Copper keeps its 'Layer' property in the editor, the term PCB tools use for copper, while still counting as a Board Side component in code

Changelog entry for PCB text moving to the bottom page of the silkscreen print-out
Traces, curved traces, ground fills, solder pads and PCB text call their layer 'Board Side', like every other part, and count as Board Side components in code; the saved field is still 'layer'
2026-11-12 18:22:10 +10:00 · 2026-11-11 21:40:33 +01:00 · 2026-11-11 21:19:55 +01:00 · 2026-11-11 21:15:26 +01:00 · 2026-11-11 20:48:35 +01:00 · 2026-11-11 20:40:39 +01:00
178 changed files with 3412 additions and 336 deletions
@@ -210,6 +210,14 @@ logic, netlist and analyzer behaviour, datasheet parsing, core utilities. Compon
 user interaction are covered by the regression suite instead, not by unit tests. Test classes are
 named `*Test` or `*Tests` and carry the license header like any other file.

+## Changelog
+
+User-facing changes are listed in `diylc-core/src/main/resources/update.xml`, one `Version` block
+per release. Within a block, all `NEW_FEATURE` entries come first, then `IMPROVEMENT`, then
+`BUG_FIX`; keep the existing order inside each group and add a new entry at the end of its own
+group, not at the end of the block. After a merge that brings entries in from both sides, sort the
+unreleased block again. Released blocks stay exactly as they shipped.
+
 ## Git

 **Do not commit or push.** Make the change in the working tree and stop; the maintainer reviews and
@@ -1,5 +1,5 @@
 {
-  "version" : "6.10.0",
+  "version" : "6.11.0",
  "components" : [ {
    "name" : "Blank Board",
    "className" : "boards.BlankBoard",
@@ -1035,7 +1035,7 @@
    }, {
      "name" : "Layer",
      "type" : "PCBLayer",
-      "possibleValues" : [ "_1", "_2", "_3", "_4", "_5", "_6", "_7", "_8" ],
+      "possibleValues" : [ "_1", "_2" ],
      "defaultValue" : "_1"
    }, {
      "name" : "Name",
@@ -1077,7 +1077,7 @@
    }, {
      "name" : "Layer",
      "type" : "PCBLayer",
-      "possibleValues" : [ "_1", "_2", "_3", "_4", "_5", "_6", "_7", "_8" ],
+      "possibleValues" : [ "_1", "_2" ],
      "defaultValue" : "_1"
    }, {
      "name" : "Name",
@@ -1196,6 +1196,11 @@
    "creationMethod" : "SINGLE_CLICK",
    "notes" : [ "A junction marker for schematics and wiring diagrams; it is drawing only and connects nothing, since ends that meet at the same point are already connected. For a pad on a board use Solder Pad" ],
    "properties" : [ {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
+    }, {
      "name" : "Color",
      "type" : "Color",
      "format" : "hex",
@@ -1277,7 +1282,7 @@
    }, {
      "name" : "Layer",
      "type" : "PCBLayer",
-      "possibleValues" : [ "_1", "_2", "_3", "_4", "_5", "_6", "_7", "_8" ],
+      "possibleValues" : [ "_1", "_2" ],
      "defaultValue" : "_1"
    }, {
      "name" : "Name",
@@ -1459,6 +1464,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -1706,7 +1716,7 @@
    }, {
      "name" : "Layer",
      "type" : "PCBLayer",
-      "possibleValues" : [ "_1", "_2", "_3", "_4", "_5", "_6", "_7", "_8" ],
+      "possibleValues" : [ "_1", "_2" ],
      "defaultValue" : "_1"
    }, {
      "name" : "Node Name",
@@ -7155,6 +7165,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Font Size Override",
      "type" : "Integer"
@@ -7228,6 +7243,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Font Size Override",
      "type" : "Integer"
@@ -7306,6 +7326,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Font Size Override",
      "type" : "Integer"
@@ -7746,6 +7771,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Display",
      "type" : "Display",
@@ -7851,6 +7881,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -8509,6 +8544,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Name",
      "type" : "String"
@@ -8577,6 +8617,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Font Size Override",
      "type" : "Integer"
@@ -8645,6 +8690,11 @@
    }, {
      "name" : "Angle Offset",
      "type" : "Angle"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Color",
      "type" : "Color",
@@ -9035,6 +9085,11 @@
    }, {
      "name" : "Angle",
      "type" : "Angle"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Color",
      "type" : "Color",
@@ -9372,6 +9427,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -9496,6 +9556,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -11842,6 +11907,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -11970,7 +12040,7 @@
    }, {
      "name" : "Layer",
      "type" : "PCBLayer",
-      "possibleValues" : [ "_1", "_2", "_3", "_4", "_5", "_6", "_7", "_8" ],
+      "possibleValues" : [ "_1", "_2" ],
      "defaultValue" : "_1"
    }, {
      "name" : "Orientation",
@@ -12082,6 +12152,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12170,6 +12245,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12252,6 +12332,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12367,6 +12452,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12492,6 +12582,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12589,6 +12684,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12693,6 +12793,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12804,6 +12909,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12913,6 +13023,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -12994,6 +13109,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -13083,6 +13203,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Coil",
      "type" : "Color",
@@ -13222,6 +13347,11 @@
      "type" : "Color",
      "format" : "hex",
      "defaultValue" : "#333333"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -13301,6 +13431,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -13459,6 +13594,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -13527,6 +13667,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -13621,6 +13766,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -13728,6 +13878,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -13786,6 +13941,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -13844,6 +14004,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -16501,6 +16666,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -16574,6 +16744,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -16837,6 +17012,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -16930,6 +17110,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Border",
      "type" : "Color",
@@ -17017,6 +17202,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Color",
      "type" : "Color",
@@ -17102,6 +17292,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -17263,6 +17458,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -17344,6 +17544,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -17779,6 +17984,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -18210,6 +18420,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -19072,6 +19287,11 @@
      "type" : "Percentage",
      "format" : "number without the % sign, e.g. 100",
      "defaultValue" : "100"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Body",
      "type" : "Color",
@@ -20011,6 +20231,11 @@
      "type" : "Base",
      "possibleValues" : [ "B9A", "OCTAL", "B7G", "B12C", "UX4" ],
      "defaultValue" : "B9A"
+    }, {
+      "name" : "Board Side",
+      "type" : "PCBLayer",
+      "possibleValues" : [ "_1", "_2" ],
+      "defaultValue" : "_2"
    }, {
      "name" : "Color",
      "type" : "Color",
@@ -1,5 +1,5 @@
 {
-  "version" : "6.10.0",
+  "version" : "6.11.0",
  "categories" : {
    "Boards" : [ {
      "name" : "Blank Board",
@@ -72,5 +72,9 @@ public enum DrawOption {
  /**
   * When applied, all colors will be converted to blackest black or whitest white
   */
-  MONOCHROMATIC;
+  MONOCHROMATIC,
+  /**
+   * Paint on the bottom side of a board is drawn at reduced opacity, as if seen through the board.
+   */
+  FADE_FAR_SIDE;
 }
@@ -110,6 +110,8 @@ public interface IPlugInPort extends ISelectionProcessor, IMouseProcessor, IKeyP

