main-old.cpp

#include <SFML/Graphics.hpp>
#include <SFML/System/Vector2.hpp>
#include <cstring>
#include <string>
#include <filesystem>
#include <vector>
#include <iostream>

/* access(), R_OK, F_OK */
#ifdef __linux__
#include <unistd.h>
#define ACCESS access
#endif

/* access(), R_OK, F_OK */
#ifdef _WIN32
#include <Windows.h>
#include <WinUser.h>
//#include "resource.h"
#include <io.h>
#define R_OK 4
#define F_OK 0
#define ACCESS _access
#endif

struct PictureData {
    std::string PicName;
};

std::vector<PictureData> Pictures;
sf::VideoMode ScreenInfo;

bool isPicture(std::string Filename) {
    bool Result = false;
    std::vector <std::string> SupportedTypes = { ".jpg", ".bmp", ".tga", ".gif", ".psd", ".pic", ".hdr" };
    for (auto Type : SupportedTypes) {
        if (Filename.find(Type) != std::string::npos) {
            Result = true;
            break;
        }
    }
    return Result;
}

bool loadPictures(std::string DirPictures) {
    try {
        const std::filesystem::path CurrentDir{ DirPictures };
        for (auto const& DirEntry : std::filesystem::directory_iterator{ CurrentDir }) {

#ifdef __linux__
            std::string Filename = DirEntry.path();
#endif

#ifdef _WIN32
            std::string Filename = (DirEntry.path()).string();
#endif

            if (ACCESS(Filename.c_str(), R_OK) == -1) {
                std::cout << Filename << ": permission denied\n";
                continue;
            }
            std::string OriginFilename = Filename;
            int Count = 0;
            for (auto Elem : Filename) { Filename[Count] = std::tolower(Elem); Count++; }
            if (isPicture(Filename)) {
                PictureData Picture;
                Picture.PicName = OriginFilename;
                Pictures.push_back(Picture);
            }
        }
    } catch(...) {
        std::cout << DirPictures << ": permission denied\n";
        return false;
    }
    return true;
}

float getReductionFactor(sf::Sprite& CurSprite) {
    sf::FloatRect SpriteSize = CurSprite.getGlobalBounds();
    unsigned int DifferenceFromWidths = ScreenInfo.width - static_cast<unsigned int>(SpriteSize.width);
    unsigned int DifferenceFromHeights = ScreenInfo.height - static_cast<unsigned int>(SpriteSize.height);
    float ReductionFactor = 1.0;
    if (DifferenceFromWidths > DifferenceFromHeights) {
        ReductionFactor = static_cast<float>(ScreenInfo.width) / static_cast<float>(SpriteSize.width);
    }
    else {
        ReductionFactor = static_cast<float>(ScreenInfo.height) / static_cast<float>(SpriteSize.height);
    }
    return ReductionFactor;
}

sf::Vector2u resizePicture(sf::Sprite& CurSprite) {
    float ReductionFactor = getReductionFactor(CurSprite);
    if (ReductionFactor > 1.0) ReductionFactor = 1.0;
    sf::FloatRect CurSpriteSize = CurSprite.getGlobalBounds();
    CurSprite.setScale(ReductionFactor, ReductionFactor);
    sf::Vector2u newSize;
    newSize.x = static_cast<unsigned int>(CurSpriteSize.width * ReductionFactor);
    newSize.y = static_cast<unsigned int>(CurSpriteSize.height * ReductionFactor);
    return newSize;
}

void displayPicture(size_t CurSpriteNum, sf::RenderWindow& Window) {
    sf::Texture CurTexture;
    if (!CurTexture.loadFromFile(Pictures[CurSpriteNum].PicName)) {
        std::cout << "Picture '" << Pictures[CurSpriteNum].PicName << "' can't be displayed\n" << "\n";
        return;
    }
    sf::Sprite CurSprite(CurTexture);
    sf::FloatRect CurSpriteSize = CurSprite.getGlobalBounds();
    unsigned int CurSpriteWidth = static_cast<unsigned int>(CurSpriteSize.width);
    unsigned int CurSpriteHeight = static_cast<unsigned int>(CurSpriteSize.height);
    do {
        sf::Vector2u pictureSize = resizePicture(CurSprite);
        CurSpriteWidth = pictureSize.x;
        CurSpriteHeight = pictureSize.y;
    } while ((CurSpriteWidth > ScreenInfo.width) || (CurSpriteHeight > ScreenInfo.height));
    Window.create(sf::VideoMode(CurSpriteWidth, CurSpriteHeight), Pictures[CurSpriteNum].PicName, sf::Style::Close);
    Window.setVisible(false);
    Window.setPosition(sf::Vector2i(sf::VideoMode::getDesktopMode().width / 2 - Window.getSize().x / 2, sf::VideoMode::getDesktopMode().height / 2 - Window.getSize().y / 2));
    Window.setVisible(true);
    Window.draw(CurSprite);
    Window.display();
    /*
    *
    * how to set an icon into application window?
    * I can't do it yet...
    *
    #ifdef _WIN32
        HICON hIcon = LoadIcon(NULL, MAKEINTRESOURCE(IDI_ICON));
        if (hIcon) {
            std::string Title = Pictures[CurSpriteNum].PicName;
            std::cout << Pictures[CurSpriteNum].PicName << "\n";
            LPCWSTR TitleWin = (LPCWSTR)Title.c_str();
            HWND hwnd = FindWindow(NULL, TitleWin);
            SendMessage(hwnd, WM_SETICON, ICON_BIG, (LPARAM)hIcon);
        }
    #endif
    */
}

int main(int argc, char* argv[]) {
    std::string CurDir = ".";
    if (argc > 1) CurDir = argv[1];
    std::filesystem::directory_entry entry{ CurDir };
    if (!entry.exists()) {
        std::cout << "Directory '" << CurDir << "' is not found.\n";
        return EXIT_FAILURE;
    }
    /* prepare images */
    if (loadPictures(CurDir) == false) return EXIT_FAILURE;
    if (Pictures.size() == 0) {
        std::cout << "Directory '" << CurDir << "' hasn't supported images.";
        return EXIT_FAILURE;
    }
    /* get screen size */
    sf::VideoMode Screen;
    ScreenInfo = Screen.getDesktopMode();
    /* common objects */
    sf::RenderWindow Window;
    std::string CurSpriteName = "";
    size_t CurSpriteNum = 0;
    bool PicReady = false;
    /* create first image window */
    Window.create(sf::VideoMode(1, 1), "");
    displayPicture(0, Window);
    /* window handle */
    while (Window.isOpen()) {
        sf::Event event;
        while (Window.pollEvent(event)) {
            /* close window by mouse */
            if (event.type == sf::Event::Closed) {
                PicReady = false;
                Window.close();
            }
            /* keys press handle */
            if (event.type == sf::Event::KeyPressed) {
                /* close window by ESC key */
                if (sf::Keyboard::isKeyPressed(sf::Keyboard::Escape)) {
                    PicReady = false;
                    Window.close();
                }
                if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right)) {
                    CurSpriteNum++;
                    if (CurSpriteNum > Pictures.size() - 1) CurSpriteNum = 0;
                    PicReady = true;
                }
                if (sf::Keyboard::isKeyPressed(sf::Keyboard::Left)) {
                    CurSpriteNum = (CurSpriteNum == 0) ? Pictures.size() - 1 : CurSpriteNum - 1;
                    PicReady = true;
                }
            }
            if (PicReady == true) {
                displayPicture(CurSpriteNum, Window);
                PicReady = false;
            }
        }
    }
    return EXIT_SUCCESS;
}