128 lines
3 KiB
C++
128 lines
3 KiB
C++
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#include <iostream>
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#include <fstream>
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#include <sstream>
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#include <exception>
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#include "ppm.h"
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//init with default values
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void ppm::init() {
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width = 0;
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height = 0;
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max_col_val = 255;
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}
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//create a PPM object
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ppm::ppm() {
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init();
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}
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//create a PPM object and fill it with data stored in fname
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ppm::ppm(const std::string &fname) {
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init();
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read(fname);
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}
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//create an "epmty" PPM image with a given width and height;the R,G,B arrays are filled with zeros
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ppm::ppm(const unsigned int _width, const unsigned int _height) {
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init();
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width = _width;
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height = _height;
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nr_lines = height;
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nr_columns = width;
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size = width*height;
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// fill r, g and b with 0
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r.resize(size);
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g.resize(size);
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b.resize(size);
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}
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//read the PPM image from fname
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void ppm::read(const std::string &fname) {
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std::ifstream inp(fname.c_str(), std::ios::in | std::ios::binary);
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if (inp.is_open()) {
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std::string line;
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std::getline(inp, line);
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if (line != "P6") {
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std::cout << "Error. Unrecognized file format." << std::endl;
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return;
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}
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std::getline(inp, line);
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while (line[0] == '#') {
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std::getline(inp, line);
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}
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std::stringstream dimensions(line);
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try {
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dimensions >> width;
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dimensions >> height;
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nr_lines = height;
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nr_columns = width;
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} catch (std::exception &e) {
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std::cout << "Header file format error. " << e.what() << std::endl;
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return;
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}
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std::getline(inp, line);
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std::stringstream max_val(line);
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try {
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max_val >> max_col_val;
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} catch (std::exception &e) {
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std::cout << "Header file format error. " << e.what() << std::endl;
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return;
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}
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size = width*height;
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r.reserve(size);
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g.reserve(size);
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b.reserve(size);
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char aux;
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for (unsigned int i = 0; i < size; ++i) {
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inp.read(&aux, 1);
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r[i] = (unsigned char) aux;
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inp.read(&aux, 1);
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g[i] = (unsigned char) aux;
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inp.read(&aux, 1);
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b[i] = (unsigned char) aux;
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}
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} else {
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std::cout << "Error. Unable to open " << fname << std::endl;
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}
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inp.close();
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}
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//write the PPM image in fname
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void ppm::write(const std::string &fname) {
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std::ofstream inp(fname.c_str(), std::ios::out | std::ios::binary);
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if (inp.is_open()) {
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inp << "P6\n";
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inp << width;
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inp << " ";
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inp << height << "\n";
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inp << max_col_val << "\n";
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char aux;
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for (unsigned int i = 0; i < size; ++i) {
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aux = (char) r[i];
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inp.write(&aux, 1);
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aux = (char) g[i];
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inp.write(&aux, 1);
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aux = (char) b[i];
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inp.write(&aux, 1);
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}
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} else {
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std::cout << "Error. Unable to open " << fname << std::endl;
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}
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inp.close();
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}
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