562 lines
14 KiB
C++
562 lines
14 KiB
C++
#include <string>
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#include <fstream>
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#include <iostream>
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#include <sstream>
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#include <cmath>
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#include <cassert>
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#include <cstring>
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using namespace std;
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template <typename T>
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struct TPoint {
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T x;
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T y;
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TPoint(T a, T b)
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: x(a)
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, y(b)
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{}
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};
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typedef TPoint<unsigned int> Point;
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typedef TPoint<int> APoint; // absolute point, can be negative
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typedef TPoint<double> DPoint; // absolute point, can be negative
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template<typename Elem, typename Traits, typename T>
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std::basic_ostream<Elem, Traits>& operator << (std::basic_ostream<Elem, Traits>& o, TPoint<T> const& p)
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{
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o << "(" << p.x << ", " << p.y << ")";
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return o;
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}
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struct Image {
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unsigned int width;
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unsigned int height;
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uint8_t* r_chan;
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uint8_t* g_chan;
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uint8_t* b_chan;
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Image()
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: width(0)
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, height(0)
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, r_chan(NULL)
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, g_chan(NULL)
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, b_chan(NULL)
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{}
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Image(unsigned int w, unsigned int h)
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{
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this->width = w;
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this->height = h;
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r_chan = new uint8_t[width * height];
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memset(r_chan, 0, width * height * sizeof (uint8_t));
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g_chan = new uint8_t[width * height];
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memset(g_chan, 0, width * height * sizeof (uint8_t));
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b_chan = new uint8_t[width * height];
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memset(b_chan, 0, width * height * sizeof (uint8_t));
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}
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Image(string const& path)
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: Image()
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{
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ifstream is(path);
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if (!is.is_open())
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{
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cerr << "Cannot open file '" << path << "'" << endl;
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abort();
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}
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if (!this->read_header(is))
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{
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cerr << "Invalid header." << endl;
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abort();
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}
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if (!this->read_body(is))
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{
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delete r_chan;
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r_chan = nullptr;
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delete g_chan;
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r_chan = nullptr;
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delete b_chan;
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r_chan = nullptr;
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cerr << "Invalid header." << endl;
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abort();
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}
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}
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bool save(string const& path)
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{
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ofstream os(path);
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if (!os.is_open())
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{
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cerr << "Cannot open file '" << path << "'" << endl;
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return false;
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}
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this->write_header(os);
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this->write_body(os);
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return true;
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}
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void set_pixel(unsigned int x, unsigned int y, uint8_t r, uint8_t g, uint8_t b)
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{
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if (x >= width || y >= height)
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{
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cerr << "Point (" << x << ", " << y << ") out of bounds" << endl;
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cerr << " Image dimensions: " << width << " x " << height << endl;
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assert(false);
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}
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int const index = y * width + x;
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r_chan[index] = r;
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g_chan[index] = g;
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b_chan[index] = b;
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}
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private:
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bool read_header(std::ifstream& istr)
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{
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// check magic
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if (istr.get() != 'P' )
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{
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return false;
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}
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char type = static_cast<char>(istr.get());
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if (type != '6')
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{
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return false;
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}
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if (istr.get() != '\n')
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{
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return false;
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}
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// skip comments
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while (istr.peek() == '#')
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{
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std::string line;
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std::getline(istr, line);
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}
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// get size
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istr >> width >> height;
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if (width == 0 || height == 0)
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{
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return false;
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}
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// get maxvalue
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if (istr.get() != '\n')
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{
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return false;
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}
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int max_value = -1;
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istr >> max_value;
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if (max_value > 255)
