--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/textord/ccnontextdetect.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,85 @@
+///////////////////////////////////////////////////////////////////////
+// File:        ccnontextdetect.h
+// Description: Connected-Component-based non-text detection.
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: rays@google.com (Ray Smith)
+// Created:     Sat Jun 11 09:52:01 PST 2011
+//
+// 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.
+//
+///////////////////////////////////////////////////////////////////////
+
+#ifndef TESSERACT_TEXTORD_CCPHOTODETECT_H_
+#define TESSERACT_TEXTORD_CCPHOTODETECT_H_
+
+#include "blobgrid.h"
+#include "scrollview.h"
+
+namespace tesseract {
+
+// The CCNonTextDetect class contains grid-based operations on blobs to create
+// a full-resolution image mask analogous yet complementary to
+// pixGenHalftoneMask as it is better at line-drawings, graphs and charts.
+class CCNonTextDetect : public BlobGrid {
+public:
+  CCNonTextDetect(int gridsize, const ICOORD &bleft, const ICOORD &tright);
+  ~CCNonTextDetect() override;
+
+  // Creates and returns a Pix with the same resolution as the original
+  // in which 1 (black) pixels represent likely non text (photo, line drawing)
+  // areas of the page, deleting from the blob_block the blobs that were
+  // determined to be non-text.
+  // The photo_map (binary image mask) is used to bias the decision towards
+  // non-text, rather than supplying a definite decision.
+  // The blob_block is the usual result of connected component analysis,
+  // holding the detected blobs.
+  // The returned Pix should be PixDestroyed after use.
+  Image ComputeNonTextMask(bool debug, Image photo_map, TO_BLOCK *blob_block);
+
+private:
+  // Computes and returns the noise_density IntGrid, at the same gridsize as
+  // this by summing the number of small elements in a 3x3 neighbourhood of
+  // each grid cell. good_grid is filled with blobs that are considered most
+  // likely good text, and this is filled with small and medium blobs that are
+  // more likely non-text.
+  // The photo_map is used to bias the decision towards non-text, rather than
+  // supplying definite decision.
+  IntGrid *ComputeNoiseDensity(bool debug, Image photo_map, BlobGrid *good_grid);
+
+  // Tests each blob in the list to see if it is certain non-text using 2
+  // conditions:
+  // 1. blob overlaps a cell with high value in noise_density_ (previously set
+  // by ComputeNoiseDensity).
+  // OR 2. The blob overlaps more than max_blob_overlaps in *this grid. This
+  // condition is disabled with max_blob_overlaps == -1.
+  // If it does, the blob is declared non-text, and is used to mark up the
+  // nontext_mask. Such blobs are fully deleted, and non-noise blobs have their
+  // neighbours reset, as they may now point to deleted data.
+  // WARNING: The blobs list blobs may be in the *this grid, but they are
+  // not removed. If any deleted blobs might be in *this, then this must be
+  // Clear()ed immediately after MarkAndDeleteNonTextBlobs is called.
+  // If the win is not nullptr, deleted blobs are drawn on it in red, and kept
+  void MarkAndDeleteNonTextBlobs(BLOBNBOX_LIST *blobs, int max_blob_overlaps, ScrollView *win,
+                                 ScrollView::Color ok_color, Image nontext_mask);
+  // Returns true if the given blob overlaps more than max_overlaps blobs
+  // in the current grid.
+  bool BlobOverlapsTooMuch(BLOBNBOX *blob, int max_overlaps);
+
+  // Max entry in noise_density_ before the cell is declared noisy.
+  int max_noise_count_;
+  // Completed noise density map, which we keep around to use for secondary
+  // noise detection.
+  IntGrid *noise_density_;
+};
+
+} // namespace tesseract.
+
+#endif // TESSERACT_TEXTORD_CCPHOTODETECT_H_