0.10.1: audio clip push-cascade + track-swap ghost, Media drawer rename

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "animatr",
   "private": true,
-  "version": "0.10.0",
+  "version": "0.10.1",
   "type": "module",
   "scripts": {
     "dev": "vite",

src/components/AssetSidebar.vue

@@ -20,6 +20,7 @@ import {
 import { useSceneStore } from '@/stores/scene'
 import { useAssetThumbsPref } from '@/composables/useAssetThumbsPref'
 import { importAudioFile, importImageFile, isAudioFile } from '@/lib/fileLoader'
+import { clearAudioDragSource, setAudioDragSource } from '@/composables/useAudioDragSource'
 import type { Asset } from '@/types/scene'
 import { confirmDialog, promptDialog } from '@/components/ui'
 import { loadSceneImages, renderButtonThumbnail } from '@/lib/render'
@@ -326,6 +327,11 @@ function onAudioAssetDragStart(e: DragEvent, asset: Extract<Asset, { kind: 'audi
   // creates a new AudioClip referencing this asset.
   e.dataTransfer.setData('application/x-animatr-audio-asset', asset.id)
   e.dataTransfer.setData('text/plain', asset.name)
+  // Surface the source info so Timeline's ghost preview has something
+  // to render during dragover (dataTransfer.getData is unreadable then).
+  setAudioDragSource({ duration: asset.duration, name: asset.name })
+  const el = e.currentTarget as HTMLElement
+  el.addEventListener('dragend', clearAudioDragSource, { once: true })
 }
 
 async function deleteAudioAsset(id: string) {

src/components/ClipartDrawer.vue

@@ -1,7 +1,9 @@
 <script setup lang="ts">
 import { onBeforeUnmount, onMounted } from 'vue'
-import { PhArrowClockwise, PhCaretLeft, PhCaretRight, PhImagesSquare, PhMusicNote } from '@phosphor-icons/vue'
+import { PhArrowClockwise, PhCaretLeft, PhCaretRight, PhFolderOpen, PhImagesSquare, PhMusicNote } from '@phosphor-icons/vue'
 import { useClipartStore } from '@/stores/clipart'
+import { readAudioDuration, readAsDataUrl } from '@/lib/fileLoader'
+import { clearAudioDragSource, setAudioDragSource } from '@/composables/useAudioDragSource'
 import { t } from '@/i18n'
 
 const clipart = useClipartStore()
@@ -22,6 +24,22 @@ function onItemDragStart(e: DragEvent, index: number) {
   e.dataTransfer.setData('application/x-animatr-clipart', String(index))
   e.dataTransfer.setData('text/plain', item.name)
   if (item.kind === 'audio') {
+    // Populate the shared drag-source so Timeline can render a ghost
+    // preview on hover. We don't know the audio duration until the
+    // file decodes, so seed with 0 (ghost renders at minimum width)
+    // and upgrade asynchronously. dragend clears both.
+    setAudioDragSource({ duration: 0, name: item.name })
+    const el = e.currentTarget as HTMLElement
+    el.addEventListener('dragend', clearAudioDragSource, { once: true })
+    void (async () => {
+      try {
+        const dataUrl = await readAsDataUrl(item.file)
+        const d = await readAudioDuration(dataUrl)
+        setAudioDragSource({ duration: d, name: item.name })
+      } catch {
+        /* leave the placeholder width — still a visible hint */
+      }
+    })()
     // No image ghost for audio — browsers render the row itself as the
     // default drag preview, which is what we want.
     return
@@ -75,9 +93,13 @@ function onItemDragStart(e: DragEvent, index: number) {
       <p v-if="!clipart.supported" class="empty-state">
         {{ t('clipart.unsupported') }}
       </p>
-      <p v-else-if="!clipart.handle" class="empty-state">
-        {{ t('clipart.empty') }}
-      </p>
+      <div v-else-if="!clipart.handle" class="empty-state empty-state-action">
+        <p>{{ t('clipart.empty') }}</p>
+        <button class="choose-folder-btn" @click="clipart.pickFolder()">
+          <PhFolderOpen :size="14" />
+          <span>{{ t('clipart.chooseFolder') }}</span>
+        </button>
+      </div>
       <p v-else-if="clipart.error" class="error-state">{{ clipart.error }}</p>
       <p v-else-if="clipart.loading" class="empty-state">{{ t('clipart.loading') }}</p>
       <p v-else-if="clipart.items.length === 0" class="empty-state">
@@ -263,6 +285,35 @@ function onItemDragStart(e: DragEvent, index: number) {
   font-style: italic;
 }
 