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{
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return false;
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}
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if (istr.get() != '\n')
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{
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return false;
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}
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cout << "width: " << width << endl;
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cout << "height: " << height << endl;
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return true;
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}
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bool write_header(std::ofstream& ostr)
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{
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ostr << "P6" << endl;
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ostr << width << " " << height << endl;
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ostr << "255" << endl;
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return true;
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}
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bool read_body(std::ifstream& istr)
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{
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r_chan = new uint8_t[width * height];
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g_chan = new uint8_t[width * height];
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b_chan = new uint8_t[width * height];
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for (unsigned int row = 0; row < height; ++row)
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{
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for (unsigned int col = 0; col < width; ++col)
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{
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int index = row * width + col;
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r_chan[index] = istr.get();
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g_chan[index] = istr.get();
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b_chan[index] = istr.get();
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}
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}
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return true;
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}
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bool write_body(std::ofstream& ostr)
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{
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for (unsigned int row = 0; row < height; ++row)
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{
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for (unsigned int col = 0; col < width; ++col)
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{
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int index = row * width + col;
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ostr << (char) r_chan[index];
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ostr << (char) g_chan[index];
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ostr << (char) b_chan[index];
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}
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}
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return true;
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}
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};
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//
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//
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// Trigonometry
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//
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DPoint convert_grid_coord(Image const& img, Point const& p)
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{
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return DPoint(p.x - img.width / 2.0f + 0.5, p.y - img.height / 2.0f + 0.5);
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}
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double convert_radian(Image const& img, Point const& p, double const ratio)
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{
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DPoint centered = convert_grid_coord(img, p);
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double const cos_value = centered.x * ratio;
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double const sin_value = - (centered.y * ratio);
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double angle = acos(cos_value);
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if (sin_value < 0)
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angle = 2 * M_PI - angle;
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return angle;
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}
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DPoint convert_abs_coord(double const angle, double const ratio)
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{
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return DPoint(cos(angle) / ratio, - (sin(angle) / ratio));
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}
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Point convert_img_coord(Image const& img, DPoint const& p)
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{
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int x = round(p.x + (img.width / 2.0f) - 0.5);
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int y = round(p.y + (img.height / 2.0f) - 0.5);
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Point p_mapped(x, y);
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// if (p_mapped.x >= img.width || p_mapped.y >= img.height)
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// {
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// cerr << "Point coord mapping" << endl;
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// cerr << " Input point:" << p << endl;
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// cerr << " Point " << p_mapped << " out of bounds" << endl;
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// cerr << " Image dimensions: " << img.width << " x " << img.height << endl;
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// assert(false);
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// }
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return p_mapped;
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}
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double compute_ratio(Image const& img)
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{
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unsigned int const nb_points = img.width * img.height;
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double const square_side = sqrt(nb_points) - 1;
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double const half_side = square_side / 2;
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double const trigo_length = ceil(half_side * sqrt(2));
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return 1.0f / trigo_length;
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}
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inline
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bool fequal(float a, float b, float sigma)
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{
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return abs(a - b) < sigma;
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}
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void compute_output_size(Image const& src, double const rotation, unsigned int& width, unsigned int& height)
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{
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double const ratio = compute_ratio(src);
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double min_w = 0;
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double max_w = 0;
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double min_h = 0;
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double max_h = 0;
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//cout << "Image dimensions: " << src.width << " x " << src.height << endl;
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Point p(0, 0);
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double angle = convert_radian(src, p, ratio);
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DPoint tl = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, tl.x);
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max_w = max(max_w, tl.x);
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min_h = min(min_h, tl.y);
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max_h = max(max_h, tl.y);
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//cout << "Rotated " << p << " (" << angle << ") = " << tl << "(" << angle + rotation << ")" << endl << endl;
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p = Point(src.width - 1, 0);
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angle = convert_radian(src, p, ratio);
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DPoint tr = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, tr.x);
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max_w = max(max_w, tr.x);
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min_h = min(min_h, tr.y);
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max_h = max(max_h, tr.y);
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//cout << "Rotated " << p << " (" << angle << ") = " << tr << "(" << angle + rotation << ")" << endl << endl;
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p = Point(0, src.height - 1);
