merge #101 101b: anteprima DXF disegnata con path (Refs #101)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jbf7qKuxsnAVjxthRy7dnB

src/backend/api/routers/vision.py

@@ -366,6 +366,20 @@ async def preview(
     return await vision_service.preview(db, task, await _read_image(image))
 
 
+@router.post("/dxf-preview")
+async def dxf_preview(
+    dxf: UploadFile = File(...),
+    current_user: User = Depends(require_maker),
+) -> dict:
+    """#101: anteprima del DXF scelto nel wizard «Crea ricetta da DXF» (contorni
+    in mm e dimensioni), letto dal worker con lo stesso lettore del confronto.
+    Non scrive nulla; stesso limite di dimensione della rotta dxf-compare."""
+    dxf_bytes = await dxf.read()
+    if not validate_file_size(len(dxf_bytes)):
+        raise _422([f"the DXF exceeds {settings.max_upload_size_mb}MB"])
+    return await vision_service.dxf_preview(dxf_bytes)
+
+
 @router.post("/tasks/{task_id}/recipe/dxf-compare")
 async def create_dxf_compare_recipe(
     task_id: int,

src/backend/services/vision_service.py

@@ -224,6 +224,25 @@ async def dxf_compare_recipe(
     return body
 
 
+async def dxf_preview(dxf_bytes: bytes, worker_url: str | None = None) -> dict:
+    """#101: anteprima del DXF (contorni in mm + dimensioni) dal worker. Sostituita dai test."""
+    body = await call_worker_multipart(
+        "/dxf/preview",
+        files={"dxf": ("disegno.dxf", dxf_bytes, "application/octet-stream")},
+        data={},
+        worker_url=worker_url,
+    )
+    # forma minima del contratto: senza contorni e dimensioni non c'e' nulla da mostrare
+    required = {"contorni", "bbox", "larghezza_mm", "altezza_mm", "entita", "punti"}
+    if not required <= body.keys():
+        raise HTTPException(
+            status_code=status.HTTP_502_BAD_GATEWAY,
+            detail="the vision worker's answer was malformed: missing "
+                   + ", ".join(sorted(required - body.keys())),
+        )
+    return body
+
+
 # Stati di fetch_station_calibration (#83)
 CAL_OK = "ok"
 CAL_NO_CAMERA = "no_camera"            # la stazione non ha camera_url/camera_source