  public static final String LOCKED_ALPHA = "lockedAlpha";

+  public static final String FADE_FAR_SIDE_KEY = "fadeFarSide";
+
  public static final String LANGUAGE = "language";
  public static final String LANGUAGE_DEFAULT = "English";

@@ -25,7 +25,11 @@ import org.diylc.core.gerber.GerberLayer;

 public enum PCBLayer {

-  _1("Bottom"), _2("Top"), _3("Inner 1"), _4("Inner 2"), _5("Inner 3"), _6("Inner 4"), _7("Inner 5"), _8("Inner 6");
+  _1("Bottom"), _2("Top"),
+  // DIYLC models two-sided boards only. The inner layers are kept, in order, so that files using
+  // them still load with the same layer ids; the editor hides them and Gerber export rejects them.
+  @Deprecated _3("Inner 1"), @Deprecated _4("Inner 2"), @Deprecated _5("Inner 3"),
+  @Deprecated _6("Inner 4"), @Deprecated _7("Inner 5"), @Deprecated _8("Inner 6");
  
  private String label;
  
@@ -0,0 +1,58 @@
+/*
+
+    DIY Layout Creator (DIYLC).
+    Copyright (c) 2009-2025 held jointly by the individual authors.
+
+    This file is part of DIYLC.
+
+    DIYLC is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    DIYLC is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DIYLC.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+package org.diylc.core;
+
+import org.diylc.common.PCBLayer;
+
+/**
+ * Interface for components on one side of a board, such as a resistor, an IC or a trace. The side
+ * says where the part sits physically; it is separate from {@link ILayeredComponent}, which drives
+ * continuity, because the leads of a through-hole part connect to copper on both sides whichever
+ * side the part is mounted on. Copper implements it through {@link IPCBLayerComponent}, whose layer
+ * is its side and also drives its continuity.
+ * 
+ * @author Branislav Stojkovic
+ */
+public interface IBoardSideComponent {
+
+  /**
+   * @return {@link PCBLayer#_2} for the top of the board or {@link PCBLayer#_1} for the bottom,
+   *         never an inner layer or null
+   */
+  PCBLayer getBoardSide();
+
+  /**
+   * Sets the side of the board the component is mounted on. The component is not mirrored.
+   * 
+   * @param boardSide {@link PCBLayer#_2} for the top or {@link PCBLayer#_1} for the bottom
+   */
+  void setBoardSide(PCBLayer boardSide);
+
+  /**
+   * @return {@link PCBLayer#_1} for a component mounted on the bottom of the board, and
+   *         {@link PCBLayer#_2} for any other, including components that have no side
+   */
+  static PCBLayer sideOf(IDIYComponent<?> component) {
+    return component instanceof IBoardSideComponent sided && sided.getBoardSide() == PCBLayer._1
+        ? PCBLayer._1 : PCBLayer._2;
+  }
+}
@@ -21,6 +21,8 @@
 */
 package org.diylc.core;

