Merge pull request #285 from Ark0N/fix/lineage-line-visibility

fix(ui): make session lineage lines read as arcs, not straight threads

src/web/public/constants.js

@@ -201,24 +201,43 @@ function computeTabScrollLeft(input) {
 // spawned (a worker started through the codeman agent skill, which passes its own
 // id as parentSessionId). Pure: the caller measures and appends, this decides.
 //
-// Two shapes, because both endpoints live in ONE horizontal strip and the subagent
-// shape (tab-bottom → window-top) has nothing to aim at:
-//   - same row: a shallow U-bridge HANGING BELOW the strip, so it reads as a
-//     bracket joining two tabs rather than as a line crossing them. The dip grows
-//     with horizontal distance and with `depth` (the child's index among its
-//     siblings), so several children of one parent nest instead of overprinting.
-//   - different rows (desktop `tabs-two-rows` / `tabs-auto-wrap`): the vertical
-//     bezier the subagent lines already use, parent edge → child edge.
+// ONE shape, because both endpoints live in the same horizontal strip and the subagent
+// shape (tab-bottom → window-top) has nothing to aim at: a U-bridge HANGING BELOW the
+// strip, from the parent's bottom edge to the child's bottom edge, so it reads as a
+// bracket joining two tabs rather than as a line crossing them. The dip grows with
+// horizontal distance and with `depth` (the child's index among its siblings), so
+// several children of one parent nest instead of overprinting.
+//
+// ⚠ A WRAPPED STRIP USED TO GET ITS OWN SHAPE, AND THAT SHAPE WAS THE BUG. When the
+// desktop strip wraps (`tabs-two-rows` / `tabs-auto-wrap`) a parent on row 1 and its
+// child on row 2 are ~4px apart vertically, so the old parent-bottom → child-TOP bezier
+// had a 4px span to work with and drew a flat horizontal line inside the row gap
+// (reported as "they connect already, but the lines are straight and not easy visible"),
+// and three siblings drew three of them on top of each other. Aiming BOTH ends at the
+// tab BOTTOMS and putting the control points below the LOWER row gives the wrapped case
+// the same bracket as the flat case: it leaves the parent downward, crosses the lower
+// row once, and comes back up under the child. Same formula, no branch.
 //
 // Returns null when the edge must not be drawn: a missing/degenerate rect, or an
 // endpoint scrolled outside the strip. `.session-tabs` is `overflow-x: auto`, so a
 // scrolled-out tab still HAS a rect — one lying over the logo or the header
 // buttons. Skipping is honest; clamping would point at a tab that isn't there.
+// ⚠ THE DIP IS WHAT MAKES THE ARC AN ARC, and the first shipped numbers were tuned
+// against two tabs sitting side by side. A worker the agent skill starts is appended
+// to the END of the strip, so the real span between a lead and its worker is 800-1500px,
+// not 200, and a 44px cap over 1300px of span is a 33px sag, i.e. a line that reads as
+// STRAIGHT and crosses the terminal instead of bracketing under the strip. The dip now
+// keeps growing with the span (0.085/px, ~3x steeper against the old cap) so the bracket
+// survives the distance the feature is actually used at. The ceiling is what keeps a
+// full-width pair out of the terminal's fourth line: 104 + the sibling step lands the
+// deepest sag around y=140 on a 1080 screen, the same proportion two adjacent tabs get.
 const LINEAGE_DIP_BASE_PX = 14;
-const LINEAGE_DIP_PER_PX = 0.06;
-const LINEAGE_DIP_MIN_PX = 16;
-const LINEAGE_DIP_MAX_PX = 44;
-const LINEAGE_SIBLING_STEP_PX = 6;
+const LINEAGE_DIP_PER_PX = 0.085;
+const LINEAGE_DIP_MIN_PX = 22;
+const LINEAGE_DIP_MAX_PX = 104;
+// Siblings nest by this much. Widened with the stroke: at 2.5px plus its glow, arcs 6px
+// apart bled into one thick band instead of reading as three separate lines.
+const LINEAGE_SIBLING_STEP_PX = 8;
 const LINEAGE_STRIP_TOLERANCE_PX = 4;
 
 function computeLineagePath(input) {
@@ -250,29 +269,20 @@ function computeLineagePath(input) {
   const cBottom = cTop + ch;
   const sameRow = Math.abs(pTop + ph / 2 - (cTop + ch / 2)) <= Math.min(ph, ch) / 2;
 