src/backend/tests/test_vision_dxf_preview.py

@@ -0,0 +1,90 @@
+"""#101: POST /api/vision/dxf-preview, anteprima del DXF nel wizard.
+
+Il worker non gira nei test: `vision_service.dxf_preview` si sostituisce.
+"""
+import pytest
+from fastapi import HTTPException
+
+from src.backend.config import settings
+from src.backend.services import vision_service
+from src.backend.tests.conftest import auth_headers
+
+BODY = {
+    "contorni": [[[0.0, 0.0], [10.0, 0.0], [10.0, 5.0], [0.0, 5.0], [0.0, 0.0]]],
+    "bbox": {"xmin": 0.0, "ymin": 0.0, "xmax": 10.0, "ymax": 5.0},
+    "larghezza_mm": 10.0, "altezza_mm": 5.0, "entita": 1, "punti": 5,
+}
+
+
+def _post(client, user, content=b"0\nEOF"):
+    return client.post(
+        "/api/vision/dxf-preview",
+        headers=auth_headers(user),
+        files={"dxf": ("d.dxf", content, "application/octet-stream")},
+    )
+
+
+@pytest.mark.asyncio
+async def test_dxf_preview_forwards_the_file_and_returns_the_worker_body(
+    client, maker_user, monkeypatch,
+):
+    calls = []
+
+    async def fake(dxf_bytes, worker_url=None):
+        calls.append(dxf_bytes)
+        return BODY
+
+    monkeypatch.setattr("src.backend.services.vision_service.dxf_preview", fake)
+    resp = await _post(client, maker_user, b"DXF-BYTES")
+    assert resp.status_code == 200, resp.text
+    assert resp.json() == BODY
+    assert calls == [b"DXF-BYTES"]
+
+
+@pytest.mark.asyncio
+async def test_dxf_preview_forwards_the_worker_422(client, maker_user, monkeypatch):
+    async def fake(dxf_bytes, worker_url=None):
+        raise HTTPException(status_code=422, detail="DXF illeggibile: file vuoto")
+
+    monkeypatch.setattr("src.backend.services.vision_service.dxf_preview", fake)
+    resp = await _post(client, maker_user, b"")
+    assert resp.status_code == 422
+    assert resp.json()["detail"] == "DXF illeggibile: file vuoto"
+
+
+@pytest.mark.asyncio
+async def test_dxf_preview_requires_maker(client, measurement_tec_user, monkeypatch):
+    async def fake(dxf_bytes, worker_url=None):
+        return BODY
+
+    monkeypatch.setattr("src.backend.services.vision_service.dxf_preview", fake)
+    resp = await _post(client, measurement_tec_user)
+    assert resp.status_code == 403
+
+
+@pytest.mark.asyncio
+async def test_dxf_preview_too_big_is_422(client, maker_user, monkeypatch):
+    monkeypatch.setattr(settings, "max_upload_size_mb", 0)
+    resp = await _post(client, maker_user, b"x" * 10)
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_dxf_preview_service_posts_to_worker_and_checks_shape(monkeypatch):
+    seen = {}
+
+    async def fake_multipart(path, *, files, data, worker_url=None, timeout=120.0):
+        seen.update(path=path, files=files)
+        return BODY
+
+    monkeypatch.setattr(vision_service, "call_worker_multipart", fake_multipart)
+    assert await vision_service.dxf_preview(b"abc") == BODY
+    assert seen["path"] == "/dxf/preview" and seen["files"]["dxf"][1] == b"abc"
+
+    async def malformed(path, *, files, data, worker_url=None, timeout=120.0):
+        return {"contorni": []}
+
+    monkeypatch.setattr(vision_service, "call_worker_multipart", malformed)
+    with pytest.raises(HTTPException) as exc:
+        await vision_service.dxf_preview(b"abc")
+    assert exc.value.status_code == 502

src/frontend/flask_app/blueprints/maker.py

@@ -701,6 +701,25 @@ def api_dxf_compare_recipe(task_id: int):
     return jsonify(resp), 200
 
 
+# #101: anteprima del DXF appena scelto nel wizard (contorni letti dal vision worker)
+@maker_bp.route("/api/vision/dxf-preview", methods=["POST"])
+@login_required
+@role_required("Maker")
+def api_dxf_preview():
+    """Proxy: anteprima del DXF (contorni, bbox, L x H) prima di creare la ricetta (#101)."""
+    dxf = request.files.get("dxf")
+    if dxf is None or not dxf.filename:
+        return jsonify({"error": True, "detail": _("Serve il file DXF")}), 400
+
+    resp = api_client.post(
+        "/api/vision/dxf-preview",
+        files={"dxf": (dxf.filename, dxf.read(), dxf.mimetype or "application/octet-stream")},
+    )
+    if resp.get("error"):
+        return jsonify(resp), resp.get("status_code", 500)
+    return jsonify(resp), 200
+
+
 @maker_bp.route("/api/files/<path:file_path>", methods=["GET"])
 @login_required
 def api_get_file(file_path: str):

