//---------------------------------------------------------------------------
/*
AsciiArter, class to convert greyscale to ASCII art
Copyright (C) 2011 Richel Bilderbeek
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppAsciiArter.htm
//---------------------------------------------------------------------------
#include <algorithm>
#include <cassert>
#include <iostream>
#include <numeric>
#include <boost/scoped_ptr.hpp>
#include <boost/numeric/conversion/cast.hpp>
#include "asciiarter.h"
//---------------------------------------------------------------------------
const std::vector<char> AsciiArter::m_gradient
= AsciiArter::GetAsciiArtGradient();
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppGetAsciiArtGradient.htm
const std::vector<char> AsciiArter::GetAsciiArtGradient()
{
std::vector<char> chars;
chars.push_back('M');
chars.push_back('N');
chars.push_back('m');
chars.push_back('d');
chars.push_back('h');
chars.push_back('y');
chars.push_back('s');
chars.push_back('o');
chars.push_back('+');
chars.push_back('/');
chars.push_back(':');
chars.push_back('-');
chars.push_back('.');
chars.push_back('`');
chars.push_back(' ');
return chars;
}
//---------------------------------------------------------------------------
double AsciiArter::GetGreyness(
const std::vector<std::vector<double> >& image,
const int x,
const int y)
{
assert(!image.empty()
&& "Image is NULL");
assert(x >= 0
&& "x coordinat is below zero");
assert(y >= 0
&& "y coordinat is below zero");
assert(y < boost::numeric_cast<int>(image.size())
&& "y coordinat is beyond image height");
assert(x < boost::numeric_cast<int>(image[y].size())
&& "x coordinat is beyond image width");
const double greyness = image[y][x];
assert(greyness >= 0.0);
assert(greyness <= 1.0);
return greyness;
}
//---------------------------------------------------------------------------
//Get a line of pixel's average greyness
double AsciiArter::GetGreyness(
const std::vector<std::vector<double> >& image,
const int x1,
const int x2,
const int y)
{
assert(!image.empty()
&& "Image is NULL");
assert(x1 >= 0
&& "x1 coordinat is below zero");
assert(x2 >= 0
&& "x2 coordinat is below zero");
assert(y >= 0
&& "y coordinat is below zero");
assert(y < boost::numeric_cast<int>(image.size())
&& "y coordinat is beyond image height");
assert(x1 < x2
&& "X-coordinats must be different and ordered");
assert(x1 < boost::numeric_cast<int>(image[y].size())
&& "x1 coordinat is beyond image width");
assert(x2 < boost::numeric_cast<int>(image[y].size())
&& "x2 coordinat is beyond image width");
assert(image[y].begin() + x2 != image[y].end()
&& "x2 coordinat iterator must not be beyond image width");
const double average_greyness = std::accumulate(
image[y].begin() + x1,
image[y].begin() + x2,
0.0) / boost::numeric_cast<double>(x2-x1);
assert(average_greyness >= 0.0);
assert(average_greyness <= 1.0);
return average_greyness;
}
//---------------------------------------------------------------------------
//Get a square of pixels' average greyness
double AsciiArter::GetGreyness(
const std::vector<std::vector<double> >& image,
const int x1,
const int y1,
const int x2,
const int y2)
{
assert(y1 < y2
&& "Y-coordinats must be ordered");
double sum = 0.0;
for (int y=y1; y!=y2; ++y)
{
const double grey = GetGreyness(image,x1,x2,y);
assert(grey >= 0 && grey < 1.0);
sum+=grey;
}
const double average_greyness = sum
/ boost::numeric_cast<double>(y2 - y1);
assert(average_greyness >=0.0 && average_greyness <= 1.0);
return average_greyness;
}
//---------------------------------------------------------------------------
//Generalizes a pixel, line or rectangle to one average greyness
double AsciiArter::GetFractionGrey(
const std::vector<std::vector<double> >& image,
const int x1,
const int y1,
const int x2,
const int y2)
{
assert(x1 <= x2);
assert(y1 <= y2);
if (x1 == x2 && y1 == y2) return GetGreyness(image,x1,y1);
if (y1 == y2) return GetGreyness(image,x1,x2,y1);
if (x1 == x2)
{
assert(y1 < y2);
double sum = 0;
for (int y=y1; y!=y2; ++y)
{
const double g = GetGreyness(image,x1,y);
assert(g >= 0.0);
assert(g <= 1.0);
sum+=g;
}
const double average_greyness
= sum / boost::numeric_cast<double>(y2-y1);
assert(average_greyness >= 0.0);
assert(average_greyness <= 1.0);
return average_greyness;
}
return GetGreyness(image,x1,y1,x2,y2);
}
//---------------------------------------------------------------------------
const std::string AsciiArter::GetVersion()
{
return "1.0";
}
//---------------------------------------------------------------------------
const std::vector<std::string> AsciiArter::GetVersionHistory()
{
std::vector<std::string> v;
v.push_back("2011-03-23: Version 1.0: initial version");
return v;
}
//---------------------------------------------------------------------------
//'image' must be a y-x-ordered std::vector of grey values
//ranging from [0.0,1.0], where 0.0 denotes black and
//1.0 denotes white.
//From http://www.richelbilderbeek.nl/CppImageToAscii.htm
const std::vector<std::string> AsciiArter::ImageToAscii(
const std::vector<std::vector<double> >& image,
const int width) const //How many chars the ASCII image will be wide
{
//If the number of chars is below 5,
//the calculation would be more complicated due to a too trivial value of charWidth
assert(width >= 5);
//Maxy is in proportion with the bitmap
const int image_width = image[0].size();
const int image_height = image.size();
const int maxy =
(static_cast<double>(width)
/ static_cast<double>(image_width))
* static_cast<double>(image_height);
assert(maxy > 0);
const double dX = static_cast<double>(image_width)
/ static_cast<double>(width);
const double dY = static_cast<double>(image_height)
/ static_cast<double>(maxy);
assert(dX > 0.0);
assert(dY > 0.0);
std::vector<std::string> v;
for (int y=0; y!=maxy; ++y)
{
std::string s;
for (int x=0; x!=width; ++x)
{
const int x1 = std::min(
static_cast<double>(x) * dX,
image_width - 1.0) + 0.5;
const int y1 = std::min(
static_cast<double>(y) * dY,
image_height - 1.0) + 0.5;
const int x2 = std::min(
(static_cast<double>(x) * dX) + dX,
image_width - 1.0) + 0.5;
const int y2 = std::min(
(static_cast<double>(y) * dY) + dY,
image_height - 1.0) + 0.5;
assert(x1 >= 0);
assert(x2 >= 0);
assert(y1 >= 0);
assert(y2 >= 0);
assert(x1 < image_width);
assert(x2 < image_width);
assert(y1 < image_height);
assert(y2 < image_height);
const double f = GetFractionGrey(image,x1,y1,x2,y2);
assert(f >= 0.0 && f <= 1.0);
const int i
= boost::numeric_cast<int>(
f * boost::numeric_cast<double>(m_gradient.size() - 1));
assert(i >= 0);
assert(i < boost::numeric_cast<int>(m_gradient.size()));
const char c = m_gradient[i];
s+=c;
}
v.push_back(s);
}
return v;
}
//---------------------------------------------------------------------------
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