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Document aliasing of tesseract renderer

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James R. Barlow
2018-05-02 14:47:38 -07:00
parent 6376f77b8c
commit 04580accb4
1 changed files with 2 additions and 6 deletions
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docs/advanced.rst
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@@ -116,7 +116,7 @@ Currently this is the best renderer for most uses, however it is implemented in
When image preprocessing features like ``--deskew`` are used, the original PDF will be rendered as a full page and the OCR layer will be placed on top.
This renderer requires Tesseract 3.05.01 or newer.
If a PDF created with this renderer using Tesseract versions older than 3.05.00 is then passed through Ghostscript's pdfwrite feature, the OCR text *may* be corrupted. The ``--output-type=pdfa`` argument will produce a warning in this situation. For this reason, OCRmyPDF automatically selects the ``hocr`` for older Tesseract versions.
The ``hocr`` renderer
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@@ -132,8 +132,4 @@ This works in all versions of Tesseract.
The ``tesseract`` renderer
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The ``tesseract`` renderer creates a PDF with the image and text layers precomposed, meaning that it always transcodes, loses image quality and rasterizes any vector objects. It does a better job on non-Latin text and document structure than ``hocr``.
If a PDF created with this renderer using Tesseract versions older than 3.05.00 is then passed through Ghostscript's pdfwrite feature, the OCR text *may* be corrupted. The ``--output-type=pdfa`` argument will produce a warning in this situation.
*This renderer is deprecated and will be removed whenever support for older versions of Tesseract is dropped.*
The ``tesseract`` renderer is deprecated, and is now an alias for the ``sandwich`` renderer. The alias will be removed in a future release.