+import org.diylc.common.PCBLayer;
+
 /**
 * Interface for tracking component drawing process. Components may use it to stop or restart
 * tracking. Anything drawn while tracking is stopped will not be added to the mouse hot-spot area.
@@ -65,4 +67,26 @@ public interface IDrawingObserver {
   * @param marker
   */
  void setContinuityMarker(String marker);
+
+  /**
+   * Notifies the observer that what follows is painted on the given side of the board, until
+   * {@link #stopDrawingSide()}. Paint that is not bracketed is on the top (component) side. The
+   * observer may draw paint on the side facing away from the viewer at reduced opacity, as if seen
+   * through the board. Inner layers count as the bottom side.
+   *
+   * @param side the layer the paint lies on
+   */
+  default void startDrawingSide(PCBLayer side) {}
+
+  /**
+   * Notifies the observer that what follows is visible from both sides of the board, such as a
+   * drilled hole or a cut through the copper, and is never drawn faded, until
+   * {@link #stopDrawingSide()}.
+   */
+  default void startDrawingBothSides() {}
+
+  /**
+   * Notifies the observer that paint is back on the top (component) side.
+   */
+  default void stopDrawingSide() {}
 }
@@ -0,0 +1,52 @@
+/*
+
+    DIY Layout Creator (DIYLC).
+    Copyright (c) 2009-2025 held jointly by the individual authors.
+
+    This file is part of DIYLC.
+
+    DIYLC is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    DIYLC is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DIYLC.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+package org.diylc.core;
+
+import org.diylc.common.PCBLayer;
+
+/**
+ * Interface for copper drawn on a layer of a PCB, such as a trace, pad, ground fill or PCB text.
+ * The layer is the copper's board side, but unlike the side of a mounted part it also decides
+ * which other copper the copper connects to. It keeps the name 'Layer' in the editor, which is
+ * what PCB tools call it for copper.
+ * 
+ * @author Branislav Stojkovic
+ */
+public interface IPCBLayerComponent extends IBoardSideComponent {
+
+  PCBLayer getLayer();
+
+  void setLayer(PCBLayer layer);
+
+  /**
+   * @return the layer, with the deprecated inner layers counted as the bottom
+   */
+  @Override
+  default PCBLayer getBoardSide() {
+    return getLayer() == PCBLayer._2 ? PCBLayer._2 : PCBLayer._1;
+  }
+
+  @Override
+  default void setBoardSide(PCBLayer boardSide) {
+    setLayer(boardSide);
+  }
+}
@@ -16,8 +16,10 @@ import org.apache.log4j.Logger;

 import com.bancika.gerberwriter.DataLayer;

+import org.diylc.common.PCBLayer;
 import org.diylc.core.ComponentState;
 import org.diylc.core.IBoard;
+import org.diylc.core.IBoardSideComponent;
 import org.diylc.core.IDIYComponent;
 import org.diylc.core.IView;
 import org.diylc.core.Project;
@@ -145,8 +147,12 @@ public class GerberExporter {
    LOG.info("Completed export to gerber");
  }

-  private static void drawComponent(Project currentProject, GerberG2DWrapper g2d,
-                                    IDIYComponent<?> c, boolean outlineMode) {
+  /**
+   * Draws the specified component into the Gerber layers it belongs to. This is the only place that
+   * decides which layer a component's output goes to.
+   */
+  static void drawComponent(Project currentProject, GerberG2DWrapper g2d,
+                            IDIYComponent<?> c, boolean outlineMode) {
    IGerberComponent gerberComponent = (IGerberComponent) c;
    g2d.startedDrawingComponent();
    if (gerberComponent instanceof IGerberComponentCustom) {
@@ -156,7 +162,10 @@ public class GerberExporter {
      IGerberComponentSimple gerberComponentSimple = (IGerberComponentSimple) gerberComponent;
      g2d.startGerberOutput(gerberComponentSimple.getGerberLayer(),
              gerberComponentSimple.getGerberFunction(), gerberComponentSimple.isGerberNegative());
+      // text on the bottom silkscreen is read from below, so it is written mirrored
+      g2d.setMirrorText(IBoardSideComponent.sideOf(c) == PCBLayer._1);
      c.draw(g2d, ComponentState.NORMAL, outlineMode, currentProject, g2d);
+      g2d.setMirrorText(false);
      g2d.stopGerberOutput();
    }
  }
@@ -58,6 +58,7 @@ public class GerberG2DWrapper extends Graphics2D
  private double tolerance;

  private Rectangle2D boardRect;
+  private boolean mirrorText = false;

  public GerberG2DWrapper(Graphics2D graphics2d, String diylcVersion, Rectangle2D boardRect) {
    super();
@@ -154,6 +155,15 @@ public class GerberG2DWrapper extends Graphics2D
    return layerMap;
  }

+  /**
+   * Sets whether text is written mirrored, each string about its own centre. The output is in top
+   * view, so text on the bottom side has to be mirrored to read correctly once the board is turned
+   * over.
+   */
+  public void setMirrorText(boolean mirrorText) {
+    this.mirrorText = mirrorText;
+  }
+
  @Override
  public void draw(Shape s) {
    if (trackingGerber && !getColor().equals(Constants.TRANSPARENT_COLOR)) {
@@ -181,6 +191,10 @@ public class GerberG2DWrapper extends Graphics2D
    GlyphVector gv = font.createGlyphVector(graphics2d.getFontRenderContext(), str);
    
    AffineTransform translateInstance = AffineTransform.getTranslateInstance(x, y);
+    if (mirrorText) {
+      translateInstance.translate(gv.getLogicalBounds().getWidth(), 0);
+      translateInstance.scale(-1, 1);
+    }

    for (int i = 0; i < gv.getNumGlyphs(); i++) {
        Shape glyphShape = gv.getGlyphOutline(i);
@@ -54,7 +54,7 @@ public enum GerberLayer {
  public boolean isMirrored() {
    return mirrored;
  }
-  
+
  public String formatFileName(String fileNameBase, String boardName) {
    return fileNameBase + (fileNameBase.endsWith(".") ? "" : ".")
        + boardName + "-" + getSuffix() + "." + getExtension();
@@ -25,29 +25,10 @@ import com.bancika.gerberwriter.Point;
 import com.bancika.gerberwriter.path.MoveTo;
 import com.bancika.gerberwriter.path.Path;

