gram: docs

> ./packages/core/src/layout-painter/__tests__/header-footer-float-left.test.ts

/**
 * Header/footer anchored-object horizontal positioning. A text box (or image)
 * anchored centered relative to the page must resolve to a centered `left`, not
 * be pinned to the container's left edge.
 */

import { describe, test, expect } from 'bun:test';
import { resolveHeaderFooterFloatLeft, type HeaderFooterLayoutInfo } from '../renderPage';

const layout: HeaderFooterLayoutInfo = {
  flowTop: 50,
  flowLeft: 100,
  contentWidth: 400,
  pageWidth: 612,
  pageHeight: 792,
  margins: { top: 72, right: 72, bottom: 72, left: 72 },
};

describe('resolveHeaderFooterFloatLeft', () => {
  test('no position → pinned left', () => {
    expect(resolveHeaderFooterFloatLeft(200, undefined, layout)).toBe('0');
  });

  test('center relative to page → centered on the page, in container coords', () => {
    // (pageWidth 612 - width 200) / 2 - flowLeft 100 = 106
    expect(resolveHeaderFooterFloatLeft(200, { relativeTo: 'page', align: 'center' }, layout)).toBe(
      '106px'
    );
  });

  test('right relative to page', () => {
    // 612 - 200 - 100 = 312
    expect(resolveHeaderFooterFloatLeft(200, { relativeTo: 'page', align: 'right' }, layout)).toBe(
      '312px'
    );
  });

  test('center without page anchor → centered in the content/margin box', () => {
    // (contentWidth 400 - 200) / 2 = 100
    expect(resolveHeaderFooterFloatLeft(200, { align: 'center' }, layout)).toBe('100px');
  });
});