Commands for focus, scrolling and the clipboard, and pictures from bytes

focus, scroll-to-end, scroll-to-start and scroll-into-view find their
control by the key of its view, and run once the update's controls are
laid out. copy-text puts text on the clipboard, and paste-text sends what
it holds. A command that sends no message ends its fiber when its work is
done, so none is left waiting until the app stops.

image-data shows a picture from the bytes of a file, read again only when
it is given another array.

start-headless! now adds the Fluent theme, as run-app does, so controls
are templated and laid out as in a window.

🤖 Generated with [ECA](https://eca.dev) (anthropic/claude-opus-4-8)

Co-Authored-By: eca-agent <git@eca.dev>

Readme.org

@@ -62,6 +62,7 @@ being changed, and they are dropped, so only the user's events are messages.
 | ~(progress-bar value)~                               | ~ProgressBar~ | nothing                       |
 | ~(dropdown options selected on-select)~              | ~ComboBox~    | ~(on-select index)~           |
 | ~(image path)~                                       | ~Image~       | nothing                       |
+| ~(image-data bytes)~, the bytes of a picture file    | ~Image~       | nothing                       |
 | ~(list-box views selected on-select)~                | ~ListBox~     | ~(on-select index)~           |
 | ~(tabs selected on-select (tab header view) ...)~    | ~TabControl~  | ~(on-select index)~           |
 | ~(column child ...)~, ~(row child ...)~              | ~StackPanel~  | nothing                       |
@@ -101,7 +102,8 @@ number is pixels. ~(at row column view)~ puts a view in a cell, counting from
         #:height 200.0)
 #+END_SRC
 
-An image that cannot be read shows nothing.
+An image that cannot be read shows nothing. ~image-data~ reads its bytes
+again only when it is given another array, so keep the array in the model.
 
 A list box's items are views, so an item can be anything: a text, a row with
 a checkbox, a dropdown. Give them keys if the list can change order. Each
@@ -379,6 +381,30 @@ The fibers belong to the app. They post their messages to the UI thread, so
 ~gui-update~ and ~view~ always run there. When the window is closed they are
 cancelled, and the program ends.
 
+** Commands that act on the controls and the clipboard
+
+Some commands do work of their own and send no message. Each finds its
+control by the key of its view, given with ~keyed~, and runs once the
+controls of the update are laid out, so a view the same update made is
+there.
+
+| Command                       | Does                                                    |
+|-------------------------------+---------------------------------------------------------|
+| ~(focus key)~                 | gives the keyboard to the control                       |
+| ~(scroll-to-end key)~         | scrolls a ~scroll~ view to its end, as a log wants      |
+| ~(scroll-to-start key)~       | scrolls a ~scroll~ view to its start                    |
+| ~(scroll-into-view key)~      | scrolls the views around the control until it is seen   |
+| ~(copy-text text)~            | puts ~text~ on the clipboard                            |
+| ~(paste-text on-text)~        | sends ~(on-text (Some text))~, or ~(on-text None)~      |
+
+#+BEGIN_SRC scheme
+(Add (next (record-set m (items (vec-add (.items m) (.draft m))) (draft ""))
+           (focus "draft")
+           (scroll-to-end "items")))
+
+(keyed "draft" (text-input (.draft m) Draft))
+#+END_SRC
+
 * Dialogs: (bjogui dialogs)
 
