feat(analysis): breathing-light fold cue + edge-jump buttons

src/renderer/css/styles.css

@@ -1120,6 +1120,61 @@ body.ana-ruler-dragging .ana-ruler-view {
   background: rgba(130, 150, 210, 0.55);
 }
 
+/* Floating "jump to this expanded run's top/bottom edge" buttons. They sit at
+   the right edge, vertically centred just left of the minimap, and only appear
+   while you browse inside an expanded fold whose edge is scrolled off-screen. */
+.ana-fold-edges {
+  position: absolute;
+  right: 44px;
+  top: 50%;
+  z-index: 6;
+  display: flex;
+  flex-direction: column;
+  gap: 7px;
+  opacity: 0;
+  pointer-events: none;
+  transform: translateY(-50%) translateX(6px);
+  transition: opacity 0.18s ease, transform 0.18s ease;
+}
+.ana-fold-edges.show {
+  opacity: 1;
+  pointer-events: auto;
+  transform: translateY(-50%) translateX(0);
+}
+.ana-fold-edge {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 30px;
+  height: 30px;
+  padding: 0;
+  border: 1px solid var(--border);
+  border-radius: 9px;
+  background: color-mix(in srgb, var(--panel) 86%, transparent);
+  color: var(--accent);
+  cursor: pointer;
+  box-shadow: 0 2px 9px rgba(0, 0, 0, 0.28);
+  -webkit-backdrop-filter: blur(4px);
+  backdrop-filter: blur(4px);
+  transition: background 0.15s ease, border-color 0.15s ease, transform 0.08s ease;
+}
+.ana-fold-edge:hover {
+  background: color-mix(in srgb, var(--accent) 20%, var(--panel));
+  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
+}
+.ana-fold-edge:active {
+  transform: scale(0.9);
+}
+.ana-fold-edge:disabled {
+  opacity: 0.32;
+  cursor: default;
+  box-shadow: none;
+}
+.ana-fold-edge:disabled:hover {
+  background: color-mix(in srgb, var(--panel) 86%, transparent);
+  border-color: var(--border);
+}
+
 /* ---------- In-viewer search (Ctrl+F) ---------- */
 .ana-find {
   position: absolute;
@@ -1412,23 +1467,49 @@ body.ana-ruler-dragging .ana-ruler-view {
   background: color-mix(in srgb, var(--accent) 14%, transparent);
 }
 
-/* Pulse a just-expanded run's background once, slowly, to point it out. */
-@keyframes anaFoldFlash {
+/* Breathing-light cue: a single quick, smooth swell of the accent wash that
+   points out a just-folded/expanded run. The brightness follows a sine profile
+   (glides up, lingers softly at the peak, eases back down) and uses `linear`
+   timing so the curve comes purely from these stops — a crisp breath, not a
+   blink. */
+@keyframes anaFoldBreath {
   0% {
     background: transparent;
   }
+  10% {
+    background: color-mix(in srgb, var(--accent) 9%, transparent);
+  }
+  20% {
+    background: color-mix(in srgb, var(--accent) 18%, transparent);
+  }
+  30% {
+    background: color-mix(in srgb, var(--accent) 24%, transparent);
+  }
+  40% {
+    background: color-mix(in srgb, var(--accent) 29%, transparent);
+  }
   50% {
-    background: color-mix(in srgb, var(--accent) 34%, transparent);
+    background: color-mix(in srgb, var(--accent) 32%, transparent);
+  }
+  60% {
+    background: color-mix(in srgb, var(--accent) 29%, transparent);
+  }
+  70% {
+    background: color-mix(in srgb, var(--accent) 24%, transparent);
+  }
+  80% {
+    background: color-mix(in srgb, var(--accent) 18%, transparent);
+  }
+  90% {
+    background: color-mix(in srgb, var(--accent) 9%, transparent);
   }
   100% {
     background: transparent;
   }
 }
-.ana-line.foldflash {
-  animation: anaFoldFlash 1.2s ease-in-out;
-}
+.ana-line.foldflash,
 .ana-foldrow.foldflash {
-  animation: anaFoldFlash 1.2s ease-in-out;
+  animation: anaFoldBreath 0.9s linear;
 }
 
 .hl-error {

src/renderer/i18n/zh.json

@@ -75,8 +75,8 @@
   "ana.fold": "收折",
   "ana.fold.title": "收折未標記的內容，只顯示被標記的行",
   "ana.fold.lines": "已收折 {n} 行，點擊展開",
-  "ana.fold.toBottom": "跳到此段最下練",
-  "ana.fold.toTop": "跳到此段最上練",
+  "ana.fold.toBottom": "跳到此段最下緣",
+  "ana.fold.toTop": "跳到此段最上緣",
   "ana.hl.auto": "自動",
   "ana.hl.none": "關閉",
   "ana.copy": "複製",

