node.getVoltage()));
           for (final Wire wire : node.getWires()) {
             final Node opposite = wire.getOpposite(node);
-            log.info("    -> %s.%s = %.2f A".formatted(opposite.getOwner().getName(), opposite.getName(), wire.getCurrent(node)));
+            final String partName = opposite instanceof final Node partNode ? partNode.getPart().getName() : "";
+            log.info("    -> %s.%s = %.2f A".formatted(partName, opposite.getName(), wire.getCurrent(node)));
           }
         }
       });

src/test/java/de/ph87/electro/circuit/io/CircuitIOServiceTest.java

@@ -2,8 +2,8 @@ package de.ph87.electro.circuit.io;
 
 import de.ph87.electro.circuit.Circuit;
 import de.ph87.electro.circuit.CircuitIOService;
-import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.part.node.Node;
+import de.ph87.electro.circuit.part.Part;
 import de.ph87.electro.circuit.part.parts.Battery;
 import de.ph87.electro.circuit.part.parts.Light;
 import org.junit.jupiter.api.Test;
@@ -16,6 +16,7 @@ import java.nio.charset.StandardCharsets;
 import static de.ph87.electro.CONFIG.RASTER;
 import static de.ph87.electro.circuit.CircuitIOService.serialize;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 
 class CircuitIOServiceTest {
 
@@ -56,7 +57,7 @@ class CircuitIOServiceTest {
         final Node reloadedNode = reloadedPart.getNodes().stream().filter(node -> node.getUuid().equals(originalNode.getUuid())).findFirst().orElseThrow();
         assertEquals(originalNode.getUuid(), reloadedNode.getUuid());
         assertEquals(originalNode.getName(), reloadedNode.getName());
-        assertEquals(originalNode.getAbsolute(), reloadedNode.getAbsolute());
+        assertEquals(originalNode.getPosition(), reloadedNode.getPosition());
         assertEquals(originalNode.getWires().size(), reloadedNode.getWires().size());
         originalNode.getWires().stream()
           .map(originalWire -> originalWire.getOpposite(originalNode))
@@ -64,7 +65,9 @@ class CircuitIOServiceTest {
               System.out.printf("    - Destinations: %s\n", originalDestination.getUuid());
               final Node reloadedDestination = reloadedNode.getWires().stream().map(wire -> wire.getOpposite(reloadedNode)).filter(destination -> destination.getUuid().equals(originalDestination.getUuid())).findFirst().orElseThrow();
               assertEquals(originalDestination.getUuid(), reloadedDestination.getUuid());
-              assertEquals(originalDestination.getOwner().getUuid(), reloadedDestination.getOwner().getUuid());
+              assertInstanceOf(Node.class, originalDestination);
+              assertInstanceOf(Node.class, reloadedDestination);
+              assertEquals(originalDestination.getPart().getUuid(), reloadedDestination.getPart().getUuid());
             }
           );
       }