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angle = convert_radian(src, p, ratio);
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DPoint bl = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, bl.x);
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max_w = max(max_w, bl.x);
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min_h = min(min_h, bl.y);
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max_h = max(max_h, bl.y);
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//cout << "Rotated " << p << " (" << angle << ") = " << bl << "(" << angle + rotation << ")" << endl << endl;
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p = Point(src.width - 1, src.height - 1);
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angle = convert_radian(src, p, ratio);
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DPoint br = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, br.x);
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max_w = max(max_w, br.x);
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min_h = min(min_h, br.y);
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max_h = max(max_h, br.y);
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//cout << "Rotated " << p << " (" << angle << ") = " << br << "(" << angle + rotation << ")" << endl << endl;
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width = (int) (max_w - min_w) + 1;
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height = (int) (max_h - min_h) + 1;
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}
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//
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//
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// Rotation
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//
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Point rotate(Image const& src, Point const& p, double const ratio, double const rotation, Image const& rotated)
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{
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double angle = convert_radian(src, p, ratio);
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DPoint a_point = convert_abs_coord(angle + rotation, ratio);
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return convert_img_coord(rotated, a_point);
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}
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Image rotate(Image const& src, double angle)
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{
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// FIXME
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Image rot(0, 0);
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cout << angle << src.width << endl; // to remove warnings
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return rot;
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}
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//
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//
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// Drawing
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//
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void draw_line(Image& img, unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2)
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{
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int x_inc = x1 <= x2 ? 1 : -1;
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unsigned int const y_min = min(y1, y2);
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unsigned int const y_max = max(y1, y2);
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double slope = (double) y2 - y1;
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if (x1 != x2)
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slope = ((double) y2 - y1) / abs((double) x2 - x1);
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int y_inc = slope > 0 ? 1 : -1;
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if (x1 == x2)
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{
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for (unsigned int runner = y1; runner != y2; runner+= y_inc)
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img.set_pixel(x1, runner, 255, 0, 0); // set line to red
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return;
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}
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if (y1 == y2)
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{
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for (unsigned int runner = x1; runner != x2; runner+= x_inc)
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img.set_pixel(runner, y1, 255, 0, 0); // set line to red
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return;
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}
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unsigned int previous_y = y1;
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for (unsigned int i = x1, steps = 0; i != x2; i += x_inc, ++steps)
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{
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unsigned int y = slope * steps + y1;
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y = min(y, y_max);
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y = max(y, y_min);
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for (unsigned int runner = previous_y; runner != y; runner+= y_inc)
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img.set_pixel(i, runner, 255, 0, 0); // set line to red
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previous_y = y;
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}
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}
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void draw_line(Image& img, Point const& p1, Point const& p2)
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{
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draw_line(img, p1.x, p1.y, p2.x, p2.y);
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}
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void draw_outline(Image const& input, unsigned int degrees, string const& name)
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{
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double const rotation = (degrees / 180.0f) * M_PI;
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unsigned int w = 0;
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unsigned int h = 0;
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compute_output_size(input, rotation, w, h);
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cout << "rotation(" << degrees << ") -> " << w << " x " << h << endl;
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Image rotated(w, h);
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double const ratio = compute_ratio(input);
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Point tl = rotate(input, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(input, Point(input.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(input, Point(0, input.height - 1), ratio, rotation, rotated);
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Point br = rotate(input, Point(input.width - 1, input.height - 1), ratio, rotation, rotated);
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cout << tl << " " << tr << " " << bl << " " << br << endl;
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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stringstream ss;
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ss << "check_lines_" << name << "_" << degrees << ".ppm";
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rotated.save(ss.str());
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}
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//
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//
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// Check
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//
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bool check_points()
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{
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Image five(5, 5);
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Point origin(0, 0);
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DPoint d1 = convert_grid_coord(five, origin);
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assert(d1.x == -2);
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assert(d1.y == -2);
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return true;
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}
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bool check_trigo()
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{
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Image square(500, 500);
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double const ratio = compute_ratio(square);
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cout << "ratio: " << ratio << endl;
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// Check that the origin of a square image is at sqrt(2) / 2
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double const angle = convert_radian(square, Point(0, 0), ratio);
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double const sigma = 1.0e-2;
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if (!fequal(angle, 3 * M_PI / 4, sigma))
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{
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cout << __LINE__ << " | Invalid angle value: " << angle << " != " << 3 * M_PI / 4 << endl;
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return false;
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}
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// Check that we can reverse the origin point.
