haader/image.cpp

#include <stdio.h>

#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#include "image.h"
#include "exif.h"

#define max_number(a, b) (a) > (b) ? (a) : (b)
#define min_number(a, b) (a) < (b) ? (a) : (b)

using namespace std;
using namespace haader;


Image::Image():
    m_width(0),
    m_height(0),
    m_components(0),
    m_exposure_time(0.0)
{
}

void Image::to_string(string &s) const {
    stringstream ss;
    ss << "Image(";
    ss << m_width << 'x' << m_height << 'x' << m_components << ")";
    s = ss.str();
}

bool Image::read_from_file(const char *file_path) {
    int x = 0;
    int y = 0;
    int components = 0;

    unsigned char *data = stbi_load(file_path, &x, &y, &components, 0);

    if (data) {
        m_width = x;
        m_height = y;
        m_components = components;
        size_t size = (size_t)x * (size_t)y * (size_t)components;
        m_image_data.assign(data, data + size);

        // try to read EXIF data
        {
            ExifTags tags;
            ifstream stream;
            stream.open(file_path);

            if (stream.is_open() and ExifTags::read_from_jpeg(stream, tags)) {
                if (tags.get_exposure_time(m_exposure_time)) {
                    cout << "Exposure time: " << m_exposure_time << " sec" << endl;
                }
            }
        }

        return true;
    } else {
        cerr << "Can not read \"" << file_path << "\" as an image." << endl;
        return false;
    }

    stbi_image_free(data);
}

bool Image::save_as_ppm_file(const char *file_path, bool ascii) const {
    if (ascii) {
        // ASCII

        ofstream out(file_path);
        out << "P3\n";
        out << m_width << ' ' << m_height << '\n';
        out << "255\n";

        unsigned int pixels = m_width * m_height;
        unsigned int index = 0;
        for (unsigned int i = 0; i < pixels; i++) {
            out << (int)m_image_data[index] << ' ' << (int)m_image_data[index + 1] << ' ' << (int)m_image_data[index + 2] << '\n';
            index += 3;
        }

        out.close();
        return true;
    } else {
        // binary

        ofstream out(file_path);
        out << "P6\n";
        out << m_width << ' ' << m_height << '\n';
        out << "255\n";

        unsigned int pixels = m_width * m_height;
        unsigned int index = 0;
        for (unsigned int i = 0; i < pixels; i++) {
            out << m_image_data[index] << m_image_data[index + 1] << m_image_data[index + 2];
            index += 3;
        }

        out.close();
        return true;
    }
}

LdrHistogram Image::histogram() const {
    LdrHistogram hist;

    hist.m_bins.resize(256, 0);

    if (m_image_data.size() == 0) {
        return hist;
    }

    for (unsigned int i = 0; i < m_image_data.size(); i++) {
        hist.m_bins[m_image_data[i]]++;
    }

    hist.m_max_freq = 0;
    for (unsigned int i = 0; i < 256; i++) {
        hist.m_max_freq = max_number(hist.m_max_freq, hist.m_bins[i]);
    }

    return hist;
}


unsigned int Image::get_width() const {
    return m_width;
}

unsigned int Image::get_height() const {
    return m_height;
}

unsigned int Image::get_components() const {
    return m_components;
}

bool Image::has_equal_dimensions(const Image &other) const {
    return (m_width == other.m_width &&
            m_height == other.m_height &&
            m_components == other.m_components);
}

double Image::get_exposure_time() const {
    return m_exposure_time;
}

const unsigned char* Image::get_const_image_data() const {
    return m_image_data.data();
}

unsigned char* Image::get_image_data() {
    return m_image_data.data();
}