src/frontend/flask_app/static/js/dxf_recipe_wizard.js

@@ -21,6 +21,10 @@ function dxfRecipeWizard(taskId, csrf, msgs) {
     imageName: '',
     imageSrc: '',
     dxfFile: null,
+    dxfPreview: null,      // #101: risposta di /dxf-preview {contorni, bbox, larghezza_mm, altezza_mm, entita, punti}
+    dxfPreviewBusy: false,
+    dxfPreviewError: '',
+    _dxfPreviewSeq: 0,     // #101: una risposta arrivata dopo un cambio di file si scarta
     mmPx: '',              // #98: mm/px a mano (immagine da file), stringa con virgola o punto
     bandMm: 0.1,
     minPointsPct: 95,
@@ -87,7 +91,67 @@ function dxfRecipeWizard(taskId, csrf, msgs) {
       const f = ev.target.files && ev.target.files[0];
       if (f) this._setImage(f);
     },
-    onDxf(ev) { this.dxfFile = (ev.target.files && ev.target.files[0]) || null; this.result = null; },
+    onDxf(ev) {
+      this.dxfFile = (ev.target.files && ev.target.files[0]) || null;
+      this.result = null;
+      this.loadDxfPreview(); // #101: anteprima appena si sceglie il file
+    },
+
+    // #101: legge il DXF sul vision worker (via Flask e backend) e ne mostra i contorni
+    async loadDxfPreview() {
+      const seq = ++this._dxfPreviewSeq;
+      this.dxfPreview = null;
+      this.dxfPreviewError = '';
+      this.dxfPreviewBusy = false;
+      if (!this.dxfFile) return; // file tolto: tutto azzerato
+      this.dxfPreviewBusy = true;
+      try {
+        const fd = new FormData();
+        fd.append('dxf', this.dxfFile, this.dxfFile.name);
+        const resp = await fetch('/maker/api/vision/dxf-preview', {
+          method: 'POST', headers: { 'X-CSRFToken': this._csrf() }, body: fd,
+        });
+        const body = await resp.json().catch(() => ({}));
+        if (seq !== this._dxfPreviewSeq) return; // file cambiato nel frattempo
+        if (!resp.ok || body.error) this.dxfPreviewError = this._errorText(body);
+        else this.dxfPreview = body;
+      } catch (e) {
+        if (seq !== this._dxfPreviewSeq) return;
+        this.dxfPreviewError = this.msgs.requestFailed || String(e);
+      }
+      if (seq === this._dxfPreviewSeq) this.dxfPreviewBusy = false;
+    },
+
+    // #101: una stringa `points` per ogni contorno, per <polyline>
+    dxfPreviewPaths() {
+      const contorni = (this.dxfPreview && this.dxfPreview.contorni) || [];
+      return contorni.filter(c => c && c.length > 1).map(c => c.map(p => p[0] + ',' + p[1]).join(' '));
+    },
+
+    // #101: tutti i contorni in un solo attributo `d` ("M x y L x y ..."): x-for non funziona dentro <svg>
+    dxfPreviewD() {
+      const contorni = (this.dxfPreview && this.dxfPreview.contorni) || [];
+      return contorni.filter(c => c && c.length > 1)
+        .map(c => c.map((p, i) => (i ? 'L ' : 'M ') + p[0] + ' ' + p[1]).join(' ')).join(' ');
+    },
+
+    // #101: viewBox sul bbox con margine 5% (minimo 0.5 mm per lato)
+    dxfPreviewViewBox() {
+      const b = this.dxfPreview && this.dxfPreview.bbox;
+      if (!b) return '0 0 1 1';
+      const w = b.xmax - b.xmin, h = b.ymax - b.ymin;
+      const m = Math.max(0.5, 0.05 * Math.max(w, h));
+      return [b.xmin - m, b.ymin - m, w + 2 * m, h + 2 * m].map(v => +v.toFixed(3)).join(' ');
+    },
+
+    // #101: «L × H mm · N entità», decimale con virgola (2 decimali) secondo la lingua pagina
+    get dxfPreviewSummary() {
+      const d = this.dxfPreview;
+      if (!d) return '';
+      const f = v => Number(v).toLocaleString(document.documentElement.lang || 'it',
+        { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+      return `${f(d.larghezza_mm)} × ${f(d.altezza_mm)} mm · ${d.entita} ${this.msgs.dxfEntities || 'entities'}`;
+    },
 