 A dialog is a command, and its answer comes back as a message.
@@ -458,6 +484,7 @@ bjo run tests/tree.bjo      # prints "bjogui tree ok"
 bjo run tests/canvas.bjo    # prints "bjogui canvas ok"
 bjo run tests/components.bjo  # prints "bjogui components ok"
 bjo run tests/native.bjo    # prints "bjogui native ok"
+bjo run tests/commands.bjo  # prints "bjogui commands ok"
 bjo run examples/counter.bjo
 bjo run examples/stopwatch.bjo
 bjo run examples/todo.bjo

src/app.bjo

@@ -29,6 +29,8 @@
   run-app next style
   ;; Subscriptions.
   every subscription
+  ;; Commands that act on the controls and the clipboard.
+  focus scroll-to-end scroll-to-start scroll-into-view copy-text paste-text
   ;; For tests and for hosts of their own: an app with no window.
   start-app app-dispatch! app-send! app-stop! app-run-pending! app-press! app-input!
   app-model app-control app-control-at start-headless!)
@@ -168,7 +170,13 @@
   (WheelArgs         (: Avalonia.Input.PointerWheelEventArgs))
   (InputElement      (: Avalonia.Input.InputElement))
   (NavigationMethod  (: Avalonia.Input.NavigationMethod))
-  (HeadlessOptions   (: Avalonia.Headless.AvaloniaHeadlessPlatformOptions (-> HeadlessOptions))))
+  (HeadlessOptions   (: Avalonia.Headless.AvaloniaHeadlessPlatformOptions (-> HeadlessOptions)))
+  ;; Commands, and pictures from memory.
+  (TopLevel          (: Avalonia.Controls.TopLevel))
+  (IClipboard        (: Avalonia.Input.Platform.IClipboard))
+  (Stream            (: System.IO.Stream))
+  (MemoryStream      (: System.IO.MemoryStream (-> (Array byte) MemoryStream)))
+  (StreamBitmap      (: Avalonia.Media.Imaging.Bitmap (-> Stream StreamBitmap))))
 
 (import/extern
   ;; Properties, as the objects `SetValue` takes.
@@ -404,7 +412,25 @@
                           (-> AppBuilder HeadlessOptions AppBuilder)))
   (headless-drawing!   (: Avalonia.Headless.AvaloniaHeadlessPlatformOptions.UseHeadlessDrawing
                           (-> HeadlessOptions bool void) #:set))
-  (setup-without-starting (: Avalonia.AppBuilder.SetupWithoutStarting (-> AppBuilder AppBuilder))))
+  (setup-without-starting (: Avalonia.AppBuilder.SetupWithoutStarting (-> AppBuilder AppBuilder)))
+
+  ;; Commands.
+  (ui-post-late   (: Avalonia.Threading.Dispatcher.InvokeAsync
+                     (-> Dispatcher (-> Unit) UiPriority (DispatcherOp Unit))))
+  (background-priority (: Avalonia.Threading.DispatcherPriority.Background #:get))
+  ;; Runs a function that starts a Task on the UI thread, and waits for the
+  ;; Task. The clipboard takes no CancellationToken, so this cannot be
+  ;; cancelled.
+  (on-ui          (: Avalonia.Threading.Dispatcher.InvokeAsync
+                     (-> Dispatcher (-> (Task %a)) %a) #:async #:uncancellable))
+  (answered       (: System.Threading.Tasks.Task.FromResult (-> %a (Task %a))))
+  (top-level-of   (: Avalonia.Controls.TopLevel.GetTopLevel (-> Visual TopLevel)))
+  (clipboard-of   (: Avalonia.Controls.TopLevel.Clipboard (-> TopLevel IClipboard) #:get))
+  (clipboard-text (: Avalonia.Input.Platform.IClipboard.GetTextAsync (-> IClipboard (Task ClrString))))
+  (clipboard-text! (: Avalonia.Input.Platform.IClipboard.SetTextAsync (-> IClipboard string Task)))
+  (scroll-end!    (: Avalonia.Controls.ScrollViewer.ScrollToEnd (-> ScrollViewer void)))
+  (scroll-home!   (: Avalonia.Controls.ScrollViewer.ScrollToHome (-> ScrollViewer void)))
+  (bring-into-view! (: Avalonia.Controls.ControlExtensions.BringIntoView (-> Control void))))
 
