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Maxim Dolgolyov 8a7091ddec chore(memory): снимок файлов памяти Claude в репозиторий для переноса

Копия пользовательской автопамяти (29 фактов + индекс MEMORY.md) в
.claude/memory/, чтобы переносить между машинами через git.
README.md — как восстановить в пользовательскую папку на другой машине.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

2026-06-05 08:32:16 +03:00

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Image Extraction from PDF — ЦТ/ЦЭ Questions

Tools available

pdftoppm (poppler, via scoop): renders PDF pages to PNG
sharp (npm, installed in backend/): crops images in Node.js
Script: backend/src/db/crop_images.js

Workflow for extracting figures from exam PDF

Step 1 — Render pages at 200 DPI

pdftoppm -png -r 200 -f <first_page> -l <last_page> "path/to/file.pdf" "/tmp/prefix"
# Output: /tmp/prefix-06.png, /tmp/prefix-07.png ...
# Copy to: frontend/img/questions/pageN.png

Step 2 — Calibrate coordinates using 72 DPI reference

pdftoppm -png -r 72 -f <first_page> -l <last_page> "path/to/file.pdf" "/tmp/pt"
# Output: /tmp/pt-06.png etc. (614×844 px for A4)
# Copy to: frontend/img/questions/ptN.png

At 72 DPI: A4 = 614×844 px. Scale to 200 DPI: ×2.777 Measure coordinates visually on 72 DPI images, multiply by 2.777 to get 200 DPI coords.

Step 3 — Test crops (Node.js)

// Run from backend/ folder
const sharp = require('sharp');
sharp('../frontend/img/questions/pt6.png')
  .extract({ left: 220, top: 80, width: 200, height: 100 })
  .toFile('../frontend/img/questions/test.png');

Step 4 — Run crop_images.js

cd backend && node src/db/crop_images.js

ЦТ 2021 — Variant 1 crop coordinates (200 DPI, 1705×2344)

File	Question	Source page	left	top	width	height
ct2021v1_a1.png	A1 triangle	page6.png	611	222	556	292
ct2021v1_a7.png	A7 graph f(x)	page6.png	278	1222	750	403
ct2021v1_a15.png	A15 parabola	page7.png	556	917	695	278
ct2021v1_a17.png	A17 grid A,B	page7.png	861	1439	639	194
ct2021v1_a18.png	A18 pyramid	page7.png	389	1656	945	472
ct2021v1_b1.png	B1 bar chart	page8.png	28	83	1167	556
ct2021v1_b3.png	B3 3D planes	page8.png	1015	1717	319	417
ct2021v1_b4.png	B4 enclosure	page9.png	945	14	542	208

PDF source: ЦТ-ЦЭ/ЦТ 2021.pdf

Page 6 = Variant 1, Part A (A1–A11)
Page 7 = Variant 1, Part A (A12–A18)
Page 8 = Variant 1, Part B (B1–B3)
Page 9 = Variant 1, Part B (B4–B14)

Images stored: frontend/img/questions/ct2021v1_*.png Served at: /img/questions/ct2021v1_*.png (via express.static on frontendDir)

DB: updating image field after seeding

const upd = db.prepare('UPDATE questions SET image = ? WHERE text LIKE ? AND year = ?');
upd.run('/img/questions/ct2021v1_a1.png', '[ЦТ 2021 · A1]%', 2021);

Notes

PDF contains scanned raster images — no extractable vector graphics
Each PDF page = one large bitmap scan
pdfimages extracts only full-page bitmaps (not individual diagram crops)
sharp must be required from backend/ directory (installed there)
Temp page renders NOT committed to git — regenerate with pdftoppm when needed

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