feat: support cross-element port alignment via align-with

Extend the port `align-with` field to accept references to ports of
other elements, in addition to the existing local-port form:

  - "<local-id>"                    → same-element port (unchanged)
  - (element: "<id>", port: "<id>") → cross-element reference
  - "<raw-anchor>"                  → arbitrary CeTZ anchor name

Cross-element alignment is implemented via CeTZ perpendicular
projection (`|-`) so the port sits on this element's side line while
sharing the remote port's y (east/west) or x (north/south) coordinate.
Local resolution still validates matching axis and detects cycles;
external refs skip axis validation (remote side unknown at eval time)
and require the target element to be drawn first.

Also enrich port-related panic messages with the element id and port
context to make offending figures easier to locate, and add a manual
example (`examples.align-with-ports`) demonstrating both local and
cross-element alignment.

doc/examples.typ

@@ -23,6 +23,31 @@ wire.stub("block-port-in2", "west")
 wire.stub("block-port-out", "east")
 ```)
 
+#let align-with-ports = example(```
+// `align-with` reuses another port's coord
+// (E/W: y, N/S: x). Forms:
+//  1. "id"                     — local
+//  2. (element:"e", port:"p")  — cross-elmt
+//  3. "raw-anchor"             — CeTZ anchor
+element.block(x: 0, y: 0, w: 2, h: 2, id: "b1",
+  ports: (
+    west: ((id: "a", name: "A", y: 30%),),
+    east: ((id: "oa", name: "A'",
+            "align-with": "a"),),
+  ))
+element.block(x: 4, y: -.3, w: 2, h: 2.6, id: "b2",
+  ports: (
+    west: ((id: "ia", name: "A",
+            "align-with":
+              (element: "b1", port: "oa")),),
+    east: ((id: "o", name: "C"),),
+  ))
+wire.stub("b1-port-a", "west")
+wire.wire("w", ("b1-port-oa", "b2-port-ia"),
+          style: "direct")
+wire.stub("b2-port-o", "east")
+```, vertical: true)
+
 #let extender = example(```
 element.extender(
   x: 0, y: 0, w: 3, h: 1,
@@ -186,9 +211,143 @@ wire.wire("w2", ("b2-port-out", "b3-port-in2"),
           style: "zigzag")
 ```)
 
+#let group-ports = example(```
+// outside-port-names: true (default) — labels outside the border
+element.group(
+  id: "g1", name: "outside (default)",
+  stroke: (dash: "dashed"),
+  fill: util.colors.blue.lighten(60%),
+  padding: 2em,
+  outside-port-names: true,
+  port-name-padding: 4pt,
+  ports: (
+    west:  ((id: "in",  name: "D"),),
+    east:  ((id: "out", name: "Q"),),
+  ),
+  { element.block(id: "b1", w: 2, h: 1.5, x: 0, y: 0,
+      fill: util.colors.green,
+      ports: (west: ((id: "d", name: "d"),),
+              east: ((id: "q", name: "q"),))) }
+)
+wire.wire("wG1in",  ("g1-port-in", "b1-port-d"), directed: true)
+wire.wire("wG1out", ("b1-port-q",  "g1-port-out"), directed: true)
+
+// outside-port-names: false — labels inside the border (block style)
+// with extra padding via port-name-padding
+element.group(
+  id: "g2", name: "inside",
+  stroke: (dash: "dashed"),
+  fill: util.colors.orange.lighten(60%),
+  padding: 2em,
+  outside-port-names: false,
+  port-name-padding: 0.4em,
+  ports: (
+    west:  ((id: "in",  name: "D"),),
+    east:  ((id: "out", name: "Q"),),
+  ),
+  { element.block(id: "b2", w: 2, h: 1.5, x: 6, y: 0,
+      fill: util.colors.green,
+      ports: (west: ((id: "d"),), east: ((id: "q"),))) }
+)
+wire.stub("g2-port-in",  "west")
+wire.stub("g2-port-out", "east")
+```, vertical: true)
+
+#let port-names-outside = example(```
+element.block(
+  x: 0, y: 0, w: 2, h: 2, id: "block",
+  port-names-outside: true,
+  port-name-padding: 4pt,
+  ports: (
+    north: ((id: "clk", name: "CLK", clock: true),),
+    west: ((id: "in1", name: "A"),
+           (id: "in2", name: "B")),
+    east: ((id: "out", name: "Y"),)
+  )
+)
+```)
+
+#let port-shape = example(```
+// Block with pentagon-shaped ports.
+// - port-shape / port-kind / port-size are element-level defaults.
+// - Any port field (shape, kind, size, stroke, fill) overrides per port.
+// - kind: "in"  → tip points into the block (default)
+//   kind: "out" → tip points away from the block
+// - clock ports with shape: "pentagon" drop their triangle and default
+//   to a gray fill.
+element.block(
+  id: "b", w: 3, h: 3, x: 0, y: 0,
+  fill: util.colors.yellow.lighten(60%),
+  port-shape: "pentagon",
+  port-size: 1em,
+  ports: (
+    // west: default input
+    west:  ((id: "in",  name: "D"),),
+    // east: output — tip points away
+    east:  ((id: "out", name: "Q", kind: "out"),),
+    // north: clock port — pentagon replaces the triangle, gray fill
+    north: ((id: "clk", name: "CLK", clock: true),),
+    // south: styled output with per-port fill and stroke
+    south: ((id: "rdy", name: "RDY", kind: "out",
+             fill: util.colors.blue, stroke: red + 1.5pt),),
+  ),
+)
+// Wires connect at the outer end of each pentagon.
+wire.stub("b-port-in",  "west")
+wire.stub("b-port-out", "east")
+wire.stub("b-port-clk", "north")
+wire.stub("b-port-rdy", "south")
+```)
+
+#let shell = example(```
+// A shell block acts as a container: port name labels are drawn
+// outside by default, and wires attach at the *inside* tip of
+// pentagon-shaped ports so child elements can sit within.
+element.block(
+  id: "sh", w: 5, h: 3, x: 0, y: 0,
+  shell: true,
+  port-shape: "pentagon",
+  fill: util.colors.blue.lighten(80%),
+  ports: (
+    west: ((id: "in",  name: "IN"),),
+    east: ((id: "out", name: "OUT", kind: "out"),),
+  ),
+  {
+    element.block(id: "inner", w: 2, h: 1.5, x: 1.5, y: 0.75,
+      fill: util.colors.yellow,
+      ports: (west: ((id: "a"),), east: ((id: "b"),)))
+  }
+)
+wire.wire("w-in",  ("sh-port-in",  "inner-port-a"))
+wire.wire("w-out", ("inner-port-b", "sh-port-out"))
+```)
+
 #let intersection = example(```
 wire.wire("w1", ((0, 0), (1, 1)), style: "zigzag")
 wire.wire("w2", ((0, 0), (1, -.5)),
           style: "zigzag", zigzag-ratio: 80%)
 wire.intersection("w1.zig")
 ```)
+
+#let port-shape-attach = example(
+  ```
+  // Pentagon ports expose `.east`, `.west`, `.north`,
+  // `.south` sub-anchors on the pentagon boundary,
+  // letting wires attach to any face.