-import org.diylc.core.ComponentState;
-import org.diylc.core.IDIYComponent;
-import org.diylc.core.Project;
 import org.diylc.core.measures.SizeUnit;

 public class GerberPathRenderer {

-  public static void drawComponent(Project currentProject, GerberG2DWrapper g2d, IDIYComponent<?> c,
-      boolean outlineMode) {
-    IGerberComponent gerberComponent = (IGerberComponent) c;
-    g2d.startedDrawingComponent();
-    if (gerberComponent instanceof IGerberComponentCustom) {
-      IGerberComponentCustom gerberComponentCustom = (IGerberComponentCustom) gerberComponent;
-      gerberComponentCustom.draw(g2d, ComponentState.NORMAL, outlineMode, currentProject, g2d, g2d);
-    } else if (gerberComponent instanceof IGerberComponentSimple) {
-      IGerberComponentSimple gerberComponentSimple = (IGerberComponentSimple) gerberComponent;
-      g2d.startGerberOutput(gerberComponentSimple.getGerberLayer(),
-          gerberComponentSimple.getGerberFunction(), gerberComponentSimple.isGerberNegative());
-      c.draw(g2d, ComponentState.NORMAL, outlineMode, currentProject, g2d);
-      g2d.stopGerberOutput();
-    }
-  }
-
  public static void outputPathArea(PathIterator pathIterator, DataLayer dataLayer, double d,
      boolean isNegative, String function) {
    List<PathWithNegative> outputPath =
@@ -1,9 +1,18 @@
 package org.diylc.core.gerber;

+import org.diylc.common.PCBLayer;
+import org.diylc.core.IBoardSideComponent;
+import org.diylc.core.IDIYComponent;
+
 public interface IGerberComponentSimple extends IGerberComponent {
-  
+
+  /**
+   * @return the silkscreen on the side of the board the component is mounted on
+   */
  default GerberLayer getGerberLayer() {
-    return GerberLayer.SilkscreenTop;
+    return this instanceof IDIYComponent<?> component
+        && IBoardSideComponent.sideOf(component) == PCBLayer._1
+            ? GerberLayer.SilkscreenBot : GerberLayer.SilkscreenTop;
  }

  default String getGerberFunction() {
@@ -21,10 +21,9 @@
 */
 package org.diylc.filter;

-import java.lang.reflect.Method;
-
 import org.diylc.common.PCBLayer;
 import org.diylc.core.IDIYComponent;
+import org.diylc.core.IPCBLayerComponent;

 public class PCBLayerFilter implements IComponentFilter {

@@ -37,13 +36,6 @@ public class PCBLayerFilter implements IComponentFilter {

  @Override
  public boolean testComponent(IDIYComponent<?> component) {
-    Class<?> clazz = component.getClass();
-    try {
-      Method m = clazz.getMethod("getLayer");
-      PCBLayer l = (PCBLayer) m.invoke(component);
-      return layer == l;
-    } catch (Exception e) {
-      return false;
-    }
+    return component instanceof IPCBLayerComponent copper && copper.getLayer() == layer;
  }
 }
@@ -1,6 +1,8 @@
 package org.diylc.filter;

+import org.diylc.common.PCBLayer;
 import org.diylc.core.IBoard;
+import org.diylc.core.IBoardSideComponent;
 import org.diylc.core.IDIYComponent;
 import org.diylc.core.gerber.GerberRenderMode;
 import org.diylc.core.gerber.IGerberComponent;
@@ -9,6 +11,20 @@ import java.util.Set;

 public class SilkScreenFilter implements IComponentFilter {

+  private PCBLayer side;
+
+  public SilkScreenFilter() {
+    this(null);
+  }
+
+  /**
+   * @param side the side of the board whose silkscreen to keep, or null for both; board outlines
+   *        are kept on either side
+   */
+  public SilkScreenFilter(PCBLayer side) {
+    this.side = side;
+  }
+
  @Override
  public boolean testComponent(IDIYComponent<?> component) {
    if (component instanceof IBoard board) {
@@ -17,6 +33,9 @@ public class SilkScreenFilter implements IComponentFilter {
    if (!(component instanceof IGerberComponent gerberComponent)) {
      return false;
    }
+    if (side != null && IBoardSideComponent.sideOf(component) != side) {
+      return false;
+    }
    Set<GerberRenderMode> gerberRenderModes = gerberComponent.getGerberRenderModes();
    return gerberRenderModes.contains(GerberRenderMode.Outline);
  }
@@ -54,6 +54,7 @@ import org.diylc.presenter.ComparatorFactory;
 import org.diylc.presenter.ComponentProcessor;
 import org.diylc.presenter.DatasheetService;
 import org.diylc.presenter.ReleaseHistory;
+import org.diylc.utils.ReflectionUtils;

 /**
 * Standalone tool that generates component catalog JSON files from the current codebase.
@@ -227,9 +228,11 @@ public class ComponentCatalogGenerator {
          }
        }

