react-native-mask-segment-canvas/docs/docs/api/ref-methods.md

id	title
ref-methods	Ref Methods

🔧 Ref Methods

Accessed via ref (type MaskSegmentCanvasRef):

Method	Signature	Description
reset	() => void	Undo last paint step (by paintHistory)
swap	(showOrigin?: boolean) => void	Toggle origin image comparison; omit arg to toggle, true/false to force
save	(options?) => Promise<SavePaintResult>	Composite and save PNG; options.destDir optional output directory
session	() => MaskSegmentSession	Export JSON-serializable session (for MMKV storage)
loadSession	(session) => void	Restore paint state (also available via initialSession)
setPaintColor	(color, configJson?) => void	Set current brush color; clears bottom color bar selection
setMaskConfig	(config) => void	Update mask config at runtime and re-segment
clearAllPaint	() => void	Clear all paint records
resegment	() => Promise<void>	Clear PNG cache and re-segment
getRegions	() => SegmentRegion[]	Snapshot of current region list
getPaintedRegions	() => PaintedRegionRecord[]	Snapshot of current paint records
getLastExport	() => SavePaintResult | null	Returns the most recent auto-export or save() result, if any
startLasso	() => void	Enter lasso mode — user can tap wall mask area to place polygon vertices
endLasso	() => ManualWallPartition[]	Exit lasso mode, convert all closed lasso polygons into wall-X sub-regions for painting
cancelLasso	() => void	Exit the current lasso editing session without saving regions
getManualRegions	() => ManualWallPartition[]	Get the current manual wall partitions (only valid after endLasso)
deleteLasso	(id: string) => void	Delete a lasso polygon by its id. Committed partitions also drop paint on that region

SavePaintResult

{ filePath, width, height, paintedCount, previewPath? }

ManualWallPartition

{ id, regionId, regionName, vertices, bbox, area }

Returned by endLasso() and getManualRegions(). Each partition maps a lasso polygon to a wall-N sub-region.

Code Examples

const ref = useRef<MaskSegmentCanvasRef>(null);

// Paint operations
ref.current?.reset();
ref.current?.swap();           // toggle
ref.current?.swap(true);       // force show origin

const result = await ref.current?.save({ destDir: '/path/to/dir' });

const session = ref.current?.session();
ref.current?.loadSession(session);

ref.current?.setPaintColor({ b: 100, g: 120, r: 140 }, { sku: 'paint-001' });
ref.current?.setMaskConfig({ semanticColors: customColors });

ref.current?.clearAllPaint();
await ref.current?.resegment();

const regions = ref.current?.getRegions();
const painted = ref.current?.getPaintedRegions();

// Lasso operations
ref.current?.startLasso();                // enter lasso mode
// ... user taps wall areas to place vertices ...
const partitions = ref.current?.endLasso();  // convert polygons to wall-N regions
ref.current?.cancelLasso();               // discard in-progress lasso

const manualRegions = ref.current?.getManualRegions();
ref.current?.deleteLasso('lasso_1');      // remove a specific polygon

save depends on the working buffer and pickMap being ready (typically after interactive); throws 'Image not ready, cannot save' if not ready.