+  element.block(x: 0, y: 0, w: 2, h: 2, id: "a",
+    port-shape: "pentagon",
+    ports: (west: ((id: "p", name: "P"),),))
+  draw.circle((-2, 0.5), radius: .05, name: "L")
+  draw.circle(( 3, 1.5), radius: .05, name: "R")
+  draw.circle((-1, 2.5), radius: .05, name: "T")
+  // .west = outer flat base
+  wire.wire("w1", ("L", "a-port-p.west"), style: "direct")
+  // .east = tip inside the block
+  wire.wire("w2", ("R", "a-port-p.east"),
+            style: "direct", color: red)
+  // .north = top edge midpoint
+  wire.wire("w3", ("T", "a-port-p.north"),
+            style: "direct", color: blue)
+  ```,
+  vertical: true,
+)

gallery/test_group_ports.typ

@@ -0,0 +1,86 @@
+// Demonstrates ports on a group element.
+// outside-port-names: true  (default) — labels outside the group border
+// outside-port-names: false           — labels inside  (block-style)
+#import "/src/lib.typ": circuit, element, util, wire
+
+#set page(width: auto, height: auto, margin: .5cm)
+
+#circuit({
+  // --- Group with port labels INSIDE (outside-port-names: false) ---
+  element.group(
+    id: "cpu",
+    name: "CPU (labels outside)",
+    name-anchor: "north",
+    stroke: (dash: "dashed"),
+    fill: util.colors.yellow.lighten(60%),
+    padding: 1em,
+    port-name-padding: .5em,
+    outside-port-names: true,
+    ports: (
+      west: (
+        (id: "in1", name: "D1"),
+        (id: "in2", name: "D2"),
+      ),
+      east: ((id: "out", name: "Q"),),
+      south: (
+        (id: "rst", name: "RST", vertical: true),
+        (id: "done", name: "DONE", vertical: true),
+      ),
+    ),
+    {
+      element.block(
+        id: "reg2",
+        w: 2.5,
+        h: 3,
+        x: 0,
+        y: 0,
+        fill: util.colors.green,
+        ports: (
+          west: ((id: "d1"), (id: "d2")),
+          east: ((id: "q"),),
+          north: ((id: "clk", clock: true),),
+        ),
+      )
+    },
+  )
+  // --- Group with port labels INSIDE (outside-port-names: false) ---
+  element.group(
+    id: "cpu2",
+    name: "CPU (labels inside)",
+    name-anchor: "north",
+    stroke: (dash: "dashed"),
+    fill: util.colors.yellow.lighten(60%),
+    padding: 4em,
+    outside-port-names: false,
+    port-name-padding: 0.5em,
+    ports: (
+      west: (
+        (id: "in1", name: "D1"),
+        (id: "in2", name: "D2"),
+      ),
+      east: ((id: "out", name: "Q"),),
+      south: (
+        (id: "rst", name: "RST", vertical: true),
+        (id: "done", name: "DONE", vertical: true),
+      ),
+    ),
+    {
+      element.block(
+        id: "reg2",
+        w: 2.5,
+        h: 3,
+        x: 10,
+        y: 0,
+        fill: util.colors.green,
+        ports: (
+          west: ((id: "d1"), (id: "d2")),
+          east: ((id: "q"),),
+          north: ((id: "clk", clock: true),),
+        ),
+      )
+    },
+  )
+  wire.stub("cpu2-port-in1", "west", name: "A")
+  wire.stub("cpu2-port-in2", "west", name: "B")
+  wire.stub("cpu2-port-out", "east", name: "Q")
+})

gallery/test_port_shape.typ

@@ -0,0 +1,117 @@
+// Demonstrates pentagon-shaped ports.
+//
+// - Element-level defaults: `port-shape`, `port-kind`, `port-size`.
+// - Per-port overrides: `shape`, `kind`, `size`, `stroke`, `fill`.
+// - Wire endpoints connect at the outer end of each pentagon.
+// - Clock ports with pentagon shape drop the clock triangle and default
+//   to a gray fill.
+#import "/src/lib.typ": circuit, element, util, wire
+
+#set page(width: auto, height: auto, margin: .5cm)
+
+#circuit({
+  // -----------------------------------------------------------------
+  // 1) All four sides × input/output
+  // -----------------------------------------------------------------
+  element.block(
+    id: "grid", w: 4, h: 4, x: 0, y: 0,
+    name: "sides × in/out", name-anchor: "center",
+    fill: util.colors.yellow.lighten(60%),
+    port-shape: "pentagon",
+    ports: (
+      west:  (
+        (id: "wi", name: "W-in"),
+        (id: "wo", name: "W-out", kind: "out"),
+      ),
+      east:  (
+        (id: "ei", name: "E-in"),
+        (id: "eo", name: "E-out", kind: "out"),
+      ),
+      north: (
+        (id: "ni", name: "N-in",  vertical: true),
+        (id: "no", name: "N-out", kind: "out", vertical: true),
+      ),
+      south: (
+        (id: "si", name: "S-in",  vertical: true),
+        (id: "so", name: "S-out", kind: "out", vertical: true),
+      ),
+    ),
+  )
+
+  // -----------------------------------------------------------------
+  // 2) Per-port styling: fill and stroke overrides + size override
+  // -----------------------------------------------------------------
+  element.block(
+    id: "styled", w: 3, h: 3, x: 10, y: 0,
+    name: "per-port styling", name-anchor: "center",
+    fill: util.colors.green.lighten(40%),
+    port-shape: "pentagon",
+    ports: (
+      west:  ((id: "a", name: "A", fill: util.colors.blue),),
+      east:  ((id: "b", name: "B", kind: "out",
+               stroke: red + 1.5pt, fill: util.colors.pink),),
+      north: ((id: "c", name: "C", size: 1.5em),),
+      south: ((id: "d", name: "D", kind: "out",
+               fill: util.colors.orange),),
+    ),
+  )
+
+  // -----------------------------------------------------------------
+  // 3) Clock port with pentagon → gray fill, no triangle
+  // -----------------------------------------------------------------
+  element.block(
+    id: "clk", w: 3, h: 2.5, x: 16, y: 0,
+    name: "clock + pentagon", name-anchor: "center",
+    fill: util.colors.orange.lighten(60%),
+    port-shape: "pentagon",
+    ports: (
+      west:  ((id: "d", name: "D"),),
+      east:  ((id: "q", name: "Q", kind: "out"),),
+      north: ((id: "clk", name: "CLK", clock: true),),
+    ),
+  )
+
+  // -----------------------------------------------------------------
+  // 4) Two pentagon-ported blocks connected by a wire
+  //    (wire terminates at outer edge of each pentagon)
+  // -----------------------------------------------------------------
+  element.block(
+    id: "src", w: 2, h: 1.5, x: 0, y: -5,
+    name: "src", name-anchor: "center",
+    fill: util.colors.pink,
+    port-shape: "pentagon",
+    ports: (east: ((id: "q", name: "Q", kind: "out"),)),
+  )
+  element.block(
+    id: "dst", w: 2, h: 1.5, x: 6, y: -5,
+    name: "dst", name-anchor: "center",
+    fill: util.colors.blue,
+    port-shape: "pentagon",
+    ports: (west: ((id: "d", name: "D"),)),
+  )
+  wire.wire("w-sd", ("src-port-q", "dst-port-d"))
+
+  // -----------------------------------------------------------------
+  // 5) Group with pentagon ports enclosing a child block
+  // -----------------------------------------------------------------
+  element.group(
+    id: "g", name: "group w/ pentagon ports", name-anchor: "north",
+    stroke: (dash: "dashed"),
+    fill: util.colors.purple.lighten(70%),
+    padding: 2em,
+    port-shape: "pentagon",
+    ports: (
+      west: ((id: "in",  name: "IN"),),
+      east: ((id: "out", name: "OUT", kind: "out"),),
+    ),
+    {
+      element.block(
+        id: "inner", w: 2, h: 1.5, x: 12, y: -5,
+        fill: util.colors.green,
+        ports: (west: ((id: "d"),), east: ((id: "q"),)),
+      )
+    },
+  )
+  wire.wire("wgi", ("g-port-in",  "inner-port-d"))
+  wire.wire("wgo", ("inner-port-q", "g-port-out"))
+})

gallery/test_xalign.typ

@@ -1,30 +0,0 @@
-// Demonstrates the `(from: <anchor>, to: <port-id>)` port-alignment shorthand
-// for the `x` parameter (analogous to the existing shorthand for `y`).