+.empty-state-action {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 10px;
+}
+
+.empty-state-action p {
+  margin: 0;
+}
+
+.choose-folder-btn {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 6px 12px;
+  border: 1px solid var(--accent);
+  background: color-mix(in srgb, var(--accent) 14%, transparent);
+  color: var(--text);
+  border-radius: var(--radius-sm);
+  font-size: 12px;
+  cursor: pointer;
+  font-style: normal;
+}
+
+.choose-folder-btn:hover {
+  background: color-mix(in srgb, var(--accent) 22%, transparent);
+}
+
 .error-state {
   margin: 0;
   padding: 16px 14px;

src/components/Timeline.vue

@@ -32,6 +32,7 @@ import {
 import { useSceneStore } from '@/stores/scene'
 import { useClipartStore } from '@/stores/clipart'
 import { importAudioFile } from '@/lib/fileLoader'
+import { audioDragSource, clearAudioDragSource } from '@/composables/useAudioDragSource'
 import { sampleLayer } from '@/lib/interpolate'
 import { snapToCandidates } from '@/lib/timelineSnap'
 import { confirmDialog, promptDialog } from '@/components/ui'
@@ -1807,14 +1808,34 @@ function onAudioLaneDragOver(e: DragEvent, audioTrackId: string) {
   if (!e.dataTransfer) return
   const el = e.currentTarget as HTMLElement
   const time = pixelTimeFromEvent(e, el)
-  // Forbid drops on top of existing clips — the browser renders a
-  // "not-allowed" cursor when dropEffect is 'none'. Width-based overlap
-  // (our drop's tail landing inside the next clip) is caught at drop time.
-  e.dataTransfer.dropEffect = audioPointInAnyClip(audioTrackId, time) ? 'none' : 'copy'
+  const collides = audioPointInAnyClip(audioTrackId, time)
+  e.dataTransfer.dropEffect = collides ? 'none' : 'copy'
+  // Show a ghost preview on the hovered lane. The source info (name +
+  // duration) comes from whichever library row the user started
+  // dragging from — see useAudioDragSource. 0-length drops (clipart
+  // pre-decode) render at the minimum 6px width so the ghost stays
+  // visible as a drop target.
+  const src = audioDragSource.value
+  if (!collides && src) {
+    audioClipGhost.value = {
+      clipId: '__external__',
+      targetTrackId: audioTrackId,
+      startTime: time,
+      length: Math.max(0, src.duration),
+    }
+  } else {
+    audioClipGhost.value = null
+  }
+}
+
+function onAudioLaneDragLeave() {
+  audioClipGhost.value = null
 }
 
 async function onAudioLaneDrop(e: DragEvent, audioTrackId: string) {
   e.preventDefault()
+  audioClipGhost.value = null
+  clearAudioDragSource()
   const track = audioTrackById.value.get(audioTrackId)
   if (!track || track.locked) return
   const el = e.currentTarget as HTMLElement
@@ -1873,11 +1894,26 @@ interface AudioClipMoveState {
   pointerId: number
   startX: number
   initialStartTime: number
+  initialTrackId: string
   moved: boolean
 }
 
 const audioClipMove = ref<AudioClipMoveState | null>(null)
 
+interface AudioClipGhost {
+  clipId: string
+  targetTrackId: string
+  startTime: number
+  length: number
+}
+
+/** While dragging a clip over a DIFFERENT audio track, this holds a
+ *  preview "where it will land" on that target lane. Rendered as a
+ *  dashed block in the template so the user sees the drop target
+ *  before committing via pointerup. Cleared whenever the cursor
+ *  returns to the clip's original lane or leaves the audio area. */
+const audioClipGhost = ref<AudioClipGhost | null>(null)
+
 function onAudioClipPointerDown(e: PointerEvent, clip: AudioClip) {
   if (e.button !== 0) return
   const track = audioTrackById.value.get(clip.audioTrackId)
@@ -1891,10 +1927,27 @@ function onAudioClipPointerDown(e: PointerEvent, clip: AudioClip) {
     pointerId: e.pointerId,
     startX: e.clientX,
     initialStartTime: clip.startTime,
+    initialTrackId: clip.audioTrackId,
     moved: false,
   }
 }
 