 ;; ---------------------------------------------------------------------------
 ;; Properties
@@ -608,6 +634,7 @@
     ((PropDate _) (when-kind (= kind DateKind) (cast AvaloniaProperty date-property)))
     ;; Set by `set-prop!` itself.
     ((PropSource _) None)
+    ((PropPicture _) None)
     ((PropColumns _) None)
     ((PropRows _) None)))
 
@@ -706,6 +733,7 @@
     ((PropStart x y) (cast Object (Point. x y)))
     ((PropEnd x y) (cast Object (Point. x y)))
     ((PropData s) (text s))
+    ((PropPicture o) o)
     ((PropDockSide i)
      (cast Object (match i (0 DockEdge.Left) (1 DockEdge.Top) (2 DockEdge.Right) (_ DockEdge.Bottom))))))
 
@@ -724,7 +752,8 @@
     ((PropRadius _) 29) ((PropShortcut _) 30) ((PropTip _) 31) ((PropExpanded _) 32) ((PropDate _) 33)
     ((PropDockSide _) 34) ((PropClasses _) 35) ((PropChosenKey _) 36)
     ((PropLeft _) 37) ((PropTop _) 38) ((PropFill _) 39) ((PropStroke _) 40)
-    ((PropStrokeWidth _) 41) ((PropStart _ _) 42) ((PropEnd _ _) 43) ((PropData _) 44)))
+    ((PropStrokeWidth _) 41) ((PropStart _ _) 42) ((PropEnd _ _) 43) ((PropData _) 44)
+    ((PropPicture _) 45)))
 
 (: (-> Control AvaloniaProperty Object void))
 (defun (put! control property value)
@@ -740,6 +769,10 @@
 (: (-> Control Kind Prop void))
 (defun (set-prop! control kind p)
   (match (Tuple kind p)
+    ((Tuple ImageKind (PropPicture o))
+     (match (try (StreamBitmap. (cast Stream (MemoryStream. (cast (Array byte) o)))) #:catch (System.Exception))
+       ((Ok b) (put! control (cast AvaloniaProperty image-source-property) (cast Object b)))
+       ((Err _) (clear-value (cast AvaloniaObject control) (cast AvaloniaProperty image-source-property)))))
     ((Tuple ImageKind (PropSource path))
      (match (load-bitmap path)
        ((Some b) (put! control (cast AvaloniaProperty image-source-property) (cast Object b)))
@@ -781,6 +814,7 @@
   (defun (clear property) (clear-value (cast AvaloniaObject control) property))
   (match (Tuple kind p)
     ((Tuple ImageKind (PropSource _)) (clear (cast AvaloniaProperty image-source-property)))
+    ((Tuple ImageKind (PropPicture _)) (clear (cast AvaloniaProperty image-source-property)))
     ((Tuple GridKind (PropColumns _)) (grid-columns! (cast Grid control) (parse-columns "*")))
     ((Tuple GridKind (PropRows _)) (grid-rows! (cast Grid control) (parse-rows "*")))
     ((Tuple GridKind (PropSpacing _))
@@ -813,6 +847,18 @@
 ;; The app
 ;; ---------------------------------------------------------------------------
 
+;; What a command finds a running app by: the control of a view with a key,
+;; and the controls at the roots of its views.
+(type (: Running (Record (: find (-> string (Option Control)))
+                         (: roots (-> (List Control))))))
+
+;; The apps started, in order. A command looks for its control in each.
+(: running (MutableVec Running))
+(def running (mutablevec))
+
+;; Raised by a command that sends no message, and caught by `run-command`.
+(def no-message (cast Exception (InvalidOperation. "bjogui: a command that sends no message")))
+
 ;; What a component was drawn with: its value, its state, and its size.
 (type (: Painted (Record (: drawn-value Object) (: drawn-state Object)
                          (: drawn-width double) (: drawn-height double))))
@@ -1015,7 +1061,11 @@
 