-  let d;
-  let endX;
-  let endY;
-  if (sameRow) {
-    const y0 = Math.max(pBottom, cBottom);
-    const span = Math.abs(cx - px);
-    const dip =
-      Math.min(LINEAGE_DIP_MAX_PX, Math.max(LINEAGE_DIP_MIN_PX, LINEAGE_DIP_BASE_PX + span * LINEAGE_DIP_PER_PX)) +
-      depth * LINEAGE_SIBLING_STEP_PX;
-    const yc = y0 + dip;
-    d = `M ${r1(px)} ${r1(y0)} C ${r1(px)} ${r1(yc)}, ${r1(cx)} ${r1(yc)}, ${r1(cx)} ${r1(y0)}`;
-    endX = cx;
-    endY = y0;
-  } else {
-    const childBelow = cTop + ch / 2 > pTop + ph / 2;
-    const y1 = childBelow ? pBottom : pTop;
-    const y2 = childBelow ? cTop : cBottom;
-    const mid = (y1 + y2) / 2;
-    d = `M ${r1(px)} ${r1(y1)} C ${r1(px)} ${r1(mid)}, ${r1(cx)} ${r1(mid)}, ${r1(cx)} ${r1(y2)}`;
-    endX = cx;
-    endY = y2;
-  }
-  return { d, endX, endY, sameRow };
+  // Both ends anchor on the tab BOTTOM, and the control points hang below whichever
+  // row is lower, so one formula covers a flat strip and a wrapped one.
+  const span = Math.abs(cx - px);
+  const rowDrop = Math.abs(cBottom - pBottom);
+  // ⚠ A wrapped pair needs the dip measured from the LOWER row, or the bracket would
+  // only reach the row gap again. Adding the row offset also keeps the curve clear of
+  // the row it crosses instead of grazing its bottom edge.
+  const dip =
+    Math.min(LINEAGE_DIP_MAX_PX, Math.max(LINEAGE_DIP_MIN_PX, LINEAGE_DIP_BASE_PX + span * LINEAGE_DIP_PER_PX)) +
+    depth * LINEAGE_SIBLING_STEP_PX +
+    rowDrop;
+  const yc = Math.max(pBottom, cBottom) + dip;
+  const d = `M ${r1(px)} ${r1(pBottom)} C ${r1(px)} ${r1(yc)}, ${r1(cx)} ${r1(yc)}, ${r1(cx)} ${r1(cBottom)}`;
+  return { d, endX: cx, endY: cBottom, sameRow };
 }
 
 // One decimal is plenty for a screen-space path and keeps the `d` string short.

src/web/public/session-lineage.js

@@ -148,7 +148,9 @@ Object.assign(CodemanApp.prototype, {
       const dot = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
       dot.setAttribute('cx', String(geom.endX));
       dot.setAttribute('cy', String(geom.endY));
-      dot.setAttribute('r', '3');
+      // Resting radius; `lineage-dot-pulse` breathes it 3.5 → 4.5 while the child
+      // works, so the two have to be changed together.
+      dot.setAttribute('r', '3.5');
       dot.setAttribute('class', 'lineage-line-dot' + working);
       dot.setAttribute('data-child-tab', edge.childId);
       svg.appendChild(dot);

src/web/public/styles.css

@@ -9257,31 +9257,46 @@ kbd {
    light skins included). Do not add a per-skin `.lineage-line` override inside the
    html:not([data-skin="og"]) block: a bare class rule in there resolves to (0,2,1)
    and would outrank this one from a surprising place. */
+/* ⚠ QUIETER THAN THE SUBAGENT LINES, NOT INVISIBLE. The first cut ran 2px at 0.55
+   with a single 5px glow, which reads on a design mock and disappears on a real
+   1080p desktop: a faint thread over terminal text, exactly what it is drawn on
+   top of. The weight stays UNDER the subagent lines' 3px so the two layers still
+   separate, and the second, wider glow is what buys the contrast instead: it lifts
+   the line off the terminal without thickening it. Dashes scale with the stroke
+   (4 4 on a 2.5px line reads as a dotted smudge), and `lineage-flow` marches by
+   exactly two dash cycles, so it has to move with them. */
 .connection-line.lineage-line {
   stroke: var(--session-purple, #a98fe0);
-  stroke-width: 2;
-  stroke-dasharray: 4 4;
+  stroke-width: 2.5;
+  stroke-dasharray: 5 5;
   stroke-linecap: round;
-  opacity: 0.55;
-  filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.55)) drop-shadow(0 0 5px var(--session-purple, #a98fe0));
+  opacity: 0.72;
+  filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.7)) drop-shadow(0 0 5px var(--session-purple, #a98fe0))
+    drop-shadow(0 0 11px var(--session-purple, #a98fe0));
+}
+
+/* ⚠ OUTSIDE the reduced-motion block below on purpose. A working child is the case
+   the line exists to signal, and pairing the brightness with the marching dashes
+   left every worker's arc at the resting 0.72 for anyone who turns motion off. */
+.connection-line.lineage-line--working {
+  opacity: 0.95;
 }
 
 .connection-line.lineage-line:hover {
-  opacity: 0.9;
-  stroke-width: 2.5;
+  opacity: 1;
+  stroke-width: 3;
 }
 
 .lineage-line-dot {
   fill: var(--session-purple, #a98fe0);
-  opacity: 0.7;
-  filter: drop-shadow(0 0 4px var(--session-purple, #a98fe0));
+  opacity: 0.85;
+  filter: drop-shadow(0 0 4px var(--session-purple, #a98fe0)) drop-shadow(0 0 9px var(--session-purple, #a98fe0));
 }
 
 /* The child end marches while that worker is actually working, so the line
    itself carries the signal. Motion is opt-out-able at the OS level. */
 @media (prefers-reduced-motion: no-preference) {
   .connection-line.lineage-line--working {
-    opacity: 0.85;
     animation: lineage-flow 1.1s linear infinite;
   }
 
@@ -9291,20 +9306,24 @@ kbd {
   }
 }
 
+/* Two full dash cycles, so the march loops seamlessly. Tied to `stroke-dasharray`
+   above: at `5 5` the cycle is 10px, so this is -20 rather than the -16 that
+   matched the old `4 4`. Leaving them out of step makes the dashes jump once per
+   iteration. */
 @keyframes lineage-flow {
   to {
-    stroke-dashoffset: -16;
+    stroke-dashoffset: -20;
   }
 }
 
 @keyframes lineage-dot-pulse {
   0%, 100% {
-    opacity: 0.6;
-    r: 3;
+    opacity: 0.75;
+    r: 3.5;
   }
   50% {
     opacity: 1;
-    r: 4;
+    r: 4.5;
   }
 }