-#import "/src/lib.typ": circuit, element, util, wire
-
-#set page(width: auto, height: auto, margin: .5cm)
-
-#circuit({
-  // Anchor block: absolute placement, with a single "addr" port on its
-  // north side (auto-centred horizontally by circuiteria).
-  element.block(
-    x: 0, y: 0, w: 2, h: 1.5,
-    id: "vcemem",
-    fill: util.colors.orange,
-    ports: (north: ((id: "addr"),), east: ((id: "out"),))
-  )
-
-  // This block's "addr" port (south side) is x-aligned with vcemem's "addr"
-  // port (north side), even though B is wider than vcemem and not
-  // horizontally aligned by default.
-  element.block(
-    x: (from: "vcemem-port-addr", to: "addr"),
-    y: (rel: 2, to: "vcemem.north"),
-    w: 4.5, h: 1,
-    id: "fsm",
-    fill: util.colors.yellow,
-    ports: (south: ((id: "addr"),), east: ((id: "out"),))
-  )
-
-  wire.wire("wAddr", ("vcemem-port-addr", "fsm-port-addr"), style: "zigzag")
-})

gallery/test_yrel.typ

@@ -1,46 +0,0 @@
-// Demonstrates the `(rel: <number>, to: <anchor>)` shorthand for the `y`
-// parameter (analogous to the existing shorthand for `x`).
-#import "/src/lib.typ": circuit, element, util, wire
-
-#set page(width: auto, height: auto, margin: .5cm)
-
-#circuit({
-  // Anchor block: absolute placement.
-  element.block(
-    x: 0, y: 0, w: 2, h: 1.5,
-    id: "A",
-    fill: util.colors.orange,
-    ports: (east: ((id: "out"),))
-  )
-
-  // X relative, Y absolute (existing feature).
-  element.block(
-    x: (rel: 1, to: "A.east"), y: 0, w: 2, h: 1.5,
-    id: "B",
-    fill: util.colors.yellow,
-    ports: (west: ((id: "in"),), east: ((id: "out"),))
-  )
-
-  // Both X and Y relative to another element's anchor (new feature).
-  element.block(
-    x: (rel: 1, to: "B.east"),
-    y: (rel: 2, to: "B.south-west"),
-    w: 2, h: 1.5,
-    id: "C",
-    fill: util.colors.green,
-    ports: (west: ((id: "in"),))
-  )
-
-  // Y relative only, X absolute.
-  element.block(
-    x: 0,
-    y: (rel: -2.5, to: "A.south-west"),
-    w: 2, h: 1.5,
-    id: "D",
-    fill: util.colors.blue,
-    ports: (east: ((id: "out"),))
-  )
-
-  wire.wire("wAB", ("A-port-out", "B-port-in"))
-  wire.wire("wBC", ("B-port-out", "C-port-in"), style: "zigzag")
-})

manual.typ

@@ -166,8 +166,24 @@ If you have installed Circuiteria directly in your project, import #link("src/li
 
 #pagebreak()
 
+#let element-scope = (
+  element: element,
+  circuit: circuit,
+  draw: draw,
+  wire: wire,
+  tidy: tidy,
+  examples: examples,
+  doc-ref: doc-ref
+)
+
+#let elmt-docs = tidy.parse-module(
+  read("src/elements/element.typ"),
+  name: "element",
+  old-syntax: true,
+  scope: element-scope
+)
+
 #let element-docs = tidy.parse-module(
-  read("src/elements/element.typ") + "\n" +
   read("src/elements/alu.typ") + "\n" +
   read("src/elements/block.typ") + "\n" +
   read("src/elements/extender.typ") + "\n" +
@@ -175,18 +191,19 @@ If you have installed Circuiteria directly in your project, import #link("src/li
   read("src/elements/group.typ"),
   name: "element",
   old-syntax: true,
-  scope: (
-    element: element,
-    circuit: circuit,
-    draw: draw,
-    wire: wire,
-    tidy: tidy,
-    examples: examples,
-    doc-ref: doc-ref
-  )
+  scope: element-scope
 )
 
-#tidy.show-module(element-docs, sort-functions: false)
+#tidy.show-module(elmt-docs, sort-functions: false, show-module-name: true)
+
+#figure(
+  examples.align-with-ports,
+  caption: [Example of the `align-with` port field (see #doc-ref("element.elmt")).],
+  kind: "example",
+  supplement: [Example],
+) <elmt-align-with-example>
+
+#tidy.show-module(element-docs, sort-functions: false, show-module-name: false)
 
 #pagebreak()
 

src/elements/block.typ

@@ -16,9 +16,22 @@
 /// Draws a block element
 ///
 /// #examples.block
+///
+/// Ports can be given a pentagon shape (with configurable direction, size,
+/// stroke and fill) via `port-shape` and per-port overrides:
+/// #examples.port-shape
+///
+/// Port name labels can be placed outside the block via `port-names-outside`:
+/// #examples.port-names-outside
 /// For other parameters description, see #doc-ref("element.elmt")
 /// - radius (number, length, ratio, dictionary): The corner radius of the block. See CeTZ documentation for more information
+/// - shell (bool): If true, the block behaves like a shell/container (analogous to a group): port name labels default to being drawn outside the block, and wires attach to the inside tip of pentagon-shaped ports. See #doc-ref("element.elmt")
+///
+/// Use `shell: true` to wrap child elements inside a bordered container without
+/// having ports overlap the interior:
+/// #examples.shell
 #let block(
+  ..args,
   x: none,
   y: none,
   w: none,
@@ -27,15 +40,22 @@
   name-anchor: "center",
   ports: (),
   ports-margins: (),
+  port-name-padding: 2pt,
+  port-names-outside: auto,
+  port-shape: none,
+  port-kind: "in",
+  port-size: 1em,
   fill: none,
   radius: 0.5em,
   stroke: black + 1pt,
   id: "",
+  shell: false,
   debug: (
     ports: false
   )
 ) = element.elmt(
   draw-shape: draw-shape.with(radius: radius),
+  body: if args.pos().len() > 0 { args.pos().first() } else { none },
   x: x,
   y: y,
   w: w,
@@ -44,8 +64,14 @@
   name-anchor: name-anchor,
   ports: ports,
   ports-margins: ports-margins,
+  port-name-padding: port-name-padding,
+  port-names-outside: port-names-outside,
+  port-shape: port-shape,
+  port-kind: port-kind,
+  port-size: port-size,
   fill: fill,
   stroke: stroke,
   id: id,
+  shell: shell,
   debug: debug
 )

src/elements/element.typ

@@ -1,5 +1,5 @@
-#import "/src/cetz.typ": draw, coordinate
-#import "ports.typ": add-ports, add-port
+#import "/src/cetz.typ": coordinate, draw
+#import "ports.typ": add-port, add-ports
 #import "../util.typ"
 
 #let find-port(ports, id) = {
@@ -21,14 +21,10 @@
 /// - draw-shape (function): Draw function
 /// - x (number, dictionary): The x position (bottom-left corner).
