Parts dragged from the component tree or toolbox into a board's Underside Display go on the bottom of the board

diylc/diylc-core/src/main/java/org/diylc/presenter/Presenter.java

@@ -1668,8 +1668,11 @@ public class Presenter implements IPlugInPort {
       // messageDispatcher.dispatchMessage(EventType.SELECTION_RECT_CHANGED,
       // selectionRect);
     } else if (instantiationManager.getComponentSlot() != null) {
+      // a component dragged in from the component tree or the toolbox
       this.previousScaledPoint = scalePoint(point);
-      instantiationManager.updateSingleClick(previousScaledPoint, isSnapToGrid(), currentProject.getGridSpacing());
+      updatePlacementMirror(previousScaledPoint);
+      instantiationManager.updateSingleClick(toPlacementSpace(previousScaledPoint), isSnapToGrid(),
+          currentProject.getGridSpacing());
     }
 
     messageDispatcher.dispatchMessage(EventType.REPAINT, false, resizeInProgress);
@@ -2086,6 +2089,9 @@ public class Presenter implements IPlugInPort {
       // calculateSelectionDimension());
     } else if (instantiationManager.getComponentSlot() != null) {
       preDragProject = currentProject.clone();
+      if (placementMirrorBoard != null) {
+        MirrorPlacement.placeOnBottom(instantiationManager.getComponentSlot());
+      }
       addPendingComponentsToProject(scaledPoint, instantiationManager.getComponentTypeSlot(), null, null, preDragProject);
     } else {
       updateSelection(selectedComponents);

diylc/diylc-swing/src/test/java/org/diylc/PresenterTests.java

@@ -368,6 +368,25 @@ public class PresenterTests extends TestBase {
     Assert.assertTrue(board.getBoardRectangle().contains(eyelet.getControlPoint(0)));
   }
 
+  @Test
+  public void testDropFromComponentTreeIntoUndersideMirror() {
+    BlankBoard board = mirroredBoard();
+    Rectangle2D region = UndersideMirror.getMirrorRegion(board);
+    Point inMirror = toScreen(new Point2D.Double(region.getCenterX(), region.getCenterY()));
+    ComponentType resistorType = presenter.getComponentTypes().get("Passive").stream()
+        .filter(x -> x.getName().equals("Resistor")).findFirst().get();
+
+    // what the component tree and the canvas drop target do for a drag and drop
+    presenter.setNewComponentTypeSlot(resistorType, null, null, true);
+    presenter.dragOver(inMirror);
+    presenter.dragEnded(inMirror);
+
+    Assert.assertEquals(2, presenter.getCurrentProject().getComponents().size());
+    Resistor resistor = (Resistor) presenter.getCurrentProject().getComponents().get(1);
+    Assert.assertEquals(PCBLayer._1, resistor.getBoardSide());
+    Assert.assertTrue(board.getBoardRectangle().contains(resistor.getControlPoint(0)));
+  }
+
   // a board with its underside mirror below it, with nothing on it yet
   private BlankBoard mirroredBoard() {
     BlankBoard board = new BlankBoard();

diylc/docs/plans/bottom-side-components.md

@@ -130,8 +130,9 @@ order.
   through that mirror, under the cursor. On placement, `MirrorPlacement.placeOnBottom` sets an
   `IBoardSideComponent` to `_1` (Bottom) and a component with a `PCBLayer` (`setLayer`, found the
   same way `PCBLayerFilter` reads `getLayer`) to `_1`; nothing is mirrored. Anything else, such as
-  a jumper, eyelet or wire, is placed at the reflected point unchanged. Dragging a new part from
-  the component tree onto a mirror still places it in the main view.
+  a jumper, eyelet or wire, is placed at the reflected point unchanged. A part dragged in from
+  the component tree or the toolbox goes through `Presenter.dragOver` and `dragEnded` instead,
+  which pick the mirror and put the part on the bottom the same way.
 
 ## 4. Open questions
 
@@ -150,7 +151,7 @@ order.
 - `MirrorPlacementTest` covers what placing through the mirror changes, and
   `PresenterTests.testPlaceThroughUndersideMirror` and `testPlaceUnsidedPartThroughUndersideMirror`
   place a resistor and an eyelet in a mirror and check that they land on the board, the resistor on
-  the bottom.
+  the bottom; `testDropFromComponentTreeIntoUndersideMirror` does the same for a drag and drop.
 - `SilkScreenFilterTest` covers which side's page each part and board outline goes on, and
   `SilkScreenDrawingProviderTest` checks that the bottom page appears only for a bottom part.
 - `DrawingManagerTest` checks rendered pixels for a part that reports its own side: a bottom part