 (: (-bjo-> (App %model %m) (Event %m) void))
 (defbjo (run-command app command)
-  (post! app (sync command)))
+  ;; A command that sends no message raises `no-message` once it has done
+  ;; its work, so that its fiber ends.
+  (match (try (sync command) #:catch (System.InvalidOperationException))
+    ((Ok msg) (post! app msg))
+    ((Err e) (unless (eq? (cast Object e) (cast Object no-message)) (raise e)))))
 
 (: (-bjo-> (App %model %m) (-> (Event %m)) void))
 (defbjo (run-sub app next-event)
@@ -1494,6 +1544,10 @@
                 (subscriptions subscriptions) (keys keys) (theme theme) (shown-theme "")
                 (root None) (patching #f) (stopped #f)
                 (home (current-scope)) (subs '()) (on-root on-root)))
+  (mutablevec-add! running (Running (find (fun (key) (keyed-control app key)))
+                                    (roots (fun () (match (.root app)
+                                                     ((Some live) (list (.control live)))
+                                                     (None '()))))))
   (step! app '())
   app)
 
@@ -1891,14 +1945,16 @@
                    (repaint! live)))
                (-> Object Object void)))))
 
-;; Sets Avalonia up with no screen, drawing with Skia, so that components can
+;; Sets Avalonia up with no screen, drawing with Skia, and with the theme
-;; be drawn and their pictures read in a test. Call it once, before
+;; `run-app` uses, so that controls are drawn and laid out as in a window: a
-;; `start-app`.
+;; test can draw components and read their pictures, and scroll a view.
+;; Call it once, before `start-app`.
 (: (-> void))
 (defun (start-headless!)
   (def options (HeadlessOptions.))
   (headless-drawing! options #f)
-  (ignore (setup-without-starting (use-headless (use-skia (configure (fun () (Application.)))) options))))
+  (ignore (setup-without-starting (use-headless (use-skia (configure (fun () (Application.)))) options)))
+  (.Add (app-styles current-app) (FluentTheme. (clr-default))))
 
