Merge pull request #266 from anwarulislam/feat/snapping

feature: add timeline snapping functionality

apps/web/src/components/editor/snap-indicator.tsx

@@ -0,0 +1,54 @@
+"use client";
+
+import { SnapPoint } from "@/hooks/use-timeline-snapping";
+import { TIMELINE_CONSTANTS } from "@/constants/timeline-constants";
+import type { TimelineTrack } from "@/types/timeline";
+
+interface SnapIndicatorProps {
+  snapPoint: SnapPoint | null;
+  zoomLevel: number;
+  isVisible: boolean;
+  tracks: TimelineTrack[];
+  timelineRef: React.RefObject<HTMLDivElement>;
+  trackLabelsRef?: React.RefObject<HTMLDivElement>;
+}
+
+export function SnapIndicator({
+  snapPoint,
+  zoomLevel,
+  isVisible,
+  tracks,
+  timelineRef,
+  trackLabelsRef,
+}: SnapIndicatorProps) {
+  if (!isVisible || !snapPoint) {
+    return null;
+  }
+
+  const timelineContainerHeight = timelineRef.current?.offsetHeight || 400;
+  const totalHeight = timelineContainerHeight - 8; // 8px padding from edges
+
+  // Get dynamic track labels width, fallback to 0 if no tracks or no ref
+  const trackLabelsWidth =
+    tracks.length > 0 && trackLabelsRef?.current
+      ? trackLabelsRef.current.offsetWidth
+      : 0;
+
+  const leftPosition =
+    trackLabelsWidth +
+    snapPoint.time * TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
+
+  return (
+    <div
+      className="absolute pointer-events-none z-[90]"
+      style={{
+        left: `${leftPosition}px`,
+        top: 0,
+        height: `${totalHeight}px`,
+        width: "2px",
+      }}
+    >
+      <div className={`w-0.5 h-full bg-primary/40 opacity-80`} />
+    </div>
+  );
+}

apps/web/src/components/editor/timeline-playhead.tsx

@@ -20,6 +20,7 @@ interface TimelinePlayheadProps {
   trackLabelsRef?: React.RefObject<HTMLDivElement>;
   timelineRef: React.RefObject<HTMLDivElement>;
   playheadRef?: React.RefObject<HTMLDivElement>;
+  isSnappingToPlayhead?: boolean;
 }
 
 export function TimelinePlayhead({
@@ -34,6 +35,7 @@ export function TimelinePlayhead({
   trackLabelsRef,
   timelineRef,
   playheadRef: externalPlayheadRef,
+  isSnappingToPlayhead = false,
 }: TimelinePlayheadProps) {
   const internalPlayheadRef = useRef<HTMLDivElement>(null);
   const playheadRef = externalPlayheadRef || internalPlayheadRef;
@@ -73,11 +75,15 @@ export function TimelinePlayhead({
       }}
       onMouseDown={handlePlayheadMouseDown}
     >
-      {/* The red line spanning full height */}
-      <div className="absolute left-0 w-0.5 bg-foreground cursor-col-resize h-full" />
+      {/* The playhead line spanning full height */}
+      <div
+        className={`absolute left-0 w-0.5 cursor-col-resize h-full ${isSnappingToPlayhead ? "bg-primary" : "bg-foreground"}`}
+      />
 
-      {/* Red dot indicator at the top (in ruler area) */}
-      <div className="absolute top-1 left-1/2 transform -translate-x-1/2 w-3 h-3 bg-foreground rounded-full border-2 border-foreground shadow-sm" />
+      {/* Playhead dot indicator at the top (in ruler area) */}
+      <div
+        className={`absolute top-1 left-1/2 transform -translate-x-1/2 w-3 h-3 rounded-full border-2 shadow-sm ${isSnappingToPlayhead ? "bg-primary border-primary" : "bg-foreground border-foreground"}`}
+      />
     </div>
   );
 }

apps/web/src/components/editor/timeline-track.tsx

@@ -22,13 +22,16 @@ import {
   TIMELINE_CONSTANTS,
 } from "@/constants/timeline-constants";
 import { useProjectStore } from "@/stores/project-store";
+import { useTimelineSnapping, SnapPoint } from "@/hooks/use-timeline-snapping";
 
 export function TimelineTrackContent({
   track,
   zoomLevel,
+  onSnapPointChange,
 }: {
   track: TimelineTrack;
   zoomLevel: number;
+  onSnapPointChange?: (snapPoint: SnapPoint | null) => void;
 }) {
   const { mediaItems } = useMediaStore();
   const {
@@ -45,8 +48,18 @@ export function TimelineTrackContent({
     endDrag: endDragAction,
     clearSelectedElements,
     insertTrackAt,
+    snappingEnabled,
   } = useTimelineStore();
 