+/** Walk the DOM under the pointer to discover which audio track (if
+ *  any) the cursor is currently over. Returns the track id, or null
+ *  when the cursor has drifted off the audio lanes entirely. Used on
+ *  pointerup to decide whether a drag should swap tracks. */
+function audioTrackIdFromPointer(clientX: number, clientY: number): string | null {
+  const el = document.elementFromPoint(clientX, clientY)
+  if (!el) return null
+  const host = (el as Element).closest('[data-audio-track-id]') as HTMLElement | null
+  if (!host) return null
+  const id = host.dataset.audioTrackId
+  if (!id) return null
+  // Only treat it as a valid target if the track exists in the store
+  // (defensive against stale DOM in the middle of re-renders).
+  return audioTrackById.value.get(id) ? id : null
+}
+
 function onAudioClipPointerMove(e: PointerEvent) {
   const m = audioClipMove.value
   if (!m || m.pointerId !== e.pointerId) return
@@ -1907,13 +1960,34 @@ function onAudioClipPointerMove(e: PointerEvent) {
   const newStart = Math.max(0, m.initialStartTime + deltaSec)
   const clip = store.scene.audioClips?.find((c) => c.id === m.clipId)
   if (!clip) return
+  // Horizontal drag always moves the clip on its CURRENT track with
+  // cascade push. Track-switch is deferred to pointerup (to keep the
+  // pointer capture anchored on a stable DOM element).
+  store.setAudioClipPosition(m.clipId, newStart, clip.audioTrackId)
+
+  // If the cursor is hovering over a different audio track, preview
+  // the drop on that lane as a dashed ghost. Users see where release
+  // will land BEFORE they commit.
+  const hovered = audioTrackIdFromPointer(e.clientX, e.clientY)
+  const canSwap =
+    hovered &&
+    hovered !== m.initialTrackId &&
+    store.scene.audioTracks &&
+    store.scene.audioTracks.length > 1
+  if (canSwap) {
     const asset = audioAssetById.value.get(clip.audioAssetId)
-  const length = asset ? Math.max(0, asset.duration - (clip.trimStart ?? 0) - (clip.trimEnd ?? 0)) : 0
-  // Refuse overlapping positions — the clip stays at its last valid
-  // startTime. Cursor keeps tracking the pointer; block stops moving
-  // once it meets a neighbour's edge.
-  if (audioWindowCollides(clip.audioTrackId, newStart, length, clip.id)) return
-  store.moveAudioClip(m.clipId, newStart)
+    const length = asset
+      ? Math.max(0, asset.duration - (clip.trimStart ?? 0) - (clip.trimEnd ?? 0))
+      : 0
+    audioClipGhost.value = {
+      clipId: clip.id,
+      targetTrackId: hovered!,
+      startTime: newStart,
+      length,
+    }
+  } else {
+    audioClipGhost.value = null
+  }
 }
 
 function onAudioClipPointerUp(e: PointerEvent) {
@@ -1922,8 +1996,13 @@ function onAudioClipPointerUp(e: PointerEvent) {
   const el = e.currentTarget as HTMLElement
   if (el.hasPointerCapture(e.pointerId)) el.releasePointerCapture(e.pointerId)
   const wasMoved = m.moved
+  const ghost = audioClipGhost.value
+  if (wasMoved && ghost && ghost.clipId === m.clipId) {
+    // Commit to the previewed target lane with cascade push.
+    store.setAudioClipPosition(m.clipId, ghost.startTime, ghost.targetTrackId)
+  }
   audioClipMove.value = null
-  // Block the contextmenu-after-drag that some browsers synthesise.
+  audioClipGhost.value = null
   if (wasMoved) e.preventDefault()
 }
 
@@ -3092,6 +3171,7 @@ onBeforeUnmount(() => {
                 muted: track.muted,
               }"
               :style="trackColorStyle(track.color)"
+              :data-audio-track-id="track.audioTrackId"
             >
               <span
                 class="track-name audio-track-name"
@@ -3114,6 +3194,7 @@ onBeforeUnmount(() => {
                 class="track-lane audio-lane"
                 :style="{ width: laneWidth + 'px' }"
                 @dragover.stop="!track.locked ? onAudioLaneDragOver($event, track.audioTrackId) : null"
+                @dragleave.stop="onAudioLaneDragLeave"
                 @drop.stop="!track.locked ? onAudioLaneDrop($event, track.audioTrackId) : null"
               >
                 <span class="playhead" :style="{ left: pxFromTime(store.playhead) + 'px' }" />
@@ -3134,6 +3215,14 @@ onBeforeUnmount(() => {
                     {{ audioAssetById.get(clip.audioAssetId)?.name ?? '—' }}
                   </span>
                 </span>
+                <span
+                  v-if="audioClipGhost && audioClipGhost.targetTrackId === track.audioTrackId"
+                  class="audio-clip-ghost"
+                  :style="{
+                    left: pxFromTime(audioClipGhost.startTime) + 'px',
+                    width: Math.max(6, pxFromTime(audioClipGhost.length)) + 'px',
+                  }"
+                ></span>
               </div>
             </div>
 