 ;; ---------------------------------------------------------------------------
 ;; Native controls
@@ -1941,3 +1997,116 @@
   (if (ui-thread? ui-dispatcher)
       (unless (.patching app) (deliver!))
       (ignore (ui-post ui-dispatcher (fun () (deliver!) unit)))))
+
+;; ---------------------------------------------------------------------------
+;; Commands that act on the controls and the clipboard
+;; ---------------------------------------------------------------------------
+
+;; The control of the view with `key`, below the root.
+(: (-> (App %model %m) string (Option Control)))
+(defun (keyed-control app key)
+  (: (-> (Live %m) (Option Control)))
+  (defun (walk live)
+    (if (= (view-key (.view live)) (Some key))
+        (Some (.control live))
+        (loop (:for c (mutablevec->vec (.children live)))
+              (:when-let (Some found) (walk c))
+              (:finish #t (Some found))
+              => None)))
+  (match (.root app)
+    ((Some live) (walk live))
+    (None None)))
+
+;; A command that runs `act` on the UI thread and sends no message. It runs
+;; after the controls are laid out, so a control the same update made is
+;; there, and its size is known.
+(: (-> (-> void) (Event %m)))
+(defun (acting act)
+  (guard (fun ()
+           (ignore (ui-post-late ui-dispatcher (fun () (act) unit) background-priority))
+           (raise no-message))))
+
+;; A command that runs `act` on the control of the view with `key`, in the
+;; first app that has one. With none, it does nothing.
+(: (-> string (-> Control void) (Event %m)))
+(defun (on-keyed key act)
+  (acting (fun ()
+            (loop (:for r (mutablevec->vec running))
+                  (:when-let (Some c) ((.find r) key))
+                  (:finish #t (act c))
+                  => unit))))
+
+;; Gives the keyboard to the control of the view with `key`, as a click
+;; would. Sends nothing.
+;;
+;;     (Add (next (add-item m) (focus "new-item")))
+(: focus (-> string (Event %m)))
+(defun (focus key)
+  (on-keyed key (fun (c) (ignore (focus! (cast InputElement c) NavigationMethod.Unspecified KeyModifiers.None)))))
+
+;; Scrolls the `scroll` view with `key` to its end, such as a log after a
+;; line is added. Sends nothing.
+(: scroll-to-end (-> string (Event %m)))
+(defun (scroll-to-end key)
+  (on-keyed key (fun (c) (match (try (cast ScrollViewer c) #:catch (System.InvalidCastException))
+                           ((Ok v) (scroll-end! v))
+                           ((Err _) unit)))))
+
+;; Scrolls the `scroll` view with `key` to its start. Sends nothing.
+(: scroll-to-start (-> string (Event %m)))
+(defun (scroll-to-start key)
+  (on-keyed key (fun (c) (match (try (cast ScrollViewer c) #:catch (System.InvalidCastException))
+                           ((Ok v) (scroll-home! v))
+                           ((Err _) unit)))))
+
+;; Scrolls the views around the view with `key` until it is seen. Sends
+;; nothing.
+(: scroll-into-view (-> string (Event %m)))
+(defun (scroll-into-view key)
+  (on-keyed key bring-into-view!))
+
+;; The clipboard of the window an app is shown in, if one is.
+(: (-> (Option IClipboard)))
+(defun (clipboard)
+  (: (-> Control (Option IClipboard)))
+  (defun (of c)
+    (def top (cast Object (top-level-of (cast Visual c))))
+    (if (eq? top (clr-default))
+        None
+        (begin
+          (def board (cast Object (clipboard-of (cast TopLevel top))))
+          (if (eq? board (clr-default)) None (Some (cast IClipboard board))))))
+  (: (-> Running (Option IClipboard)))
+  (defun (in r)
+    (loop (:for c ((.roots r)))
+          (:when-let (Some board) (of c))
+          (:finish #t (Some board))
+          => None))
+  (loop (:for r (mutablevec->vec running))
+        (:when-let (Some board) (in r))
+        (:finish #t (Some board))
+        => None))
+
+;; Puts `text` on the clipboard. Sends nothing.
+(: copy-text (-> string (Event %m)))
+(defun (copy-text text)
+  (acting (fun ()
+            (match (clipboard)
+              ((Some board) (ignore (clipboard-text! board text)))
+              (None unit)))))
+
+(: (-bjo-> (Option string)))
+(defbjo (read-clipboard)
+  (def text (on-ui ui-dispatcher
+                   (fun () (match (clipboard)
+                             ((Some board) (clipboard-text board))
+                             (None (answered (: (clr-default) ClrString)))))))
+  (if (eq? (cast Object text) (clr-default)) None (Some (.ToString text))))
+
+;; Reads the clipboard, and sends `(on-text (Some text))`, or `(on-text None)`
+;; when it holds no text or there is no window.
+(: paste-text (-> (-> (Option string) %m) (Event %m)))
+(defun (paste-text on-text)
+  (guard (fun ()
+           (wrap (promise-join (bjo (read-clipboard)))
+                 (fun (r) (on-text (match r ((Ok t) t) ((Err _) None))))))))

src/view.bjo

@@ -22,7 +22,7 @@
   View Kind Prop On
 
   ;; Constructors.
-  text button text-input text-area checkbox slider progress-bar dropdown image
+  text button text-input text-area checkbox slider progress-bar dropdown image image-data
   list-box tabs tab
   menu-bar submenu menu-item menu-separator
   toggle-switch radio number-input date-picker auto-complete expander
@@ -115,7 +115,8 @@
                      (: PropStrokeWidth double)
                      (: PropStart double double)    ; the ends of a line
                      (: PropEnd double double)
-                     (: PropData string))))         ; a path, as "M 0 0 L 10 10 Z"
+                     (: PropData string)            ; a path, as "M 0 0 L 10 10 Z"
+                     (: PropPicture Object))))      ; an image's bytes, as an (Array byte)
 
