Library-Thumbnails: Auto-Capture + Base64-Preview in der UI

Beim Hinzufuegen oder Importieren eines Library-Items wird automatisch
ein PNG-Thumbnail vom Item generiert (Top-View, 128x128) und in
library/previews/<id>.png abgelegt. Frontend rendert die Previews als
Base64-Data-URIs (sicher gegen WebKit-file://-Restriktionen).

library.py:
- _previews_dir(): legt previews/-Folder an
- _preview_rel_for(asset_rel): predictable PNG-Pfad pro Item
- _capture_thumbnail_of_objects(): hided andere Objekte temporaer,
  switcht auf Top-Parallel, ZoomBoundingBox, CaptureToBitmap → PNG,
  restored Viewport + Hidden-State
- read_preview_data_uri(): liest PNG + encoded als data:image/png;base64
- Hook in convert_to_3dm_via_import (vor Cleanup) + save_selection_to_asset

rhinopanel.py:
- _enrich_library_items_with_previews(): haengt previewDataUri an
  jedes Item das ein preview-Feld hat
- Initial-Params + _send_library + ElementeBridge._cmd_list_library
  liefern angereicherte Items
- _add_library_file + _save_selection_as_library setzen preview-Pfad
  im Item wenn Thumbnail-Datei existiert

Frontend:
- SymbolPicker.ItemPreview: rendert <div backgroundImage> mit Base64-URI
  wenn vorhanden, sonst Icon-Fallback
- ProjectSettingsDialog Symbole-Tab: List-Row + Detail-Identity zeigen
  Thumbnail (32px in Liste, 56px im Detail), Icon nur als Fallback

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

rhino/elemente.py

@@ -8096,9 +8096,10 @@ class ElementeBridge(panel_base.BaseBridge):
         Library-Items + Handling von PICK (User waehlt Item → CREATE_SYMBOL
         im aktiven Doc) und CANCEL (Fenster schliessen)."""
         try:
-            import library
+            import library, rhinopanel
             manifest = library.load_manifest()
-            items = manifest.get("items", [])
+            items = rhinopanel._enrich_library_items_with_previews(
+                manifest.get("items", []))
         except Exception as ex:
             print("[ELEMENTE] list library:", ex)
             items = []

rhino/library.py

@@ -210,6 +210,137 @@ def add_item(item):
     return ok, load_manifest()
 
