mirror of
https://github.com/tesseract-ocr/tesseract.git
synced 2024-12-12 15:39:04 +08:00
73 lines
3.2 KiB
C
73 lines
3.2 KiB
C
|
///////////////////////////////////////////////////////////////////////
|
||
|
|
// File: cjkpitch.h
|
||
|
|
// Description: Code to determine fixed pitchness and the pitch if fixed,
|
||
|
|
// for CJK text.
|
||
|
|
// Copyright 2011 Google Inc. All Rights Reserved.
|
||
|
|
// Author: takenaka@google.com (Hiroshi Takenaka)
|
||
|
|
// Created: Mon Jun 27 12:48:35 JST 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 CJKPITCH_H_
|
||
|
|
#define CJKPITCH_H_
|
||
|
|
|
||
|
|
#include "blobbox.h"
|
||
|
|
#include "notdll.h"
|
||
|
|
|
||
|
|
// Function to test "fixed-pitchness" of the input text and estimating
|
||
|
|
// character pitch parameters for it, based on CJK fixed-pitch layout
|
||
|
|
// model.
|
||
|
|
//
|
||
|
|
// This function assumes that a fixed-pitch CJK text has following
|
||
|
|
// characteristics:
|
||
|
|
//
|
||
|
|
// - Most glyphs are designed to fit within the same sized square
|
||
|
|
// (imaginary body). Also they are aligned to the center of their
|
||
|
|
// imaginary bodies.
|
||
|
|
// - The imaginary body is always a regular rectangle.
|
||
|
|
// - There may be some extra space between character bodies
|
||
|
|
// (tracking).
|
||
|
|
// - There may be some extra space after punctuations.
|
||
|
|
// - The text is *not* space-delimited. Thus spaces are rare.
|
||
|
|
// - Character may consists of multiple unconnected blobs.
|
||
|
|
//
|
||
|
|
// And the function works in two passes. On pass 1, it looks for such
|
||
|
|
// "good" blobs that has the pitch same pitch on the both side and
|
||
|
|
// looks like a complete CJK character. Then estimates the character
|
||
|
|
// pitch for every row, based on those good blobs. If we couldn't find
|
||
|
|
// enough good blobs for a row, then the pitch is estimated from other
|
||
|
|
// rows with similar character height instead.
|
||
|
|
//
|
||
|
|
// Pass 2 is an iterative process to fit the blobs into fixed-pitch
|
||
|
|
// character cells. Once we have estimated the character pitch, blobs
|
||
|
|
// that are almost as large as the pitch can be considered to be
|
||
|
|
// complete characters. And once we know that some characters are
|
||
|
|
// complete characters, we can estimate the region occupied by its
|
||
|
|
// neighbors. And so on.
|
||
|
|
//
|
||
|
|
// We repeat the process until all ambiguities are resolved. Then make
|
||
|
|
// the final decision about fixed-pitchness of each row and compute
|
||
|
|
// pitch and spacing parameters.
|
||
|
|
//
|
||
|
|
// (If a row is considered to be propotional, pitch_decision for the
|
||
|
|
// row is set to PITCH_CORR_PROP and the later phase
|
||
|
|
// (i.e. Textord::to_spacing()) should determine its spacing
|
||
|
|
// parameters)
|
||
|
|
//
|
||
|
|
// This function doesn't provide all information required by
|
||
|
|
// fixed_pitch_words() and the rows need to be processed with
|
||
|
|
// make_prop_words() even if they are fixed pitched.
|
||
|
|
void compute_fixed_pitch_cjk(ICOORD page_tr, // top right
|
||
|
|
TO_BLOCK_LIST *port_blocks); // input list
|
||
|
|
|
||
|
|
#endif // CJKPITCH_H_
|