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DPoint const abs_reverse_point = convert_abs_coord(angle, ratio);
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cout << "reversed abs origin: " << abs_reverse_point << endl;
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Point const reverse_point = convert_img_coord(square, abs_reverse_point);
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cout << "reversed origin in square: " << reverse_point << endl;
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if (abs(0.0 - reverse_point.x) > sigma)
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{
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cerr << "Reverse origin:" << endl;
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cout << "Invalid x value: " << reverse_point.x << " != " << 0 << endl;
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return false;
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}
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if (abs(0.0 - reverse_point.y) > sigma)
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{
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cerr << "Reverse origin:" << endl;
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cout << "Invalid y value: " << reverse_point.y << " != " << 0 << endl;
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return false;
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}
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// Check that when rotating the origin by 45 degrees
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double const rotation = M_PI / 4; // 45 degrees
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unsigned int w = 0;
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unsigned int h = 0;
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compute_output_size(square, rotation, w, h);
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// failed check: is precision an issue?
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if (true)
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{
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if (!fequal(w, square.width * sqrt(2), sigma * square.width)
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|| !fequal(h, square.height * sqrt(2), sigma * square.height))
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{
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cerr << "Invalid rotated image dimensions " << w << " x " << h << endl;
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cerr << " expected " << (int) ceil(square.width * sqrt(2)) << " x " << (int) ceil(square.height * sqrt(2)) << endl;
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return false;
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}
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Image rotated(w, h);
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DPoint const a_p45 = convert_abs_coord(angle + rotation, ratio);
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Point const p45 = convert_img_coord(rotated, a_p45);
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if (!fequal(0, p45.x, sigma))
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{
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cerr << __LINE__ << " > Rotation origin by 45 degrees:" << endl;
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cerr << " invalid x value: " << p45.x << " != " << 0 << endl;
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cerr << " absolute point: " << a_p45 << endl;
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cerr << " relative point: " << p45 << endl;
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return false;
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}
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if (!fequal(p45.y, h / 2.0f - 1, sigma))
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{
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cerr << __LINE__ << " > Rotation origin by 45 degrees:" << endl;
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cerr << "Invalid y value: " << p45.y << " != " << h / 2.0f - 1 << endl;
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cerr << " absolute point: " << a_p45 << endl;
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cerr << " relative point: " << p45 << endl;
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return false;
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}
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}
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return true;
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}
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void check_lines()
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{
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Image const square(500, 500);
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draw_outline(square, 5, "square");
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draw_outline(square, 12, "square");
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draw_outline(square, 22, "square");
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draw_outline(square, 33, "square");
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draw_outline(square, 45, "square");
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draw_outline(square, 60, "square");
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draw_outline(square, 75, "square");
|
|
draw_outline(square, 90, "square");
|
|
|
|
Image const rect1(640, 480);
|
|
draw_outline(rect1, 22, "rect1");
|
|
draw_outline(rect1, 33, "rect1");
|
|
draw_outline(rect1, 45, "rect1");
|
|
draw_outline(rect1, 90, "rect1");
|
|
}
|
|
|
|
|
|
|
|
//
|
|
//
|
|
// Main
|
|
//
|
|
|
|
int main()
|
|
{
|
|
check_points();
|
|
|
|
if (!check_trigo())
|
|
return 1;
|
|
|
|
check_lines();
|
|
|
|
return 0;
|
|
|
|
Image img("img/luigi.ppm");
|
|
|
|
Image rotated = rotate(img, 30);
|
|
rotated.save("rotated.ppm");
|
|
|
|
return 0;
|
|
}
|