 
+def _previews_dir():
+    """Pfad zum previews/-Subfolder. Wird angelegt falls fehlt."""
+    p = os.path.join(library_root(), "previews")
+    if not os.path.isdir(p):
+        try: os.makedirs(p)
+        except Exception: pass
+    return p
+
+
+def _preview_rel_for(asset_rel_or_id):
+    """Erzeugt einen relativen Preview-Pfad fuer ein Asset (oder Item-ID).
+    Liefert z.B. 'previews/<name>.png'. Wir benutzen den Stamm des
+    .3dm-Files damit Asset + Preview gleichen Namen haben (debuggbar)."""
+    stem = asset_rel_or_id
+    if "/" in stem: stem = stem.split("/")[-1]
+    if "\\" in stem: stem = stem.split("\\")[-1]
+    if stem.lower().endswith(".3dm"): stem = stem[:-4]
+    safe = "".join(c if (c.isalnum() or c in "-_") else "_" for c in stem)
+    return "previews/" + safe + ".png"
+
+
+def _capture_thumbnail_of_objects(target_objects, png_abs_path, size=128):
+    """Captured einen Top-View der gegebenen Objekte als PNG. Hided
+    temporaer alle anderen Objekte damit der Background sauber ist.
+    Returns True/False."""
+    if Rhino is None: return False
+    doc = Rhino.RhinoDoc.ActiveDoc
+    if doc is None or not target_objects: return False
+    try:
+        from System.Drawing import Size
+        import scriptcontext as sc
+    except Exception:
+        return False
+    # IDs der Ziel-Objekte
+    target_ids = set()
+    for o in target_objects:
+        try:
+            if not o.IsDeleted: target_ids.add(str(o.Id))
+        except Exception: pass
+    if not target_ids: return False
+    # Andere Objekte temporaer ausblenden
+    hidden_by_us = []
+    try:
+        for o in list(doc.Objects):
+            try:
+                if o.IsDeleted: continue
+                if str(o.Id) in target_ids: continue
+                if o.IsHidden: continue
+                if not o.IsNormal: continue   # bereits hidden/locked → skip
+                doc.Objects.Hide(o.Id, True)
+                hidden_by_us.append(o.Id)
+            except Exception: pass
+    except Exception: pass
+    capture_ok = False
+    try:
+        view = doc.Views.ActiveView
+        if view is None:
+            return False
+        vp = view.ActiveViewport
+        # Viewport-State sichern damit User nichts verliert
+        saved_target = vp.CameraTarget
+        saved_loc    = vp.CameraLocation
+        saved_proj   = vp.IsParallelProjection
+        try:
+            # Auf Top-Parallel wechseln + Zoom auf Ziel
+            vp.SetProjection(Rhino.Display.DefinedViewportProjection.Top, "Top", True)
+            try:
+                bbox = Rhino.Geometry.BoundingBox.Empty
+                for o in target_objects:
+                    g = o.Geometry
+                    if g is None: continue
+                    try:
+                        bb = g.GetBoundingBox(True)
+                        if bb.IsValid: bbox.Union(bb)
+                    except Exception: pass
+                if bbox.IsValid:
+                    # Etwas Padding
+                    bbox.Inflate(bbox.Diagonal.Length * 0.1)
+                    vp.ZoomBoundingBox(bbox)
+            except Exception as ex:
+                print("[LIBRARY] thumbnail zoom:", ex)
+            view.Redraw()
+            # Capture
+            try:
+                bmp = view.CaptureToBitmap(Size(int(size), int(size)))
+                if bmp is not None:
+                    # Sicherstellen dass Verzeichnis da ist
+                    try:
+                        d = os.path.dirname(png_abs_path)
+                        if d and not os.path.isdir(d): os.makedirs(d)
+                    except Exception: pass
+                    bmp.Save(png_abs_path)
+                    capture_ok = True
+            except Exception as ex:
+                print("[LIBRARY] thumbnail capture:", ex)
+        finally:
+            # Viewport wiederherstellen
+            try:
+                vp.SetCameraLocation(saved_loc, False)
+                vp.SetCameraTarget(saved_target, True)
+                if saved_proj:
+                    vp.IsParallelProjection = True
+                else:
+                    vp.IsParallelProjection = False
+            except Exception: pass
+    finally:
+        # Hidden Objekte wieder einblenden
+        for gid in hidden_by_us:
+            try: doc.Objects.Show(gid, True)
+            except Exception: pass
+        try: doc.Views.Redraw()
+        except Exception: pass
+    return capture_ok
+
+
+def read_preview_data_uri(rel_path):
+    """Liest die PNG-Vorschau als data:image/png;base64-URI fuer
+    direktes Einsetzen in <img src='...'>. Liefert None wenn Datei fehlt."""
+    if not rel_path: return None
+    abs_p = os.path.join(library_root(), rel_path)
+    if not os.path.isfile(abs_p): return None
+    try:
+        import base64
+        with open(abs_p, "rb") as f:
+            data = f.read()
+        return "data:image/png;base64," + base64.b64encode(data).decode("ascii")
+    except Exception as ex:
+        print("[LIBRARY] read_preview:", ex)
+        return None
+
+
 def convert_to_3dm_via_import(src_path, target_name):
     """Konvertiert eine beliebige CAD-Datei (.dwg/.obj/.fbx/.dae/.stl/...)
     nach .3dm. Strategie: Rhinos _-Import in den aktiven Doc, dann die
@@ -321,6 +452,14 @@ def convert_to_3dm_via_import(src_path, target_name):
             print("[LIBRARY] convert_to_3dm File3dm:", ex)
             return None
         finally:
+            # Thumbnail-Capture BEVOR die Objekte geloescht werden.
+            try:
+                rel_for_preview = os.path.relpath(target, library_root())
+                preview_rel = _preview_rel_for(rel_for_preview)
+                preview_abs = os.path.join(library_root(), preview_rel)
+                _capture_thumbnail_of_objects(new_objs, preview_abs)
+            except Exception as ex:
+                print("[LIBRARY] convert thumbnail:", ex)
             # Cleanup: importierte Objekte wieder loeschen
             for o in new_objs:
                 try: doc.Objects.Delete(o.Id, True)
@@ -419,6 +558,13 @@ def save_selection_to_asset(doc, target_name):
                 print("[LIBRARY] save_selection write:", ex)
                 return None
         rel = os.path.relpath(target, library_root())
+        # Thumbnail aus den (noch selektierten) Objekten capturen
+        try:
+            preview_rel = _preview_rel_for(rel)
+            preview_abs = os.path.join(library_root(), preview_rel)
+            _capture_thumbnail_of_objects(sel, preview_abs)
+        except Exception as ex:
+            print("[LIBRARY] save_selection thumbnail:", ex)
         print("[LIBRARY] save_selection: {} objs → {}".format(len(geoms), rel))
         return rel
     except Exception as ex:

