viewer: add ifc:// URL links and clickable images to embedded snapshots

- ifc_url.go: wrap figcaption URL in <a href="ifc://"> for future protocol handler
- footer.tmpl: wrap diff snapshot images in viewer links; add ifc:// URL anchor below each snapshot (Cases 3 and 4)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.beads/issues.jsonl

@@ -2,6 +2,7 @@
 {"id":"ifcurl-p60","title":"Viewer: no element click-to-identify — can't get GlobalId or properties","description":"There is no way to click on a mesh in the viewer and see which IFC element it represents. Reviewers can see geometry but cannot reference specific elements — they can't discover a GlobalId to put in a selector URL, can't see the element name/type/Psets, and can't say 'this specific wall' in a BCF or Forgejo comment. This breaks the collaboration workflow at its foundation: every useful feedback comment needs to identify specific elements. Need: click or hover on a surface to highlight it and show a properties panel (name, type, GlobalId, key Psets). The GlobalId should be copyable into the selector field or URL. The ThatOpen components library provides the tools for this (OBC.IfcRelationsIndexer, element property queries).","status":"closed","priority":1,"issue_type":"feature","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-24T11:02:33Z","created_by":"Bruno Postle","updated_at":"2026-04-24T11:47:23Z","started_at":"2026-04-24T11:14:57Z","closed_at":"2026-04-24T11:47:23Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-4l7","title":"viewer.html: scale= URLs don't load in orthographic mode","description":"applyCameraParam() reads the camera= and fov= parameters from the URL and applies them, but never reads scale= or switches the camera to orthographic (parallel) projection. URLs like ?camera=...\u0026scale=50 will load in perspective mode instead of orthographic. The OBC OrthoPerspectiveCamera can switch modes, but the code path to set parallel projection and apply the scale value is missing from applyCameraParam.","status":"closed","priority":1,"issue_type":"bug","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-24T09:04:51Z","created_by":"Bruno Postle","updated_at":"2026-04-24T10:56:29Z","started_at":"2026-04-24T10:50:19Z","closed_at":"2026-04-24T10:56:29Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-362","title":"Add missing server-config files: gitconfig-ifcmerge and gitattributes","description":"forgejo/README.md documents deploying two files that don't exist in the repo: forgejo/server-config/gitconfig-ifcmerge and forgejo/server-config/gitattributes. Both are required for the ifcmerge git merge driver to work in bare Forgejo repos. The README even includes 'sudo cp forgejo/server-config/gitattributes /etc/gitattributes' and 'sudo git config --system include.path .../gitconfig-ifcmerge', but the files themselves are absent. Anyone following the deployment instructions will hit a 'file not found' error. Need to create both files with the content described in the README.","status":"closed","priority":1,"issue_type":"bug","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-24T09:04:31Z","created_by":"Bruno Postle","updated_at":"2026-04-24T10:51:47Z","started_at":"2026-04-24T10:50:15Z","closed_at":"2026-04-24T10:51:47Z","close_reason":"Files already exist: forgejo/server-config/gitconfig-ifcmerge and gitattributes are both present and correct. Missed in initial review.","dependency_count":0,"dependent_count":0,"comment_count":0}
+{"id":"ifcurl-22n","title":"viewer: add ifc:// URL and clickable image link to embedded snapshots","description":"Forgejo commit pages and pull requests embed IFC snapshots as visual diffs. Each snapshot should have two additions: (1) the ifc:// URL that addresses this exact view at the commit hash displayed as text alongside the image, and (2) the snapshot image itself should be a clickable link that opens the viewer at this view. This makes snapshots navigable and shareable.","status":"closed","priority":2,"issue_type":"feature","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-27T05:36:16Z","created_by":"Bruno