-        // Include enum possible values (using name() instead of toString())
+        // Include enum possible values (using name() instead of toString()), leaving out the
+        // deprecated ones the editor does not offer either
        if (propType.isEnum()) {
          List<String> possibleValues = Arrays.stream(propType.getEnumConstants())
+              .filter(e -> !ReflectionUtils.isDeprecated((Enum<?>) e))
              .map(e -> ((Enum<?>) e).name())
              .collect(Collectors.toList());
          prop.put("possibleValues", possibleValues);
@@ -37,6 +37,7 @@ import org.diylc.common.ComponentType;
 import org.diylc.common.DrawOption;
 import org.diylc.core.ComponentForRender;
 import org.diylc.core.ComponentState;
+import org.diylc.core.IBoardSideComponent;
 import org.diylc.core.IDIYComponent;
 import org.diylc.core.Project;
 import org.diylc.core.annotations.ComponentDescriptor;
@@ -153,12 +154,16 @@ public class DrawingCache {
        if (Math.abs(1.0 - zoom) > 1e-4) {
          g2d.getCanvasGraphics().scale(1 / zoom, 1 / zoom);
        }
+        // the image was rendered with the far-side fade already applied, so pasting it must not
+        // fade it again
+        g2d.startDrawingBothSides();
        try {
          // draw cached image
          g2d.scale(1 / scaleFactor, 1 / scaleFactor);
          g2d.getCanvasGraphics().drawImage(value.getImage(), (int) ((firstPoint.getX() - value.getDx()) * zoom * scaleFactor),
              (int) ((firstPoint.getY() - value.getDy())* zoom * scaleFactor), null);
        } finally {
+          g2d.stopDrawingSide();
          if (Math.abs(1.0 - zoom) > 1e-4) {
            g2d.getCanvasGraphics().scale(zoom, zoom);
          }
@@ -347,6 +352,7 @@ public class DrawingCache {

      // initialize wrapper
      wrapper.startedDrawingComponent(zOrder);
+      wrapper.setUndeclaredSide(IBoardSideComponent.sideOf(component));
      
      long componentStart = System.nanoTime();

@@ -66,7 +66,7 @@ import org.diylc.utils.Constants;
 public class DrawingManager {

  private static final Logger LOG = Logger.getLogger(DrawingManager.class);
-  public static final Percentage MIRROR_ALPHA = new Percentage(50);
+  public static Percentage FAR_SIDE_ALPHA = new Percentage(55);

  public static int CONTROL_POINT_SIZE = 7;
  public static double EXTRA_SPACE = 0.25;
@@ -118,6 +118,9 @@ public class DrawingManager {

  private List<Area> proximityMarkers = null;

+  // the board whose underside mirror the component in the slot is being placed through
+  private IBoard slotMirrorBoard = null;
+
  public DrawingManager(MessageDispatcher<EventType> messageDispatcher,
      IConfigurationManager<?> configManager) {
    super();
@@ -193,37 +196,12 @@ public class DrawingManager {

    configureRenderingHints(g2d, drawOptions);

-    // group components with boards that contain them
-    Map<IBoard, List<IDIYComponent<?>>> boardMap = project.getComponents().stream()
-            .filter(IBoard.class::isInstance)
-            .map(IBoard.class::cast)
-            .filter(b -> b.getUndersideDisplay() != null && b.getUndersideDisplay() != BoardUndersideDisplay.NONE)
-            .collect(Collectors.toMap(x -> x, x -> new ArrayList<IDIYComponent<?>>()));
+    // group components with the boards whose underside mirror shows them
    Map<IDIYComponent<?>, Set<IBoard>> componentBoardMap = new HashMap<IDIYComponent<?>, Set<IBoard>>();
-
-    for (IBoard board : boardMap.keySet()) {
-      Rectangle2D boardRect = board.getBoardRectangle();
-      if (boardRect == null) {
-        continue;
-      }
-      double minX = Math.min(boardRect.getMinX(), boardRect.getMaxX());
-      double maxX = Math.max(boardRect.getMinX(), boardRect.getMaxX());
-      double minY = Math.min(boardRect.getMinY(), boardRect.getMaxY());
-      double maxY = Math.max(boardRect.getMinY(), boardRect.getMaxY());
-      Rectangle2D normalizedBoardRect = new Rectangle2D.Double(minX, minY, maxX - minX, maxY - minY);
+    List<IBoard> mirroringBoards = UndersideMirror.getMirroringBoards(project);
+    for (IBoard board : mirroringBoards) {
      for (IDIYComponent<?> c : project.getComponents()) {
-        if (c == board) {
-          continue;
-        }
-        boolean include = false;
-        for (int i = 0; i < c.getControlPointCount(); i++) {
-          if (normalizedBoardRect.contains(c.getControlPoint(i))) {
-            include = true;
-            break;
-          }
-        }
-        if (include) {
-          boardMap.get(board).add(c);
+        if (c != board && UndersideMirror.isMirrored(board, c)) {
          componentBoardMap.computeIfAbsent(c, key -> new HashSet<IBoard>()).add(board);
        }
      }
@@ -328,6 +306,8 @@ public class DrawingManager {
        if (lockedComponents.contains(component) && drawOptions.contains(DrawOption.LOCKED_ALPHA)) {
          g2d.setComposite(lockedComposite);
        }
+        // after the locked composite, which is set on the canvas and would replace the fade
+        g2dWrapper.setUndeclaredSide(IBoardSideComponent.sideOf(component));
        // Draw the component through the g2dWrapper.
        long componentStart = System.nanoTime();
        try {
@@ -359,6 +339,7 @@ public class DrawingManager {
          }
        }
        ComponentArea area = g2dWrapper.finishedDrawingComponent();
+        g2dWrapper.setUndeclaredSide(PCBLayer._2);
        // after finishedDrawingComponent, which reverts the transform the clip was taken in
        if (visibleClip != null) {
          g2d.setClip(visibleClip);
@@ -427,20 +408,23 @@ public class DrawingManager {
                  || component.getControlPointVisibilityPolicy(i) == VisibilityPolicy.ALWAYS)) {

