Joshua Moerman
11 years ago
6 changed files with 295 additions and 98 deletions
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#pragma once |
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// I got sick of all those includes I need everywhere -.-
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// So here is a list I'll always include
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#include <vector> |
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#include <fstream> |
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#include <iostream> |
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#include <iterator> |
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#include <numeric> |
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#include <cassert> |
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#include <cmath> |
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#pragma once |
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#include <string> |
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inline bool is_pow_of_two(int n){ |
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return (n & (n - 1)) == 0; |
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} |
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inline std::string human_string(int n){ |
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static const std::string names [] = {"", "K", "M", "G"}; |
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int i = 0; |
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while(n > 1000 && i < sizeof(names)){ |
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n /= 1000; |
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++i; |
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} |
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return std::to_string(n) + names[i]; |
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} |
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inline std::string field(std::string const & str){ |
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const int length = 12; |
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if(str.size() > length) return str + ":\t"; |
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auto add = length - str.size(); |
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return str + ":" + std::string(add, ' ') + "\t"; |
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} |
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#pragma once |
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#include <includes.hpp> |
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// joshua's compression :D
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namespace jcmp { |
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typedef uint32_t uint; |
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struct __attribute__ ((__packed__)) header { |
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const char signature[4]; |
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uint width; |
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uint height; |
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uint length; |
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header(uint width = 0, uint height = 0, uint length = 0) |
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: signature{'J', 'C', 'M', 'P'} |
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, width(width) |
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, height(height) |
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, length(length) |
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{} |
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}; |
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struct __attribute__ ((__packed__)) coefficient { |
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double c; |
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uint x; |
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uint y; |
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}; |
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struct image { |
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header header; |
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std::vector<coefficient> data; |
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image() = default; |
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image(uint width, uint height, std::vector<coefficient> const & data_in) |
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: header(width, height, data_in.size()) |
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, data(data_in) |
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{} |
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void clear(){ |
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header.length = header.height = header.width = 0; |
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data.clear(); |
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} |
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}; |
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inline void write_to_file(image const & image, std::string filename){ |
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std::filebuf file; |
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file.open(filename, std::ios_base::out|std::ios_base::trunc); |
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file.sputn(reinterpret_cast<const char*>(&image.header), sizeof(header)); |
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file.sputn(reinterpret_cast<const char*>(image.data.data()), image.data.size() * sizeof(coefficient)); |
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} |
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inline image read_from_file(std::string const& filename){ |
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std::filebuf file; |
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file.open(filename, std::ios_base::in); |
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image image; |
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file.sgetn(reinterpret_cast<char*>(&image.header), sizeof(header)); |
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assert(strncmp("JCMP", image.header.signature, 4) == 0); |
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image.data.resize(image.header.length); |
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file.sgetn(reinterpret_cast<char*>(image.data.data()), image.data.size() * sizeof(coefficient)); |
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return image; |
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} |
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} |
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#include <includes.hpp> |
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#include "compressed_image.hpp" |
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namespace jcmp{ |
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bool operator==(coefficient const & lhs, coefficient const & rhs){ |
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return lhs.c == rhs.c && lhs.x == rhs.x && lhs.y == rhs.y; |
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} |
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} |
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struct gen{ |
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jcmp::uint width, x, y; |
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jcmp::coefficient operator()(){ |
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++x; |
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if(x > width){ |
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x = 0; |
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++y; |
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} |
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// only for testing purpose :D
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return {rand() / double(RAND_MAX), x, y}; |
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} |
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}; |
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int main(){ |
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const int w = 1024, h = 512; |
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srand(time(0)); |
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std::vector<jcmp::coefficient> v(w*h / 100); |
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std::generate(v.begin(), v.end(), gen{w, 0, 0}); |
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jcmp::image i(w, h, std::move(v)); |
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jcmp::write_to_file(i, "test.jcmp"); |
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auto j = jcmp::read_from_file("test.jcmp"); |
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assert(w == j.header.width); |
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assert(h == j.header.height); |
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assert(i.data.size() == j.data.size()); |
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assert(i.data == j.data); |
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std::cout << "Test succeeded" << std::endl; |
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} |
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@ -1,116 +1,105 @@ |
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#include <vector> |
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#include <iostream> |
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#include <iterator> |
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#include <numeric> |
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#include <cassert> |
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#include <cmath> |
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#include <boost/assign.hpp> |
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#include <includes.hpp> |
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#include <boost/filesystem.hpp> |
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#include <png.hpp> |
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#include <utilities.hpp> |
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#include "compressed_image.hpp" |
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#include "striding_iterator.hpp" |
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#include "periodic_iterator.hpp" |
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#include "wavelet.hpp" |
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bool is_pow_of_two(int n){ |
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return (n & (n - 1)) == 0; |
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} |
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// note: we take a copy, because we will modify it in place
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jcmp::image compress(std::vector<double> image, int width, double threshold, int& zeros){ |
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auto height = image.size() / width; |
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assert(is_pow_of_two(width)); |
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assert(is_pow_of_two(height)); |
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template <typename Iterator> |
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void shuffle(Iterator begin, Iterator end){ |
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typedef typename std::iterator_traits<Iterator>::value_type value_type; |
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typedef typename std::iterator_traits<Iterator>::difference_type diff_type; |
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diff_type s = end - begin; |
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assert(s % 2 == 0); |
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std::vector<value_type> v(s); |
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std::copy(strided(begin , 2), strided(end , 2), v.begin()); |