Postle","updated_at":"2026-04-27T05:59:52Z","started_at":"2026-04-27T05:59:51Z","closed_at":"2026-04-27T05:59:52Z","close_reason":"Closed","dependencies":[{"issue_id":"ifcurl-22n","depends_on_id":"ifcurl-5a6","type":"blocks","created_at":"2026-04-27T06:37:10Z","created_by":"Bruno Postle","metadata":"{}"}],"dependency_count":1,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-dkz","title":"Viewer bundle: upgrade @thatopen/components 3.3.1 → 3.4.2 to fix fast-xml-parser CVEs","description":"npm audit reports 2 critical CVEs in fast-xml-parser (a transitive dep of @thatopen/components 3.3.1). These are DoS/injection issues in XML parsing. Risk in the viewer context is low (client-side, user's own files) but should be addressed. Fix: bump @thatopen/components to 3.4.2 in forgejo/package.json, run npm install \u0026\u0026 npm run build, and commit the regenerated bundle.","status":"closed","priority":2,"issue_type":"task","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-25T17:12:37Z","created_by":"Bruno Postle","updated_at":"2026-04-25T17:59:50Z","started_at":"2026-04-25T17:31:59Z","closed_at":"2026-04-25T17:59:50Z","close_reason":"Upgraded to @thatopen/components 3.4.2 + three 0.184.0 + web-ifc 0.0.77. Severity reduced from 2 critical to 1 high + 1 low. Remaining fast-xml-parser CVEs are upstream in @thatopen \u003e= 3.3.3 with no fix released yet.","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-bue","title":"Split service into ifcurl-api and ifcurl-render for RCE isolation","description":"The ifcopenshell C++ bindings are the main RCE attack surface (memory corruption on malformed IFC). The git/token code is not at risk but currently shares the same process and systemd security profile.\n\nSplit the service into two systemd units with different security profiles:\n\nifcurl-api (renamed from ifcurl-preview): handles HTTP, git fetch, caching, auth token lookup. Needs execve (git CLI via GitPython) and AF_INET/AF_INET6. No ifcopenshell.\n\nifcurl-render: handles IFC parsing and PNG rendering only. Listens on Unix socket /run/ifcurl-render/render.sock. Has SystemCallFilter ~execve ~execveat (confirmed safe: strace shows pyvista and ifcopenshell geom iterator use fork/clone only, never exec). Has RestrictAddressFamilies=AF_UNIX only. No access to /etc/ifcurl tokens. Runs as separate user ifcurl-render.\n\nCommunication: API service calls render service via httpx over the Unix socket. Both service users belong to a shared ifcurl group for socket access.\n\nInterface (three endpoints on render service):\n  POST /render        multipart(ifc, params JSON) → JSON {png: base64, guids: list|null}\n  POST /select        multipart(ifc, params JSON) → JSON {guids: list}\n  POST /render_diff   multipart(head_ifc, base_ifc, params JSON) → image/png binary\n\nsandbox.py crash isolation is kept inside the render service for per-request segfault containment.\n\nBackward compat: if IFCURL_RENDER_SOCKET is unset, API service falls back to direct in-process rendering (current sandbox.py path).\n\nImplementation steps:\n1. ifcurl/render_service.py — FastAPI app with the three endpoints wrapping sandboxed functions\n2. ifcurl/service.py — delegate to render service when IFCURL_RENDER_SOCKET is set\n3. ifcurl/__main__.py — add 'render-service' CLI subcommand\n4. pyproject.toml — add httpx to service optional deps\n5. forgejo/server-config/ifcurl-api.service (rename + update)\n6. forgejo/server-config/ifcurl-render.service (new, hardened unit)\n7. forgejo/README.md — update deployment docs for two-service setup\n8. tests/test_render_service.py — integration tests for the render service endpoints","acceptance_criteria":"render service cannot exec /bin/sh even with RCE (verified by strace showing no execve during normal render); normal renders still produce correct PNG; API service correctly delegates to render service when socket is configured; fallback to in-process rendering works when socket is unset","status":"closed","priority":2,"issue_type":"feature","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-25T08:32:27Z","created_by":"Bruno