PAGE XML renderer / export by JKamlah · Pull Request #4214 · tesseract-ocr/tesseract

JKamlah · 2024-03-20T11:31:33Z

Hi everyone,

I've created a PAGE-XML renderer/export.

It's not just a simple PAGE-XML export, it can also produce a textline polygon instead of a simple bounding box, and it can output up to word level.
The output can be customised with three bool parameters

   tessedit_create_page_xml -> "Write .page.xml PAGE file".
   page_xml_polygon -> "Create PAGE file with polygons instead of box values (default:True)".
   page_xml_level -> "Create PAGE with 0 - line or 1 - word level (default:0)".

After installing tesseract you can use the preconfigured settings: 'page' .
page -> Output page.xml file with polygon and line-level

As word-level is more of a niche requirement, you need to enable it via -c:
-c page_xml_polygon=1 // True polygon or False bounding boxes
-c page_xml_level=1 // 0 line or 1 word level

The output is valid for PAGE XML version 2019-07-15.

If the textlines contains only ltr or rtl characters, the output is correct, but for mixed lines (BiDi) I am not quite sure.
Can anyone help me here?

egorpugin · 2024-03-20T12:25:31Z

Can you send a result file of this code for some example image?

stweil

The CI builds fail because some include statements are missing.

src/api/pagerenderer.cpp

README.md

include/tesseract/renderer.h

JKamlah · 2024-03-20T14:10:20Z

Thanks for suggestion and fixes @stweil

Here are examples for eurotext and hebrew with 'page' and 'page-poly':
https://digi.bib.uni-mannheim.de/~jkamlah/PAGERenderer/

stweil · 2024-03-20T14:20:29Z

Can you send a result file of this code for some example image?

PAGE XML with box coordinates:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<PcGts xmlns="http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15 http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15/pagecontent.xsd">
        <Metadata>
                <Creator>Tesseract - 5.3.4-27-ge2f3</Creator>
                <Created>2024-03-20T14:16:51</Created>
                <LastChange>2024-03-20T14:16:51</LastChange>
        </Metadata>
        <Page imageFilename="test/testing/HelloGoogle.tif" imageWidth="400" imageHeight="200" type="content">
                <ReadingOrder>
                        <OrderedGroup id="ro6814328771458624830" caption="Regions reading order">
                                <RegionRefIndexed index="0" regionRef="r0"/>
                        </OrderedGroup>
                </ReadingOrder>
                <TextRegion id="r0" custom="readingOrder {index:0;} readingDirection {left-to-right;} orientation {0;}">
                        <Coords points="10,20 331,20 331,71 10,71"/>
                        <TextLine id="r0l0" readingDirection="left-to-right" custom="readingOrder {index:0;}">
                                <Coords points="10,20 331,20 331,71 10,71"/>
                                <Baseline points="10,59 331,63"/>
                                <TextEquiv index="1" conf="0.9585">
                                        <Unicode>Hello Google</Unicode>
                                </TextEquiv>
                        </TextLine>
                        <TextEquiv index="1" conf="0.9585">
                                <Unicode>Hello Google</Unicode>
                        </TextEquiv>
                </TextRegion>
                </Page>
</PcGts>

PAGE XML with polygon:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<PcGts xmlns="http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15 http://schema.primaresearch.org/PAGE/gts/pagecontent/2019-07-15/pagecontent.xsd">
        <Metadata>
                <Creator>Tesseract - 5.3.4-27-ge2f3</Creator>
                <Created>2024-03-20T14:19:36</Created>
                <LastChange>2024-03-20T14:19:36</LastChange>
        </Metadata>
        <Page imageFilename="test/testing/HelloGoogle.tif" imageWidth="400" imageHeight="200" type="content">
                <ReadingOrder>
                        <OrderedGroup id="ro6814328771458624830" caption="Regions reading order">
                                <RegionRefIndexed index="0" regionRef="r0"/>
                        </OrderedGroup>
                </ReadingOrder>
                <TextRegion id="r0" custom="readingOrder {index:0;} readingDirection {left-to-right;} orientation {0;}">
                        <Coords points="10,20 331,20 331,71 10,71"/>
                        <TextLine id="r0l0" readingDirection="left-to-right" custom="readingOrder {index:0;}">
                                <Coords points="10,21 42,21 46,30 74,30 79,20 102,20 105,30 132,30 158,22 193,22 197,32 276,32 276,22 298,22 331,23 331,63 298,63 298,71 259,71 256,62 197,62 158,61 74,60 46,60 10,58"/>
                                <Baseline points="10,59 158,60 331,63"/>
                                <TextEquiv index="1" conf="0.9585">
                                        <Unicode>Hello Google</Unicode>
                                </TextEquiv>
                        </TextLine>
                        <TextEquiv index="1" conf="0.9585">
                                <Unicode>Hello Google</Unicode>
                        </TextEquiv>
                </TextRegion>
                </Page>
</PcGts>

src/api/pagerenderer.cpp

JKamlah · 2024-03-20T14:36:09Z

Added terminating linefeed, removed trailing whitespaces and fixed typos (found by typos-cli).
For the unused functions and variables I need some time.

CMakeLists.txt

include/tesseract/baseapi.h

src/ccmain/tesseractclass.cpp

src/ccmain/tesseractclass.h

src/api/pagerenderer.cpp

stweil · 2024-04-10T11:17:14Z

Maybe we can merge this new feature in a new 5.4.0 pre-release.

Co-authored-by: Stefan Weil <sw@weilnetz.de>

Unused variables Co-authored-by: Stefan Weil <sw@weilnetz.de>

Remove unused variables Co-authored-by: Stefan Weil <sw@weilnetz.de>

…lygon.