src/renderer/index.html

@@ -305,6 +305,14 @@ <h2 id="anaViewName" data-i18n="ana.viewer">檢視</h2>
                   <div class="ana-ruler-ticks" id="anaRulerTicks"></div>
                   <div class="ana-ruler-view" id="anaRulerView"></div>
                 </div>
+                <div class="ana-fold-edges" id="anaFoldEdges">
+                  <button class="ana-fold-edge" id="btnAnaFoldTop" type="button" data-i18n-title="ana.fold.toTop" title="跳到此段最上緣" aria-label="跳到此段最上緣">
+                    <svg viewBox="0 0 24 24" width="16" height="16" fill="none" stroke="currentColor" stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round"><polyline points="18 15 12 9 6 15"/></svg>
+                  </button>
+                  <button class="ana-fold-edge" id="btnAnaFoldBottom" type="button" data-i18n-title="ana.fold.toBottom" title="跳到此段最下緣" aria-label="跳到此段最下緣">
+                    <svg viewBox="0 0 24 24" width="16" height="16" fill="none" stroke="currentColor" stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round"><polyline points="6 9 12 15 18 9"/></svg>
+                  </button>
+                </div>
               </div>
             </section>
           </div>

src/renderer/js/app.js

@@ -1002,6 +1002,9 @@ const ana = {
 // Which collapsed runs are currently expanded, keyed by the run's first line
 // index. Reset whenever a file is (re)rendered.
 const anaFold = { open: new Set() };
+// The expanded run currently under the viewport (start/end line indices) that
+// the floating edge-jump buttons target; {-1, -1} when none is in view.
+const anaFoldEdge = { start: -1, end: -1 };
 const anaNav = { markers: [], targets: [], pos: -1, line: -1, levels: {} };
 // Bookmarks: `lines` points at the active file's set; `store` keeps one set per
 // file path so bookmarks survive switching files and coming back (per session).
@@ -1708,6 +1711,7 @@ const anaVirt = {
   end: -1,
   scheduled: false,
   rows: null,
+  runs: null,
   rowCount: 0,
   lineRow: null,
   lineDisplayRow: null,
@@ -1721,6 +1725,7 @@ const anaVirt = {
 function anaBuildRows() {
   const total = anaVirt.total;
   const rows = [];
+  const runs = [];
   const lineRow = total ? new Int32Array(total).fill(-1) : new Int32Array(0);
   const dispRow = total ? new Int32Array(total) : new Int32Array(0);
   const hl = anaVirt.hlSet;
@@ -1742,6 +1747,7 @@ function anaBuildRows() {
         const a = i;
         while (i < total && !hl.has(i)) i += 1;
         const count = i - a;
+        runs.push({ start: a, end: i - 1 });
         const open = anaFold.open.has(a);
         if (open) {
           // Expanded: a collapse bar above and below the revealed lines so the
@@ -1765,6 +1771,7 @@ function anaBuildRows() {
   }
   anaVirt.rows = rows;
   anaVirt.rowCount = rows.length;
+  anaVirt.runs = runs;
   anaVirt.lineRow = lineRow;
   anaVirt.lineDisplayRow = dispRow;
 }
@@ -1798,11 +1805,83 @@ function anaFoldApply(anchorLine) {
   anaVirtRender();
   anaBuildRuler(anaNav.markers, anaVirt.total);
   anaUpdateRuler();
+  anaUpdateFoldEdges();
 }
 