 ///
-///   If it is a dictionary, it can take one of two forms:
-///     - `(rel: number, to: str)`: `rel` is the x offset and `to` the base anchor
-///     - `(from: str, to: str)`: `from` is the base anchor and `to` is the id of the port to align with the anchor (analogous to `y`)
+///   If it is a dictionary, it should be in the format `(rel: number, to: str)`, where `rel` is the offset and `to` the base anchor
 /// - y (number, dictionary): The y position (bottom-left corner).
 ///
-///   If it is a dictionary, it can take one of two forms:
-///     - `(rel: number, to: str)`: `rel` is the y offset and `to` the base anchor (analogous to `x`)
-///     - `(from: str, to: str)`: `from` is the base anchor and `to` is the id of the port to align with the anchor
+///   If it is a dictionary, it should be in the format `(from: str, to: str)`, where `from` is the base anchor and `to` is the id of the port to align with the anchor
 /// - w (number): Width of the element
 /// - h (number): Height of the element
 /// - name (none, str): Optional name of the block
@@ -38,13 +34,26 @@
 ///   - `name` (`str`): Optional name displayed *in* the block
 ///   - `clock` (`bool`): Whether it is a clock port (triangle symbol)
 ///   - `vertical` (`bool`): Whether the name should be drawn vertically
+///   - `align-with` (`str`, `dictionary`): Optional. Reuse another port's placement coordinate (east/west: y, north/south: x). Accepted forms: `"<local-id>"` (same-element port; axis must match, transitively resolved, cycles panic), `(element: "<id>", port: "<id>")` (cross-element; axis not validated; target element must be drawn first), or `"<raw-anchor>"` (any unrecognised string is used as a CeTZ anchor name). See @elmt-align-with-example.
+///   - `x` (length, ratio, function): Optional. North/south ports only. Explicit x-offset override measured from the left corner of the side. A `ratio` is used as a percentage along the side; a length/number is used as an absolute offset; a function is called with the element width and must return a length/number. Panics if used together with `align-with` or on an east/west port.
+///   - `y` (length, ratio, function): Optional. East/west ports only. Analogous to `x`, measured from the top corner of the side and called with the element height when a function is passed.
+///   - `shape` (`none`, `str`): Optional. Per-port override of the element-level `port-shape` (e.g. `"pentagon"`). Lets a single port on a block or group opt into (or out of) a shape independently of the element default. See the `port-shape` parameter below.
+///   - `kind` (`str`): Optional. Per-port override of the element-level `port-kind` (`"in"` / `"out"`). Affects pentagon orientation.
+///   - `size` (length): Optional. Per-port override of the element-level `port-size` (unit size of pentagon-shaped ports).
+///   - `stroke` (stroke): Optional. Per-port override of the pentagon stroke. Defaults to the element stroke.
+///   - `fill` (none, color): Optional. Per-port override of the pentagon fill. Defaults to the element fill (or `gray` for clock ports with `shape: "pentagon"`).
 /// - ports-margins (dictionary): Dictionary of ports margins (used with automatic port placement). They keys are cardinal directions ("north", "east", "south", "west"). The values are tuples of (`<start>`, `<end>`) margins (numbers)
+/// - port-name-padding (number, length): Padding between the port name label and the port anchor point (default `2pt`)
+/// - port-names-outside (bool, auto): If true, port name labels are drawn on the outside of the block instead of the inside. When `auto` (default), follows the `shell` setting (outside if `shell: true`, inside otherwise)
+/// - port-shape (none, str): Default port shape for all ports of this element. Set to `"pentagon"` to draw pentagon-shaped ports. Overridable per port via the port's `shape` field (see the ports dictionary above); a per-port `shape: none` also removes the shape for just that port. See #examples.port-shape
+/// - port-kind (str): Default direction of ports (`"in"` or `"out"`). Overridable per port via the port's `kind` field
+/// - port-size (length): Default unit size of pentagon-shaped ports (default `1em`). Overridable per port via the port's `size` field
 /// - fill (none, color): Fill color
 /// - stroke (stroke): Border stroke
 /// - id (str): The block id (for future reference)
 /// - auto-ports (bool): Whether to use auto port placements or not. If false, `draw-shape` is responsible for adding the appropiate ports
-/// - ports-x (dictionary): Dictionary of the ports x offsets (used with `auto-ports: false`)
 /// - ports-y (dictionary): Dictionary of the ports y offsets (used with `auto-ports: false`)
+/// - shell (bool): If true, the block behaves like a shell/container (analogous to a group): port name labels default to being drawn *outside* the block border, and wires attach to the *inside* tip of pentagon-shaped ports instead of the outside base. Useful for wrapping child elements without having ports overlap them (default `false`)
 /// - debug (dictionary): Dictionary of debug options.
