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Camera

Camera​

ICamera is the world-view controller in Flowscape.

It maps world space to screen space and exposes interaction-safe controls for pan, zoom, and rotation.

Core Types​

ICamera works with:

  • Point
  • CameraState

From the usage examples, camera state includes at least:

  • x
  • y
  • scale
  • rotation

State and Conversion API​

getState()​

Returns the current camera snapshot.

const { x, y, scale, rotation } = camera.getState();

worldToScreen(world: Point)​

Converts a world coordinate into pixel/screen coordinate.

screenToWorld(screen: Point)​

Converts a screen coordinate into world coordinate.

This pair is the base for hit-testing, cursor tools, drag logic, and anchored zoom.

Constraints and Direct Setters​

setLimits(minScale, maxScale)​

Defines zoom boundaries and prevents unstable extreme zoom values.

setPosition(x, y)​

Moves camera center in world space.

setScale(scale)​

Sets zoom level (with configured limits applied).

setRotationRadians(radians)​

Sets absolute camera rotation in radians.

reset()​

Restores default camera state.

update(newState: Partial<CameraState>)​

Applies partial state changes in one call.

camera.update({ x: 200, scale: 1.5 });

Interaction-Focused Methods​

panByScreen(dx, dy)​

Pans camera using screen deltas (pixels).
Useful for drag-to-pan tools.

zoomAtScreen(screenPoint, factor)​

Zooms around a specific screen anchor (usually cursor position), preserving that anchor context during zoom.

rotateAtScreen(screenPoint, deltaRadians)​

Rotates around a specific screen anchor point.

Minimal Example​

import type { ICamera } from '@flowscape-ui/core-sdk';

function handleWheelZoom(camera: ICamera, clientX: number, clientY: number, deltaY: number) {
  const factor = deltaY > 0 ? 1 / 1.08 : 1.08;
  camera.zoomAtScreen({ x: clientX, y: clientY }, factor);
}

function handlePan(camera: ICamera, dx: number, dy: number) {
  camera.panByScreen(dx, dy);
}

Practical Rules​

  • Use zoomAtScreen(...) instead of manual setScale(...) during pointer zoom.
  • Use conversion methods (screenToWorld / worldToScreen) as the single coordinate bridge.
  • Keep limits configured early (setLimits) to avoid invalid interaction states.

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