     // Frame dalla camera della stazione scelta
     async grab() {

src/frontend/flask_app/templates/maker/task_editor.html

@@ -662,7 +662,7 @@
                 <!-- ========== Crea ricetta da DXF (#83): solo dxf_compare ========== -->
                 <template x-if="task.task_type === 'dxf_compare'">
                   <div class="mt-4 pt-3 border-t border-[var(--border-color)]"
-                       x-data="dxfRecipeWizard(task.id, () => csrfToken(), {{ {'requestFailed': _('Richiesta non riuscita'), 'saved': _('Ricetta salvata')}|tojson_attr }})">
+                       x-data="dxfRecipeWizard(task.id, () => csrfToken(), {{ {'requestFailed': _('Richiesta non riuscita'), 'saved': _('Ricetta salvata'), 'dxfEntities': _('entità')}|tojson_attr }})">
                     <button type="button" class="btn btn-secondary text-xs" @click="toggle()">
                       {{ _('Crea ricetta da DXF') }}
                     </button>
@@ -714,6 +714,20 @@
                         <div>
                           <label class="tmf-label text-xs">{{ _('Disegno (.dxf)') }}</label>
                           <input type="file" accept=".dxf" class="tmf-input text-xs" @change="onDxf($event)">
+                          <!-- #101: anteprima del disegno appena scelto il .dxf -->
+                          <p x-show="dxfPreviewBusy" class="mt-1 text-xs text-[var(--text-muted)]">{{ _('Lettura DXF…') }}</p>
+                          <p x-show="dxfPreviewError" class="mt-1 text-xs text-red-500" x-text="dxfPreviewError"></p>
+                          <div x-show="dxfPreview" class="mt-2">
+                            <svg x-bind:view-box.camel="dxfPreviewViewBox()" preserveAspectRatio="xMidYMid meet"
+                                 class="block w-full rounded border border-[var(--border-color)]"
+                                 style="max-height: 240px; background: var(--bg-primary);">
+                              <!-- #101: un solo path (x-for/template non funziona nel namespace SVG); view-box.camel perche' il parser HTML abbassa viewBox -->
+                              <path :d="dxfPreviewD()" fill="none" stroke="var(--color-primary, #2563eb)"
+                                    stroke-width="1.5" vector-effect="non-scaling-stroke"
+                                    stroke-linejoin="round"></path>
+                            </svg>
+                            <p class="mt-1 text-xs text-[var(--text-muted)]" x-text="dxfPreviewSummary"></p>
+                          </div>
                         </div>
                       </div>
                       <!-- Pochi parametri -->