Postle","updated_at":"2026-04-25T08:57:22Z","started_at":"2026-04-25T08:32:57Z","closed_at":"2026-04-25T08:57:22Z","close_reason":"Two-service split implemented: render_service.py with /render /select /render_diff endpoints, service.py delegates via httpx when IFCURL_RENDER_SOCKET is set, render-service CLI subcommand added, two systemd units created","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-ndf","title":"gitconfig-ifcmerge: update to use ifcmerge --prioritise-local instead of swapping LOCAL/REMOTE","description":"The current gitconfig-ifcmerge uses the old technique of swapping the order of %A and %B arguments to preserve the base branch's STEP ID space:\n\n    driver = ifcmerge %O %A %B %L    (standard)\n    driver = ifcmerge %O %B %A %L    (ours variant)\n\nBonsai's current ifcgit code (tool/ifcgit.py, config_ifcmerge) uses the newer --prioritise-local flag instead:\n\n    ifcmerge --prioritise-local $BASE $LOCAL $REMOTE $MERGED\n\nThe --prioritise-local flag tells ifcmerge to preserve LOCAL's STEP ID space without needing to swap argument order. This is cleaner, more readable, and follows the canonical ifcmerge interface.\n\nThe gitconfig-ifcmerge needs updating to:\n    driver = ifcmerge --prioritise-local %O %A %B %A\n\n(where %A is both LOCAL and the output file — git merge drivers write their result to %A)\n\nThe ifcmerge_ours variant (for rebase direction where base branch arrives as %B) would become:\n    driver = ifcmerge --prioritise-local %O %B %A %B\n\nVerify that the --prioritise-local flag exists in the version of ifcmerge being used before merging.","status":"closed","priority":2,"issue_type":"task","owner":"bruno@postle.net","created_at":"2026-04-25T06:06:59Z","created_by":"Bruno Postle","updated_at":"2026-04-25T06:41:59Z","closed_at":"2026-04-25T06:41:59Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
@@ -43,6 +44,10 @@
 {"id":"ifcurl-ei8","title":"Fix syncCameraUrl: convert WebGL coords to IFC world space","description":"syncCameraUrl in viewer.py currently records camera.position/direction/up directly from Three.js, which are in WebGL/Three.js coordinate space (Y-up, different scale/orientation than IFC). The ifc:// URL spec expects IFC world coordinates (Z-up, matching BCF viewpoint conventions). Need to find the IFC→Three.js transform that @thatopen/components applies when loading a model, then apply its inverse in syncCameraUrl before serialising the camera params. Repos cloned for reference: ~/src/engine_components and ~/src/engine_fragment.","status":"closed","priority":2,"issue_type":"bug","owner":"bruno@postle.net","created_at":"2026-04-23T05:53:06Z","created_by":"Bruno Postle","updated_at":"2026-04-23T06:14:36Z","closed_at":"2026-04-23T06:14:36Z","close_reason":"Split into atomic tasks: ifcurl-ldk, ifcurl-j2s, ifcurl-cmd","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-i1s","title":"Test Phase 3b web viewer end-to-end","description":"After deploying the footer template (ifcurl-ach), test the full flow: open an .ifc file in Forgejo at localhost:3000, click 'View in 3D', verify the viewer loads the model. CDN versions (@thatopen/components 2.4.0, three 0.160.0, web-ifc 0.0.66) may need adjustment if the API has changed.","status":"closed","priority":2,"issue_type":"task","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-23T05:48:01Z","created_by":"Bruno Postle","updated_at":"2026-04-23T20:05:04Z","started_at":"2026-04-23T19:54:56Z","closed_at":"2026-04-23T20:05:04Z","close_reason":"Closed","dependencies":[{"issue_id":"ifcurl-i1s","depends_on_id":"ifcurl-49o","type":"blocks","created_at":"2026-04-23T07:14:12Z","created_by":"Bruno Postle","metadata":"{}"},{"issue_id":"ifcurl-i1s","depends_on_id":"ifcurl-4yu","type":"blocks","created_at":"2026-04-23T07:14:11Z","created_by":"Bruno Postle","metadata":"{}"},{"issue_id":"ifcurl-i1s","depends_on_id":"ifcurl-ach","type":"blocks","created_at":"2026-04-23T06:48:10Z","created_by":"Bruno Postle","metadata":"{}"},{"issue_id":"ifcurl-i1s","depends_on_id":"ifcurl-ahd","type":"blocks","created_at":"2026-04-23T07:02:54Z","created_by":"Bruno Postle","metadata":"{}"}],"dependency_count":4,"dependent_count":1,"comment_count":0}