 ;; Where the pointer is on a component, from its top left corner, and how.
 ;; `button` is "left", "right" or "middle" for a press and a release, and ""
@@ -433,6 +434,15 @@
 (defun (image path #:width 0.0 #:height 0.0 #:margin 0.0)
   (leaf ImageKind (with-layout [(PropSource path)] width height margin 0.0) []))
 
+;; The picture in `bytes`, the contents of a PNG, JPEG, BMP or other file
+;; that Avalonia reads, such as an image made by the program or downloaded.
+;; Bytes that cannot be read show nothing. The picture is read again only
+;; when the view is given another array, so keep the array in the model and
+;; do not make it anew for each view.
+(: (-> (Array byte) (#:width double) (#:height double) (#:margin double) (View %m)))
+(defun (image-data bytes #:width 0.0 #:height 0.0 #:margin 0.0)
+  (leaf ImageKind (with-layout [(PropPicture (cast Object bytes))] width height margin 0.0) []))
+
 ;; A list of views to choose one of, with the one at `selected` chosen, or
 ;; none for -1. A choice sends `(on-select index)`. Give the items keys if
 ;; the list can change order.

tests/commands.bjo

@@ -0,0 +1,125 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+;; bjogui/tests/commands.bjo — commands that act on the controls and the
+;; clipboard, and pictures from memory.
+;;
+;;     bjo run tests/commands.bjo
+;;
+;; Avalonia runs with no screen, and the app is shown in a window of it, so
+;; that a control can take the keyboard, a scroll view is laid out, and there
+;; is a clipboard.
+
+(import (std prelude))
+(import (std simpletest))
+(import (std interop))
+(import (bjogui view))
+(import (bjogui app))
+
+(import/class
+  (Object        (: System.Object))
+  (Control       (: Avalonia.Controls.Control))
+  (Window        (: Avalonia.Controls.Window (-> Window)))
+  (ContentControl (: Avalonia.Controls.ContentControl))
+  (Layoutable    (: Avalonia.Layout.Layoutable))
+  (InputElement  (: Avalonia.Input.InputElement))
+  (ScrollViewer  (: Avalonia.Controls.ScrollViewer))
+  (Image         (: Avalonia.Controls.Image))
+  (IImage        (: Avalonia.Media.IImage))
+  (Vector        (: Avalonia.Vector)))
+
+(import/extern
+  (content!      (: Avalonia.Controls.ContentControl.Content (-> ContentControl Object void) #:set))
+  (show!         (: Avalonia.Controls.Window.Show (-> Window void)))
+  (width!        (: Avalonia.Layout.Layoutable.Width (-> Layoutable double void) #:set))
+  (height!       (: Avalonia.Layout.Layoutable.Height (-> Layoutable double void) #:set))
+  (update-layout! (: Avalonia.Layout.Layoutable.UpdateLayout (-> Layoutable void)))
+  (focused?      (: Avalonia.Input.InputElement.IsFocused (-> InputElement bool) #:get))
+  (offset-of     (: Avalonia.Controls.ScrollViewer.Offset (-> ScrollViewer Vector) #:get))
+  (vector-y      (: Avalonia.Vector.Y (-> Vector double) #:get))
+  (source-of     (: Avalonia.Controls.Image.Source (-> Image IImage) #:get))
+  (sleep-ms      (: System.Threading.Thread.Sleep (-> int void) #:blocking)))
+
+(type (: Msg (Union FocusName FocusOther End Start Into (: Copy string) Paste (: Pasted (Option string)))))
+(type (: Model (Record (: messages int) (: pasted (Option string)))))
+
+(: (-> Msg Model (Tuple Model (List (Event Msg)))))
+(defun (gui-update msg m0)
+  (def m (record-set m0 (messages (+ (.messages m0) 1))))
+  (match msg
+    (FocusName (next m (focus "name")))
+    (FocusOther (next m (focus "other")))
+    (End (next m (scroll-to-end "log")))
