--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/classify/blobclass.cpp	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,73 @@
+/******************************************************************************
+ **      Filename:       blobclass.c
+ **      Purpose:        High level blob classification and training routines.
+ **      Author:         Dan Johnson
+ **
+ **      (c) Copyright Hewlett-Packard Company, 1988.
+ ** Licensed under the Apache License, Version 2.0 (the "License");
+ ** you may not use this file except in compliance with the License.
+ ** You may obtain a copy of the License at
+ ** http://www.apache.org/licenses/LICENSE-2.0
+ ** Unless required by applicable law or agreed to in writing, software
+ ** distributed under the License is distributed on an "AS IS" BASIS,
+ ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ ** See the License for the specific language governing permissions and
+ ** limitations under the License.
+ ******************************************************************************/
+
+#include <cstdio>
+
+#include "classify.h"
+#include "featdefs.h"
+#include "mf.h"
+#include "normfeat.h"
+
+namespace tesseract {
+
+/*---------------------------------------------------------------------------*/
+
+// Extracts features from the given blob and saves them in the tr_file_data_
+// member variable.
+// fontname:  Name of font that this blob was printed in.
+// cn_denorm: Character normalization transformation to apply to the blob.
+// fx_info:   Character normalization parameters computed with cn_denorm.
+// blob_text: Ground truth text for the blob.
+void Classify::LearnBlob(const std::string &fontname, TBLOB *blob, const DENORM &cn_denorm,
+                         const INT_FX_RESULT_STRUCT &fx_info, const char *blob_text) {
+  std::unique_ptr<CHAR_DESC_STRUCT> CharDesc(new CHAR_DESC_STRUCT(feature_defs_));
+  CharDesc->FeatureSets[0] = ExtractMicros(blob, cn_denorm);
+  CharDesc->FeatureSets[1] = ExtractCharNormFeatures(fx_info);
+  CharDesc->FeatureSets[2] = ExtractIntCNFeatures(*blob, fx_info);
+  CharDesc->FeatureSets[3] = ExtractIntGeoFeatures(*blob, fx_info);
+
+  if (ValidCharDescription(feature_defs_, CharDesc.get())) {
+    // Label the features with a class name and font name.
+    tr_file_data_ += "\n";
+    tr_file_data_ += fontname;
+    tr_file_data_ += " ";
+    tr_file_data_ += blob_text;
+    tr_file_data_ += "\n";
+
+    // write micro-features to file and clean up
+    WriteCharDescription(feature_defs_, CharDesc.get(), tr_file_data_);
+  } else {
+    tprintf("Blob learned was invalid!\n");
+  }
+} // LearnBlob
+
+// Writes stored training data to a .tr file based on the given filename.
+// Returns false on error.
+bool Classify::WriteTRFile(const char *filename) {
+  bool result = false;
+  std::string tr_filename = filename;
+  tr_filename += ".tr";
+  FILE *fp = fopen(tr_filename.c_str(), "wb");
+  if (fp) {
+    result = tesseract::Serialize(fp, &tr_file_data_[0], tr_file_data_.length());
+    fclose(fp);
+  }
+  tr_file_data_.resize(0);
+  return result;
+}
+
+} // namespace tesseract