 ///
 ///   Supported fields include:
@@ -59,15 +68,21 @@
   name-anchor: "center",
   ports: (:),
   ports-margins: (:),
+  port-name-padding: 2pt,
+  port-names-outside: auto,
+  port-shape: none,
+  port-kind: "in",
+  port-size: 1em,
   fill: none,
   stroke: black + 1pt,
   id: "",
   auto-ports: true,
-  ports-x: (:),
   ports-y: (:),
+  shell: false,
+  body: none,
   debug: (
-    ports: false
-  )
+    ports: false,
+  ),
 ) = draw.get-ctx(ctx => {
   let width = w
   let height = h
@@ -79,45 +94,14 @@
   if w == none { panic("Parameter w must be set") }
   if h == none { panic("Parameter h must be set") }
 
-  if (type(x) == dictionary and "rel" in x) {
-    x = util.resolve-rel-coord(ctx, x, 0)
-  } else if (type(x) == dictionary) {
-    let from = x.from
+  if (type(x) == dictionary) {
+    let offset = x.rel
     let to = x.to
-    let (to-side, i) = find-port(ports, to)
-    let margins = (0%, 0%)
-    if to-side in ports-margins {
-      margins = ports-margins.at(to-side)
-    }
-
-    let dx
-    let left-margin
-    if to-side in ("north", "south") {
-      let used-pct = 100% - margins.at(0) - margins.at(1)
-      let used-width = width * used-pct / 100%
-      left-margin = width * margins.at(0) / 100%
-
-      dx = used-width * (i + 1) / (ports.at(to-side).len() + 1)
-
-      if not auto-ports {
-        left-margin = 0
-        dx = ports-x.at(to)(width)
-      }
-    } else if to-side == "west" {
-      dx = 0
-      left-margin = 0
-    } else if to-side == "east" {
-      dx = width
-      left-margin = 0
-    }
-
-    let (ctx, from-pos) = coordinate.resolve(ctx, from)
-    x = from-pos.at(0) + dx - width + left-margin
+    let (ctx, to-pos) = coordinate.resolve(ctx, (rel: (offset, 0), to: to))
+    x = to-pos.at(0)
   }
   
-  if (type(y) == dictionary and "rel" in y) {
-    y = util.resolve-rel-coord(ctx, y, 1)
-  } else if (type(y) == dictionary) {
+  if (type(y) == dictionary) {
     let from = y.from
     let to = y.to
     let (to-side, i) = find-port(ports, to)
@@ -132,7 +116,7 @@
       let used-pct = 100% - margins.at(0) - margins.at(1)
       let used-height = height * used-pct / 100%
       top-margin = height * margins.at(0) / 100%
-      
+
       dy = used-height * (i + 1) / (ports.at(to-side).len() + 1)
 
       if not auto-ports {
@@ -146,7 +130,7 @@
       dy = height
       top-margin = 0
     }
-    
+
     let (ctx, from-pos) = coordinate.resolve(ctx, from)
     y = from-pos.at(1) + dy - height + top-margin
   }
@@ -164,19 +148,37 @@
   if (name != none) {
     draw.content(
       (name: id, anchor: name-anchor),
-      anchor: if name-anchor in util.valid-anchors {name-anchor} else {"center"},
+      anchor: if name-anchor in util.valid-anchors { name-anchor } else { "center" },
       padding: 0.5em,
-      align(center)[*#name*]
+      align(center)[*#name*],
     )
   }
 
   if auto-ports {
+    let outside-name = if port-names-outside == auto { shell } else { port-names-outside }
     add-ports(
       id,
-      tl, tr, br, bl,
+      tl,
+      tr,
+      br,
+      bl,
       ports,
       ports-margins,
-      debug: debug.ports
+      width: width,
+      height: height,
+      debug: debug.ports,
+      name-padding: port-name-padding,
+      outside-name: outside-name,
+      port-shape: port-shape,
+      port-kind: port-kind,
+      port-size: port-size,
+      elmt-stroke: stroke,
+      elmt-fill: fill,
+      wire-inside: shell,
     )
   }
-})
+
+  if body != none {
+    body
+  }
+})

src/elements/group.typ

@@ -1,9 +1,15 @@
 #import "/src/cetz.typ": draw, coordinate
 #import "../util.typ"
+#import "ports.typ": add-ports
 
 /// Draws a group of elements
 ///
 /// #examples.group
+///
+/// Ports can also be defined on a group, just like on a block. By default
+/// port labels are drawn *outside* the group border so they do not overlap
+/// child elements. Set `outside-port-names: false` to draw them inside.
+/// #examples.group-ports
 /// - body (elements, function): Elements to group
 /// - id (str): see #doc-ref("element.elmt")
 /// - name (str): The group's name
@@ -16,6 +22,14 @@
 ///    - array: either (`<all>`,), (`<vertical>`, `<horizontal>`) or (`<top>`, `<right>`, `<bottom>`, `<left>`)
 ///    - dictionary: valid keys are "top", "right", "bottom" and "left"
 /// - radius (number): The corner radius
+/// - ports (dictionary): see #doc-ref("element.elmt")
+/// - ports-margins (dictionary): see #doc-ref("element.elmt")
+/// - outside-port-names (bool): If `true` (default), port name labels are drawn outside the group border so they do not overlap child elements. Set to `false` to draw labels inside, matching the block behaviour
+/// - port-name-padding (number, length): Padding between the port name label and the group border (default `2pt`). Accepts anything CeTZ accepts as `padding` (number or length)
+/// - port-shape (none, str): see #doc-ref("element.elmt")
+/// - port-kind (str): see #doc-ref("element.elmt")
+/// - port-size (length): see #doc-ref("element.elmt")
+/// - debug (dictionary): see #doc-ref("element.elmt")
 #let group(
   body,
   id: "",
@@ -24,7 +38,17 @@
   fill: none,
   stroke: black + 1pt,
   padding: 0.5em,
-  radius: 0.5em
+  radius: 0.5em,
+  ports: (:),
+  ports-margins: (:),
+  outside-port-names: true,
+  port-name-padding: 2pt,
+  port-shape: none,
+  port-kind: "in",
+  port-size: 1em,
+  debug: (
+    ports: false
+  )
 ) = {
   let min-x = none
   let max-x = none
@@ -68,6 +92,25 @@
     stroke: stroke,
     fill: fill
   )
+
+  add-ports(
+    id,
+    id + ".north-west",
+    id + ".north-east",
+    id + ".south-east",
+    id + ".south-west",
+    ports,
+    ports-margins,
+    debug: debug.ports,
+    outside-name: outside-port-names,
+    name-padding: port-name-padding,
+    port-shape: port-shape,
+    port-kind: port-kind,
+    port-size: port-size,
+    elmt-stroke: stroke,
+    elmt-fill: fill,
+  )
+
   if name != none {
     draw.content(
       id + "." + name-anchor,

src/elements/logic/gate.typ

@@ -1,5 +1,4 @@
 #import "/src/cetz.typ": draw, coordinate
-#import "/src/util.typ"
 #import "../ports.typ": add-ports, add-port
 #import "../element.typ"
 
@@ -50,12 +49,13 @@
   if h == none { panic("Parameter h must be set") }
 
   if (type(x) == dictionary) {
-    x = util.resolve-rel-coord(ctx, x, 0)
+    let offset = x.rel
+    let to = x.to
+    let (ctx, to-pos) = coordinate.resolve(ctx, (rel: (offset, 0), to: to))
+    x = to-pos.at(0)
   }
   
-  if (type(y) == dictionary and "rel" in y) {
-    y = util.resolve-rel-coord(ctx, y, 1)
-  } else if (type(y) == dictionary) {
+  if (type(y) == dictionary) {
     let from = y.from
     let to = y.to
     

src/elements/logic/iec_gate.typ

@@ -1,5 +1,4 @@
 #import "/src/cetz.typ": draw, coordinate
-#import "/src/util.typ"
 #import "../ports.typ": add-ports, add-port
 #import "../element.typ"
 
@@ -61,12 +60,13 @@
   if h == none { panic("Parameter h must be set") }
 
   if (type(x) == dictionary) {
-    x = util.resolve-rel-coord(ctx, x, 0)
+    let offset = x.rel
+    let to = x.to
+    let (ctx, to-pos) = coordinate.resolve(ctx, (rel: (offset, 0), to: to))
+    x = to-pos.at(0)
   }
   
-  if (type(y) == dictionary and "rel" in y) {
-    y = util.resolve-rel-coord(ctx, y, 1)
-  } else if (type(y) == dictionary) {
+  if (type(y) == dictionary) {
     let from = y.from
     let to = y.to
     

src/elements/ports.typ

@@ -1,116 +1,446 @@
 #import "/src/cetz.typ": draw
-#import "../util.typ": rotate-anchor
+#import "../util.typ": opposite-anchor, port-shape-vertices, rotate-anchor
 
 #let add-port(
-  elmt-id, side, port, pos,
+  elmt-id,
+  side,
+  port,
+  pos,
   prev: none,
   next: none,
-  debug: false
+  debug: false,
+  outside-name: false,
+  name-padding: 2pt,
+  port-shape: none,
+  port-kind: "in",
+  port-size: 1em,
+  elmt-stroke: black + 1pt,
+  elmt-fill: none,
+  wire-inside: false,
 ) = {
   let name = port.at("name", default: "")
   let name-rotate = port.at("vertical", default: false)
+  let is-clock = port.at("clock", default: false)
 
-  if (port.at("clock", default: false)) {
+  // Per-port overrides fall back to element-level defaults.
