Why PDF compression quietly turns your text into a picture

Описание и применение

Сжатие PDF часто приводит к потере текста, но правильный подход с использованием PDFLib и CompressionStream позволяет уменьшить размер, сохранив все символы.

Задача

Compressing a text PDF often results in a rasterized image, losing selectable text.

Результат

The lossless repack reduced file size by 3.4× compared to the best raster result while keeping all text selectable.

Рабочий процесс

• Load source PDF
• Copy pages into a fresh document
• Save with useObjectStreams:true
• Identify raw streams without /Filter
• Deflate those streams with FlateDecode
• Replace original streams with compressed ones
• Preserve original if deflate not beneficial
• Re‑save document

Доказательства

A 6-page text PDF went from 298.7 KB to 8.9 KB with every one of its 26,652 characters still selectable.

Источник

Lossless came out 3.4× smaller than the best raster result, and it was the only row where the text survived at all.

Источник

Walk every indirect object in the document. For each raw stream whose dictionary has no /Filter, deflate it and label it…

Источник