src/frontend/flask_app/tests/js/test_dxf_preview.js

@@ -0,0 +1,90 @@
+/**
+ * #101: anteprima DXF del wizard «Crea ricetta da DXF», con plain node.
+ * Copre dxfPreviewPaths, dxfPreviewViewBox, dxfPreviewSummary e lo scarto
+ * di una risposta arrivata dopo un cambio di file.
+ *
+ * Run from src/frontend/flask_app: node tests/js/test_dxf_preview.js
+ */
+'use strict';
+const fs = require('fs');
+const path = require('path');
+
+global.document = { documentElement: { lang: 'it' } };
+const src = fs.readFileSync(
+  path.join(__dirname, '..', '..', 'static', 'js', 'dxf_recipe_wizard.js'), 'utf8',
+);
+eval(src + ';global.dxfRecipeWizard = dxfRecipeWizard;');
+
+let failures = 0;
+function check(label, cond, extra) {
+  if (cond) console.log('ok - ' + label);
+  else { failures++; console.log('FAIL - ' + label + (extra ? ' :: ' + extra : '')); }
+}
+
+const PREVIEW = {
+  contorni: [[[0, -5], [12.3, -5], [12.3, 0], [0, 0], [0, -5]], [[1, -1]]],
+  bbox: { xmin: 0, ymin: -5.1, xmax: 12.3, ymax: 0 },
+  larghezza_mm: 12.3, altezza_mm: 5.1, entita: 2, punti: 6,
+};
+
+(async () => {
+  const w = dxfRecipeWizard(1, () => 'tok', { dxfEntities: 'entità' });
+
+  check('senza anteprima: nessun path', w.dxfPreviewPaths().length === 0);
+  check('senza anteprima: summary vuoto', w.dxfPreviewSummary === '');
+
+  w.dxfPreview = PREVIEW;
+  const paths = w.dxfPreviewPaths();
+  check('un contorno con >1 punti diventa una polyline (quello da 1 punto no)', paths.length === 1);
+  check('formato points', paths[0] === '0,-5 12.3,-5 12.3,0 0,0 0,-5', paths[0]);
+
+  // #101: path unico per <path :d>
+  check('dxfPreviewD', w.dxfPreviewD() === 'M 0 -5 L 12.3 -5 L 12.3 0 L 0 0 L 0 -5', w.dxfPreviewD());
+  w.dxfPreview = null;
+  check('dxfPreviewD vuoto senza anteprima', w.dxfPreviewD() === '');
+  w.dxfPreview = PREVIEW;
+
+  const vb = w.dxfPreviewViewBox().split(' ').map(Number);
+  const m = Math.max(0.5, 0.05 * 12.3);
+  check('viewBox con margine 5%', Math.abs(vb[0] + m) < 1e-3 && Math.abs(vb[2] - (12.3 + 2 * m)) < 1e-3, vb.join(' '));
+
+  // Disegno minuscolo: margine minimo 0.5 mm
+  w.dxfPreview = { ...PREVIEW, bbox: { xmin: 0, ymin: 0, xmax: 1, ymax: 1 } };
+  check('margine minimo 0.5 mm', Math.abs(w.dxfPreviewViewBox().split(' ').map(Number)[0] + 0.5) < 1e-3);
+
+  w.dxfPreview = PREVIEW;
+  const s = w.dxfPreviewSummary;
+  check('summary L × H mm · N entità', s.includes('×') && s.includes('mm') && s.endsWith('2 entità')
+    && /12[,.]30/.test(s) && /5[,.]10/.test(s), s);
+
+  // Risposta tardiva scartata: due scelte di file, la prima risponde per ultima
+  const resolvers = [];
+  global.fetch = () => new Promise(res => resolvers.push(res));
+  global.FormData = class { append() {} };
+  const w2 = dxfRecipeWizard(1, () => 'tok', {});
+  const reply = (body, ok = true) => ({ ok, json: async () => body });
+  w2.dxfFile = { name: 'a.dxf' };
+  const p1 = w2.loadDxfPreview();
+  w2.dxfFile = { name: 'b.dxf' };
+  const p2 = w2.loadDxfPreview();
+  resolvers[1](reply(PREVIEW));
+  await p2;
+  resolvers[0](reply({ ...PREVIEW, entita: 99 }));
+  await p1;
+  check('la risposta vecchia non sovrascrive la nuova', w2.dxfPreview && w2.dxfPreview.entita === 2);
+  check('busy spento', w2.dxfPreviewBusy === false);
+
+  // File tolto: tutto azzerato
+  w2.dxfFile = null;
+  await w2.loadDxfPreview();
+  check('file tolto azzera anteprima ed errore', w2.dxfPreview === null && w2.dxfPreviewError === '');
+
+  // Errore 422 con detail
+  global.fetch = async () => reply({ detail: 'DXF illeggibile: x' }, false);
+  w2.dxfFile = { name: 'c.dxf' };
+  await w2.loadDxfPreview();
+  check('errore col detail', w2.dxfPreviewError === 'DXF illeggibile: x' && w2.dxfPreview === null, w2.dxfPreviewError);
+
+  if (failures) { console.log(failures + ' fallimenti'); process.exit(1); }
+  console.log('tutto ok');
+})();

src/frontend/flask_app/tests/test_dxf_preview_js.py

@@ -0,0 +1,35 @@
+"""Runs the plain-node DXF preview behaviour test (tests/js/test_dxf_preview.js).
+
+Same thin pytest wrapper pattern as test_numpad_js.py: shells out to ``node``
+and asserts the script's own exit code. Skips (does not fail) when node is
+not installed.
+
+Covers gitea:Adriano/TieMeasureFlow#101.
+"""
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+FLASK_APP_DIR = Path(__file__).resolve().parent.parent
+JS_TEST = Path(__file__).resolve().parent / "js" / "test_dxf_preview.js"
+
+
+def test_dxf_preview_js_behaviour():
+    node = shutil.which("node")
+    if not node:
+        pytest.skip("node non installato: test JS di dxf_recipe_wizard.js saltato")
+
+    result = subprocess.run(
+        [node, str(JS_TEST)],
+        cwd=str(FLASK_APP_DIR),
+        capture_output=True,
+        text=True,
+        timeout=30,
+    )
+
+    assert result.returncode == 0, (
+        f"tests/js/test_dxf_preview.js fallito (exit {result.returncode})\n"
+        f"stdout:\n{result.stdout}\nstderr:\n{result.stderr}"
+    )

src/frontend/flask_app/tests/test_dxf_recipe_routes.py

@@ -210,6 +210,49 @@ class TestDxfCompareProxy:
         mock_api_client.post.assert_not_called()
 
