Implements the second pillar of #574: keyboard-driven selection on the
diagram canvas.
Tab / Shift+Tab select the next / previous item on the current
diagram, cycling through items() (z-order) and wrapping at either
end. If nothing is selected, Tab selects the first item and
Shift+Tab the last. Skipped while a text item has focus, for the
same reason arrow-key movement already guards on !focusItem().
Candidates use the same "what counts as a real selectable diagram
item" filter (QetGraphicsItem / DiagramTextItem / Conductor) already
established by Diagram::invertSelection(), so the cycling order
always matches what a user could reach by clicking.
Getting Tab to actually reach the scene needed two separate fixes,
each independently discovered by empirical testing rather than
assumption:
- QWidget (DiagramView) intercepts Tab/Backtab for widget focus-chain
traversal before generating a key event at all. Overriding
DiagramView::focusNextPrevChild() to return false disables that.
- QGraphicsScene (Diagram) has its own, separate item-focus-chain
traversal, checked before keyPressEvent() is ever reached. The
obvious fix -- overriding Diagram::focusNextPrevChild() the same
way -- silently does nothing on Qt 5, because
QGraphicsScene::focusNextPrevChild() only becomes virtual in Qt 6
(guarded by the QT6_VIRTUAL macro); a compile error surfaced this
immediately when attempted directly, rather than shipping a fix
that worked on Qt 6 and silently no-opped on Qt 5. Intercepting
QEvent::KeyPress in Diagram::event() instead is virtual on every Qt
version and sidesteps the scene's internal traversal entirely.
Also adds Diagram::selectAllConductors() / selectAllTextFields(),
wired up as two new actions in the existing select_all /
select_nothing / select_invert action group in
qetdiagrameditor.cpp, so they appear in the Edit menu and go through
the same QAction -> data() -> selectGroupTriggered() dispatch as the
existing selection commands.
Verified end-to-end in a real running session (Xvfb + xdotool) with
a multi-transistor schematic: Tab/Shift+Tab correctly move a single
selection forward/backward through elements and text fields
(confirmed via the properties panel updating to each new item and
the visual selection box moving on canvas); Tab/Shift+Tab from no
selection correctly select the first/last item; "Select all
conductors" and "Select all text fields" each correctly select every
matching item and deselect everything else.
See discussion #574.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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