 {"id":"ifcurl-ach","title":"Deploy Phase 3b footer template to Forgejo","description":"The footer.tmpl file that injects a 'View in 3D' button on .ifc file pages has been written but not yet deployed. Deploy it to /etc/forgejo/templates/custom/footer.tmpl and verify the button appears when viewing an .ifc file on localhost:3000.","status":"closed","priority":2,"issue_type":"task","owner":"bruno@postle.net","created_at":"2026-04-23T05:47:53Z","created_by":"Bruno Postle","updated_at":"2026-04-23T06:14:35Z","closed_at":"2026-04-23T06:14:35Z","close_reason":"Split into atomic tasks: ifcurl-ohq, ifcurl-49o","dependencies":[{"issue_id":"ifcurl-ach","depends_on_id":"ifcurl-ahd","type":"blocks","created_at":"2026-04-23T07:02:40Z","created_by":"Bruno Postle","metadata":"{}"}],"dependency_count":1,"dependent_count":1,"comment_count":0}
+{"id":"ifcurl-5u6","title":"Evaluate replacing ifc_url.go markdown extension with JS injection","description":"ifc_url.go is a Goldmark AST extension that replaces ifc:// URLs in rendered markdown with preview figure elements (img + link). This requires patching and recompiling Forgejo. A JS alternative in footer.tmpl could handle the [title](ifc://...) markdown link case by scanning document.querySelectorAll('a[href^=\"ifc://\"]') and replacing matched anchors with figure elements at runtime — no Go changes needed. The limitation: bare ifc://... text in markdown won't be auto-linked by Goldmark (unknown scheme renders as plain text), so bare URLs would need text-node scanning in JS, which is fiddly and causes a render flash. Decision: replace with JS if users can commit to always using [title](ifc://...) link syntax; keep Go extension if bare URLs in markdown are a real use case.","status":"open","priority":3,"issue_type":"task","owner":"bruno@postle.net","created_at":"2026-04-27T06:05:32Z","created_by":"Bruno Postle","updated_at":"2026-04-27T06:05:32Z","dependency_count":0,"dependent_count":0,"comment_count":0}
+{"id":"ifcurl-71f","title":"Extract footer.tmpl JS into a separate ifcurl.js asset file","description":"footer.tmpl is 200 lines of JavaScript wrapped in a single \u003cscript\u003e tag. Moving it to /var/lib/forgejo/custom/public/assets/ifcurl.js (served at /assets/ifcurl.js) would reduce footer.tmpl to a one-liner \u003cscript src='/assets/ifcurl.js'\u003e\u003c/script\u003e. Benefits: proper editor syntax highlighting and linting, no HTML-escaping concerns, cleaner separation of concerns. Two files to deploy instead of one, but that's manageable.","status":"open","priority":3,"issue_type":"task","owner":"bruno@postle.net","created_at":"2026-04-27T06:05:05Z","created_by":"Bruno Postle","updated_at":"2026-04-27T06:05:05Z","dependency_count":0,"dependent_count":0,"comment_count":0}
+{"id":"ifcurl-5a6","title":"viewer: wrap ifc:// text in anchor tags for future browser URL handler","description":"At some point we will register a browser protocol handler for ifc:// URLs so they can open desktop tools (Bonsai etc). In preparation, all ifc:// URLs generated alongside embedded snapshots should be wrapped in \u003ca href=\"ifc://...\"\u003e anchor tags. Currently they will not do anything (no handler registered), but having them as links now means the UI is ready when the handler exists, and users can at least see and copy the URL.","status":"closed","priority":3,"issue_type":"task","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-27T05:36:42Z","created_by":"Bruno Postle","updated_at":"2026-04-27T05:59:25Z","started_at":"2026-04-27T05:39:30Z","closed_at":"2026-04-27T05:59:25Z","close_reason":"Closed","dependency_count":0,"dependent_count":1,"comment_count":0}
