690628b318
Enhance text normalization by incorporating font ascent and descent data to more accurately position glyphs, especially for decorative initials. Update merge logic to better detect line membership using vertical overlap, ensuring drop caps and overlapping glyphs are merged correctly. Extend tests to cover these layout scenarios.
94 lines
2.8 KiB
TypeScript
94 lines
2.8 KiB
TypeScript
import { describe, expect, test } from 'vitest';
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import { normalizeTextItemsForLayout } from '@openreader/compute-core';
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import type { TextItem } from 'pdfjs-dist/types/src/display/api';
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function makeTextItem(
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str: string,
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transform: [number, number, number, number, number, number],
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width = 100,
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): TextItem {
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return {
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str,
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transform,
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width,
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height: Math.abs(transform[3]),
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dir: 'ltr',
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fontName: 'test',
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hasEOL: false,
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} as unknown as TextItem;
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}
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describe('normalizeTextItemsForLayout', () => {
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test('keeps horizontal body text and drops rotated/skewed margin text', () => {
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const horizontal = makeTextItem(
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'Powered by large language models',
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[10, 0, 0, 10, 100, 600],
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);
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// Typical 90deg-ish rotated/skewed run (like side metadata labels).
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const rotated = makeTextItem(
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'arXiv:2407.16741v3 [cs.SE] 18 Apr 2025',
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[0, 10, -10, 0, 30, 400],
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);
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const normalized = normalizeTextItemsForLayout([horizontal, rotated], {
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height: 800,
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transform: [1, 0, 0, -1, 0, 800],
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}, {
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test: { ascent: 0.8, descent: -0.2 },
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});
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expect(normalized).toHaveLength(1);
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expect(normalized[0]?.text).toBe('Powered by large language models');
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});
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test('drops malformed/vertical-only runs so downstream layout planning sees no body text', () => {
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const vertical = makeTextItem('Side label', [0, 10, -10, 0, 30, 200]);
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const skewed = makeTextItem('Watermark', [10, 5, 2, 10, 200, 500]);
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const normalized = normalizeTextItemsForLayout([vertical, skewed], {
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height: 800,
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transform: [1, 0, 0, -1, 0, 800],
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}, {
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test: { ascent: 0.8, descent: -0.2 },
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});
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expect(normalized).toEqual([]);
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});
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test('accounts for non-zero page origins in the viewport transform', () => {
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const croppedPageLine = makeTextItem(
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'Vasher turned away.',
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[11.2, 0, 0, 11.2, 127.5, 644.4128],
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100,
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);
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const normalized = normalizeTextItemsForLayout([croppedPageLine], {
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height: 666.0074,
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transform: [1, 0, 0, -1, -53.4352, 720.565],
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}, {
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test: { ascent: 0.716, descent: -0.269 },
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});
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expect(normalized).toHaveLength(1);
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expect(normalized[0]?.x).toBeCloseTo(74.0648, 4);
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expect(normalized[0]?.y).toBeCloseTo(68.1356, 2);
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});
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test('uses font ascent to place decorative initials closer to the visible glyph top', () => {
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const dropCap = makeTextItem(
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'I',
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[60, 0, 0, 60, 111.1326, 434.46],
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9.18,
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);
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const normalized = normalizeTextItemsForLayout([dropCap], {
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height: 666.0074,
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transform: [1, 0, 0, -1, -53.4352, 720.565],
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}, {
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test: { ascent: 0.638, descent: -0.134 },
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});
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expect(normalized).toHaveLength(1);
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expect(normalized[0]?.y).toBeCloseTo(247.825, 3);
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});
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});
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