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https://github.com/tesseract-ocr/tesseract.git
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64 lines
2.4 KiB
C++
64 lines
2.4 KiB
C++
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/******************************************************************************
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** Filename: xform2d.c
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** Purpose: Library routines for performing 2D point transformations
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** Author: Dan Johnson
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** History: Fri Sep 22 09:54:17 1989, DSJ, Created.
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**
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** (c) Copyright Hewlett-Packard Company, 1988.
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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** http://www.apache.org/licenses/LICENSE-2.0
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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******************************************************************************/
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/**----------------------------------------------------------------------------
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Include Files and Type Defines
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----------------------------------------------------------------------------**/
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#include "xform2d.h"
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#include <math.h>
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/**----------------------------------------------------------------------------
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Public Code
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----------------------------------------------------------------------------**/
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/*---------------------------------------------------------------------------*/
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void RotateMatrix(MATRIX_2D_PTR Matrix, FLOAT32 Angle) {
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/*
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** Parameters:
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** Matrix transformation matrix to rotate
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** Angle angle to rotate matrix
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** Globals: none
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** Operation:
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** Rotate the coordinate system (as specified by Matrix) about
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** its origin by Angle radians. In matrix notation the
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** effect is as follows:
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**
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** Matrix = R X Matrix
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**
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** where R is the following matrix
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**
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** cos Angle sin Angle 0
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** -sin Angle cos Angle 0
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** 0 0 1
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** Return: none
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** Exceptions: none
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** History: 7/27/89, DSJ, Create.
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*/
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FLOAT32 Cos, Sin;
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FLOAT32 NewA, NewB;
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Cos = cos ((double) Angle);
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Sin = sin ((double) Angle);
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NewA = Matrix->a * Cos + Matrix->c * Sin;
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NewB = Matrix->b * Cos + Matrix->d * Sin;
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Matrix->c = Matrix->a * -Sin + Matrix->c * Cos;
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Matrix->d = Matrix->b * -Sin + Matrix->d * Cos;
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Matrix->a = NewA;
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Matrix->b = NewB;
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} /* RotateMatrix */
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