            Point2D controlPoint = component.getControlPoint(i);
-            int pointSize = CONTROL_POINT_SIZE;
-
-            g2dWrapper.setColor(SELECTED_CONTROL_POINT_COLOR.darker());
-            g2dWrapper.fillOval((int) Math.round(controlPoint.getX() - pointSize / 2),
-                (int) Math.round(controlPoint.getY() - pointSize / 2), pointSize, pointSize);
-            g2dWrapper.setColor(SELECTED_CONTROL_POINT_COLOR);
-            g2dWrapper.fillOval((int) Math.round(controlPoint.getX() - CONTROL_POINT_SIZE / 2 + 1),
-                (int) Math.round(controlPoint.getY() - CONTROL_POINT_SIZE / 2 + 1), CONTROL_POINT_SIZE - 2,
-                CONTROL_POINT_SIZE - 2);
+            drawSelectedControlPoint(g2dWrapper, controlPoint);
+            // the part can be selected through its mirrored copy, which then shows its points too
+            for (IBoard board : mirroringBoards) {
+              if (UndersideMirror.isMirrored(board, component)) {
+                drawSelectedControlPoint(g2dWrapper,
+                    UndersideMirror.createTransform(board).transform(controlPoint, null));
+              }
+            }
          }
        }
      }
    }

+    // a component being placed through an underside mirror is shown there, under the cursor
+    AffineTransform slotTx =
+        slotMirrorBoard == null ? null : UndersideMirror.createTransform(slotMirrorBoard);
+
    // Draw component slot in a separate composite.
    if (componentSlot != null) {
      for (IDIYComponent<?> component : componentSlot) {
@@ -448,6 +432,9 @@ public class DrawingManager {
        // leaves behind (e.g. a rotated Label) is reverted before the next one is drawn
        g2dWrapper.startedDrawingComponent(project.getComponents().size());
        g2dWrapper.setComposite(slotComposite);
+        if (slotTx != null) {
+          viewThroughMirror(g2dWrapper, slotMirrorBoard, slotTx, component);
+        }
        try {
          component.draw(g2dWrapper, ComponentState.NORMAL,
              drawOptions.contains(DrawOption.OUTLINE_MODE), project, g2dWrapper);
@@ -455,6 +442,9 @@ public class DrawingManager {
          LOG.error("Error drawing " + component.getName(), e);
          failedComponents.add(component);
        } finally {
+          if (slotTx != null) {
+            stopViewingThroughMirror(g2dWrapper);
+          }
          g2dWrapper.finishedDrawingComponent();
        }
      }
@@ -462,7 +452,9 @@ public class DrawingManager {

    // Draw control points of the component in the slot.
    if (controlPointSlot != null) {
-      for (Point2D point : controlPointSlot) {
+      for (Point2D slotPoint : controlPointSlot) {
+        Point2D point =
+            slotTx == null || slotPoint == null ? slotPoint : slotTx.transform(slotPoint, null);
        if (point != null) {
          g2dWrapper.setColor(SELECTED_CONTROL_POINT_COLOR.darker());
          g2dWrapper.fillOval((int) Math.round(point.getX() - CONTROL_POINT_SIZE / 2),
@@ -553,89 +545,58 @@ public class DrawingManager {
    return failedComponents;
  }

+  private static void drawSelectedControlPoint(G2DWrapper g2dWrapper, Point2D controlPoint) {
+    g2dWrapper.setColor(SELECTED_CONTROL_POINT_COLOR.darker());
+    g2dWrapper.fillOval((int) Math.round(controlPoint.getX() - CONTROL_POINT_SIZE / 2),
+        (int) Math.round(controlPoint.getY() - CONTROL_POINT_SIZE / 2), CONTROL_POINT_SIZE,
+        CONTROL_POINT_SIZE);
+    g2dWrapper.setColor(SELECTED_CONTROL_POINT_COLOR);
+    g2dWrapper.fillOval((int) Math.round(controlPoint.getX() - CONTROL_POINT_SIZE / 2 + 1),
+        (int) Math.round(controlPoint.getY() - CONTROL_POINT_SIZE / 2 + 1), CONTROL_POINT_SIZE - 2,
+        CONTROL_POINT_SIZE - 2);
+  }
+
  private static void drawMirroredComponent(Project project, IBoard board, IDIYComponent<?> component,
                                            G2DWrapper g2dWrapper, ComponentState state, boolean outlineMode) {
-    if (board.getUndersideDisplay() == null || board.getUndersideDisplay() == BoardUndersideDisplay.NONE) {
+    AffineTransform mirrorTx = UndersideMirror.createTransform(board);
+    if (mirrorTx == null) {
      return;
    }
-    double offset = board.getUndersideOffset() == null ? 0 : board.getUndersideOffset().convertToPixels();
-    Rectangle2D boardRectangle = board.getBoardRectangle();
-    if (boardRectangle == null) {
-      return;
-    }
-
-    double minX = Math.min(boardRectangle.getMinX(), boardRectangle.getMaxX());
-    double maxX = Math.max(boardRectangle.getMinX(), boardRectangle.getMaxX());
-    double minY = Math.min(boardRectangle.getMinY(), boardRectangle.getMaxY());
-    double maxY = Math.max(boardRectangle.getMinY(), boardRectangle.getMaxY());
-
-    AffineTransform mirrorTx = new AffineTransform();
-    switch (board.getUndersideDisplay()) {
-      case ABOVE: {
-        double pivotY = minY - offset / 2;
-        mirrorTx.translate(0, pivotY);
-        mirrorTx.scale(1.0, -1.0);
-        mirrorTx.translate(0, -pivotY);
-        break;
-      }
-      case BELOW: {
-        double pivotY = maxY + offset / 2;
-        mirrorTx.translate(0, pivotY);
-        mirrorTx.scale(1.0, -1.0);
-        mirrorTx.translate(0, -pivotY);
-        break;
-      }
-      case LEFT: {
-        double pivotX = minX - offset / 2;
-        mirrorTx.translate(pivotX, 0);
-        mirrorTx.scale(-1.0, 1.0);
-        mirrorTx.translate(-pivotX, 0);
-        break;
-      }
-      case RIGHT: {
-        double pivotX = maxX + offset / 2;
-        mirrorTx.translate(pivotX, 0);
-        mirrorTx.scale(-1.0, 1.0);
-        mirrorTx.translate(-pivotX, 0);
-        break;
-      }
-      default:
-        return;
-    }
-
-    G2DWrapper.MirrorDirection mirrorDirection;
-    switch (board.getUndersideDisplay()) {
-      case ABOVE:
-      case BELOW:
-        mirrorDirection = G2DWrapper.MirrorDirection.VERTICAL;
-        break;
-      case LEFT:
-      case RIGHT:
-        mirrorDirection = G2DWrapper.MirrorDirection.HORIZONTAL;
-        break;
-      default:
-        mirrorDirection = G2DWrapper.MirrorDirection.NONE;
-        break;
-    }

