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/**********************************************************************
* File: points.cpp (Formerly coords.c)
* Description: Member functions for coordinate classes.
* Author: Ray Smith
*
* (C) Copyright 1991, Hewlett-Packard Ltd.
** 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.
*
**********************************************************************/
#define _USE_MATH_DEFINES // for M_PI
#include "points.h"
#include "helpers.h"
#include "serialis.h"
#include <algorithm>
#include <cmath> // for M_PI
#include <cstdlib>
namespace tesseract {
ELISTIZE (ICOORDELT) //turn to list
bool FCOORD::normalise() { //Convert to unit vec
float len = length ();
if (len < 0.0000000001) {
return false;
}
xcoord /= len;
ycoord /= len;
return true;
}
// Set from the given x,y, shrinking the vector to fit if needed.
void ICOORD::set_with_shrink(int x, int y) {
// Fit the vector into an ICOORD, which is 16 bit.
int factor = 1;
int max_extent = std::max(abs(x), abs(y));
if (max_extent > INT16_MAX)
factor = max_extent / INT16_MAX + 1;
xcoord = x / factor;
ycoord = y / factor;
}
// The fortran/basic sgn function returns -1, 0, 1 if x < 0, x == 0, x > 0
// respectively.
static int sign(int x) {
if (x < 0)
return -1;
else
return x > 0 ? 1 : 0;
}
// Writes to the given file. Returns false in case of error.
bool ICOORD::Serialize(FILE* fp) const {
return tesseract::Serialize(fp, &xcoord) &&
tesseract::Serialize(fp, &ycoord);
}
// Reads from the given file. Returns false in case of error.
// If swap is true, assumes a big/little-endian swap is needed.
bool ICOORD::DeSerialize(bool swap, FILE* fp) {
if (!tesseract::DeSerialize(fp, &xcoord)) return false;
if (!tesseract::DeSerialize(fp, &ycoord)) return false;
if (swap) {
ReverseN(&xcoord, sizeof(xcoord));
ReverseN(&ycoord, sizeof(ycoord));
}
return true;
}
// Setup for iterating over the pixels in a vector by the well-known
// Bresenham rendering algorithm.
// Starting with major/2 in the accumulator, on each step add major_step,
// and then add minor to the accumulator. When the accumulator >= major
// subtract major and step a minor step.
void ICOORD::setup_render(ICOORD* major_step, ICOORD* minor_step,
int* major, int* minor) const {
int abs_x = abs(xcoord);
int abs_y = abs(ycoord);
if (abs_x >= abs_y) {
// X-direction is major.
major_step->xcoord = sign(xcoord);
major_step->ycoord = 0;
minor_step->xcoord = 0;
minor_step->ycoord = sign(ycoord);
*major = abs_x;
*minor = abs_y;
} else {
// Y-direction is major.
major_step->xcoord = 0;
major_step->ycoord = sign(ycoord);
minor_step->xcoord = sign(xcoord);
minor_step->ycoord = 0;
*major = abs_y;
*minor = abs_x;
}
}
// Returns the standard feature direction corresponding to this.
// See binary_angle_plus_pi below for a description of the direction.
uint8_t FCOORD::to_direction() const {
return binary_angle_plus_pi(angle());
}
// Sets this with a unit vector in the given standard feature direction.
void FCOORD::from_direction(uint8_t direction) {
double radians = angle_from_direction(direction);
xcoord = cos(radians);
ycoord = sin(radians);
}
// Converts an angle in radians (from ICOORD::angle or FCOORD::angle) to a
// standard feature direction as an unsigned angle in 256ths of a circle
// measured anticlockwise from (-1, 0).
uint8_t FCOORD::binary_angle_plus_pi(double radians) {
return Modulo(IntCastRounded((radians + M_PI) * 128.0 / M_PI), 256);
}
// Inverse of binary_angle_plus_pi returns an angle in radians for the
// given standard feature direction.
double FCOORD::angle_from_direction(uint8_t direction) {
return direction * M_PI / 128.0 - M_PI;
}
// Returns the point on the given line nearest to this, ie the point such
// that the vector point->this is perpendicular to the line.
// The line is defined as a line_point and a dir_vector for its direction.
FCOORD FCOORD::nearest_pt_on_line(const FCOORD& line_point,
const FCOORD& dir_vector) const {
FCOORD point_vector(*this - line_point);
// The dot product (%) is |dir_vector||point_vector|cos theta, so dividing by
// the square of the length of dir_vector gives us the fraction of dir_vector
// to add to line1 to get the appropriate point, so
// result = line1 + lambda dir_vector.
double lambda = point_vector % dir_vector / dir_vector.sqlength();
return line_point + (dir_vector * lambda);
}
} // namespace tesseract
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