path2d.custom — API & validation

Signature: await painter.path2d.custom(options, canvasBuffer)

• options — one CustomOptions object or an array processed in order (later segments paint above earlier ones unless singleLine chains geometry).
• canvasBuffer — Buffer or CanvasResults (.buffer PNG bytes).

Implementation: runDrawCustomLines (apex-painter/path-custom-lines.ts) loads the buffer into a fresh canvas, runs customLines(ctx, opts), returns image/png Buffer.

#Validation

Throws if:

#CustomOptions shape (top level)

Full lineStyle / arrow / markers tables live in the next chapters.

#Batch drawing

Pass CustomOptions[] to paint multiple independent connectors (flowcharts, timelines). Order matters for overlaps — draw guides before foreground strokes.

#Chained segments (lineStyle.singleLine)

When singleLine: true, customLines keeps beginPath open across consecutive rows:

• Row i > 0 reuses previousEndCoordinates as the effective moveTo anchor (start vertex omitted from lineTo chain except on the first row of the sequence).
• Stroke executes when singleLine ends or on the last row of the batch.

Use this for one continuous stroke through several endCoordinates knots while varying arrow/markers only on relevant rows.

#Scene parity

SceneLayer { type: 'customLines', lines: CustomOptions | CustomOptions[] } uses the same validation (scene-normalizer) before customLines runs.

#Example — two hops + arrow

1await painter.path2d.custom(2  [3    {4      startCoordinates: { x: 60, y: 180 },5      endCoordinates: { x: 260, y: 180 },6      lineStyle: { width: 3, color: '#cbd5e1', lineCap: 'round' },7    },8    {9      startCoordinates: { x: 260, y: 180 },10      endCoordinates: { x: 460, y: 280 },11      lineStyle: { width: 3, color: '#cbd5e1', lineCap: 'round' },12      arrow: { end: true, size: 12 },13    },14  ],15  buffer16);