@@ -4653,6 +4742,17 @@ onBeforeUnmount(() => {
   cursor: default;
 }
 
+.audio-clip-ghost {
+  position: absolute;
+  top: 4px;
+  bottom: 4px;
+  border: 1.5px dashed var(--accent);
+  border-radius: var(--radius-sm);
+  background: color-mix(in srgb, var(--accent) 15%, transparent);
+  pointer-events: none;
+  box-sizing: border-box;
+}
+
 .audio-track.muted .audio-clip-block {
   opacity: 0.45;
 }

src/composables/useAudioDragSource.ts

@@ -0,0 +1,28 @@
+import { ref } from 'vue'
+
+/**
+ * Shared reactive state describing what the user is currently dragging
+ * from the asset sidebar or the media drawer. Read by Timeline's audio
+ * lane to render a ghost preview at the hover position.
+ *
+ * The browser hides `dataTransfer.getData()` during `dragover` for
+ * security ("protected mode"), so we can't look up the source asset
+ * through the DragEvent itself. Dragstart handlers on the library
+ * rows write here instead; Timeline reads it; dragend/drop clears it.
+ */
+export interface AudioDragSource {
+  /** Seconds. 0 when unknown (clipart files before decode). */
+  duration: number
+  /** Display label shown inside the ghost. */
+  name: string
+}
+
+export const audioDragSource = ref<AudioDragSource | null>(null)
+
+export function setAudioDragSource(src: AudioDragSource): void {
+  audioDragSource.value = src
+}
+
+export function clearAudioDragSource(): void {
+  audioDragSource.value = null
+}

src/devtools/tests.ts

@@ -3889,6 +3889,35 @@ export function registerAllTests(): void {
       handle.unmount()
     })
 
+    test('empty state shows a Choose-Folder button that calls pickFolder', async () => {
+      const { useClipartStore } = await import('@/stores/clipart')
+      const s = useClipartStore()
+      s.setOpen(true)
+      s.supported = true
+      // No handle → empty-state with action.
+      s.handle = null
+      s.folderName = null
+      s.items = []
+      // Spy on pickFolder so we don't actually open a folder picker.
+      const calls: number[] = []
+      const orig = s.pickFolder
+      s.pickFolder = async () => {
+        calls.push(1)
+      }
+      try {
+        const handle = mountComponent(ClipartDrawer, {})
+        await nextTick()
+        const btn = handle.host.querySelector('.choose-folder-btn') as HTMLButtonElement | null
+        expect(btn).toBeTruthy()
+        btn!.click()
+        expect(calls.length).toBe(1)
+        handle.unmount()
+      } finally {
+        s.pickFolder = orig
+        s.setOpen(false)
+      }
+    })
+
     test('audio clipart items render as .audio-tile with the music-note icon, not an img', async () => {
       const { useClipartStore } = await import('@/stores/clipart')
       const s = useClipartStore()
@@ -4287,20 +4316,213 @@ export function registerAllTests(): void {
       handle.unmount()
     })
 