    AffineTransform oldTx = g2dWrapper.getTransform();
    Composite oldComposite = g2dWrapper.getComposite();
-    g2dWrapper.setMirrorDirection(mirrorDirection);
    try {
-      g2dWrapper.transform(mirrorTx);
-      if (Boolean.TRUE.equals(board.getUndersideTransparency())) {
-        g2dWrapper.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, (float)(MIRROR_ALPHA.getValue().doubleValue() / 100d)));
-      }
+      viewThroughMirror(g2dWrapper, board, mirrorTx, component);
      component.draw(g2dWrapper, state, outlineMode, project, g2dWrapper);
    } catch (Exception e) {
      LOG.error("Error drawing mirrored " + component.getName(), e);
    } finally {
-      g2dWrapper.setMirrorDirection(G2DWrapper.MirrorDirection.NONE);
+      stopViewingThroughMirror(g2dWrapper);
      g2dWrapper.setTransform(oldTx);
      g2dWrapper.setComposite(oldComposite);
    }
  }

+  /**
+   * Sets the wrapper up to draw the component into the board's underside mirror: reflected, with
+   * text kept readable, and seen from the bottom.
+   */
+  private static void viewThroughMirror(G2DWrapper g2dWrapper, IBoard board,
+      AffineTransform mirrorTx, IDIYComponent<?> component) {
+    g2dWrapper.setMirrorDirection(UndersideMirror.getMirrorDirection(board));
+    g2dWrapper.transform(mirrorTx);
+    // the mirror is the copper side, so copper and the parts mounted on it are drawn solid and
+    // the component side faded
+    g2dWrapper.setViewedSide(PCBLayer._1, Boolean.TRUE.equals(board.getUndersideTransparency()),
+        component instanceof IBoard ? PCBLayer._1 : IBoardSideComponent.sideOf(component));
+  }
+
+  private static void stopViewingThroughMirror(G2DWrapper g2dWrapper) {
+    g2dWrapper.setMirrorDirection(G2DWrapper.MirrorDirection.NONE);
+    g2dWrapper.stopDrawingSide();
+    g2dWrapper.resetViewedSide();
+  }
+
  private static void drawComponent(Project project, Set<DrawOption> drawOptions, Double scaleFactor,
      Rectangle2D visibleRect, IDIYComponent<?> component, G2DWrapper g2dWrapper, ComponentState state,
      double zoom, int i, boolean outlineMode, boolean cacheable) {
@@ -777,6 +738,16 @@ public class DrawingManager {
    proximityMarkers = null;
  }

+  /**
+   * Sets the board whose underside mirror the component being placed is drawn through, or null to
+   * draw it in the main view.
+   * 
+   * @param slotMirrorBoard
+   */
+  public void setSlotMirrorBoard(IBoard slotMirrorBoard) {
+    this.slotMirrorBoard = slotMirrorBoard;
+  }
+
  public void clearContinuityArea() {
    currentContinuityAreas = null;
    continuityGraphCache = null;
@@ -796,6 +767,50 @@ public class DrawingManager {
    return components;
  }

