Modifier.magnetic¶

Drag horizontally; on release, snap to the nearest anchor.

When to use¶

Drawer-style "swipe to reveal actions" rows where settled positions are 0 / partial / full.
Slider-with-stops inputs (volume presets, intensity levels).
"Drag the chip into a category" gestures.

When not to use¶

Continuous-range sliders (use Slider from Material).
Gestures where overshoot/elastic feel matters more than discreteness.

Usage¶

Box(
    modifier = Modifier
        .size(48.dp)
        .magnetic(anchors = listOf((-120).dp, 0.dp, 120.dp))
        .background(Color.Blue, CircleShape),
)

Parameters¶

Name	Type	Default	Notes
`anchors`	`List<Dp>`	required	Offsets from rest. `0.dp` is included implicitly as a rest anchor.
`snapThreshold`	`Dp`	`24.dp`	Distance from an anchor within which snap occurs. Larger = stickier.

Design notes¶

Node subtype: DelegatingNode + LayoutModifierNode. Delegates to a SuspendingPointerInputModifierNode running detectDragGestures. On release, we find the nearest anchor in pixel-space and Animatable.animateTo it.
Density handling: the modifier needs density to convert the dp-typed anchors to pixels at snap time. We snapshot density inside measure() (where the MeasureScope provides it) and use the captured value at gesture-end time.
Implicit rest anchor: if your anchor list doesn't include 0.dp, the modifier adds it. Lets you write anchors = listOf(120.dp) for a single non-zero detent and still get spring-back.
No haptic by default: intentional. Wire your own HapticFeedback.performHapticFeedback(LongPress) from a state observer if you want a tap-on-snap.