-    test('drag stops at the neighbour\'s edge when the move would overlap', async () => {
-      // Two clips on the same track: A at t=0 (length 2), B at t=5.
-      // Drag B leftward; it must not be pushed into A's 0..2 window.
-      // The last valid position is startTime=2 (exactly abutting A).
+    test('pointerup over a different audio track switches the clip to that track', async () => {
+      // The live app (which our tests render alongside) ALSO has a
+      // Timeline mounted. `document.elementFromPoint` would return
+      // whatever element is topmost at a given screen coord — often
+      // belonging to the live Timeline, not the one we just mounted.
+      // Override the lookup for this test to pin the expected hit.
       const s = makeFreshStore()
       const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const t1 = s.addAudioTrack('one')
+      const t2 = s.addAudioTrack('two')
+      const clip = s.addAudioClip(asset.id, 1, t1.id)!
+      const handle = mountComponent(Timeline, {})
+      await nextTick()
+      const block = handle.host.querySelector(
+        `.audio-track[data-audio-track-id="${t1.id}"] .audio-clip-block`,
+      ) as HTMLElement
+      const targetLane = handle.host.querySelector(
+        `.audio-track[data-audio-track-id="${t2.id}"]`,
+      ) as HTMLElement
+      expect(block).toBeTruthy()
+      expect(targetLane).toBeTruthy()
+
+      const origFromPoint = document.elementFromPoint.bind(document)
+      ;(document as unknown as { elementFromPoint: (x: number, y: number) => Element | null }).elementFromPoint = (
+        _x: number,
+        y: number,
+      ): Element | null => {
+        // Only intercept the sentinel Y we use for the drop — let the
+        // original handle every other call so the rest of the app
+        // isn't disturbed.
+        if (y === 42424242) return targetLane
+        return origFromPoint(_x, y)
+      }
+
+      const captured = new Set<number>()
+      ;(block as unknown as { setPointerCapture: (id: number) => void }).setPointerCapture = (id) => {
+        captured.add(id)
+      }
+      ;(block as unknown as { releasePointerCapture: (id: number) => void }).releasePointerCapture = (id) => {
+        captured.delete(id)
+      }
+      ;(block as unknown as { hasPointerCapture: (id: number) => boolean }).hasPointerCapture = (id) => captured.has(id)
+      try {
+        block.dispatchEvent(
+          new PointerEvent('pointerdown', { bubbles: true, cancelable: true, button: 0, pointerId: 1, clientX: 100, clientY: 10 }),
+        )
+        block.dispatchEvent(
+          new PointerEvent('pointermove', { bubbles: true, cancelable: true, pointerId: 1, clientX: 110, clientY: 42424242 }),
+        )
+        block.dispatchEvent(
+          new PointerEvent('pointerup', { bubbles: true, cancelable: true, pointerId: 1, clientX: 110, clientY: 42424242 }),
+        )
+        await nextTick()
+        expect(clip.audioTrackId).toBe(t2.id)
+      } finally {
+        ;(document as unknown as { elementFromPoint: (x: number, y: number) => Element | null }).elementFromPoint =
+          origFromPoint
+        handle.unmount()
+      }
+    })
+
+    test('dragging an audio asset from the library shows a ghost preview on the hovered lane', async () => {
+      const { setAudioDragSource, clearAudioDragSource } = await import(
+        '@/composables/useAudioDragSource'
+      )
+      const s = makeFreshStore()
+      const asset = s.addAudioAsset({ name: 'intro', src: 'data:audio/mp3;x', duration: 3 })
       const track = s.addAudioTrack()
-      s.addAudioClip(asset.id, 0, track.id) // A
-      const b = s.addAudioClip(asset.id, 5, track.id)! // B
+      const handle = mountComponent(Timeline, {})
+      await nextTick()
+      const lane = handle.host.querySelector('.audio-track .audio-lane') as HTMLElement
+      const { timeToX } = stubAudioLane(lane)
+      // Library dragstart would populate the shared source ref; simulate it.
+      setAudioDragSource({ duration: asset.duration, name: asset.name })
+      try {
+        const dt = new DataTransfer()
+        dt.setData('application/x-animatr-audio-asset', asset.id)
+        const over = new DragEvent('dragover', {
+          bubbles: true, cancelable: true, dataTransfer: dt,
+          clientX: timeToX(5, s.scene.duration), clientY: 10,
+        })
+        lane.dispatchEvent(over)
+        await nextTick()
+        const ghost = handle.host.querySelector('.audio-clip-ghost') as HTMLElement
+        expect(ghost).toBeTruthy()
+        // The ghost width reflects the asset duration (3s * pps).
+        const expectedWidthPx = parseFloat(ghost.style.width)
+        expect(expectedWidthPx).toBeGreaterThan(0)
+        // And dragleave wipes it.
+        lane.dispatchEvent(new DragEvent('dragleave', { bubbles: true, cancelable: true, dataTransfer: dt }))
+        await nextTick()
+        expect(handle.host.querySelector('.audio-clip-ghost')).toBeNull()
+        void track
+      } finally {
+        clearAudioDragSource()
+        handle.unmount()
+      }
+    })
+
+    test('dragging over a different track renders an .audio-clip-ghost preview on that lane', async () => {
+      const s = makeFreshStore()
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const t1 = s.addAudioTrack('one')
+      const t2 = s.addAudioTrack('two')
+      s.addAudioClip(asset.id, 1, t1.id)
+      const handle = mountComponent(Timeline, {})
+      await nextTick()
+      const block = handle.host.querySelector(
+        `.audio-track[data-audio-track-id="${t1.id}"] .audio-clip-block`,
+      ) as HTMLElement
+      const targetLane = handle.host.querySelector(
+        `.audio-track[data-audio-track-id="${t2.id}"]`,
+      ) as HTMLElement
+      expect(block).toBeTruthy()
+      expect(targetLane).toBeTruthy()
+
+      const origFromPoint = document.elementFromPoint.bind(document)
+      ;(document as unknown as { elementFromPoint: (x: number, y: number) => Element | null }).elementFromPoint = (
+        _x,
+        y: number,
+      ) => (y === 42424242 ? targetLane : origFromPoint(_x, y))
+
+      const captured = new Set<number>()
+      ;(block as unknown as { setPointerCapture: (id: number) => void }).setPointerCapture = (id) => {
+        captured.add(id)
+      }
+      ;(block as unknown as { releasePointerCapture: (id: number) => void }).releasePointerCapture = (id) => {
