--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/classify/outfeat.cpp	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,160 @@
+/******************************************************************************
+ ** Filename:    outfeat.c
+ ** Purpose:     Definition of outline-features.
+ ** 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 "outfeat.h"
+
+#include "classify.h"
+#include "featdefs.h"
+#include "mfoutline.h"
+#include "ocrfeatures.h"
+
+#include <cstdio>
+
+namespace tesseract {
+
+/*----------------------------------------------------------------------------
+              Public Code
+----------------------------------------------------------------------------*/
+
+/**
+ * Convert each segment in the outline to a feature
+ * and return the features.
+ * @param Blob blob to extract pico-features from
+ * @return Outline-features for Blob.
+ * @note Globals: none
+ */
+FEATURE_SET Classify::ExtractOutlineFeatures(TBLOB *Blob) {
+  auto FeatureSet = new FEATURE_SET_STRUCT(MAX_OUTLINE_FEATURES);
+  if (Blob == nullptr) {
+    return (FeatureSet);
+  }
+
+  auto Outlines = ConvertBlob(Blob);
+
+  float XScale, YScale;
+  NormalizeOutlines(Outlines, &XScale, &YScale);
+  auto RemainingOutlines = Outlines;
+  iterate(RemainingOutlines) {
+    auto Outline = static_cast<MFOUTLINE>(RemainingOutlines->first_node());
+    ConvertToOutlineFeatures(Outline, FeatureSet);
+  }
+  if (classify_norm_method == baseline) {
+    NormalizeOutlineX(FeatureSet);
+  }
+  FreeOutlines(Outlines);
+  return (FeatureSet);
+} /* ExtractOutlineFeatures */
+
+/*----------------------------------------------------------------------------
+              Private Code
+----------------------------------------------------------------------------*/
+/*---------------------------------------------------------------------------*/
+/**
+ * This routine computes the midpoint between Start and
+ * End to obtain the x,y position of the outline-feature.  It
+ * also computes the direction from Start to End as the
+ * direction of the outline-feature and the distance from
+ * Start to End as the length of the outline-feature.
+ * This feature is then
+ * inserted into the next feature slot in FeatureSet.
+ * @param Start starting point of outline-feature
+ * @param End ending point of outline-feature
+ * @param FeatureSet set to add outline-feature to
+ */
+void AddOutlineFeatureToSet(FPOINT *Start, FPOINT *End, FEATURE_SET FeatureSet) {
+  auto Feature = new FEATURE_STRUCT(&OutlineFeatDesc);
+  Feature->Params[OutlineFeatDir] = NormalizedAngleFrom(Start, End, 1.0);
+  Feature->Params[OutlineFeatX] = AverageOf(Start->x, End->x);
+  Feature->Params[OutlineFeatY] = AverageOf(Start->y, End->y);
+  Feature->Params[OutlineFeatLength] = DistanceBetween(*Start, *End);
+  AddFeature(FeatureSet, Feature);
+
+} /* AddOutlineFeatureToSet */
+
+/*---------------------------------------------------------------------------*/
+/**
+ * This routine steps converts each section in the specified
+ * outline to a feature described by its x,y position, length
+ * and angle.
+ * Results are returned in FeatureSet.
+ * @param Outline outline to extract outline-features from
+ * @param FeatureSet set of features to add outline-features to
+ */
+void ConvertToOutlineFeatures(MFOUTLINE Outline, FEATURE_SET FeatureSet) {
+  MFOUTLINE Next;
+  MFOUTLINE First;
+  FPOINT FeatureStart;
+  FPOINT FeatureEnd;
+
+  if (DegenerateOutline(Outline)) {
+    return;
+  }
+
+  First = Outline;
+  Next = First;
+  do {
+    FeatureStart = PointAt(Next)->Point;
+    Next = NextPointAfter(Next);
+
+    /* note that an edge is hidden if the ending point of the edge is
+   marked as hidden.  This situation happens because the order of
+   the outlines is reversed when they are converted from the old
+   format.  In the old format, a hidden edge is marked by the
+   starting point for that edge. */
+    if (!PointAt(Next)->Hidden) {
+      FeatureEnd = PointAt(Next)->Point;
+      AddOutlineFeatureToSet(&FeatureStart, &FeatureEnd, FeatureSet);
+    }
+  } while (Next != First);
+} /* ConvertToOutlineFeatures */
+
+/*---------------------------------------------------------------------------*/
+/**
+ * This routine computes the weighted average x position
+ * over all of the outline-features in FeatureSet and then
+ * renormalizes the outline-features to force this average
+ * to be the x origin (i.e. x=0).
+ * FeatureSet is changed.
+ * @param FeatureSet outline-features to be normalized
+ */
+void NormalizeOutlineX(FEATURE_SET FeatureSet) {
+  int i;
+  FEATURE Feature;
+  float Length;
+  float TotalX = 0.0;
+  float TotalWeight = 0.0;
+  float Origin;
+
+  if (FeatureSet->NumFeatures <= 0) {
+    return;
+  }
+
+  for (i = 0; i < FeatureSet->NumFeatures; i++) {
+    Feature = FeatureSet->Features[i];
+    Length = Feature->Params[OutlineFeatLength];
+    TotalX += Feature->Params[OutlineFeatX] * Length;
+    TotalWeight += Length;
+  }
+  Origin = TotalX / TotalWeight;
+
+  for (i = 0; i < FeatureSet->NumFeatures; i++) {
+    Feature = FeatureSet->Features[i];
+    Feature->Params[OutlineFeatX] -= Origin;
+  }
+} /* NormalizeOutlineX */
+
+} // namespace tesseract