feat: replace motion blur toggle with intensity slider

Motion blur was a boolean switch (on/off). This changes it to a slider
from 0 (off) to 1 (full intensity), with 0.35 as the recommended sweet
spot per feedback on PR #207.

- EditorState/ProjectEditorState: motionBlurEnabled:bool → motionBlurAmount:number
- SettingsPanel: Switch → Slider (0–1, step 0.01); shows 'off' or value
- VideoPlayback/zoomTransform: scale blur by amount instead of boolean gate
- FrameRenderer/VideoExporter/GifExporter: propagate numeric amount
- projectPersistence: backward-compat loader (old true → 0.35, false → 0)

src/components/video-editor/SettingsPanel.tsx

@@ -92,8 +92,8 @@ interface SettingsPanelProps {
 	onShadowCommit?: () => void;
 	showBlur?: boolean;
 	onBlurChange?: (showBlur: boolean) => void;
-	motionBlurEnabled?: boolean;
-	onMotionBlurChange?: (enabled: boolean) => void;
+	motionBlurAmount?: number;
+	onMotionBlurChange?: (amount: number) => void;
 	borderRadius?: number;
 	onBorderRadiusChange?: (radius: number) => void;
 	onBorderRadiusCommit?: () => void;
@@ -157,7 +157,7 @@ export function SettingsPanel({
 	onShadowCommit,
 	showBlur,
 	onBlurChange,
-	motionBlurEnabled = false,
+	motionBlurAmount = 0,
 	onMotionBlurChange,
 	borderRadius = 0,
 	onBorderRadiusChange,
@@ -574,14 +574,6 @@ export function SettingsPanel({
 						</AccordionTrigger>
 						<AccordionContent className="pb-3">
 							<div className="grid grid-cols-2 gap-2 mb-3">
-								<div className="flex items-center justify-between p-2 rounded-lg bg-white/5 border border-white/5">
-									<div className="text-[10px] font-medium text-slate-300">Motion Blur</div>
-									<Switch
-										checked={motionBlurEnabled}
-										onCheckedChange={onMotionBlurChange}
-										className="data-[state=checked]:bg-[#34B27B] scale-90"
-									/>
-								</div>
 								<div className="flex items-center justify-between p-2 rounded-lg bg-white/5 border border-white/5">
 									<div className="text-[10px] font-medium text-slate-300">Blur BG</div>
 									<Switch
@@ -593,6 +585,23 @@ export function SettingsPanel({
 							</div>
 
 							<div className="grid grid-cols-2 gap-2">
+								<div className="p-2 rounded-lg bg-white/5 border border-white/5">
+									<div className="flex items-center justify-between mb-1">
+										<div className="text-[10px] font-medium text-slate-300">Motion Blur</div>
+										<span className="text-[10px] text-slate-500 font-mono">
+											{motionBlurAmount === 0 ? "off" : motionBlurAmount.toFixed(2)}
+										</span>
+									</div>
+									<Slider
+										value={[motionBlurAmount]}
+										onValueChange={(values) => onMotionBlurChange?.(values[0])}
+										onValueCommit={(values) => onMotionBlurChange?.(values[0])}
+										min={0}
+										max={1}
+										step={0.01}
+										className="w-full [&_[role=slider]]:bg-[#34B27B] [&_[role=slider]]:border-[#34B27B] [&_[role=slider]]:h-3 [&_[role=slider]]:w-3"
+									/>
+								</div>
 								<div className="p-2 rounded-lg bg-white/5 border border-white/5">
 									<div className="flex items-center justify-between mb-1">
 										<div className="text-[10px] font-medium text-slate-300">Shadow</div>

