From db7520331733b49205e8c492a0cdcb4117d1250d Mon Sep 17 00:00:00 2001
From: Sara Hentzel <sara_hentzel@sil.org>
Date: Fri, 29 May 2026 14:56:35 -0500
Subject: [PATCH] TT-7376 audio editing zoom and position fixes

---
 src/renderer/src/components/WSAudioPlayer.tsx  | 18 +++++++++++++++++-
 .../src/components/WSAudioPlayerZoom.tsx       |  8 ++++++--
 src/renderer/src/crud/useWaveSurfer.tsx        |  3 ++-
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/renderer/src/components/WSAudioPlayer.tsx b/src/renderer/src/components/WSAudioPlayer.tsx
index 4632b719..df58b81a 100644
--- a/src/renderer/src/components/WSAudioPlayer.tsx
+++ b/src/renderer/src/components/WSAudioPlayer.tsx
@@ -409,6 +409,9 @@ function WSAudioPlayer(props: IProps) {
     useContext(HotKeyContext).state;
   const [pxPerSec, setPxPerSecx] = useState(maxZoom);
   const pxPerSecRef = useRef(maxZoom);
+  /** When set, the zoom to re-apply after an edit reload (snip/undo) so the
+   * waveform doesn't snap back to fit-to-width. Cleared once consumed. */
+  const preserveZoomOnReloadRef = useRef<number | undefined>(undefined);
   const insertingRef = useRef(false);
   /** Bumped when user stops recording so in-flight preview inserts are ignored after await. */
   const recordPreviewGenerationRef = useRef(0);
@@ -1171,7 +1174,18 @@ function WSAudioPlayer(props: IProps) {
     setDuration(duration);
     if (loadingAnother) return;
     setReady(true);
-    if (!recordingRef.current) setPxPerSec(wsFillPx());
+    if (!recordingRef.current) {
+      // After an edit reload (snip/undo) restore the prior zoom instead of
+      // snapping to fit-to-width. Only restore when it was zoomed in past fit.
+      const preserved = preserveZoomOnReloadRef.current;
+      preserveZoomOnReloadRef.current = undefined;
+      if (preserved !== undefined && preserved > wsFillPx()) {
+        setPxPerSec(preserved);
+        wsZoom(preserved);
+      } else {
+        setPxPerSec(wsFillPx());
+      }
+    }
     if (segmentsRef.current) loadRegions();
 
     if (setBusy) setBusy(false);
@@ -1275,12 +1289,14 @@ function WSAudioPlayer(props: IProps) {
 
   const handleDeleteRegion = () => {
     setPlaying(false);
+    preserveZoomOnReloadRef.current = pxPerSecRef.current;
     wsRegionDelete().then(() => {
       handleChanged();
     });
   };
 
   const handleUndo = useCallback(() => {
+    preserveZoomOnReloadRef.current = pxPerSecRef.current;
     wsUndo().then(() => {
       handleChanged();
     });
diff --git a/src/renderer/src/components/WSAudioPlayerZoom.tsx b/src/renderer/src/components/WSAudioPlayerZoom.tsx
index 70ba2b43..eb1fc965 100644
--- a/src/renderer/src/components/WSAudioPlayerZoom.tsx
+++ b/src/renderer/src/components/WSAudioPlayerZoom.tsx
@@ -53,11 +53,15 @@ function WSAudioPlayerZoom(props: IProps) {
   };
   useEffect(() => {
     setZoomMin(fillPx);
-    // Only sync zoom to fillPx when fillPx actually changes (e.g. resize), not on mount.
+    // fillPx is the fit-to-width minimum. When it changes (resize, or duration
+    // change after a snip), only pull the zoom up if the current zoom is now
+    // below that minimum. Otherwise keep the user's zoom so editing audio
+    // doesn't reset how far they were zoomed in.
     // On mount, curPx effect sets zoom; avoid overwriting with fillPx so menu reopen keeps zoom.
     if (
       prevFillPxRef.current !== undefined &&
-      prevFillPxRef.current !== fillPx
+      prevFillPxRef.current !== fillPx &&
+      zoomRef.current < fillPx
     ) {
       setZoom(fillPx);
     }
diff --git a/src/renderer/src/crud/useWaveSurfer.tsx b/src/renderer/src/crud/useWaveSurfer.tsx
index 436741a1..a31fc530 100644
--- a/src/renderer/src/crud/useWaveSurfer.tsx
+++ b/src/renderer/src/crud/useWaveSurfer.tsx
@@ -786,7 +786,8 @@ export function useWaveSurfer(
   };
 
   const wsUndo = async () => {
-    if (undoBuffer) await loadDecoded(undoBuffer, 0);
+    // wsGoto clamps the position to the restored duration on load, so no harm if past end.
+    if (undoBuffer) await loadDecoded(undoBuffer, progress());
     else {
       wsClear();
     }