+{"id":"ifcurl-tga","title":"docs: reorganise README to lead with Forgejo features","description":"The project is now primarily a Forgejo mod that enables IFC previews in commit and PR pages. The README should lead with what this enables for users (embedded snapshots, visual diffs, clickable model links), then move into the ifc:// URL specification as the technical foundation. The current README leads with the URL spec which buries the headline feature.","status":"open","priority":3,"issue_type":"task","owner":"bruno@postle.net","created_at":"2026-04-27T05:36:41Z","created_by":"Bruno Postle","updated_at":"2026-04-27T05:36:41Z","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-0n8","title":"viewer: storey filter has no 'show all' / reset option","description":"Clicking a storey row in the model overview panel isolates that storey via hider.isolate(). There is no way to reset back to the full model view. Clicking the active storey row should toggle it off (show all), and/or a 'show all' button should appear at the top of the Storeys section when a storey is active. Note: the storey click handler at line ~1016 already has toggle-off logic (if activeRow === row → hider.set(true)) but it only works if you click the same row a second time — the bug is that clicking a different storey, then trying to go back, leaves no 'all storeys' option visible.","status":"closed","priority":3,"issue_type":"bug","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-26T07:33:19Z","created_by":"Bruno Postle","updated_at":"2026-04-26T08:40:03Z","started_at":"2026-04-26T08:01:13Z","closed_at":"2026-04-26T08:40:03Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-21x","title":"viewer: smooth transition when URL settings change","description":"Changing the visibility dropdown, selector, or other settings triggers a full page reload, causing the screen to go blank for several seconds while the model re-fetches and re-parses. Options: (a) CSS fade-in on load only — minimal change; (b) capture canvas snapshot before navigate and show as placeholder during reload; (c) in-place model reload without page navigation — best UX but requires refactoring main() to support hot-reload. Option (b) requires preserveDrawingBuffer:true in the WebGL renderer.","status":"closed","priority":3,"issue_type":"feature","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-26T07:13:24Z","created_by":"Bruno Postle","updated_at":"2026-04-26T07:17:15Z","started_at":"2026-04-26T07:15:10Z","closed_at":"2026-04-26T07:17:15Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"id":"ifcurl-npy","title":"viewer: add zoom-all / reset-view button","description":"When the camera has panned or zoomed away from the building, there is no way to get back to a full view of the model. Add a 'zoom all' or 'reset view' button in the toolbar that calls cameraControls.fitToBox(model.box, true) to fit the entire model back in view.","status":"closed","priority":3,"issue_type":"feature","assignee":"Bruno Postle","owner":"bruno@postle.net","created_at":"2026-04-26T07:12:59Z","created_by":"Bruno Postle","updated_at":"2026-04-26T07:17:14Z","started_at":"2026-04-26T07:15:07Z","closed_at":"2026-04-26T07:17:14Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}

forgejo/modules/markup/markdown/ifc_url.go

@@ -233,9 +233,9 @@ func (r *ifcURLRenderer) render(w util.BufWriter, _ []byte, node ast.Node, enter
 			`<a href="%s" title="%s">`+
 			`<img src="%s" alt="IFC preview" loading="lazy" style="max-width:100%%"/>`+
 			`</a>`+
-			`<figcaption><code>%s</code></figcaption>`+
+			`<figcaption><a href="%s"><code>%s</code></a></figcaption>`+
 			`</figure>`,
-		safeViewer, safeIfc, safePreview, safeIfc,
+		safeViewer, safeIfc, safePreview, safeIfc, safeIfc,
 	)
 	return ast.WalkSkipChildren, nil
 }

forgejo/templates/custom/footer.tmpl

@@ -80,14 +80,29 @@
             img.src = origin + "/render_diff"
                     + "?base=" + encodeURIComponent(baseIfc)
                     + "&head=" + encodeURIComponent(headIfc);
-            img.style.cssText = "max-width:100%;display:block;margin:8px 0";
+            img.style.cssText = "max-width:100%;display:block";
             img.alt = info.treePath;
+            var imgLink = document.createElement("a");
+            imgLink.href = VIEWER_BASE + "?url=" + encodeURIComponent(headIfc);
+            imgLink.target = "_blank";
+            imgLink.rel = "noopener noreferrer";
+            imgLink.appendChild(img);
+            var code = document.createElement("code");
+            code.style.cssText = "display:block;font-size:0.85em;word-break:break-all;margin-top:4px";
