1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
import { useCallback } from "react";
import { TimelineTrack } from "@/types/timeline";
import { TIMELINE_CONSTANTS } from "@/constants/timeline-constants";
export interface SnapPoint {
time: number;
type: "element-start" | "element-end" | "playhead";
elementId?: string;
trackId?: string;
}
export interface SnapResult {
snappedTime: number;
snapPoint: SnapPoint | null;
snapDistance: number;
}
export interface UseTimelineSnappingOptions {
snapThreshold?: number; // Distance in pixels to trigger snapping
enableElementSnapping?: boolean;
enablePlayheadSnapping?: boolean;
}
export function useTimelineSnapping({
snapThreshold = 10,
enableElementSnapping = true,
enablePlayheadSnapping = true,
}: UseTimelineSnappingOptions = {}) {
const findSnapPoints = useCallback(
(
tracks: TimelineTrack[],
currentTime: number,
playheadTime: number,
zoomLevel: number,
excludeElementId?: string
): SnapPoint[] => {
const snapPoints: SnapPoint[] = [];
// Add element snap points
if (enableElementSnapping) {
tracks.forEach((track) => {
track.elements.forEach((element) => {
// Skip the element being dragged
if (element.id === excludeElementId) return;
const elementStart = element.startTime;
const elementEnd =
element.startTime +
(element.duration - element.trimStart - element.trimEnd);
snapPoints.push(
{
time: elementStart,
type: "element-start",
elementId: element.id,
trackId: track.id,
},
{
time: elementEnd,
type: "element-end",
elementId: element.id,
trackId: track.id,
}
);
});
});
}
// Add playhead snap point
if (enablePlayheadSnapping) {
snapPoints.push({
time: playheadTime,
type: "playhead",
});
}
return snapPoints;
},
[enableElementSnapping, enablePlayheadSnapping]
);
const snapToNearestPoint = useCallback(
(
targetTime: number,
snapPoints: SnapPoint[],
zoomLevel: number
): SnapResult => {
const pixelsPerSecond = TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
const thresholdInSeconds = snapThreshold / pixelsPerSecond;
let closestSnapPoint: SnapPoint | null = null;
let closestDistance = Infinity;
snapPoints.forEach((snapPoint) => {
const distance = Math.abs(targetTime - snapPoint.time);
if (distance < thresholdInSeconds && distance < closestDistance) {
closestDistance = distance;
closestSnapPoint = snapPoint;
}
});
return {
snappedTime: closestSnapPoint
? (closestSnapPoint as SnapPoint).time
: targetTime,
snapPoint: closestSnapPoint,
snapDistance: closestDistance,
};
},
[snapThreshold]
);
const snapElementPosition = useCallback(
(
targetTime: number,
tracks: TimelineTrack[],
playheadTime: number,
zoomLevel: number,
excludeElementId?: string
): SnapResult => {
const snapPoints = findSnapPoints(
tracks,
targetTime,
playheadTime,
zoomLevel,
excludeElementId
);
return snapToNearestPoint(targetTime, snapPoints, zoomLevel);
},
[findSnapPoints, snapToNearestPoint]
);
const snapElementEdge = useCallback(
(
targetTime: number,
elementDuration: number,
tracks: TimelineTrack[],
playheadTime: number,
zoomLevel: number,
excludeElementId?: string,
snapToStart = true // true for start edge, false for end edge
): SnapResult => {
const snapPoints = findSnapPoints(
tracks,
targetTime,
playheadTime,
zoomLevel,
excludeElementId
);
// For end edge snapping, we need to account for element duration
const effectiveTargetTime = snapToStart
? targetTime
: targetTime + elementDuration;
const snapResult = snapToNearestPoint(
effectiveTargetTime,
snapPoints,
zoomLevel
);
// Adjust the snapped time back for end edge
if (!snapToStart && snapResult.snapPoint) {
snapResult.snappedTime = snapResult.snappedTime - elementDuration;
}
return snapResult;
},
[findSnapPoints, snapToNearestPoint]
);
return {
snapElementPosition,
snapElementEdge,
findSnapPoints,
snapToNearestPoint,
};
}
|