 
+class TestDxfPreviewProxy:
+    """#101: anteprima del DXF scelto nel wizard (proxy verso il backend)."""
+    URL = "/maker/api/vision/dxf-preview"
+    OK = {
+        "contorni": [[[0.0, -5.0], [10.0, -5.0], [10.0, 0.0], [0.0, 0.0]]],
+        "bbox": {"xmin": 0.0, "ymin": -5.0, "xmax": 10.0, "ymax": 0.0},
+        "larghezza_mm": 10.0, "altezza_mm": 5.0, "entita": 1, "punti": 4,
+    }
+
+    def _post(self, client, with_file=True):
+        data = {"dxf": (io.BytesIO(b"0\nEOF"), "d.dxf")} if with_file else {}
+        return client.post(self.URL, data=data, content_type="multipart/form-data")
+
+    def test_forwards_file(self, logged_in_client, mock_api_client):
+        mock_api_client.post.return_value = self.OK
+        resp = self._post(logged_in_client)
+        assert resp.status_code == 200
+        assert resp.get_json()["larghezza_mm"] == 10.0
+        args, kwargs = mock_api_client.post.call_args
+        assert args[0] == "/api/vision/dxf-preview"
+        assert set(kwargs["files"]) == {"dxf"}
+        assert kwargs["files"]["dxf"][0] == "d.dxf"
+        assert kwargs["files"]["dxf"][1] == b"0\nEOF"
+
+    def test_missing_file_is_400(self, logged_in_client, mock_api_client):
+        resp = self._post(logged_in_client, with_file=False)
+        assert resp.status_code == 400
+        mock_api_client.post.assert_not_called()
+
+    def test_backend_422_propagates(self, logged_in_client, mock_api_client):
+        mock_api_client.post.return_value = {
+            "error": True, "status_code": 422, "detail": "DXF illeggibile: x"}
+        resp = self._post(logged_in_client)
+        assert resp.status_code == 422
+        assert resp.get_json()["detail"] == "DXF illeggibile: x"
+
+    def test_requires_maker_role(self, logged_in_client, mock_api_client):
+        with logged_in_client.session_transaction() as sess:
+            sess["user"] = {**sess["user"], "roles": ["MeasurementTec"]}
+        assert self._post(logged_in_client).status_code == 403
+        mock_api_client.post.assert_not_called()
+
+
 class TestPages:
     def test_stations_page_has_calibration_cell(self, logged_in_client):
         with patch("blueprints.admin.api_client") as admin_api:
@@ -236,4 +279,5 @@ class TestPages:
         assert "dxfRecipeWizard(" in html
         assert "@dxf-recipe-saved" in html
         assert 'x-model="mmPx"' in html  # #98: campo mm/px a mano
+        assert "dxfPreviewD()" in html and "view-box.camel" in html  # #101: anteprima SVG del DXF
         assert "Pezzo scuro su fondo chiaro" in html or "Dark part on light" in html

src/frontend/flask_app/translations/en/LC_MESSAGES/messages.po

@@ -3489,3 +3489,13 @@ msgstr "Invalid response from the camera service"
 #: templates/statistics/dashboard.html (#100)
 msgid "Scegli un punto per carta di controllo e istogramma"
 msgstr "Choose a point for the control chart and histogram"
+
+#: templates/maker/task_editor.html blueprints/maker.py (#101)
+msgid "Serve il file DXF"
+msgstr "The DXF file is required"
+
+msgid "Lettura DXF…"
+msgstr "Reading DXF…"
+
+msgid "entità"
+msgstr "entities"

src/frontend/flask_app/translations/it/LC_MESSAGES/messages.po

@@ -3473,3 +3473,13 @@ msgstr "Indirizzo della camera non valido"
 #: templates/admin/stations.html blueprints/admin.py (#88)
 msgid "Risposta non valida dal servizio camera"
 msgstr "Risposta non valida dal servizio camera"
+
+#: templates/maker/task_editor.html blueprints/maker.py (#101)
+msgid "Serve il file DXF"
+msgstr "Serve il file DXF"
+
+msgid "Lettura DXF…"
+msgstr "Lettura DXF…"
+
+msgid "entità"
+msgstr "entità"