+    (Start (next m (scroll-to-start "log")))
+    (Into (next m (scroll-into-view "line 25")))
+    ((Copy s) (next m (copy-text s)))
+    (Paste (next m (paste-text Pasted)))
+    ((Pasted s) (next (record-set m (pasted s))))))
+
+(def picture (file-read-bytes "docs/mixer.png"))
+
+(: (-> Model (View Msg)))
+(defun (view m)
+  (column
+    (keyed "name" (text-input "" (fun (s) Start)))                                    ; 0
+    (keyed "other" (text-input "" (fun (s) Start)))                                   ; 1
+    (keyed "log" (scroll (apply column (vec->array (vec-map (fun (i) (keyed #"line ${i}" (text #"line ${i}")))
+                                                            (->vec (range 0 40)))))
+                         #:height 60.0))                                              ; 2
+    (image-data picture #:width 46.0 #:height 30.0)                                   ; 3
+    (image-data (: (make-array 3 #:fill (cast byte 7)) (Array byte)))))               ; 4
+
+(defun (main)
+  (start-headless!)
+  (def w (Window.))
+  (width! (cast Layoutable w) 300.0)
+  (height! (cast Layoutable w) 400.0)
+  (def app (start-app (Model (messages 0) (pasted None)) gui-update view
+                      (fun (c) (content! (cast ContentControl w) (cast Object c)))))
+  (show! w)
+  (defun (ctl path) (app-control-at app path))
+  (defun (settle) (app-run-pending! app) (update-layout! (cast Layoutable w)))
+  (: (-> (-> bool) bool))
+  (defun (wait-for done?)
+    (let go ((tries 0))
+      (settle)
+      (cond ((done?) #t)
+            ((> tries 200) #f)
+            (else (sleep-ms 10) (go (+ tries 1))))))
+  (defun (log-offset) (vector-y (offset-of (cast ScrollViewer (ctl '(2))))))
+  (settle)
+
+  ;; --- focus ------------------------------------------------------------------------
+  (app-dispatch! app FocusName)
+  (expect "focus gives the keyboard to the keyed control"
+          (wait-for (fun () (focused? (cast InputElement (ctl '(0)))))) #t)
+  (app-dispatch! app FocusOther)
+  (expect "and to another" (wait-for (fun () (focused? (cast InputElement (ctl '(1)))))) #t)
+  (expect "which the first has no more" (focused? (cast InputElement (ctl '(0)))) #f)
+
+  ;; --- scrolling --------------------------------------------------------------------
+  (expect "the log starts at the top" (log-offset) 0.0)
+  (app-dispatch! app End)
+  (expect "scroll-to-end" (wait-for (fun () (> (log-offset) 500.0))) #t)
+  (app-dispatch! app Start)
+  (expect "scroll-to-start" (wait-for (fun () (= (log-offset) 0.0))) #t)
+  (app-dispatch! app Into)
+  (expect "scroll-into-view" (wait-for (fun () (> (log-offset) 300.0))) #t)
+
+  ;; --- the clipboard -----------------------------------------------------------------
+  (app-dispatch! app (Copy "copied"))
+  (app-dispatch! app Paste)
+  (expect "a copy is pasted" (wait-for (fun () (= (.pasted (app-model app)) (Some "copied")))) #t)
+
+  ;; --- commands that send nothing --------------------------------------------------
+  (sleep-ms 50)
+  (settle)
+  (expect "send nothing: only the messages dispatched, and Pasted" (.messages (app-model app)) 8)
+
+  ;; --- pictures from memory ---------------------------------------------------------
+  (expect "a picture from bytes" (eq? (cast Object (source-of (cast Image (ctl '(3))))) (clr-default)) #f)
+  (expect "bytes that are no picture show nothing"
+          (eq? (cast Object (source-of (cast Image (ctl '(4))))) (clr-default)) #t)
+
+  (println "bjogui commands ok"))