+  const { currentTime } = usePlaybackStore();
+
+  // Initialize snapping hook
+  const { snapElementPosition } = useTimelineSnapping({
+    snapThreshold: 10,
+    enableElementSnapping: snappingEnabled,
+    enablePlayheadSnapping: snappingEnabled,
+  });
+
   const timelineRef = useRef<HTMLDivElement>(null);
   const [isDropping, setIsDropping] = useState(false);
   const [dropPosition, setDropPosition] = useState<number | null>(null);
@@ -85,12 +98,34 @@ export function TimelineTrackContent({
         mouseX / (TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel)
       );
       const adjustedTime = Math.max(0, mouseTime - dragState.clickOffsetTime);
-      // Use frame snapping if project has FPS, otherwise use decimal snapping
-      const projectStore = useProjectStore.getState();
-      const projectFps = projectStore.activeProject?.fps || 30;
-      const snappedTime = snapTimeToFrame(adjustedTime, projectFps);
 
-      updateDragTime(snappedTime);
+      // Apply snapping if enabled
+      let finalTime = adjustedTime;
+      let snapPoint = null;
+      if (snappingEnabled) {
+        const snapResult = snapElementPosition(
+          adjustedTime,
+          tracks,
+          currentTime,
+          zoomLevel,
+          dragState.elementId || undefined
+        );
+        finalTime = snapResult.snappedTime;
+        snapPoint = snapResult.snapPoint;
+
+        // Notify parent component about snap point change
+        onSnapPointChange?.(snapPoint);
+      } else {
+        // Use frame snapping if project has FPS, otherwise use decimal snapping
+        const projectStore = useProjectStore.getState();
+        const projectFps = projectStore.activeProject?.fps || 30;
+        finalTime = snapTimeToFrame(adjustedTime, projectFps);
+
+        // Clear snap point when not snapping
+        onSnapPointChange?.(null);
+      }
+
+      updateDragTime(finalTime);
     };
 
     const handleMouseUp = (e: MouseEvent) => {
@@ -108,6 +143,8 @@ export function TimelineTrackContent({
             dragState.currentTime
           );
           endDragAction();
+          // Clear snap point when drag ends
+          onSnapPointChange?.(null);
         }
         return;
       }
@@ -204,6 +241,8 @@ export function TimelineTrackContent({
 
       if (isTrackThatStartedDrag) {
         endDragAction();
+        // Clear snap point when drag ends
+        onSnapPointChange?.(null);
       }
     };
 
@@ -229,6 +268,7 @@ export function TimelineTrackContent({
     endDragAction,
     selectedElements,
     selectElement,
+    onSnapPointChange,
   ]);
 
   const handleElementMouseDown = (

apps/web/src/components/editor/timeline.tsx

@@ -15,6 +15,8 @@ import {
   Video,
   Music,
   TypeIcon,
+  Magnet,
+  Lock,
 } from "lucide-react";
 import {
   Tooltip,
@@ -36,13 +38,6 @@ import { useTimelineZoom } from "@/hooks/use-timeline-zoom";
 import { processMediaFiles } from "@/lib/media-processing";
 import { toast } from "sonner";
 import { useState, useRef, useEffect, useCallback } from "react";
-import {
-  Select,
-  SelectContent,
-  SelectItem,
-  SelectTrigger,
-  SelectValue,
-} from "../ui/select";
 import { TimelineTrackContent } from "./timeline-track";
 import {
   TimelinePlayhead,
@@ -50,6 +45,8 @@ import {
 } from "./timeline-playhead";
 import { SelectionBox } from "./selection-box";
 import { useSelectionBox } from "@/hooks/use-selection-box";
+import { SnapIndicator } from "./snap-indicator";
+import { SnapPoint } from "@/hooks/use-timeline-snapping";
 import type { DragData, TimelineTrack } from "@/types/timeline";
 import {
   getTrackHeight,
@@ -78,6 +75,9 @@ export function Timeline() {
     separateAudio,
     undo,
     redo,
+    snappingEnabled,
+    toggleSnapping,
+    dragState,
   } = useTimelineStore();
   const { mediaItems, addMediaItem } = useMediaStore();
   const { activeProject } = useProjectStore();
@@ -118,7 +118,7 @@ export function Timeline() {
   const lastVerticalSync = useRef(0);
 