+  let shape = port.at("shape", default: port-shape)
+  let kind = port.at("kind", default: port-kind)
+  let size = port.at("size", default: port-size)
+  let shape-stroke = port.at("stroke", default: elmt-stroke)
+  // Pentagon fill defaults to the element's fill (so the pentagon covers the
+  // block-border segment it crosses). Clock ports default to gray. Per-port
+  // `fill` overrides both.
+  let shape-fill = port.at("fill", default: if is-clock and shape == "pentagon" { gray } else {
+    elmt-fill
+  })
+
+  // When shape is enabled, wire-connection anchor moves outside the block, and
+  // inside-name labels reference the inner tip/base; otherwise both collapse to
+  // the boundary point (unchanged behaviour).
+  let outer-pos = pos
+  let inner-pos = pos
+
+  if shape == "pentagon" {
+    let sh = port-shape-vertices(side, kind, size)
+    let v = sh.vertices.map(off => (rel: off, to: pos))
+    // Draw pentagon on a higher layer so it always renders on top of wires
+    // and neighbouring elements.
+    draw.on-layer(1, draw.line(
+      v.at(0),
+      v.at(1),
+      v.at(2),
+      v.at(3),
+      v.at(4),
+      close: true,
+      stroke: shape-stroke,
+      fill: shape-fill,
+    ))
+    outer-pos = (rel: sh.outer, to: pos)
+    inner-pos = (rel: sh.inner, to: pos)
+  } else if is-clock {
     if prev == none or next == none {
       panic("Clock port must have previous and next positions")
     }
-    
-    let size = if port.at("small", default: false) {8pt} else {1em}
+
+    let csize = if port.at("small", default: false) { 8pt } else { 1em }
     let offset
-    if      (side == "north") { offset = (    0, -size) }
-    else if (side == "east")  { offset = (-size,     0) }
-    else if (side == "south") { offset = (    0,  size) }
-    else if (side == "west")  { offset = ( size,     0) }
+    if (side == "north") { offset = (0, -csize) } else if (side == "east") {
+      offset = (-csize, 0)
+    } else if (side == "south") { offset = (0, csize) } else if (side == "west") {
+      offset = (csize, 0)
+    }
 
     let pos1 = (rel: offset, to: pos)
 
     // TODO: use context or vectors to have the height relative to the width
     draw.line(prev, pos1, next)
   }
+
+  // When outside-name is true (e.g. for groups) the label is placed on the
+  // exterior of the element border so it does not overlap child elements.
+  // Horizontal labels: anchor = opposite of the side (e.g. east port → west-anchored text, outside).
+  // Vertical labels:   same opposite side but rotated 90°, keeping text readable.
+  let name-anchor = if outside-name {
+    if name-rotate { rotate-anchor(opposite-anchor(side)) } else { opposite-anchor(side) }
+  } else {
+    if name-rotate { rotate-anchor(side) } else { side }
+  }
+
+  // Label sits at the outer edge of the shape for outside-name, inner edge for
+  // inside-name. `name-padding` is thus naturally measured from the shape edge
+  // (or from the boundary when shape is disabled).
+  let label-pos = if outside-name { outer-pos } else { inner-pos }
+
+  // For "shell" containers, wires must attach at the inside of the pentagon
+  // (the tip that points inward), not at the exterior base.
+  let anchor-pos = if wire-inside and shape == "pentagon" { inner-pos } else { outer-pos }
+
   draw.content(
-    pos,
-    anchor: if name-rotate {rotate-anchor(side)} else {side},
-    padding: 2pt,
-    angle: if name-rotate {90deg} else {0deg},
-    name
+    label-pos,
+    anchor: name-anchor,
+    padding: name-padding,
+    angle: if name-rotate { 90deg } else { 0deg },
+    name,
   )
   let id = elmt-id + "-port-" + port.at("id")
 
+  // Cardinal sub-anchor positions.
+  //   - Pentagon ports: the four world-cardinal midpoints of the pentagon's
+  //     bounding box (all lie on the pentagon boundary).
+  //   - Non-pentagon ports: all four collapse to the default attach point.
+  let sub-east = anchor-pos
+  let sub-west = anchor-pos
+  let sub-north = anchor-pos
+  let sub-south = anchor-pos
+  if shape == "pentagon" {
+    let sh = port-shape-vertices(side, kind, size)
+    sub-east = (rel: sh.east, to: pos)
+    sub-west = (rel: sh.west, to: pos)
+    sub-north = (rel: sh.north, to: pos)
+    sub-south = (rel: sh.south, to: pos)
+  }
+
+  // Expose the port as a CeTZ group carrying the default attach point plus
+  // the four cardinal sub-anchors (`.east`, `.west`, `.north`, `.south`).
+  // The custom anchors override CeTZ's auto-generated bbox anchors of the
+  // same name.
+  draw.group(name: id, {
+    draw.anchor("default", anchor-pos)
+    draw.anchor("east", sub-east)
+    draw.anchor("west", sub-west)
+    draw.anchor("north", sub-north)
+    draw.anchor("south", sub-south)
+  })
+
   if debug {
     draw.circle(
-      pos,
-      name: id,
+      anchor-pos,
       radius: .1,
       stroke: none,
-      fill: red
+      fill: red,
     )
-    
-  } else {
-    draw.hide(draw.circle(
-      pos,
-      radius: 0,
-      stroke: none,
-      name: id
-    ))
   }
 }
 
+// Normalize an `align-with` value to either:
+//   - `(local: <id>)`    → reference to another port of the *same* element
+//   - `(external: <anchor-name>)` → CeTZ anchor name of a port in another element
+// Accepted input forms:
+//   - `str` matching a local port id → local
+//   - `str` not matching any local port id → external, used as-is as CeTZ anchor
+//   - `(element: <str>, port: <str>)` → external, anchor = `<element>-port-<port>`
+#let classify-align-with(raw-val, placements) = {
+  if type(raw-val) == dictionary {
+    if "element" in raw-val and "port" in raw-val {
+      return (external: raw-val.element + "-port-" + raw-val.port)
+    }
+    panic("`align-with` dictionary must contain `element` and `port` keys, got: " + repr(raw-val))
+  }
+  if type(raw-val) != str {
+    panic("`align-with` must be a string or `(element:, port:)` dictionary, got: " + repr(raw-val))
+  }
+  if raw-val in placements {
+    return (local: raw-val)
+  }
+  return (external: raw-val)
+}
+
+// Resolve a single port's placement, following `align-with` references
+// transitively and detecting cycles.
