Repaint the key line when a drag crosses into a selection

skills/leaf/assets/runtime/composing/surface.js

@@ -382,6 +382,16 @@ export function createSelectionSurface({
     fabInputTakingFocus = false;
   });
   let primaryPointerPressed = false;
+  // Whether the page's own words stood selected when the key line was last painted for
+  // this press. The bar waits for the release; the Escape rung cannot, because from the
+  // first glyph a drag takes, Escape clears the selection rather than letting go of the
+  // control the reader is standing on, and until now nothing repainted the line inside a
+  // press — the word only became true when the frame the press itself scheduled happened
+  // to land after the drag had moved, and stayed a lie for a whole heartbeat when it
+  // landed before. Only the crossing is painted: a drag growing a selection that already
+  // stands says the same word, and repainting the chrome on every move of a drag would
+  // put a whole `paintHere` inside every frame of one.
+  let selectionStood = false;
   const rememberPointerSelection = () => {
     const selection = pageSelection();
     const anchor = selection ? selectionAnchor(selection) : null;
@@ -399,6 +409,9 @@ export function createSelectionSurface({
       selectionDragged = false;
       selectionRangeDuringPress = null;
       selectionPressPoint = pointerSelecting ? { x: ev.clientX, y: ev.clientY } : null;
+      // Read here, ahead of the browser's own collapse, so the first crossing this press
+      // makes is measured against what the line already says rather than against nothing.
+      selectionStood = Boolean(pageSelection());
       const selection = pointerSelecting ? pageSelection() : null;
       if (selection) {
         const range = pageRange(selection);
@@ -449,6 +462,11 @@ export function createSelectionSurface({
     if (primaryPointerPressed) {
       selectionChangedDuringPress = true;
       rememberPointerSelection();
+      const stands = Boolean(pageSelection());
+      if (stands !== selectionStood) {
+        selectionStood = stands;
+        paintHere();
+      }
       return;
     }
     if (

tests/render_harness.py

@@ -1455,9 +1455,17 @@ def resized(page, width, height):
     page.evaluate(ONE_FRAME)
 
 
-def hold_selection(page, start, end, steps=8):
+def hold_selection(page, start, end, steps=8, frame_the_press=False):
     """Drag a selection without releasing, pressing on a whole pixel.
 
+    `frame_the_press` lets the frame the press itself schedules land before the drag
+    begins, which is the ordering a loaded machine gives every drag and an idle one
+    gives almost none. Without it a surface repainted inside the press is read as
+    following the drag whenever the round trips outrun the frame, and as stale
+    whenever they do not — a coin toss written as an assertion. State it wherever the
+    read is of something the press repaints, so the drag is the only thing the read
+    can be about.
+
     A fractional start point loses the selection outright wherever it and its own
     floor fall either side of a glyph's caret boundary: the drag runs, the mouseup
     lands, and `getSelection()` comes back empty. It reads as the widget under the
@@ -1472,6 +1480,8 @@ def hold_selection(page, start, end, steps=8):
     moves the selection a character."""
     page.mouse.move(math.floor(start[0]), math.floor(start[1]))
     page.mouse.down()
+    if frame_the_press:
+        page.evaluate(RENDERED)
     page.mouse.move(end[0], end[1], steps=steps)
 
 

tests/test_render_navigation.py

@@ -3840,11 +3840,18 @@ def test_a_label_press_keeps_the_controls_keyboard_standing(browser, serve):
     expect(control).to_be_focused()
     expect(page.locator("#frame-question-decision[data-lf-decision]")).to_have_count(1)
 
+    # The press has its own frame and the drag comes after it, so the line's only route
+    # to the word is the selection the drag makes: the reader is taking words out of a
+    # label, and from the first glyph Escape clears that selection rather than letting
+    # go of the control. Framed the other way round the press's frame painted the line
+    # after the drag had already run, and the word arrived whether or not anything
+    # followed the selection.
     hold_selection(
         page,
         (bounds["x"] + 2, middle[1]),
         (bounds["x"] + bounds["width"] - 2, middle[1]),
         steps=10,
+        frame_the_press=True,
     )
     assert "after state" in page.evaluate("() => getSelection().toString()")
     assert "unselect" in key_line(page)