src/vision_worker/main.py

@@ -11,6 +11,7 @@ import io
 import json
 import os
 import re
+import tempfile  # #101
 from pathlib import Path
 
 import numpy as np
@@ -288,3 +289,89 @@ async def recipes_dxf_compare(
                 status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                 detail=f"recipe build failed: {type(exc).__name__}: {exc}",
             ) from exc
+
+
+# #101: tetto ai punti dell'anteprima DXF (un profilo fitto non deve gonfiare
+# la risposta ne' rallentare il disegno SVG nel browser).
+_PREVIEW_MAX_POINTS = 20000
+
+
+def _decimate(points: list[list[float]], keep: int) -> list[list[float]]:
+    """Decimazione uniforme a `keep` punti (>= 2), primo e ultimo sempre inclusi."""
+    n = len(points)
+    if n <= keep or keep < 2:
+        return points
+    idx = sorted({round(i * (n - 1) / (keep - 1)) for i in range(keep)})
+    return [points[i] for i in idx]
+
+
+def _dxf_preview(dxf_bytes: bytes) -> dict:
+    """#101: legge il DXF con lo stesso lettore di CompareDxf (read_xld_dxf) e ne
+    ritorna i contorni in mm, asse y verso il basso (come immagine e SVG).
+
+    Funzione sincrona e pura: la rotta la esegue in un thread. Solleva
+    CostruttoreError per DXF vuoto, illeggibile o senza geometria.
+    """
+    if not dxf_bytes:
+        raise CostruttoreError("DXF illeggibile: file vuoto")
+    from visionsuite.io.dxf import read_xld_dxf
+    with tempfile.TemporaryDirectory() as tmp:
+        path = Path(tmp) / "disegno.dxf"
+        path.write_bytes(dxf_bytes)
+        try:
+            # flip_y=False + scale=1: coordinate native del DXF, in mm; il
+            # ribaltamento dell'asse y lo facciamo noi sotto (y = -y_dxf)
+            conts = list(read_xld_dxf(str(path), sampling_distance=0.05,
+                                      scale=1.0, flip_y=False))
+        except Exception as exc:  # noqa: BLE001 - qualunque errore di lettura = DXF illeggibile
+            raise CostruttoreError(f"DXF illeggibile: {type(exc).__name__}: {exc}") from exc
+
+    contorni: list[list[list[float]]] = []
+    for cont in conts:
+        pts = np.asarray(cont.points, dtype=float)  # (riga, colonna) = (y_dxf, x_dxf)
+        if pts.ndim != 2 or pts.shape[0] < 2:
+            continue
+        line = [[float(c), float(-r)] for r, c in pts]
+        if cont.closed and line[0] != line[-1]:
+            line.append(list(line[0]))  # chiude il giro anche nella polilinea SVG
+        contorni.append(line)
+    if not contorni:
+        raise CostruttoreError("DXF senza geometria")
+
+    # #101: le dimensioni si misurano sui punti completi, prima della decimazione
+    xs = [p[0] for c in contorni for p in c]
+    ys = [p[1] for c in contorni for p in c]
+    xmin, xmax, ymin, ymax = min(xs), max(xs), min(ys), max(ys)
+
+    total = len(xs)
+    if total > _PREVIEW_MAX_POINTS:
+        # quota per contorno proporzionale, minimo 2 punti
+        contorni = [
+            _decimate(c, max(2, int(len(c) * _PREVIEW_MAX_POINTS / total))) for c in contorni
+        ]
+    contorni = [[[round(x, 3), round(y, 3)] for x, y in c] for c in contorni]
+    xmin, xmax, ymin, ymax = (round(v, 3) for v in (xmin, xmax, ymin, ymax))
+    return {
+        "contorni": contorni,
+        "bbox": {"xmin": xmin, "ymin": ymin, "xmax": xmax, "ymax": ymax},
+        "larghezza_mm": round(xmax - xmin, 3),
+        "altezza_mm": round(ymax - ymin, 3),
+        "entita": len(contorni),
+        "punti": sum(len(c) for c in contorni),
+    }
+
+
+@app.post("/dxf/preview")
+async def dxf_preview(dxf: UploadFile = File(...)) -> dict:
+    """#101: anteprima del disegno DXF (contorni + dimensioni in mm) per il
+    wizard «Crea ricetta da DXF». Solo lettura, leggera: nessun run slot."""
+    dxf_bytes = await dxf.read()
+    try:
+        return await asyncio.to_thread(_dxf_preview, dxf_bytes)
+    except CostruttoreError as exc:
+        raise _unprocessable(str(exc)) from exc
+    except Exception as exc:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"dxf preview failed: {type(exc).__name__}: {exc}",
+        ) from exc