+//
+// Returns `(placements, result)` where `result` is either:
+//   - `(pct: <ratio>)`               → percentage along the side (local placement)
+//   - `(external: <anchor-name>)`    → align with the given remote CeTZ anchor
+#let resolve-placement(placements, id, visiting, elmt-id: "") = {
+  let where = if elmt-id != "" { " (element '" + elmt-id + "')" } else { "" }
+  let p = placements.at(id)
+  if p.at("resolved", default: false) {
+    if "external-ref" in p {
+      return (placements, (external: p.external-ref))
+    }
+    return (placements, (pct: p.pct))
+  }
+  if id in visiting {
+    panic(
+      "align-with cycle involving port '"
+        + id
+        + "'"
+        + where
+        + " (path: "
+        + visiting.join(" -> ")
+        + " -> "
+        + id
+        + ")",
+    )
+  }
+
+  let raw = p.raw
+  let side = p.side
+  let is-ew = side in ("east", "west")
+
+  let has-align = "align-with" in raw
+  let has-x = "x" in raw
+  let has-y = "y" in raw
+  let has-num = has-x or has-y
+
+  if has-align and has-num {
+    panic("Port '" + id + "'" + where + ": cannot combine `align-with` with `x`/`y` override")
+  }
+  if is-ew and has-x {
+    panic(
+      "Port '"
+        + id
+        + "'"
+        + where
+        + " on side '"
+        + side
+        + "': use `y` for placement override on east/west sides, not `x`",
+    )
+  }
+  if (not is-ew) and has-y {
+    panic(
+      "Port '"
+        + id
+        + "'"
+        + where
+        + " on side '"
+        + side
+        + "': use `x` for placement override on north/south sides, not `y`",
+    )
+  }
+
+  let result = none
+  if has-num {
+    let val = if is-ew { raw.y } else { raw.x }
+    let dim = if is-ew { p.height } else { p.width }
+    if type(val) == function {
+      val = val(dim)
+    }
+    let pct
+    if type(val) == ratio {
+      pct = val
+    } else {
+      // Numeric length: measured from `pt0` along the side.
+      pct = (val / dim) * 100%
+    }
+    result = (pct: pct)
+  } else if has-align {
+    let classified = classify-align-with(raw.at("align-with"), placements)
+    if "external" in classified {
+      // Cross-element / raw anchor reference: axis cannot be validated here
+      // (remote side unknown at eval time). Propagate as external.
+      result = (external: classified.external)
+    } else {
+      let ref-id = classified.local
+      let ref-side = placements.at(ref-id).side
+      let ref-ew = ref-side in ("east", "west")
+      if is-ew != ref-ew {
+        panic(
+          "Port '"
+            + id
+            + "'"
+            + where
+            + " on '"
+            + side
+            + "' cannot `align-with` port '"
+            + ref-id
+            + "' on '"
+            + ref-side
+            + "': incompatible axis",
+        )
+      }
+      let new-visiting = visiting + (id,)
+      let res = resolve-placement(placements, ref-id, new-visiting, elmt-id: elmt-id)
+      placements = res.at(0)
+      result = res.at(1)
+    }
+  } else {
+    result = (pct: p.pct-auto)
+  }
+
+  if "external" in result {
+    p.insert("external-ref", result.external)
+    p.insert("pct", none)
+  } else {
+    p.insert("pct", result.pct)
+  }
+  p.insert("resolved", true)
+  placements.insert(id, p)
+  return (placements, result)
+}
+
 #let add-ports(
   elmt-id,
-  tl, tr, br, bl,
+  tl,
+  tr,
+  br,
+  bl,
   ports,
   ports-margins,
-  debug: false
+  width: 0,
+  height: 0,
+  debug: false,
+  outside-name: false,
+  name-padding: 2pt,
+  port-shape: none,
+  port-kind: "in",
+  port-size: 1em,
+  elmt-stroke: black + 1pt,
+  elmt-fill: none,
+  wire-inside: false,
 ) = {
   let sides = (
     "north": (tl, tr),
     "east": (tr, br),
     "south": (bl, br),
-    "west": (tl, bl)
+    "west": (tl, bl),
   )
 
   if type(ports) != dictionary {
     return
   }
 
+  // ---- Phase 1: build placement table with per-port baseline pct. ----
+  let placements = (:)
+  // Preserve iteration order for phase 3.
+  let order = ()
+  // Per-side (pt0, pt1) after margin adjustment, and per-side spacing.
+  let side-info = (:)
+
   for (side, props) in sides {
     let side-ports = ports.at(side, default: ())
+    let pt0 = props.at(0)
+    let pt1 = props.at(1)
+
+    if side in ports-margins {
+      let margins = ports-margins.at(side)
+      let a = (pt0, margins.at(0), pt1)
+      let b = (pt0, 100% - margins.at(1), pt1)
+      pt0 = a
+      pt1 = b
+    }
+
     let space = 100% / (side-ports.len() + 1)
+    side-info.insert(side, (pt0: pt0, pt1: pt1, space: space))
 
     for (i, port) in side-ports.enumerate() {
-      let pct = (i + 1) * space
-      let pt0 = props.at(0)
-      let pt1 = props.at(1)
-
-      if side in ports-margins {
-        let (a, b) = (pt0, pt1)
-        let margins = ports-margins.at(side)
-        a = (pt0, margins.at(0), pt1)
-        b = (pt0, 100% - margins.at(1), pt1)
-        pt0 = a
-        pt1 = b
+      let pid = port.at("id")
+      if pid in placements {
+        panic(
+          "Duplicate port id '"
+            + pid
+            + "' in element '"
+            + elmt-id
+            + "' on side '"
+            + side
+            + "' (existing side: '"
+            + placements.at(pid).side
+            + "', new port: "
+            + repr(port)
+            + ")",
+        )
       }
-      
-      let pos = (pt0, pct, pt1)
-      let pct-prev = (i + 0.5) * space
-      let pct-next = (i + 1.5) * space
-      let pos-prev = (pt0, pct-prev, pt1)
-      let pos-next = (pt0, pct-next, pt1)
+      let pct-auto = (i + 1) * space
+      placements.insert(pid, (
+        side: side,
+        raw: port,
+        index: i,
+        pct-auto: pct-auto,
+        width: width,
+        height: height,
+        resolved: false,
+      ))
+      order.push(pid)
+    }
+  }
+
+  // ---- Phase 2: resolve overrides & align-with references. ----
+  for pid in order {
+    let res = resolve-placement(placements, pid, (), elmt-id: elmt-id)
+    placements = res.at(0)
+  }
+
+  // ---- Phase 3: draw. ----
+  for pid in order {
+    let p = placements.at(pid)
+    let side = p.side
+    let info = side-info.at(side)
+    let pt0 = info.pt0
+    let pt1 = info.pt1
+    let space = info.space
+    let port = p.raw
+    let is-ew = side in ("east", "west")
+
+    let pos
+    let pos-prev
+    let pos-next
+
+    if "external-ref" in p {
+      // Cross-element alignment: build pos via CeTZ perpendicular so this
+      // port shares one coordinate with the remote anchor and stays on this
+      // element's side line for the other coordinate.
+      //   east/west: same y as remote, x from this side (pt0.x == pt1.x)
+      //   north/south: same x as remote, y from this side (pt0.y == pt1.y)
+      let ref = p.external-ref
+      if is-ew {
+        pos = (pt0, "|-", ref)
+        // Fallback prev/next: just the pos itself; clock ports do not
+        // combine meaningfully with cross-element align.