+        captured.delete(id)
+      }
+      ;(block as unknown as { hasPointerCapture: (id: number) => boolean }).hasPointerCapture = (id) => captured.has(id)
+      try {
+        block.dispatchEvent(
+          new PointerEvent('pointerdown', { bubbles: true, cancelable: true, button: 0, pointerId: 1, clientX: 100, clientY: 10 }),
+        )
+        block.dispatchEvent(
+          new PointerEvent('pointermove', { bubbles: true, cancelable: true, pointerId: 1, clientX: 110, clientY: 42424242 }),
+        )
+        await nextTick()
+        // The ghost materialises inside t2's lane, NOT t1's.
+        const ghostInT2 = handle.host.querySelector(
+          `.audio-track[data-audio-track-id="${t2.id}"] .audio-clip-ghost`,
+        )
+        const ghostInT1 = handle.host.querySelector(
+          `.audio-track[data-audio-track-id="${t1.id}"] .audio-clip-ghost`,
+        )
+        expect(ghostInT2).toBeTruthy()
+        expect(ghostInT1).toBeNull()
+        // Release disposes the ghost either way.
+        block.dispatchEvent(
+          new PointerEvent('pointerup', { bubbles: true, cancelable: true, pointerId: 1, clientX: 110, clientY: 42424242 }),
+        )
+        await nextTick()
+        expect(handle.host.querySelector('.audio-clip-ghost')).toBeNull()
+      } finally {
+        ;(document as unknown as { elementFromPoint: (x: number, y: number) => Element | null }).elementFromPoint =
+          origFromPoint
+        handle.unmount()
+      }
+    })
+
+    test('with only one audio track, pointerup cannot switch the track', async () => {
+      const s = makeFreshStore()
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const only = s.addAudioTrack()
+      const clip = s.addAudioClip(asset.id, 1, only.id)!
+      const handle = mountComponent(Timeline, {})
+      await nextTick()
+      const block = handle.host.querySelector('.audio-track .audio-clip-block') as HTMLElement
+      const captured = new Set<number>()
+      ;(block as unknown as { setPointerCapture: (id: number) => void }).setPointerCapture = (id) => {
+        captured.add(id)
+      }
+      ;(block as unknown as { releasePointerCapture: (id: number) => void }).releasePointerCapture = (id) => {
+        captured.delete(id)
+      }
+      ;(block as unknown as { hasPointerCapture: (id: number) => boolean }).hasPointerCapture = (id) => captured.has(id)
+      // Drag horizontally + release anywhere (even way off-lane). The
+      // clip must stay on its only track — no neighbours to swap to.
+      block.dispatchEvent(
+        new PointerEvent('pointerdown', { bubbles: true, cancelable: true, button: 0, pointerId: 1, clientX: 100, clientY: 10 }),
+      )
+      block.dispatchEvent(
+        new PointerEvent('pointermove', { bubbles: true, cancelable: true, pointerId: 1, clientX: 140, clientY: 9999 }),
+      )
+      block.dispatchEvent(
+        new PointerEvent('pointerup', { bubbles: true, cancelable: true, pointerId: 1, clientX: 140, clientY: 9999 }),
+      )
+      await nextTick()
+      expect(clip.audioTrackId).toBe(only.id)
+      handle.unmount()
+    })
+
+    test('dragging a clip into a neighbour pushes the neighbour forward (cascade)', async () => {
+      // Two clips on the same track: A at t=5 (length 2, 5..7),
+      // B at t=0 (length 2, 0..2). Drag B rightward past A — A must
+      // shift forward so the two don't overlap.
+      const s = makeFreshStore()
+      s.setDuration(30)
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const track = s.addAudioTrack()
+      const b = s.addAudioClip(asset.id, 0, track.id)! // B at 0..2
+      const a = s.addAudioClip(asset.id, 5, track.id)! // A at 5..7
       const handle = mountComponent(Timeline, {})
       await nextTick()
       const blocks = handle.host.querySelectorAll('.audio-track .audio-clip-block') as NodeListOf<HTMLElement>
       expect(blocks.length).toBe(2)
-      const blockB = blocks[1]
+      const blockB = blocks[0] // rendered in insertion order; B was added first
       const captured = new Set<number>()
       ;(blockB as unknown as { setPointerCapture: (id: number) => void }).setPointerCapture = (id) => {
         captured.add(id)
@@ -4309,25 +4531,26 @@ export function registerAllTests(): void {
         captured.delete(id)
       }
       ;(blockB as unknown as { hasPointerCapture: (id: number) => boolean }).hasPointerCapture = (id) => captured.has(id)
+
+      // A (second block) sits at startTime=5, its style.left = pps*5.
+      // Read pps back from that so the drag delta we synthesise is in
+      // timeline-seconds, not pixels.
+      const pps = parseFloat(blocks[1].style.left) / 5
+      const startX = 500
       blockB.dispatchEvent(
-        new PointerEvent('pointerdown', { bubbles: true, cancelable: true, button: 0, pointerId: 1, clientX: 500 }),
+        new PointerEvent('pointerdown', { bubbles: true, cancelable: true, button: 0, pointerId: 1, clientX: startX }),
       )
-      // Big leftward drag — would end up at some negative position if
-      // unconstrained, but overlap with A blocks further movement.
+      // Drag right by 5s → B wants startTime=5, which overlaps A.
+      // Cascade pushes A from 5 to 5+2=7.
       blockB.dispatchEvent(
-        new PointerEvent('pointermove', { bubbles: true, cancelable: true, pointerId: 1, clientX: -5000 }),
+        new PointerEvent('pointermove', { bubbles: true, cancelable: true, pointerId: 1, clientX: startX + 5 * pps }),
       )
       blockB.dispatchEvent(
-        new PointerEvent('pointerup', { bubbles: true, cancelable: true, pointerId: 1, clientX: -5000 }),
+        new PointerEvent('pointerup', { bubbles: true, cancelable: true, pointerId: 1, clientX: startX + 5 * pps }),
       )
       await nextTick()
-      // B never entered A's window; it stayed at its last valid pos
-      // (≥ 2). Depending on the number of move events (just one here),
-      // it'll actually have stopped at 5 since the first evaluated
-      // newStart would already collide. Either way: no overlap.
-      expect(b.startTime >= 2 - 1e-9).toBe(true)
-      // And most importantly: A stayed put.
-      expect(s.activeScene.audioClips.find((c) => c.id !== b.id)!.startTime).toBe(0)
+      expect(Math.abs(b.startTime - 5) < 0.1).toBe(true)
+      expect(Math.abs(a.startTime - 7) < 0.1).toBe(true)
       handle.unmount()
     })
 