src/vision_worker/tests/test_dxf_compare.py

@@ -80,3 +80,67 @@ async def test_dxf_compare_immagine_non_decodificabile_e_422():
 async def test_dxf_compare_parametro_fuori_range_e_422():
     response = await _post(_png(a_scene(0.0)), SAMPLE_DXF.read_bytes(), polarity="grigio")
     assert response.status_code == 422
+
+
+# --- #101: POST /dxf/preview ---------------------------------------------------
+
+def _rect_dxf(width: float, height: float, y0: float = 3.0) -> bytes:
+    """DXF minimo con ezdxf: un rettangolo chiuso, y in alto rispetto a 0."""
+    import ezdxf
+    doc = ezdxf.new()
+    doc.modelspace().add_lwpolyline(
+        [(1, y0), (1 + width, y0), (1 + width, y0 + height), (1, y0 + height)], close=True,
+    )
+    buffer = io.StringIO()
+    doc.write(buffer)
+    return buffer.getvalue().encode("utf-8")
+
+
+def _post_preview(dxf: bytes):
+    # TestClient sincrono: non serve pytest-asyncio (assente nel venv del worker)
+    from fastapi.testclient import TestClient
+    return TestClient(app).post(
+        "/dxf/preview", files={"dxf": ("d.dxf", dxf, "application/octet-stream")},
+    )
+
+
+def test_dxf_preview_rettangolo_10x5():
+    resp = _post_preview(_rect_dxf(10, 5))
+    assert resp.status_code == 200, resp.text
+    body = resp.json()
+    assert body["larghezza_mm"] == 10 and body["altezza_mm"] == 5
+    assert body["entita"] == 1 and body["punti"] == sum(len(c) for c in body["contorni"])
+    # y ribaltata: il rettangolo stava a y 3..8 nel DXF, ora a -8..-3 (asse verso il basso)
+    assert body["bbox"] == {"xmin": 1, "ymin": -8, "xmax": 11, "ymax": -3}
+    ring = body["contorni"][0]
+    assert ring[0] == ring[-1]  # contorno chiuso: primo == ultimo
+    assert all(-8 <= y <= -3 for _, y in ring)
+
+
+@pytest.mark.parametrize("content", [b"", b"questo non e' un dxf"])
+def test_dxf_preview_illeggibile_e_422(content):
+    resp = _post_preview(content)
+    assert resp.status_code == 422
+    assert resp.json()["detail"].startswith("DXF")
+
+
+def test_dxf_preview_senza_geometria_e_422():
+    import ezdxf
+    doc = ezdxf.new()
+    buffer = io.StringIO()
+    doc.write(buffer)
+    resp = _post_preview(buffer.getvalue().encode("utf-8"))
+    assert resp.status_code == 422
+    assert "senza geometria" in resp.json()["detail"]
+
+
+def test_dxf_preview_decima_oltre_il_tetto(monkeypatch):
+    from src.vision_worker import main
+    monkeypatch.setattr(main, "_PREVIEW_MAX_POINTS", 50)
+    import ezdxf
+    doc = ezdxf.new()
+    doc.modelspace().add_circle((0, 0), 20)
+    buffer = io.StringIO()
+    doc.write(buffer)
+    full = main._dxf_preview(buffer.getvalue().encode("utf-8"))
+    assert full["punti"] <= 50 + 1 and full["larghezza_mm"] == pytest.approx(40, abs=0.01)  # dimensioni dai punti completi