+            code.textContent = headIfc;
+            var urlLink = document.createElement("a");
+            urlLink.href = headIfc;
+            urlLink.appendChild(code);
+            var container = document.createElement("div");
+            container.style.cssText = "margin:8px 0";
+            container.appendChild(imgLink);
+            container.appendChild(urlLink);
             var fileBox = a.closest(".diff-file-box");
             var header = fileBox && fileBox.querySelector(".file-header");
             if (header) {
-              header.insertAdjacentElement("afterend", img);
+              header.insertAdjacentElement("afterend", container);
             } else {
-              a.insertAdjacentElement("afterend", img);
+              a.insertAdjacentElement("afterend", container);
             }
           });
         })
@@ -120,31 +135,48 @@
         var newIsIfc = newFile.toLowerCase().endsWith(".ifc");
         var oldIsIfc = oldFile.toLowerCase().endsWith(".ifc");
 
-        var ifcPath, imgSrc;
+        var ifcPath, imgSrc, viewerIfc;
         if (newIsIfc && oldIsIfc && newFile === oldFile && parentSha) {
           // Modified: show colour-coded diff
           ifcPath = newFile;
           var baseIfc = "ifc://" + host + "/" + repoPath + "@" + parentSha + "?path=" + encodeURIComponent(ifcPath);
-          var headIfc = "ifc://" + host + "/" + repoPath + "@" + headSha + "?path=" + encodeURIComponent(ifcPath);
+          viewerIfc = "ifc://" + host + "/" + repoPath + "@" + headSha + "?path=" + encodeURIComponent(ifcPath);
-          imgSrc = origin + "/render_diff?base=" + encodeURIComponent(baseIfc) + "&head=" + encodeURIComponent(headIfc);
+          imgSrc = origin + "/render_diff?base=" + encodeURIComponent(baseIfc) + "&head=" + encodeURIComponent(viewerIfc);
         } else if (newIsIfc) {
           // Added (or renamed to .ifc): plain preview of new version
           ifcPath = newFile;
-          imgSrc = origin + "/preview?url=" + encodeURIComponent("ifc://" + host + "/" + repoPath + "@" + headSha + "?path=" + encodeURIComponent(ifcPath));
+          viewerIfc = "ifc://" + host + "/" + repoPath + "@" + headSha + "?path=" + encodeURIComponent(ifcPath);
+          imgSrc = origin + "/preview?url=" + encodeURIComponent(viewerIfc);
         } else if (oldIsIfc && parentSha) {
           // Deleted (or renamed from .ifc): plain preview of old version
           ifcPath = oldFile;
-          imgSrc = origin + "/preview?url=" + encodeURIComponent("ifc://" + host + "/" + repoPath + "@" + parentSha + "?path=" + encodeURIComponent(ifcPath));
+          viewerIfc = "ifc://" + host + "/" + repoPath + "@" + parentSha + "?path=" + encodeURIComponent(ifcPath);
+          imgSrc = origin + "/preview?url=" + encodeURIComponent(viewerIfc);
         } else {
           return;
         }
 
         var img = document.createElement("img");
         img.src = imgSrc;
-        img.style.cssText = "max-width:100%;display:block;margin:8px 0";
+        img.style.cssText = "max-width:100%;display:block";
         img.alt = ifcPath;
+        var imgLink = document.createElement("a");
+        imgLink.href = VIEWER_BASE + "?url=" + encodeURIComponent(viewerIfc);
+        imgLink.target = "_blank";
+        imgLink.rel = "noopener noreferrer";
+        imgLink.appendChild(img);
+        var code = document.createElement("code");
+        code.style.cssText = "display:block;font-size:0.85em;word-break:break-all;margin-top:4px";
+        code.textContent = viewerIfc;
+        var urlLink = document.createElement("a");
+        urlLink.href = viewerIfc;
+        urlLink.appendChild(code);
+        var container = document.createElement("div");
+        container.style.cssText = "margin:8px 0";
+        container.appendChild(imgLink);
+        container.appendChild(urlLink);
         var header = box.querySelector(".diff-file-header");
-        if (header) header.insertAdjacentElement("afterend", img);
+        if (header) header.insertAdjacentElement("afterend", container);
       });
       return;
     }