@@ -5536,6 +5759,49 @@ export function registerAllTests(): void {
       expect(copy.audioClips[0].audioAssetId).toBe(asset.id)
     })
 
+    test('setAudioClipPosition cascades pushes on target track, leaves earlier clips alone', () => {
+      const s = makeFreshStore()
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const track = s.addAudioTrack()
+      const early = s.addAudioClip(asset.id, 0, track.id)! // 0..2
+      const mid = s.addAudioClip(asset.id, 5, track.id)! // 5..7
+      const late = s.addAudioClip(asset.id, 8, track.id)! // 8..10
+      // Move `mid` to startTime=4 — it overlaps nothing before, but
+      // `late` (at 8) is still OK. Expect `mid` to land at 4 and no
+      // cascade for `late`.
+      expect(s.setAudioClipPosition(mid.id, 4)).toBe(true)
+      expect(mid.startTime).toBe(4)
+      expect(late.startTime).toBe(8)
+      expect(early.startTime).toBe(0)
+      // Now move `early` to startTime=4, which overlaps `mid` at 4..6.
+      // Cascade: push `mid` to 6, which then overlaps `late` at 8 —
+      // actually 6+2=8, so late stays at 8 (abutting).
+      s.setAudioClipPosition(early.id, 4)
+      expect(early.startTime).toBe(4)
+      expect(mid.startTime).toBe(6)
+      expect(late.startTime).toBe(8)
+    })
+
+    test('setAudioClipPosition with audioTrackId swaps the clip to another track', () => {
+      const s = makeFreshStore()
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 2 })
+      const t1 = s.addAudioTrack('one')
+      const t2 = s.addAudioTrack('two')
+      const clip = s.addAudioClip(asset.id, 1, t1.id)!
+      s.setAudioClipPosition(clip.id, 3, t2.id)
+      expect(clip.audioTrackId).toBe(t2.id)
+      expect(clip.startTime).toBe(3)
+    })
+
+    test('setAudioClipPosition returns false for unknown clip or unknown track', () => {
+      const s = makeFreshStore()
+      expect(s.setAudioClipPosition('no-such-clip', 0)).toBe(false)
+      const asset = s.addAudioAsset({ name: 'a', src: 'data:audio/mp3;x', duration: 1 })
+      const track = s.addAudioTrack()
+      const clip = s.addAudioClip(asset.id, 0, track.id)!
+      expect(s.setAudioClipPosition(clip.id, 0, 'ghost-track')).toBe(false)
+    })
+
     test('normalizeScenePage drops orphan audio clips pointing at a missing track', () => {
       const s = makeFreshStore()
       const asset = addAsset(s)