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std::copy(strided(begin+1, 2), strided(end+1, 2), v.begin() + s/2); |
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std::copy(v.begin(), v.end(), begin); |
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} |
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// wavelet transform in x-direction
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for(int i = 0; i < height; ++i){ |
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wavelet(image.begin() + i*width, image.begin() + (i+1)*width); |
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} |
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template <typename Iterator> |
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void unshuffle(Iterator begin, Iterator end){ |
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typedef typename std::iterator_traits<Iterator>::value_type value_type; |
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typedef typename std::iterator_traits<Iterator>::difference_type diff_type; |
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diff_type s = end - begin; |
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assert(s % 2 == 0); |
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std::vector<value_type> v(s); |
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std::copy(begin, begin + s/2, strided(v.begin(), 2)); |
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std::copy(begin + s/2, end, strided(v.begin()+1, 2)); |
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std::copy(v.begin(), v.end(), begin); |
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} |
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// wavelet transform in y-direction
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for(int i = 0; i < width; ++i){ |
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wavelet(strided(image.begin() + i, width), strided(image.end() + i, width)); |
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} |
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template <typename Iterator> |
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void wavelet(Iterator begin, Iterator end){ |
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int s = end - begin; |
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for(int i = s; i >= 4; i >>= 1){ |
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// half interval
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end = begin + i; |
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assert(is_pow_of_two(end - begin)); |
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// multiply with Wn
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wavelet_mul(begin, end); |
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// then with Sn
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shuffle(begin, end); |
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// save the principal coefficients
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std::vector<jcmp::coefficient> v; |
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for(int y = 0; y < height; ++y){ |
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for(int x = 0; x < width; ++x){ |
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auto&& el = image[x + width*y]; |
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if(std::abs(el) > threshold) v.push_back({el, jcmp::uint(x), jcmp::uint(y)}); |
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else ++zeros; |
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} |
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} |
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return jcmp::image(width, height, std::move(v)); |
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} |
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template <typename Iterator> |
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void unwavelet(Iterator begin, Iterator end){ |
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int s = end - begin; |
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for(int i = 4; i <= s; i <<= 1){ |
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// double interval
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end = begin + i; |
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assert(is_pow_of_two(end - begin)); |
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// unshuffle: Sn^-1
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unshuffle(begin, end); |
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// then Wn^-1
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wavelet_inv(begin, end); |
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std::vector<double> decompress(jcmp::image in){ |
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auto width = in.header.width; |
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auto height = in.header.height; |
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assert(is_pow_of_two(width)); |
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assert(is_pow_of_two(height)); |
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std::vector<double> image(width * height, 0.0); |
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// read in coefficient on coordinates
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for(auto it = in.data.begin(); it != in.data.end(); ++it){ |
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auto&& x = *it; |
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image[x.x + width*x.y] = x.c; |
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} |
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} |
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struct filter{ |
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filter(double threshold) |
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: threshold(threshold) |
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{} |
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in.clear(); |
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void operator()(double& x){ |
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if(std::abs(x) <= threshold) x = 0; |
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// inverse wavelet transform in y-direction
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for(int i = 0; i < width; ++i){ |
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unwavelet(strided(image.begin() + i, width), strided(image.end() + i, width)); |
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} |
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double threshold; |
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}; |
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// inverse wavelet transform in x-direction
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for(int i = 0; i < height; ++i){ |
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unwavelet(image.begin() + i*width, image.begin() + (i+1)*width); |
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} |
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return image; |
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} |
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int main(){ |
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using namespace boost::assign; |
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std::vector<double> input; |
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input += 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0; |
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// print input
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std::copy(input.begin(), input.end(), std::ostream_iterator<double>(std::cout, "\n")); |
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std::cout << std::endl; |
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std::vector<double> thresholds; |
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thresholds += 0.0, 0.1, 0.2, 0.5; |
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for(int i = 0; i < thresholds.size(); ++i){ |
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std::vector<double> v; |
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v = input; |
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// transform to wavelet domain
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wavelet(v.begin(), v.end()); |
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// apply threshold
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std::for_each(v.begin(), v.end(), filter(thresholds[i])); |
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int zeros = std::count(v.begin(), v.end(), 0.0); |
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// transform back to sample domain
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unwavelet(v.begin(), v.end()); |
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// print compressed
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std::cout << "\ncp: " << zeros / double(v.size()) << std::endl; |
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std::copy(v.begin(), v.end(), std::ostream_iterator<double>(std::cout, "\n")); |
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std::cout << std::endl; |
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namespace fs = boost::filesystem; |
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fs::path directory("images"); |
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fs::directory_iterator eod; |
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for(fs::directory_iterator it(directory); it != eod; ++it){ |
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auto && path = it->path(); |
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if(path.extension() != ".png") continue; |
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// open file
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std::string filename = path.string(); |
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std::cout << field("file") << filename << std::endl; |
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png::istream image(filename); |
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auto width = image.get_width(); |
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auto height = image.get_height(); |
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// read into vector
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std::vector<double> image_vec; |
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image_vec.reserve(width * height); |
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for(unsigned char c = 0; image >> c;) image_vec.push_back(c/255.0); |
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// compress and decompress to see how we lost information
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int zeros = 0; |
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auto compressed_vec = decompress(compress(image_vec, width, 0.5, zeros)); |
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// output some information
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std::cout << field("raw") << human_string(image_vec.size()) << std::endl; |
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std::cout << field("compressed") << human_string(image_vec.size() - zeros) << std::endl; |
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// save to output file
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std::string cfilename = "compressed/" + path.filename().string(); |
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png::gray_ostream compressed_image(width, height, cfilename); |
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for(int i = 0; i < compressed_vec.size(); ++i) compressed_image << compressed_vec[i]; |
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} |
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} |
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Reference in new issue