fix(painter-dom): simplify paint API around resolved layout

packages/layout-engine/contracts/src/index.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import { cloneColumnLayout, extractHeaderFooterSpace, normalizeColumnLayout, widthsEqual } from './index.js';
-import type { FlowBlock, Layout, PainterDOM, PainterPDF } from './index.js';
+import type { FlowBlock, Layout } from './index.js';
 
 describe('contracts', () => {
   it('accepts a basic FlowBlock structure', () => {
@@ -20,7 +20,7 @@ describe('contracts', () => {
     expect(block.id).toBe('block-1');
   });
 
-  it('describes a minimal layout', async () => {
+  it('describes a minimal layout', () => {
     const layout: Layout = {
       pageSize: { w: 612, h: 792 },
       pages: [
@@ -62,25 +62,8 @@ describe('contracts', () => {
       },
     };
 
-    const domPainter: PainterDOM = {
-      paint(received, mount) {
-        mount.dataset.pageCount = String(received.pages.length);
-      },
-    };
-
-    const pdfPainter: PainterPDF = {
-      async render(received) {
-        expect(received.pages.length).toBeGreaterThan(0);
-        return new Blob([JSON.stringify(received)]);
-      },
-    };
-
-    const mount = document.createElement('div');
-    domPainter.paint(layout, mount);
-    expect(mount.dataset.pageCount).toBe('1');
-
-    const blob = await pdfPainter.render(layout);
-    expect(blob).toBeInstanceOf(Blob);
+    expect(layout.pages.length).toBe(1);
+    expect(layout.pages[0].fragments.length).toBe(1);
   });
 
   it('extracts header/footer spacing from margins', () => {

packages/layout-engine/contracts/src/index.ts

@@ -1880,87 +1880,13 @@ export type WrapExclusion = {
   wrapText: WrapTextMode;
 };
 
-export type RenderedLineInfo = {
-  el: HTMLElement;
-  top: number;
-  height: number;
-};
-
-/**
- * Interface for position mapping from ProseMirror transactions.
- * Used to efficiently update DOM position attributes without full re-render.
- */
-export interface PositionMapping {
-  /** Transform a position from old to new document coordinates */
-  map(pos: number, bias?: number): number;
-  /** Array of step maps - length indicates transaction complexity */
-  readonly maps: readonly unknown[];
-}
-
 /**
  * Rendering flow mode.
  * - `paginated`: discrete page surfaces
  * - `semantic`: continuous flow surface
  */
 export type FlowMode = 'paginated' | 'semantic';
 
-export interface PainterDOM {
-  paint(layout: Layout, mount: HTMLElement, mapping?: PositionMapping): void;
-  /**
-   * Updates the painter's internal block and measure data without reinstantiating.
-   *
-   * This method is an optimization for incremental rendering pipelines that need to
-   * refresh the underlying data (e.g., after content edits) without creating a new
-   * painter instance. It updates the painter's internal lookup tables to reflect
-   * the new blocks and measures.
-   *
-   * Header and footer blocks should be provided when the layout includes header/footer
-   * content that needs to be rendered. These are typically generated by the layout
-   * engine's header/footer adapter and should be passed through to the painter.
-   *
-   * @param blocks - Main document blocks to be rendered in the page body
-   * @param measures - Measurements corresponding to the main document blocks (must match blocks array length)
-   * @param headerBlocks - Optional array of blocks for header content. When provided, headerMeasures must also be provided.
-   * @param headerMeasures - Optional measurements for header blocks (must match headerBlocks array length when provided)
-   * @param footerBlocks - Optional array of blocks for footer content. When provided, footerMeasures must also be provided.
-   * @param footerMeasures - Optional measurements for footer blocks (must match footerBlocks array length when provided)
-   *
-   * @throws {Error} When blocks and measures array lengths don't match
-   * @throws {Error} When headerBlocks is provided without headerMeasures or vice versa
-   * @throws {Error} When headerBlocks and headerMeasures lengths don't match
-   * @throws {Error} When footerBlocks is provided without footerMeasures or vice versa
-   * @throws {Error} When footerBlocks and footerMeasures lengths don't match
-   *
-   * @example
-   * ```typescript
-   * // Basic usage with main document only
-   * painter.setData(blocks, measures);
-   *
-   * // With headers and footers
-   * painter.setData(
-   *   mainBlocks,
-   *   mainMeasures,
-   *   headerBlocks,
-   *   headerMeasures,
-   *   footerBlocks,
-   *   footerMeasures
-   * );
-   * ```
-   */
-  setData?(
-    blocks: FlowBlock[],
-    measures: Measure[],
-    headerBlocks?: FlowBlock[],
-    headerMeasures?: Measure[],
-    footerBlocks?: FlowBlock[],
-    footerMeasures?: Measure[],
-  ): void;
-}
-
-export interface PainterPDF {
-  render(layout: Layout): Promise<Blob>;
-}
-
 export const extractHeaderFooterSpace = (
   margins?: PageMargins | null,
 ): {