src/components/video-editor/VideoEditor.tsx

@@ -70,7 +70,7 @@ export default function VideoEditor() {
 		wallpaper,
 		shadowIntensity,
 		showBlur,
-		motionBlurEnabled,
+		motionBlurAmount,
 		borderRadius,
 		padding,
 		aspectRatio,
@@ -139,7 +139,7 @@ export default function VideoEditor() {
 				wallpaper: normalizedEditor.wallpaper,
 				shadowIntensity: normalizedEditor.shadowIntensity,
 				showBlur: normalizedEditor.showBlur,
-				motionBlurEnabled: normalizedEditor.motionBlurEnabled,
+				motionBlurAmount: normalizedEditor.motionBlurAmount,
 				borderRadius: normalizedEditor.borderRadius,
 				padding: normalizedEditor.padding,
 				cropRegion: normalizedEditor.cropRegion,
@@ -198,7 +198,7 @@ export default function VideoEditor() {
 				wallpaper,
 				shadowIntensity,
 				showBlur,
-				motionBlurEnabled,
+				motionBlurAmount,
 				borderRadius,
 				padding,
 				cropRegion,
@@ -220,7 +220,7 @@ export default function VideoEditor() {
 		wallpaper,
 		shadowIntensity,
 		showBlur,
-		motionBlurEnabled,
+		motionBlurAmount,
 		borderRadius,
 		padding,
 		cropRegion,
@@ -294,7 +294,7 @@ export default function VideoEditor() {
 				wallpaper,
 				shadowIntensity,
 				showBlur,
-				motionBlurEnabled,
+				motionBlurAmount,
 				borderRadius,
 				padding,
 				cropRegion,
@@ -347,7 +347,7 @@ export default function VideoEditor() {
 			wallpaper,
 			shadowIntensity,
 			showBlur,
-			motionBlurEnabled,
+			motionBlurAmount,
 			borderRadius,
 			padding,
 			cropRegion,
@@ -933,7 +933,7 @@ export default function VideoEditor() {
 						showShadow: shadowIntensity > 0,
 						shadowIntensity,
 						showBlur,
-						motionBlurEnabled,
+						motionBlurAmount,
 						borderRadius,
 						padding,
 						videoPadding: padding,
@@ -1060,7 +1060,7 @@ export default function VideoEditor() {
 						showShadow: shadowIntensity > 0,
 						shadowIntensity,
 						showBlur,
-						motionBlurEnabled,
+						motionBlurAmount,
 						borderRadius,
 						padding,
 						cropRegion,
@@ -1121,7 +1121,7 @@ export default function VideoEditor() {
 			speedRegions,
 			shadowIntensity,
 			showBlur,
-			motionBlurEnabled,
+			motionBlurAmount,
 			borderRadius,
 			padding,
 			cropRegion,
@@ -1270,7 +1270,7 @@ export default function VideoEditor() {
 											showShadow={shadowIntensity > 0}
 											shadowIntensity={shadowIntensity}
 											showBlur={showBlur}
-											motionBlurEnabled={motionBlurEnabled}
+											motionBlurAmount={motionBlurAmount}
 											borderRadius={borderRadius}
 											padding={padding}
 											cropRegion={cropRegion}
@@ -1369,8 +1369,8 @@ export default function VideoEditor() {
 					onShadowCommit={commitState}
 					showBlur={showBlur}
 					onBlurChange={(v) => pushState({ showBlur: v })}
-					motionBlurEnabled={motionBlurEnabled}
-					onMotionBlurChange={(v) => pushState({ motionBlurEnabled: v })}
+					motionBlurAmount={motionBlurAmount}
+					onMotionBlurChange={(v) => pushState({ motionBlurAmount: v })}
 					borderRadius={borderRadius}
 					onBorderRadiusChange={(v) => updateState({ borderRadius: v })}
 					onBorderRadiusCommit={commitState}

src/components/video-editor/VideoPlayback.tsx

@@ -70,7 +70,7 @@ interface VideoPlaybackProps {
 	showShadow?: boolean;
 	shadowIntensity?: number;
 	showBlur?: boolean;
-	motionBlurEnabled?: boolean;
+	motionBlurAmount?: number;
 	borderRadius?: number;
 	padding?: number;
 	cropRegion?: import("./types").CropRegion;
@@ -113,7 +113,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 			showShadow,
 			shadowIntensity = 0,
 			showBlur,
-			motionBlurEnabled = false,
+			motionBlurAmount = 0,
 			borderRadius = 0,
 			padding = 50,
 			cropRegion,
@@ -128,7 +128,6 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 		},
 		ref,
 	) => {
-		const ZOOM_MOTION_BLUR_AMOUNT = 0.35;
 		const videoRef = useRef<HTMLVideoElement | null>(null);
 		const containerRef = useRef<HTMLDivElement | null>(null);
 		const appRef = useRef<Application | null>(null);
@@ -169,7 +168,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 		const layoutVideoContentRef = useRef<(() => void) | null>(null);
 		const trimRegionsRef = useRef<TrimRegion[]>([]);
 		const speedRegionsRef = useRef<SpeedRegion[]>([]);
-		const motionBlurEnabledRef = useRef(motionBlurEnabled);
+		const motionBlurAmountRef = useRef(motionBlurAmount);
 		const motionBlurStateRef = useRef<MotionBlurState>(createMotionBlurState());
 		const onTimeUpdateRef = useRef(onTimeUpdate);
 		const onPlayStateChangeRef = useRef(onPlayStateChange);
@@ -400,8 +399,8 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 		}, [speedRegions]);
 
 		useEffect(() => {
-			motionBlurEnabledRef.current = motionBlurEnabled;
-		}, [motionBlurEnabled]);
+			motionBlurAmountRef.current = motionBlurAmount;
+		}, [motionBlurAmount]);
 
 		useEffect(() => {
 			onTimeUpdateRef.current = onTimeUpdate;
@@ -475,7 +474,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 					focusY: DEFAULT_FOCUS.cy,
 					motionIntensity: 0,
 					isPlaying: false,
-					motionBlurAmount: motionBlurEnabledRef.current ? ZOOM_MOTION_BLUR_AMOUNT : 0,
+					motionBlurAmount: motionBlurAmountRef.current,
 				});
 
 				requestAnimationFrame(() => {
@@ -739,7 +738,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(
 					motionIntensity,
 					motionVector,
 					isPlaying: isPlayingRef.current,
-					motionBlurAmount: motionBlurEnabledRef.current ? ZOOM_MOTION_BLUR_AMOUNT : 0,
+					motionBlurAmount: motionBlurAmountRef.current,
 					transformOverride: transform,
 					motionBlurState: motionBlurStateRef.current,
 					frameTimeMs: performance.now(),

