[boyan01]

Summary

Stacked on #550. The right-click menu ignored where you clicked, always showed the same items, and stayed open on scroll and Escape. The menu now lives in MarkdownSelectionHost, so MarkdownWidget and MixinSelectionArea behave the same.

 on(secondary pointer down)
+  if contextMenuBuilder == null → return            # no menu, selection untouched
+  if pointer is inside the selection → keep it
+  else if macOS / iOS → select the word under the pointer
+  else → clear the selection
   show menu
-    Copy                                             # even with nothing selected
+    Copy        if text is selected
+    Copy link   if the pointer is over a link       # from the block model, incl. emphasis / table cells
     Select all
     Copy all    if enabled
-    Clear selection
+  hide on Escape, scroll (ancestor or descendant), any click, or after a button

Breaking API:

-typedef MarkdownContextMenuBuilder = Widget Function(
-  BuildContext, MarkdownSelectionController, List<ContextMenuButtonItem>, TextSelectionToolbarAnchors);
+typedef MarkdownContextMenuBuilder = Widget Function(BuildContext, MarkdownContextMenuDetails);
+// details: anchors, buttonItems (defaults, each closes the menu), selectionController, linkDestination, hide()
-contextMenuBuilder: null            # meant "use MarkdownContextMenu"
+contextMenuBuilder: defaultMarkdownContextMenuBuilder   # null now means no menu
-MarkdownContextMenu                 # removed
 showCopyAllInContextMenu            # @Deprecated: filter details.buttonItems instead

flutter-app's contextMenuBuilder: (_, _, _, _) => SizedBox.shrink() becomes contextMenuBuilder: null. Version and CHANGELOG are left for the release (0.4.0).

Evidence

Before: the new markdown_context_menu_test.dart (the 6 behavior tests) against the old lib/, 5 failed:

macOS right click selects the word under the pointer   Expected: 'brave'  Actual: ''
Windows right click outside the selection clears it    Expected: ''       Actual: 'brave'
applies inside MixinSelectionArea                      Expected: 'brave'  Actual: ''
Escape closes the menu and keeps the selection         menu still shown
scrolling closes the menu                              menu still shown

After: 13/13, including the new API: Copy writes the selection, Copy link writes the destination for a plain link, an emphasized link, and a link in a table cell, no Copy link on plain text, a null builder shows nothing and keeps the selection, a custom builder receives the details and closes the menu with details.hide.

Package flutter test on macOS: 280 passed. flutter analyze (package and example): no issues. Checked by hand in the macOS example: right click word selection (incl. Chinese), Copy link on plain / emphasized / table links, closing on Escape, scroll, click, and button press, and the custom item. Windows and Linux not checked in the GUI.

Merge Danger

Door: two-way

Blast Radius: consumers

Callers that pass a 4-argument contextMenuBuilder or use MarkdownContextMenu stop compiling. Callers that pass contextMenuBuilder: null to get the default menu now get no menu. Right click on Windows/Linux outside the selection now clears it.