Editor Shell Standard

The WND, Texture, and future INI editors share one shell so canvas behavior is implemented once and every editor feels familiar. New editors must reuse these pieces instead of reimplementing pan, zoom, tabs, or menus.

Shared pieces (GenHub.Common.Editors)

• EditorToolViewModelBase: zoom (Zoom, ZoomIn/Out/ResetZoom), dirty tracking, busy operations with cancellation, clipboard verbs, and the open folder / open file / save / save-as command surface.
• EditorCanvasControl: pan and zoom canvas host. Middle-drag always pans, left-drag pans while IsPanMode is set, and Ctrl+mouse wheel zooms anchored at the cursor. Bind Zoom and IsPanMode two-way; set MaxZoom when a tool needs a tighter limit (bind the tool ViewModel's zoom maximum). Call FrameTo(offset) to scroll to a content offset after layout.
• FileExplorerViewModel + EditorFileExplorerControl: project folder tree with BrowseFolderAsync and the DirectoryAdoptedAsync hook. Hosts set the hook to scan and open a default file so header Open folder and the Files tab Browse button share one flow.
• EditorShellStyles.axaml (merged in App.axaml): the canvas control template and the compact-tabs sidebar tab style. Never copy these styles into a tool view.

Shell chrome conventions

• Header: leading context or hamburger menu, centered document title, zoom cluster (pan toggle, zoom out, percentage, zoom in, reset) on the right. Keep at most the primary open action and save visible; everything else goes in the hamburger MenuFlyout.
• Sidebars: CardBackground cards with BorderBrush, CornerRadius 10, Padding 8,6, and compact-tabs tab strips.
• Empty state: Open folder (primary) plus Open file (secondary) buttons.
• Feedback: INotificationService toasts only, never status labels.

Constants (EditorConstants)

Zoom defaults, limits, the additive zoom step, the wheel zoom factor, and the file explorer depth cap. Tool-specific limits (for example WND canvas sizes) stay in the tool's own constants.