+  /**
+   * Finds the components that the underside mirror of a board shows at the specified point, top
+   * first, or none when the point is not in a mirror.
+   *
+   * @param point
+   * @param project
+   * @return
+   */
+  public List<IDIYComponent<?>> findMirroredComponentsAt(Point2D point, Project project) {
+    List<IDIYComponent<?>> components = new ArrayList<IDIYComponent<?>>();
+    for (IBoard board : UndersideMirror.findBoardsMirroredAt(project, point)) {
+      for (IDIYComponent<?> component : findMirroredComponentsAt(point, project, board)) {
+        if (!components.contains(component)) {
+          components.add(component);
+        }
+      }
+    }
+    return components;
+  }
+
+  /**
+   * Finds the components that the underside mirror of the specified board shows at the specified
+   * point, top first, or none when the point is not in that mirror.
+   *
+   * @param point
+   * @param project
+   * @param board
+   * @return
+   */
+  public List<IDIYComponent<?>> findMirroredComponentsAt(Point2D point, Project project,
+      IBoard board) {
+    List<IDIYComponent<?>> components = new ArrayList<IDIYComponent<?>>();
+    AffineTransform mirrorTx = UndersideMirror.createTransform(board);
+    if (mirrorTx == null || !UndersideMirror.getMirrorRegion(board).contains(point)) {
+      return components;
+    }
+    for (IDIYComponent<?> component : findComponentsAt(mirrorTx.transform(point, null), project)) {
+      if (UndersideMirror.isMirrored(board, component)) {
+        components.add(component);
+      }
+    }
+    return components;
+  }
+
  public double getExtraSpace(Project project) {
    double width = project.getWidth().convertToPixels();
    double height = project.getHeight().convertToPixels();
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Bane Stojkovic	d166c58161	Copper keeps its 'Layer' property in the editor, the term PCB tools use for copper, while still counting as a Board Side component in code	2026-11-11 21:40:33 +01:00
Bane Stojkovic	144c19b44b	Changelog entry for PCB text moving to the bottom page of the silkscreen print-out	2026-11-11 21:19:55 +01:00
Bane Stojkovic	aef300d902	Traces, curved traces, ground fills, solder pads and PCB text call their layer 'Board Side', like every other part, and count as Board Side components in code; the saved field is still 'layer'	2026-11-11 21:15:26 +01:00
Bane Stojkovic	7ae773ab77	A part's Gerber silkscreen layer follows its Board Side in IGerberComponentSimple's default, so the exporter no longer swaps layers after the fact and GerberLayer.flip() is gone	2026-11-11 20:48:35 +01:00
Bane Stojkovic	698fba5630	Changelog: the Underside Display editing and the realistic board rendering get their own entries, and entries are ordered new features, improvements, bug fixes; CLAUDE.md records the ordering rule	2026-11-11 20:40:39 +01:00
Bane Stojkovic	34d475b18a	Merge branch 'master' into copper-improvements # Conflicts: # diylc/diylc-core/src/main/resources/update.xml	2026-11-11 18:39:47 +01:00
Bane Stojkovic	1fe823270e	Hovering over a control point in a board's Underside Display shows its node name tooltip, as it does on the board itself	2026-11-11 18:39:29 +01:00
Bane Stojkovic	13b31e6dd5	Review fixes: a drag in the Underside Display picks the part a click would, the part being placed there is drawn like the parts already there, a bottom Dot no longer adds an empty silkscreen page; one helper decides a part's board side and copper layers share an interface	2026-11-11 17:32:46 +01:00
Bane Stojkovic	5ef6952ef4	The AI component catalog no longer offers the deprecated inner layers, and lists the new 'Board Side' property	2026-11-11 17:05:44 +01:00
Bane Stojkovic	19c78e5fa9	Parts dragged from the component tree or toolbox into a board's Underside Display go on the bottom of the board	2026-11-11 17:02:06 +01:00
Bane Stojkovic	7f8c790936	A 'Dot' used as a solder joint can be put on the bottom of the board with the 'Board Side' property	2026-11-11 16:57:35 +01:00
Bane Stojkovic	27b32b0b3c	Changelog entries for the faded copper view, the true underside view and the hidden inner layers	2026-11-11 16:39:49 +01:00
Bane Stojkovic	eeca9f112d	New parts can be placed in a board's Underside Display; a part placed there goes on the bottom of the board	2026-11-11 15:46:29 +01:00
Bane Stojkovic	122a91a6f0	The silkscreen print-out has a separate page for parts placed on the bottom of the board	2026-11-11 15:37:27 +01:00
Bane Stojkovic	246763419c	All PCB parts with a top silkscreen, including tube sockets, rotary switches, relays and transformers, have the 'Board Side' property	2026-11-11 15:34:40 +01:00
Bane Stojkovic	9721307586	Bottom-side plan: the board side is a plain property and parts are not mirrored for the user	2026-11-11 15:31:32 +01:00
Bane Stojkovic	9765f04e3c	Parts placed on the bottom of the board are drawn faded on the canvas and solid in the Underside Display mirror	2026-11-11 15:20:06 +01:00
Bane Stojkovic	df873df04a	Resistors, capacitors, diodes, ICs, transistors and other PCB parts can be placed on the bottom of the board with the new 'Board Side' property; Gerber export puts their silkscreen on the bottom layer with the text mirrored	2026-11-11 15:15:19 +01:00
Bane Stojkovic	16f54fa479	'Solder Pad' on the top layer put its solder mask opening on the bottom layer in Gerber export	2026-11-11 15:15:10 +01:00
Bane Stojkovic	b76d315f44	Components can be dragged and their points stretched through the Underside Display mirror of a board	2026-11-11 15:05:28 +01:00
Bane Stojkovic	90e10f4597	Components can be selected by clicking them in the Underside Display mirror of a board	2026-11-11 14:56:02 +01:00
Bane Stojkovic	3506c97403	A component can report which side of the board it is mounted on, and Gerber export puts the silkscreen of a part mounted underneath on the bottom layer	2026-11-11 14:48:57 +01:00
Bane Stojkovic	324cb20634	Gerber export decides each component's layer in one place, and Gerber layers can be mapped to the other side of the board	2026-11-11 14:46:02 +01:00
Bane Stojkovic	39c7743c30	Regenerated regression reference images for the far-side copper fade	2026-11-11 14:25:25 +01:00
Bane Stojkovic	0c26a71174	Merge branch 'master' into copper-improvements # Conflicts: # diylc/diylc-core/src/test/java/org/diylc/presenter/DrawingManagerTest.java	2026-11-11 10:26:39 +01:00
Bane Stojkovic	f73574641c	phase 1	2026-11-10 22:50:16 +01:00