+        pos-prev = pos
+        pos-next = pos
+      } else {
+        pos = (ref, "|-", pt0)
+        pos-prev = pos
+        pos-next = pos
+      }
+    } else {
+      let pct = p.pct
+      pos = (pt0, pct, pt1)
+      pos-prev = (pt0, pct - 0.5 * space, pt1)
+      pos-next = (pt0, pct + 0.5 * space, pt1)
 
       if port.at("small", default: false) {
         pos-prev = (pos, 4pt, pt0)
         pos-next = (pos, 4pt, pt1)
       }
-
-      add-port(
-        elmt-id,
-        side,
-        port,
-        pos,
-        prev: pos-prev,
-        next: pos-next,
-        debug: debug
-      )
     }
+
+    add-port(
+      elmt-id,
+      side,
+      port,
+      pos,
+      prev: pos-prev,
+      next: pos-next,
+      debug: debug,
+      outside-name: outside-name,
+      name-padding: name-padding,
+      port-shape: port-shape,
+      port-kind: port-kind,
+      port-size: port-size,
+      elmt-stroke: elmt-stroke,
+      elmt-fill: elmt-fill,
+      wire-inside: wire-inside,
+    )
   }
-}
+}

src/util.typ

@@ -1,23 +1,3 @@
-#import "cetz.typ": coordinate
-
-/// Resolves a relative coordinate shorthand of the form `(rel: <number>, to: <anchor>)`
-/// to a single scalar along the requested axis.
-///
-/// Used to implement the shared `(rel:, to:)` shorthand accepted by the `x` and
-/// `y` parameters of `elmt`, `gate` and `iec-gate`.
-///
-/// - ctx (dictionary): The current CeTZ context
-/// - val (dictionary): A dictionary with fields `rel` (number) and `to` (anchor)
-/// - axis (int): `0` for x, `1` for y
-/// -> number
-#let resolve-rel-coord(ctx, val, axis) = {
-  let offset = val.rel
-  let to = val.to
-  let delta = if axis == 0 { (offset, 0) } else { (0, offset) }
-  let (_, to-pos) = coordinate.resolve(ctx, (rel: delta, to: to))
-  return to-pos.at(axis)
-}
-
 /// Predefined color palette
 /// #let w = 4
 /// #box(width: 100%, align(center)[
@@ -36,7 +16,7 @@
   green: rgb(127, 200, 172),
   pink: rgb(236, 127, 178),
   purple: rgb(189, 151, 255),
-  blue: rgb(127, 203, 235)
+  blue: rgb(127, 203, 235),
 )
 
 /// Pads a string on the left with 0s to the given length
@@ -67,7 +47,7 @@
     north-west: "south-east",
     north-east: "south-west",
     south-east: "north-west",
-    south-west: "north-east"
+    south-west: "north-east",
   ).at(anchor)
 }
 
@@ -86,13 +66,98 @@
     north-west: "north-east",
     north-east: "south-east",
     south-east: "south-west",
-    south-west: "north-west"
+    south-west: "north-west",
   ).at(anchor)
 }
 
+/// Returns the pentagon port shape vertices and the outer/inner anchor
+/// offsets for the given side and direction.
+///
+/// The pentagon straddles the block boundary: 1 unit outside, 1 unit inside;
+/// height ±0.5 units. For `kind: "in"` the tip points into the block; for
+/// `kind: "out"` it points away.
+///
+/// - side (str): One of `"north"`, `"east"`, `"south"`, `"west"`
+/// - kind (str): `"in"` or `"out"`
+/// - u (length,number): The pentagon unit size
+/// -> dictionary: `(vertices: (..5 pairs..), outer: (dx, dy), inner: (dx, dy))`
+#let port-shape-vertices(side, kind, u) = {
+  // Base case: west port, input (tip east / into block).
+  // Vertices as (dx, dy) offsets relative to the boundary anchor.
+  let base-vertices = (
+    (-u, -u / 2),
+    (-u, +u / 2),
+    (u / 2, +u / 2),
+    (u, 0), // tip east (inner side)
+    (u / 2, -u / 2),
+  )
+  // For output, mirror horizontally so the tip points west (outside).
+  if kind == "out" {
+    base-vertices = base-vertices.map(p => (-p.at(0), p.at(1)))
+  }
+  // Outer (wire-connection) and inner (inside-label) anchors for a west port.
+  // Outer is always 1u outside the boundary along the port normal; inner is 1u
+  // inside. Independent of `kind` (only the pentagon fill/tip direction change).
+  let base-outer = (-u, 0)
+  let base-inner = (u, 0)
+
+  // Rotation from west's frame to target side:
+  //   west:  identity (x, y)
+  //   north: (x, y) → (y, -x)
+  //   east:  (x, y) → (-x, -y)
+  //   south: (x, y) → (-y, x)
+  let rot = if side == "west" { p => p } else if side == "north" {
+    p => (p.at(1), -p.at(0))
+  } else if side == "east" { p => (-p.at(0), -p.at(1)) } else if side == "south" {
+    p => (-p.at(1), p.at(0))
+  } else { panic("Unknown side: " + side) }
+
+  // World-cardinal midpoints of the pentagon's bounding box. These are
+  // named in *world* coordinates (not rotated with the shape), so `.east`
+  // always sits at the world +x extent of the pentagon, `.north` at +y, etc.
+  // Consequently the tip's cardinal name follows its world direction:
+  //   - west side, kind "in"   → tip world +x → tip = .east
+  //   - west side, kind "out"  → tip world -x → tip = .west
+  //   - east side, kind "in"   → tip world -x → tip = .west
+  //   - east side, kind "out"  → tip world +x → tip = .east
+  //   - north side, kind "in"  → tip world -y → tip = .south
+  //   - north side, kind "out" → tip world +y → tip = .north
+  //   - south side, kind "in"  → tip world +y → tip = .north
+  //   - south side, kind "out" → tip world -y → tip = .south
+  //
+  // The pentagon bounding box extents depend only on the side's orientation
+  // (horizontal for west/east, vertical for north/south), not on `kind`.
+  let (hx, hy) = if side == "west" or side == "east" {
+    (u, u / 2)
+  } else {
+    (u / 2, u)
+  }
+  let world-east = (hx, 0)
+  let world-west = (-hx, 0)
+  let world-north = (0, hy)
+  let world-south = (0, -hy)
+
+  return (
+    vertices: base-vertices.map(rot),
+    outer: rot(base-outer),
+    inner: rot(base-inner),
+    east: world-east,
+    west: world-west,
+    north: world-north,
+    south: world-south,
+  )
+}
+
 #let valid-anchors = (
-  "center", "north", "east", "west", "south",
-  "north-east", "north-west", "south-east", "south-west"
+  "center",
+  "north",
+  "east",
+  "west",
+  "south",
+  "north-east",
+  "north-west",
+  "south-east",
+  "south-west",
 )
 
 /// Normalizes a coordinate so that 2D points (x, y) are padded
@@ -113,16 +178,19 @@
       // Function-based coordinate: (fn, point)
       if type(a) == function {
         let orig = a
-        return (v => {
-          let result = orig(v)
-          if type(result) == array and result.len() == 2 {
-            let (rx, ry) = result
-            if type(rx) in (int, float) and type(ry) in (int, float) {
-              return (rx, ry, 0)
+        return (
+          v => {
+            let result = orig(v)
+            if type(result) == array and result.len() == 2 {
+              let (rx, ry) = result
+              if type(rx) in (int, float) and type(ry) in (int, float) {
+                return (rx, ry, 0)
+              }
             }
-          }
-          return result
-        }, b)
+            return result
+          },
+          b,
+        )
       }
     }
   }
@@ -134,4 +202,4 @@
     return result
   }
   return coord
-}
+}