Review fix pass 1 on the task 7 work; four findings, all closed.
1. The Qt demo's region sat across the middle of the window, which is exactly
where its own scripted input check pans: after the check's box zoom the press
opened DragMode::MoveRegion, the x range never moved, and the check printed
'input check pan FAIL' -- under an exit 0, because the verdict was printed and
not returned. The region now rides the left sixth (as the GLFW demo's does),
both checks pass, and the verdict is wired to the exit status. The same audit
found two more printed-only verdicts -- the GTK demo's scripted-resize layout
check and its screenshot write (and Qt's) -- now wired too. What stays
printed-only is the screenshot line of the GLFW host and the ImGui widget,
where the dump happens inside the adapter's frame loop.
2. A follow-ing link group was invisible to the input layer: a member's own axis
must be XFollow::Off (link_x() refuses a Live member), so Controller's
x_zoom_anchor() extrapolated a coordinate from the pointer instead of using
the live edge and a wheel over a row's axis strip walked the window back by
19% of its width (behind 0.000000 -> 0.285809 s). The group now publishes its
own edge to every member (Axis::live_owner + Plot::set_x_live_owner, written
by Figure::push_link, cleared when the group stops following or the row
unlinks), and x_zoom_anchor() reads it. Public-header addition, called out.
Measured after: behind 0.012992 s and the window's right edge bit-identical to
the edge the group published at the gesture.
3. The multiplot summary printed x_link_count() -- a number of groups -- under
'rows in it'. It now reports the members and the group count separately, and
every row line carries its own group id.
4. Host::controller_at() promised to clamp a pixel in a row gap to the nearest
row and only clamped below the last one, so a gap pixel went to row 0. It now
selects by distance, and tests/test_glfw_host.cpp pins it with a 40 px gap --
the first coverage of the host's figure routing, which needs no window.
New cases: tests/test_controller.cpp x2 (the anchor and the hint's lifecycle),
tests/test_glfw_host.cpp x3 (routing, the gap, the single-plot fallback): 229
cases, 0 failed, ASan clean. All five demos exit 0, the three self-checking
modes exit 0, and the amended assertions were confirmed failing against the
pre-fix behaviour.
Zeroing an unusable wheel amount turned it into a zero-notch zoom: the factor was
exactly one, the range did not change, but the zoom body still ran through
set_x_range/set_y_range, which clear auto_scale unconditionally. One garbage wheel
therefore disarmed auto-fit on every axis. on_wheel now rejects an unusable amount
before the event can mutate anything, keeping the position fallback.
The tests that should have caught it are strengthened: the wheel case now asserts
auto scale is still armed (it was passing either way), and the invalid-position
case checks a pan measured from the last real position with the drag alive, rather
than a range nothing could have moved.
The widget drew a region derived from the child's content rect alone, so a child
the hosting window cut off cleared and painted over the host's pixels; it also
scaled ImGui's (-FLT_MAX, -FLT_MAX) no-pointer sentinel and differenced it against
the last real position, turning a drag out of the window into a ~1e35 pan, and it
forgot the host's button levels across a re-bind, handing the next plot a press
that never happened.
The region is now the content rect intersected with the child's clip rect (a
no-op when nothing clips it), an invalid position is no position update, and the
button levels survive a re-bind. The controller sanitises non-finite coordinates
and deltas for any host, and the widget's input translation now has a committed
test on the headless EGL context.
Every pixel-to-data conversion in the controller now maps through the
same rectangle Plot::x_transform/y_transform are built from:
- pan() derives the scale from layout().axes.w/.h, so a drag moves the
grabbed data point by exactly the drag distance (the viewport model
stranded it behind the pointer by the label-strip fraction).
- apply_box_zoom() clamps the selection to layout().axes and sets each
range from the transforms (x_transform().to_data_x(l/r), y_transform()
.to_data_y(bottom/top)); the selection's bottom edge is the y minimum.
- end_drag() takes the release event and refreshes the selection from its
coordinates before applying, so a host that reports only press and
release still frames the box instead of degrading it to a click.
- axis_zoom() uses a per-pixel sensitivity (200 px == one decade) rather
than reusing the wheel's per-notch constant, so a pixel drag is no
longer treated as a wheel notch.
Tests now assert the grab-and-drag invariant through the transform (the
old pixel-fraction assertions certified the viewport defect), add a
press+release-only box zoom, and pin the axis-zoom magnitude.
Martino Ferrari