   // Timeline playhead ruler handlers
-  const { handleRulerMouseDown, isDraggingRuler } = useTimelinePlayheadRuler({
+  const { handleRulerMouseDown } = useTimelinePlayheadRuler({
     currentTime,
     duration,
     zoomLevel,
@@ -145,6 +145,18 @@ export function Timeline() {
     },
   });
 
+  // Calculate snap indicator state
+  const [currentSnapPoint, setCurrentSnapPoint] = useState<SnapPoint | null>(
+    null
+  );
+  const showSnapIndicator =
+    dragState.isDragging && snappingEnabled && currentSnapPoint !== null;
+
+  // Callback to handle snap point changes from TimelineTrackContent
+  const handleSnapPointChange = useCallback((snapPoint: SnapPoint | null) => {
+    setCurrentSnapPoint(snapPoint);
+  }, []);
+
   // Timeline content click to seek handler
   const handleTimelineContentClick = useCallback(
     (e: React.MouseEvent) => {
@@ -686,136 +698,168 @@ export function Timeline() {
       onMouseLeave={() => setIsInTimeline(false)}
     >
       {/* Toolbar */}
-      <div className="border-b flex items-center px-2 py-1 gap-1">
-        <TooltipProvider delayDuration={500}>
-          {/* Play/Pause Button */}
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button
-                variant="text"
-                size="icon"
-                onClick={toggle}
-                className="mr-2"
-              >
-                {isPlaying ? (
-                  <Pause className="h-4 w-4" />
-                ) : (
-                  <Play className="h-4 w-4" />
-                )}
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>
-              {isPlaying ? "Pause (Space)" : "Play (Space)"}
-            </TooltipContent>
-          </Tooltip>
-          <div className="w-px h-6 bg-border mx-1" />
-          {/* Time Display */}
-          <div
-            className="text-xs text-muted-foreground font-mono px-2"
-            style={{ minWidth: "18ch", textAlign: "center" }}
-          >
-            {currentTime.toFixed(1)}s / {duration.toFixed(1)}s
-          </div>
-          {/* Test Clip Button - for debugging */}
-          {tracks.length === 0 && (
-            <>
-              <div className="w-px h-6 bg-border mx-1" />
-              <Tooltip>
-                <TooltipTrigger asChild>
-                  <Button
-                    variant="outline"
-                    size="sm"
-                    onClick={() => {
-                      const trackId = addTrack("media");
-                      addElementToTrack(trackId, {
-                        type: "media",
-                        mediaId: "test",
-                        name: "Test Clip",
-                        duration: TIMELINE_CONSTANTS.DEFAULT_TEXT_DURATION,
-                        startTime: 0,
-                        trimStart: 0,
-                        trimEnd: 0,
-                      });
-                    }}
-                    className="text-xs"
-                  >
-                    Add Test Clip
-                  </Button>
-                </TooltipTrigger>
-                <TooltipContent>Add a test clip to try playback</TooltipContent>
-              </Tooltip>
-            </>
-          )}
-          <div className="w-px h-6 bg-border mx-1" />
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button variant="text" size="icon" onClick={handleSplitSelected}>
-                <Scissors className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Split element (Ctrl+S)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button
-                variant="text"
-                size="icon"
-                onClick={handleSplitAndKeepLeft}
-              >
-                <ArrowLeftToLine className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Split and keep left (Ctrl+Q)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button
-                variant="text"
-                size="icon"
-                onClick={handleSplitAndKeepRight}
-              >
-                <ArrowRightToLine className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Split and keep right (Ctrl+W)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button variant="text" size="icon" onClick={handleSeparateAudio}>
-                <SplitSquareHorizontal className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Separate audio (Ctrl+D)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button
-                variant="text"
-                size="icon"
-                onClick={handleDuplicateSelected}
-              >
-                <Copy className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Duplicate element (Ctrl+D)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button variant="text" size="icon" onClick={handleFreezeSelected}>
-                <Snowflake className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Freeze frame (F)</TooltipContent>
-          </Tooltip>
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button variant="text" size="icon" onClick={handleDeleteSelected}>
-                <Trash2 className="h-4 w-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Delete element (Delete)</TooltipContent>
-          </Tooltip>
-        </TooltipProvider>
+      <div className="border-b flex items-center justify-between px-2 py-1">
+        <div className="flex items-center gap-1 w-full">
+          <TooltipProvider delayDuration={500}>
+            {/* Play/Pause Button */}
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={toggle}
+                  className="mr-2"
+                >
+                  {isPlaying ? (
+                    <Pause className="h-4 w-4" />
+                  ) : (
+                    <Play className="h-4 w-4" />
+                  )}
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>
+                {isPlaying ? "Pause (Space)" : "Play (Space)"}
+              </TooltipContent>
+            </Tooltip>
+            <div className="w-px h-6 bg-border mx-1" />
+            {/* Time Display */}
+            <div
+              className="text-xs text-muted-foreground font-mono px-2"
+              style={{ minWidth: "18ch", textAlign: "center" }}
+            >
+              {currentTime.toFixed(1)}s / {duration.toFixed(1)}s
+            </div>
+            {/* Test Clip Button - for debugging */}
+            {tracks.length === 0 && (
+              <>
+                <div className="w-px h-6 bg-border mx-1" />
+                <Tooltip>
+                  <TooltipTrigger asChild>
+                    <Button
+                      variant="outline"
+                      size="sm"
+                      onClick={() => {
+                        const trackId = addTrack("media");
+                        addElementToTrack(trackId, {
+                          type: "media",
+                          mediaId: "test",
+                          name: "Test Clip",
+                          duration: TIMELINE_CONSTANTS.DEFAULT_TEXT_DURATION,
+                          startTime: 0,
+                          trimStart: 0,
+                          trimEnd: 0,
+                        });
+                      }}
+                      className="text-xs"
+                    >
+                      Add Test Clip
+                    </Button>
+                  </TooltipTrigger>
+                  <TooltipContent>
+                    Add a test clip to try playback
+                  </TooltipContent>
+                </Tooltip>
+              </>
+            )}
+            <div className="w-px h-6 bg-border mx-1" />
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleSplitSelected}
+                >
+                  <Scissors className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Split element (Ctrl+S)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleSplitAndKeepLeft}
+                >
+                  <ArrowLeftToLine className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Split and keep left (Ctrl+Q)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleSplitAndKeepRight}
+                >
+                  <ArrowRightToLine className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Split and keep right (Ctrl+W)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleSeparateAudio}
+                >
+                  <SplitSquareHorizontal className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Separate audio (Ctrl+D)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleDuplicateSelected}
+                >
+                  <Copy className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Duplicate element (Ctrl+D)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleFreezeSelected}
+                >
+                  <Snowflake className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Freeze frame (F)</TooltipContent>
+            </Tooltip>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="text"
+                  size="icon"
+                  onClick={handleDeleteSelected}
+                >
+                  <Trash2 className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Delete element (Delete)</TooltipContent>
+            </Tooltip>
+          </TooltipProvider>
+        </div>
+        <div className="flex items-center gap-1">
+          <TooltipProvider delayDuration={500}>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button variant="text" size="icon" onClick={toggleSnapping}>
+                  <Lock className="h-4 w-4" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Auto snapping</TooltipContent>
+            </Tooltip>
+          </TooltipProvider>
+        </div>
       </div>
 