rhino/rhinopanel.py

@@ -147,6 +147,24 @@ def _list_hatch_patterns_full(doc):
     return out
 
 
+def _enrich_library_items_with_previews(items):
+    """Liefert Liste mit zusaetzlichem 'previewDataUri'-Feld pro Item
+    (base64-PNG falls preview-Datei existiert). Items werden NICHT
+    persistiert — nur fuer den Transport ans Frontend angereichert."""
+    import library
+    out = []
+    for it in (items or []):
+        if not isinstance(it, dict):
+            out.append(it); continue
+        enriched = dict(it)
+        prev = it.get("preview")
+        if prev:
+            uri = library.read_preview_data_uri(prev)
+            if uri: enriched["previewDataUri"] = uri
+        out.append(enriched)
+    return out
+
+
 def _list_linetypes_full(doc):
     """Vollstaendiges Linetype-Listing fuer die Verwaltungs-UI.
     Mac Rhino 8 GetSegment(i) returnt (length: float, isLine: bool):
@@ -893,7 +911,8 @@ class EbenenBridge(panel_base.BaseBridge):
         try:
             import library
             lib_manifest = library.load_manifest()
-            lib_items = lib_manifest.get("items", [])
+            lib_items = _enrich_library_items_with_previews(
+                lib_manifest.get("items", []))
             lib_root = library.library_root()
         except Exception:
             lib_items = []; lib_root = ""
@@ -1183,12 +1202,15 @@ class EbenenBridge(panel_base.BaseBridge):
             # ---- Library-Item CRUD ----
             def _send_library(self):
                 """Sendet aktuelle Library-Items ans Frontend
-                (LIBRARY_ITEMS-Message)."""
+                (LIBRARY_ITEMS-Message). Items kommen mit
+                previewDataUri (base64 PNG) wenn Vorschau vorhanden."""
                 try:
                     import library
                     m = library.load_manifest()
+                    enriched = _enrich_library_items_with_previews(
+                        m.get("items", []))
                     self.send("LIBRARY_ITEMS", {
-                        "items": m.get("items", []),
+                        "items": enriched,
                         "libraryRoot": library.library_root(),
                     })
                 except Exception as ex:
@@ -1247,18 +1269,21 @@ class EbenenBridge(panel_base.BaseBridge):
                         self.send("LIBRARY_ERROR", {
                             "msg": "Konnte Datei nicht importieren — siehe Log."})
                         return
+                    # Preview-Pfad falls Thumbnail erzeugt wurde
+                    preview_rel = library._preview_rel_for(rel)
+                    preview_abs = os.path.join(library.library_root(), preview_rel)
+                    has_preview = os.path.isfile(preview_abs)
                     if target_id:
-                        # Bestehendes Item updaten
                         m = library.load_manifest()
                         for it in m.get("items", []):
                             if it.get("id") == target_id:
                                 key = "files" + variant
                                 it[key] = [rel]
                                 if not it.get("type"): it["type"] = item_type
+                                if has_preview: it["preview"] = preview_rel
                                 break
                         library.save_manifest(m)
                     else:
-                        # Neues Item — stem aus dem Pfad oben bereits berechnet
                         import uuid as _uuid
                         new_id = "obj-" + _uuid.uuid4().hex[:10]
                         item = {
@@ -1269,6 +1294,7 @@ class EbenenBridge(panel_base.BaseBridge):
                             "tags":    [],
                             "files" + variant: [rel],
                         }
+                        if has_preview: item["preview"] = preview_rel
                         library.add_item(item)
                     self._send_library()
                 except Exception as ex:
@@ -1343,10 +1369,13 @@ class EbenenBridge(panel_base.BaseBridge):
                     self.send("LIBRARY_ERROR", {
                         "msg": "Konnte Selection nicht speichern."})
                     return
+                preview_rel = library._preview_rel_for(rel)
+                preview_abs = os.path.join(library.library_root(), preview_rel)
+                has_preview = os.path.isfile(preview_abs)
                 if target_id:
-                    library.update_item(target_id, {
+                    patch = {("files" + variant): [rel]}
-                        ("files" + variant): [rel],
+                    if has_preview: patch["preview"] = preview_rel
-                    })
+                    library.update_item(target_id, patch)
                 else:
                     import uuid as _uuid
                     new_id = "obj-" + _uuid.uuid4().hex[:10]
@@ -1358,6 +1387,7 @@ class EbenenBridge(panel_base.BaseBridge):
                         "tags":    [],
                         ("files" + variant): [rel],
                     }
+                    if has_preview: item["preview"] = preview_rel
                     library.add_item(item)
                 self._send_library()
         b = _ProjectSettingsBridge()