-// Flash the lines of a just-expanded run (once, slowly) so the user can see
-// which section opened. Best-effort: only the lines currently in the rendered
-// window animate; off-screen lines are ignored.
+// Line index -> its non-highlighted run {start, end} (binary search over the
+// run table cached by anaBuildRows), or null when the line is highlighted.
+function anaRunAtLine(idx) {
+  const runs = anaVirt.runs;
+  if (!runs || !runs.length || idx == null || idx < 0) return null;
+  let lo = 0;
+  let hi = runs.length - 1;
+  while (lo <= hi) {
+    const mid = (lo + hi) >> 1;
+    const r = runs[mid];
+    if (idx < r.start) hi = mid - 1;
+    else if (idx > r.end) lo = mid + 1;
+    else return r;
+  }
+  return null;
+}
+
+// The expanded (currently open) run that contains line `idx`, or null.
+function anaOpenRunAt(idx) {
+  if (!ana.fold) return null;
+  const r = anaRunAtLine(idx);
+  return r && anaFold.open.has(r.start) ? r : null;
+}
+
+// The expanded run filling the viewport now: prefer the line at the vertical
+// centre (where the buttons sit), fall back to the first visible line.
+function anaCurrentOpenRun() {
+  if (!ana.fold || !anaVirt.rows || !anaVirt.rowCount) return null;
+  const scroller = document.getElementById('anaScroll');
+  if (!scroller) return null;
+  const lineH = anaVirt.lineH || 19;
+  const rows = anaVirt.rows;
+  const lineAtPx = (px) => {
+    const r = Math.max(0, Math.min(rows.length - 1, Math.floor(px / lineH)));
+    const row = rows[r];
+    return row.fold ? row.start : row.line;
+  };
+  const mid = lineAtPx(scroller.scrollTop + scroller.clientHeight / 2);
+  return anaOpenRunAt(mid) || anaOpenRunAt(anaFirstVisibleLine());
+}
+
+// Show the floating top/bottom edge-jump buttons while an expanded run is in
+// view and an edge is off-screen; disable the button whose edge is already
+// visible. Remembers the target run for the click handlers.
+function anaUpdateFoldEdges() {
+  const box = document.getElementById('anaFoldEdges');
+  if (!box) return;
+  const topBtn = document.getElementById('btnAnaFoldTop');
+  const bottomBtn = document.getElementById('btnAnaFoldBottom');
+  const run = anaCurrentOpenRun();
+  let upUseful = false;
+  let downUseful = false;
+  if (run) {
+    const scroller = document.getElementById('anaScroll');
+    const lineH = anaVirt.lineH || 19;
+    const lr = anaVirt.lineRow;
+    const topRow = lr && run.start < lr.length ? lr[run.start] : -1;
+    const botRow = lr && run.end < lr.length ? lr[run.end] : -1;
+    const firstVis = Math.floor(scroller.scrollTop / lineH);
+    const lastVis = Math.ceil((scroller.scrollTop + scroller.clientHeight) / lineH);
+    upUseful = topRow >= 0 && topRow < firstVis;
+    downUseful = botRow >= 0 && botRow > lastVis;
+  }
+  const show = upUseful || downUseful;
+  anaFoldEdge.start = show ? run.start : -1;
+  anaFoldEdge.end = show ? run.end : -1;
+  if (topBtn) topBtn.disabled = !upUseful;
+  if (bottomBtn) bottomBtn.disabled = !downUseful;
+  box.classList.toggle('show', show);
+}
+
+// Breathe the lines of a just-expanded run (a gentle accent pulse) so the user
+// can see which section opened. Best-effort: only the lines currently in the
+// rendered window animate; off-screen lines are ignored.
 function anaFoldFlashRun(start) {
   if (start == null || start < 0 || !anaVirt.hlSet) return;
   let end = start;
@@ -1819,10 +1898,10 @@ function anaFoldFlashRun(start) {
       const el = anaLineEl(i);
       if (el) el.classList.remove('foldflash');
     }
-  }, 1300);
+  }, 1100);
 }
 
-// Flash the collapsed fold bar of a just-folded run, so it's clear where the
+// Breathe the collapsed fold bar of a just-folded run, so it's clear where the
 // hidden lines went.
 function anaFoldFlashBar(start) {
   const el = document.getElementById('anaViewContent');
@@ -1832,7 +1911,7 @@ function anaFoldFlashBar(start) {
   bar.classList.remove('foldflash');
   void bar.offsetWidth; // restart the animation if the class lingered
   bar.classList.add('foldflash');
-  window.setTimeout(() => bar.classList.remove('foldflash'), 1300);
+  window.setTimeout(() => bar.classList.remove('foldflash'), 1100);
 }
 
 // Toolbar toggle: fold/unfold the non-highlighted runs.
@@ -2005,6 +2084,7 @@ function anaRenderContent(text, rules) {
   anaNavRebuild();
   // Rebuild search highlights (e.g. after a highlight-type change) without moving.
   if (anaFind.q) anaFindRun(anaFind.q, { keepPos: true, noScroll: true });
+  anaUpdateFoldEdges();
 }
 
 
@@ -2078,6 +2158,7 @@ function anaScrollToLine(idx, opts) {
   scroller.scrollTop = Math.max(0, rowIdx * lineH - scroller.clientHeight / 2 + lineH / 2);
   anaVirtRender(); // render the window at the new position so the row exists
   anaUpdateRuler();
+  anaUpdateFoldEdges();
   if (opts && opts.noFlash) return;
   const row = anaLineEl(idx);
   if (!row) return;
@@ -2652,12 +2733,29 @@ function anaUpdateRulerThrottled() {
     anaRulerRaf = 0;
     anaVirtRender();
     anaUpdateRuler();
+    anaUpdateFoldEdges();
   });
 }
 if (document.getElementById('anaScroll')) {
   document.getElementById('anaScroll').addEventListener('scroll', anaUpdateRulerThrottled, { passive: true });
 }
 window.addEventListener('resize', anaUpdateRulerThrottled);
+// Floating edge-jump buttons: hop to the top / bottom edge of the expanded run
+// currently in view (its fold bars may be scrolled off-screen).
+if (document.getElementById('btnAnaFoldTop')) {
+  document.getElementById('btnAnaFoldTop').addEventListener('click', () => {
+    if (anaFoldEdge.start < 0) return;
+    anaScrollToLine(anaFoldEdge.start);
+    anaSetCurrentLine(anaFoldEdge.start);
+  });
+}
+if (document.getElementById('btnAnaFoldBottom')) {
+  document.getElementById('btnAnaFoldBottom').addEventListener('click', () => {
+    if (anaFoldEdge.end < 0) return;
+    anaScrollToLine(anaFoldEdge.end);
+    anaSetCurrentLine(anaFoldEdge.end);
+  });
+}
 $('#btnAnaPrev').addEventListener('click', () => anaNavGo(-1));
 $('#btnAnaNext').addEventListener('click', () => anaNavGo(1));
 $('#chipBm').addEventListener('click', () => anaBmGo(1));