src/i18n/messages.ts

@@ -326,7 +326,7 @@ export const en = {
     title: 'Settings',
     tab: {
       document: 'Document',
-      clipart: 'Clipart',
+      clipart: 'Media',
       interface: 'Interface',
       theme: 'UI Theme',
     },
@@ -413,12 +413,12 @@ export const en = {
   },
 
   clipart: {
-    title: 'Clipart library',
-    open: 'Open clipart library',
-    close: 'Close clipart library',
+    title: 'Media',
+    open: 'Open media',
+    close: 'Close media',
     refresh: 'Reload folder',
-    empty: 'Choose a folder in settings to populate the library.',
-    noFiles: 'No image files in this folder.',
+    empty: 'Choose a folder with images and audio to populate the library.',
+    noFiles: 'No images or audio files in this folder.',
     loading: 'Loading…',
     unsupported: 'Your browser does not support folder access. Try Chrome or Edge.',
     chooseFolder: 'Choose folder…',
@@ -426,7 +426,7 @@ export const en = {
     folderLabel: 'Folder',
     noFolder: 'No folder selected',
     settingsHint:
-      'Point to a local folder with your SVG/PNG/JPG clipart. The app remembers the folder; permissions may be re-asked after browser restart.',
+      'Point to a local folder with your images and audio files. The app remembers the folder; permissions may be re-asked after browser restart.',
   },
 
   scenes: {

src/stores/scene.ts

@@ -1666,6 +1666,50 @@ export const useSceneStore = defineStore('scene', {
       }
     },
 
+    /** Move a clip to `(startTime, audioTrackId)` on the active page and
+     *  cascade-push any existing clips on the target track out of the way
+     *  (forward in time) so no overlap survives. Clips that end BEFORE
+     *  the moved clip's new startTime are left alone. Returns `false`
+     *  when the clip or target track is unknown. */
+    setAudioClipPosition(id: string, startTime: number, audioTrackId?: string): boolean {
+      const page = this.activeScene
+      const clip = page.audioClips.find((c) => c.id === id)
+      if (!clip) return false
+      const targetTrackId = audioTrackId ?? clip.audioTrackId
+      const targetTrack = page.audioTracks.find((t) => t.id === targetTrackId)
+      if (!targetTrack) return false
+
+      const lenOf = (c: AudioClip): number => {
+        const a = this.project.assets.find((x) => x.id === c.audioAssetId)
+        if (!a || a.kind !== 'audio') return 0
+        return Math.max(0, a.duration - (c.trimStart ?? 0) - (c.trimEnd ?? 0))
+      }
+
+      const newStart = Math.max(0, startTime)
+      const clipLen = lenOf(clip)
+
+      // Anything already on the target track, minus the one we're moving.
+      const others = page.audioClips
+        .filter((c) => c.audioTrackId === targetTrackId && c.id !== id)
+        .slice()
+        .sort((a, b) => a.startTime - b.startTime)
+
+      let floor = newStart + clipLen
+      for (const other of others) {
+        const len = lenOf(other)
+        // Clip entirely before the moved block — no cascade needed.
+        if (other.startTime + len <= newStart) continue
+        // Overlapping or sitting past the moved block but below the
+        // rolling floor → push it forward to the floor.
+        if (other.startTime < floor) other.startTime = floor
+        floor = other.startTime + len
+      }
+
+      clip.audioTrackId = targetTrackId
+      clip.startTime = newStart
+      return true
+    },
+
     /** Trim from the head and/or tail of an audio clip. Keeps the audible
      *  block at least `MIN_VISIBLE` (0.05s) long — mirrors trimClipInstance. */
     trimAudioClip(