…grees.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

Add PAGE XML export and documentation. To generate PAGE XML output just add 'page' to the tesseract command. The output is outputname + '.page.xml' to avoid conflicts with ALTO export. The output can be customized with the flags: tessedit_create_page_polygon and tessedit_create_page_wordlevel. Co-authored-by: Stefan Weil <sw@weilnetz.de>

egorpugin · 2024-04-19T19:22:01Z

Should we squash long PRs?

Upd.:
I see, seems squashed.

Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

Fixes: 577e8a8 ("Add PAGE XML renderer / export (tesseract-ocr#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

Use also enum names instead of numeric values where possible. Fixes: 577e8a8 ("Add PAGE XML renderer / export (tesseract-ocr#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

Use also enum names instead of numeric values where possible. Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

stweil · 2026-02-09T12:14:52Z

src/api/pagerenderer.cpp

+/// Sort baseline points ascending and deleting duplicates
+///
+Pta *SortBaseline(Pta *baseline_pts,
+                  tesseract::WritingDirection writing_direction) {


@JKamlah, writing_direction is not used in this function. Should this parameter be removed?

This input var can be removed. Initially, the function depended on the writing direction, but this part has been removed.

stweil · 2026-02-09T12:17:30Z

src/api/pagerenderer.cpp

+///
+Pta *RecalcPolygonline(Pta *pts, bool upper) {
+  int num_pts, num_bin, index = 0;
+  int y, x0, y0, x1, y1;


y is assigned a float value, and it is compared to float or double values. Should it be declared as a float value? Or is it an integer, and type casts should be added?

Related compiler warnings:

../../../src/api/pagerenderer.cpp:139:19: warning: implicit conversion turns floating-point number into integer: 'float' to 'int' [-Wfloat-conversion] ../../../src/api/pagerenderer.cpp:157:21: warning: implicit conversion turns floating-point number into integer: 'float' to 'int' [-Wfloat-conversion] ../../../src/api/pagerenderer.cpp:159:13: warning: implicit conversion increases floating-point precision: 'l_float32' (aka 'float') to 'double' [-Wdouble-promotion] ../../../src/api/pagerenderer.cpp:163:13: warning: implicit conversion increases floating-point precision: 'l_float32' (aka 'float') to 'double' [-Wdouble-promotion] ../../../src/api/pagerenderer.cpp:175:11: warning: implicit conversion turns floating-point number into integer: 'l_float32' (aka 'float') to 'int' [-Wfloat-conversion] ../../../src/api/pagerenderer.cpp:184:11: warning: implicit conversion turns floating-point number into integer: 'l_float32' (aka 'float') to 'int' [-Wfloat-conversion]

It is indeed an int and type cast should be applied.

Done now. In addition I fixed several memory leaks which were detected by a recently added new test case which was contributed by Copilot.

Thanks a lot @stweil

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stweil marked this pull request as ready for review April 10, 2024 11:16

JKamlah and others added 14 commits April 19, 2024 21:04

Formatting with clang and added parethesis to one-line if statements.

f294bb2

Update src/ccmain/tesseractclass.cpp

ed966fd

Co-authored-by: Stefan Weil <sw@weilnetz.de>

Apply suggestions from code review

4d52d1b

Unused variables Co-authored-by: Stefan Weil <sw@weilnetz.de>

Update src/api/pagerenderer.cpp

9130d34

Remove unused variables Co-authored-by: Stefan Weil <sw@weilnetz.de>

Refactor: Enforce 'page' cmd, rename params, and prune unused vars

4d3737c

Fix typos for level description.

49abc07

Change generation of line string to default (as text).

df29f8b

Fix problem, if all original baselinepoints are outside of the new po…

ea659cb

…lygon.

Use fallback bbox values for text with orientation with 90 and 180 de…

cdf6e5d

…grees.

Rename flag for skewed lines.

81f0ebb

Delete old comments.

a84e4be

Fix XML escape for UTF-8 content.

65a40ec

Check for skewed lines on TextRegion level.

4e9053b

Format code with clang-format

bc12457

Signed-off-by: Stefan Weil <sw@weilnetz.de>

stweil force-pushed the PAGERenderer branch from bedd9bc to bc12457 Compare April 19, 2024 19:06

stweil merged commit a789b2d into tesseract-ocr:main Apr 19, 2024

stweil added a commit that referenced this pull request Apr 24, 2024

Add missing new function prototypes for PAGE renderer to C API

88771ca

Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

stweil added a commit that referenced this pull request Apr 24, 2024

Remove unused local variables in PAGE renderer

d6f0073

Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

stweil added a commit to stweil/tesseract that referenced this pull request May 3, 2024

Remove trailing whitespace from PAGE XML <Unicode> output

72fe0eb

Fixes: 577e8a8 ("Add PAGE XML renderer / export (tesseract-ocr#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

stweil added a commit that referenced this pull request May 3, 2024

Remove trailing whitespace from PAGE XML <Unicode> output

4a49e03

Fixes: 577e8a8 ("Add PAGE XML renderer / export (#4214)") Signed-off-by: Stefan Weil <sw@weilnetz.de>

BrewTestBot mentioned this pull request Jun 6, 2024

tesseract 5.4.0 Homebrew/homebrew-core#173888

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Sicos1977 mentioned this pull request Oct 22, 2024

Add support for Tesseract 5.4.1 Sicos1977/TesseractOCR#60

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stweil mentioned this pull request Oct 28, 2024

Add renderer for PAGE XML #4335

Closed

amitdo added the output issues related output formats label Nov 11, 2024

stweil reviewed Feb 9, 2026

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