src/components/video-editor/projectPersistence.ts

@@ -28,7 +28,7 @@ export interface ProjectEditorState {
 	wallpaper: string;
 	shadowIntensity: number;
 	showBlur: boolean;
-	motionBlurEnabled: boolean;
+	motionBlurAmount: number;
 	borderRadius: number;
 	padding: number;
 	cropRegion: CropRegion;
@@ -302,8 +302,13 @@ export function normalizeProjectEditor(editor: Partial<ProjectEditorState>): Pro
 		wallpaper: typeof editor.wallpaper === "string" ? editor.wallpaper : WALLPAPER_PATHS[0],
 		shadowIntensity: typeof editor.shadowIntensity === "number" ? editor.shadowIntensity : 0,
 		showBlur: typeof editor.showBlur === "boolean" ? editor.showBlur : false,
-		motionBlurEnabled:
-			typeof editor.motionBlurEnabled === "boolean" ? editor.motionBlurEnabled : false,
+		motionBlurAmount: isFiniteNumber(editor.motionBlurAmount)
+			? clamp(editor.motionBlurAmount, 0, 1)
+			: typeof (editor as { motionBlurEnabled?: unknown }).motionBlurEnabled === "boolean"
+				? (editor as { motionBlurEnabled?: boolean }).motionBlurEnabled
+					? 0.35
+					: 0
+				: 0,
 		borderRadius: typeof editor.borderRadius === "number" ? editor.borderRadius : 0,
 		padding: isFiniteNumber(editor.padding) ? clamp(editor.padding, 0, 100) : 50,
 		cropRegion: {

src/hooks/useEditorHistory.ts

@@ -20,7 +20,7 @@ export interface EditorState {
 	wallpaper: string;
 	shadowIntensity: number;
 	showBlur: boolean;
-	motionBlurEnabled: boolean;
+	motionBlurAmount: number;
 	borderRadius: number;
 	padding: number;
 	aspectRatio: AspectRatio;
@@ -35,7 +35,7 @@ export const INITIAL_EDITOR_STATE: EditorState = {
 	wallpaper: "/wallpapers/wallpaper1.jpg",
 	shadowIntensity: 0,
 	showBlur: false,
-	motionBlurEnabled: false,
+	motionBlurAmount: 0,
 	borderRadius: 0,
 	padding: 50,
 	aspectRatio: "16:9",

src/lib/exporter/frameRenderer.ts

@@ -40,7 +40,7 @@ interface FrameRenderConfig {
 	showShadow: boolean;
 	shadowIntensity: number;
 	showBlur: boolean;
-	motionBlurEnabled?: boolean;
+	motionBlurAmount?: number;
 	borderRadius?: number;
 	padding?: number;
 	cropRegion: CropRegion;
@@ -351,7 +351,7 @@ export class FrameRenderer {
 			focusY: this.animationState.focusY,
 			motionIntensity: maxMotionIntensity,
 			isPlaying: true,
-			motionBlurAmount: this.config.motionBlurEnabled ? 0.35 : 0,
+			motionBlurAmount: this.config.motionBlurAmount ?? 0,
 			motionBlurState: this.motionBlurState,
 			frameTimeMs: timeMs,
 		});

src/lib/exporter/gifExporter.ts

@@ -32,7 +32,7 @@ interface GifExporterConfig {
 	showShadow: boolean;
 	shadowIntensity: number;
 	showBlur: boolean;
-	motionBlurEnabled?: boolean;
+	motionBlurAmount?: number;
 	borderRadius?: number;
 	padding?: number;
 	videoPadding?: number;
@@ -106,7 +106,7 @@ export class GifExporter {
 				showShadow: this.config.showShadow,
 				shadowIntensity: this.config.shadowIntensity,
 				showBlur: this.config.showBlur,
-				motionBlurEnabled: this.config.motionBlurEnabled,
+				motionBlurAmount: this.config.motionBlurAmount,
 				borderRadius: this.config.borderRadius,
 				padding: this.config.padding,
 				cropRegion: this.config.cropRegion,

src/lib/exporter/videoExporter.ts

@@ -20,7 +20,7 @@ interface VideoExporterConfig extends ExportConfig {
 	showShadow: boolean;
 	shadowIntensity: number;
 	showBlur: boolean;
-	motionBlurEnabled?: boolean;
+	motionBlurAmount?: number;
 	borderRadius?: number;
 	padding?: number;
 	videoPadding?: number;
@@ -70,7 +70,7 @@ export class VideoExporter {
 				showShadow: this.config.showShadow,
 				shadowIntensity: this.config.shadowIntensity,
 				showBlur: this.config.showBlur,
-				motionBlurEnabled: this.config.motionBlurEnabled,
+				motionBlurAmount: this.config.motionBlurAmount,
 				borderRadius: this.config.borderRadius,
 				padding: this.config.padding,
 				cropRegion: this.config.cropRegion,