JSON canvas initial

assets/page/canvas-actions.js

@@ -0,0 +1,43 @@
+// canvas-actions.js — creating a canvas from a normal page.
+//
+// The canvas view itself owns everything else (rename, delete, editing); this
+// only covers the one action that has to start from the page, since a folder
+// with no canvases has no canvas view to reach.
+//
+// Reuses openModal and postReplace from page/actions.js, which the page
+// template loads first.
+
+// validCanvasName mirrors canvasNameRe in canvas.go. Checking here only buys a
+// better error message — the server rejects the same set regardless.
+function validCanvasName(name) {
+    if (!name || name.length > 100) return false;
+    if (name.charAt(0) === '.') return false;
+    return !/[\/\\]/.test(name);
+}
+
+function newCanvas() {
+    var input = document.createElement('input');
+    input.type = 'text';
+    input.className = 'input';
+    input.placeholder = 'Canvas name';
+
+    openModal({
+        title: 'New canvas',
+        body: input,
+        confirm: {
+            label: 'CREATE',
+            onConfirm: function () {
+                var name = input.value.trim();
+                if (!validCanvasName(name)) {
+                    alert('A canvas name cannot be empty, start with a dot, or contain a slash.');
+                    return;
+                }
+                closeModal();
+                var base = window.location.pathname;
+                if (base.slice(-1) !== '/') base += '/';
+                var target = base + '?canvas=' + encodeURIComponent(name);
+                postReplace(target + '&create=1', null, target);
+            }
+        }
+    });
+}

assets/page/main.html

@@ -1,4 +1,5 @@
-{{define "headScripts"}}<script src="/_/page/actions.js"></script>{{end}}
+{{define "headScripts"}}<script src="/_/page/actions.js"></script>
+<script src="/_/page/canvas-actions.js"></script>{{end}}
 
 {{define "headerActions"}}{{if .CanEdit}}
 <button class="btn btn-block" onclick="newPage()" title="New page (N)">NEW</button>
@@ -8,9 +9,20 @@
 <button class="btn btn-block danger" onclick="deletePage()" title="Delete page">DELETE</button>
 {{end}}
 <a class="btn btn-block" href="?edit" title="Edit page (E)">EDIT</a>
+<button class="btn btn-block" onclick="newCanvas()" title="New canvas">NEW CANVAS</button>
 {{end}}{{end}}
 
 {{define "content"}}
+{{/* Canvases in this folder are alternative views of the same page, so they
+     read as a tab strip above the content rather than as rows in the file
+     listing (listEntries filters them out for exactly this reason). */}}
+{{if .Canvases}}
+<nav class="canvas-tabs row" aria-label="Page views">
+    <span class="canvas-tab is-active">PAGE</span>
+    {{range .Canvases}}<a class="canvas-tab" href="{{.URL}}">{{.Name}}</a>{{end}}
+    {{if .CanEdit}}<button type="button" class="canvas-tab canvas-tab-add" onclick="newCanvas()" title="New canvas">+</button>{{end}}
+</nav>
+{{end}}
 {{if .Content}}
 <div class="content">{{.Content}}</div>
 {{end}}