       {/* Timeline Container */}
@@ -835,6 +879,17 @@ export function Timeline() {
           trackLabelsRef={trackLabelsRef}
           timelineRef={timelineRef}
           playheadRef={playheadRef}
+          isSnappingToPlayhead={
+            showSnapIndicator && currentSnapPoint?.type === "playhead"
+          }
+        />
+        <SnapIndicator
+          snapPoint={currentSnapPoint}
+          zoomLevel={zoomLevel}
+          tracks={tracks}
+          timelineRef={timelineRef}
+          trackLabelsRef={trackLabelsRef}
+          isVisible={showSnapIndicator}
         />
         {/* Timeline Header with Ruler */}
         <div className="flex bg-panel sticky top-0 z-10">
@@ -1016,6 +1071,7 @@ export function Timeline() {
                             <TimelineTrackContent
                               track={track}
                               zoomLevel={zoomLevel}
+                              onSnapPointChange={handleSnapPointChange}
                             />
                           </div>
                         </ContextMenuTrigger>

apps/web/src/components/ui/tooltip.tsx

@@ -20,7 +20,7 @@ const TooltipContent = React.forwardRef<
       ref={ref}
       sideOffset={sideOffset}
       className={cn(
-        "z-50 overflow-hidden rounded-md bg-primary px-3 py-1.5 text-xs text-primary-foreground animate-in fade-in-0 zoom-in-95 data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=closed]:zoom-out-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2",
+        "z-50 overflow-hidden rounded-md bg-foreground/10 px-3 py-1.5 text-xs text-foreground animate-in fade-in-0 zoom-in-95 data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=closed]:zoom-out-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2",
         className
       )}
       {...props}