src/components/ProjectSettingsDialog.jsx

@@ -1115,8 +1115,8 @@ export default function ProjectSettingsDialog({
                         onClick={() => setSelLib(it.id)}
                         style={{
                           display: 'grid',
-                          gridTemplateColumns: '20px 1fr',
+                          gridTemplateColumns: '32px 1fr',
-                          alignItems: 'center', gap: 6,
+                          alignItems: 'center', gap: 8,
                           padding: '5px 10px',
                           cursor: 'pointer',
                           background: isSel ? 'var(--accent-dim)' : 'transparent',
@@ -1129,9 +1129,21 @@ export default function ProjectSettingsDialog({
                         onMouseLeave={(e) => {
                           if (!isSel) e.currentTarget.style.background = 'transparent'
                         }}>
+                        <div style={{
+                          width: 32, height: 32, borderRadius: 4,
+                          background: it.previewDataUri
+                            ? `url("${it.previewDataUri}") center/contain no-repeat, var(--bg-input)`
+                            : 'var(--bg-input)',
+                          border: '1px solid var(--border-light)',
+                          display: 'flex', alignItems: 'center', justifyContent: 'center',
+                          flexShrink: 0,
+                        }}>
+                          {!it.previewDataUri && (
                             <Icon name={it.type === 'symbol' ? 'navigation' : 'forest'}
-                              size={13}
+                                  size={14}
                                   style={{ color: 'var(--text-muted)' }} />
+                          )}
+                        </div>
                         <div style={{ minWidth: 0 }}>
                           <div style={{ fontSize: 11,
                                          color: 'var(--text-primary)',
@@ -1177,10 +1189,22 @@ export default function ProjectSettingsDialog({
                   return (
                     <>
                       <DetailSection title="Identität">
-                        <div style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
+                        <div style={{ display: 'flex', alignItems: 'center', gap: 10 }}>
+                          <div style={{
+                            width: 56, height: 56, borderRadius: 6,
+                            background: it.previewDataUri
+                              ? `url("${it.previewDataUri}") center/contain no-repeat, var(--bg-input)`
+                              : 'var(--bg-input)',
+                            border: '1px solid var(--border)',
+                            display: 'flex', alignItems: 'center', justifyContent: 'center',
+                            flexShrink: 0,
+                          }}>
+                            {!it.previewDataUri && (
                               <Icon name={it.type === 'symbol' ? 'navigation' : 'forest'}
-                                size={28}
+                                    size={22}
                                     style={{ color: 'var(--accent)' }} />
+                            )}
+                          </div>
                           <input type="text" value={it.name || ''}
                             onChange={(ev) => {
                               const nm = ev.target.value

src/components/SymbolPicker.jsx

@@ -6,17 +6,29 @@ import { BarToggle, BarButton, BAR_H } from './BarControls'
    Grid. Klick auf Item → onPick(id). Schliesst via onClose. */
 
 function ItemPreview({ item }) {
-  // Vorschau: type-spezifisches Icon im Center auf bg-input.
+  // Thumbnail wenn vorhanden, sonst type-spezifisches Icon
-  // Spaeter: PNG-Thumbnail aus library/previews/.
+  if (item.previewDataUri) {
+    return (
+      <div style={{
+        height: 80,
+        background: 'var(--bg-input)',
+        borderBottom: '1px solid var(--border-light)',
+        backgroundImage: `url("${item.previewDataUri}")`,
+        backgroundSize: 'contain',
+        backgroundPosition: 'center',
+        backgroundRepeat: 'no-repeat',
+      }} />
+    )
+  }
   const iconName = item.type === 'symbol' ? 'navigation' : 'forest'
   return (
     <div style={{
-      height: 56,
+      height: 80,
       background: 'var(--bg-input)',
       borderBottom: '1px solid var(--border-light)',
       display: 'flex', alignItems: 'center', justifyContent: 'center',
     }}>
-      <Icon name={iconName} size={24}
+      <Icon name={iconName} size={28}
             style={{ color: 'var(--text-muted)' }} />
     </div>
   )