JSON canvas initial

render.go

@@ -64,6 +64,39 @@ type pageData struct {
 	SidebarWidget  template.HTML
 	SuppressTOC    bool
 	RenderMS       int64
+
+	// Canvases lists every .canvas file in this folder as a view-switcher tab.
+	// ActiveCanvas names the one currently being viewed ("" on a normal page),
+	// and is what makes this page render as a canvas rather than as markdown.
+	Canvases     []canvasRef
+	ActiveCanvas string
+	// CanvasJSON is the whole canvas document plus its server-rendered node
+	// HTML, inlined into the page so opening a canvas costs one request.
+	CanvasJSON template.JS
+	// CanvasError carries a parse/validation failure to the template, which
+	// shows it in place of the canvas instead of failing the request.
+	CanvasError string
+}
+
+// layoutData is the contract every view built on assets/layout.html satisfies.
+// The layout is shared by pageData and searchPageData, and a method only one of
+// them has fails at render time with a half-written response rather than at
+// build time — so each is asserted against the interface here.
+type layoutData interface {
+	ShowPageChrome() bool
+}
+
+var (
+	_ layoutData = pageData{}
+	_ layoutData = searchPageData{}
+)
+
+// ShowPageChrome reports whether the standard page furniture — search box,
+// folder-tree rail, right sidebar, and the collapsed ACTIONS dropdown — should
+// render. The editor and the canvas view both take the full width and supply
+// their own controls, so both opt out.
+func (d pageData) ShowPageChrome() bool {
+	return !d.EditMode && d.ActiveCanvas == ""
 }
 
 // Allowed values for the listing view settings. Unknown values in the file or
@@ -130,6 +163,7 @@ var (
 	iconAudio   = readIcon("audio")
 	iconArchive = readIcon("archive")
 	iconGeneric = readIcon("generic")
+	iconCanvas  = readIcon("canvas")
 )
 
 // renderMarkdown converts raw markdown to trusted HTML.
@@ -211,6 +245,9 @@ func listEntries(fsPath, urlPath, sortKey, order string) []entry {
 			if name == "index.md" {
 				continue // rendered above, don't list it
 			}
+			if isCanvasFile(name) {
+				continue // surfaced as a view-switcher tab above the content
+			}
 			f := entry{
 				Icon:    fileIcon(name),
 				Name:    name,
@@ -300,6 +337,8 @@ func readIcon(name string) template.HTML {
 func fileIcon(name string) template.HTML {
 	ext := strings.ToLower(path.Ext(name))
 	switch ext {
+	case ".canvas":
+		return iconCanvas
 	case ".md", ".pdf":
 		return iconDoc
 	case ".png", ".jpg", ".jpeg", ".gif", ".webp", ".svg":