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Window / Scaling to pixels math

« on: February 18, 2025, 07:07:33 pm »

Hello, I am a new SFML and C++ programmer (but I've coded others) btw.

I am trying to get my game window to stay 16:9 whenever it's resized by scaling a 160 x 90 image and resizing the window to that sprite's scale.

Currently, it just.. well, I don't know how exactly to explain it, but the image is not scaling to the window's width.

Here's the code only necessary to share

int lastW = 1600; //window size at startup
int lastH = 900;
bool showDevTool1 = true;
float ratioW = 16.0f / 9.0f;
float ratioH = 9.0f / 16.0f;
std::string RatioHandles = "Images/Debug/Aspect_ratio_handles.png";

//Render window
int main() {
    sf::RenderWindow
    window(sf::VideoMode(lastW, lastH), "Gaem");

//16:9 ratio handles
        sf::Texture RHtexture;
        if (!RHtexture.loadFromFile(RatioHandles)) {
            return -1; // Exit if loading fails
        };
        sf::Sprite devTool1;
        devTool1.setTexture(RHtexture);

//Keep window open
    while (window.isOpen()) {
        sf::Event event;

//Close button closes window
    while (window.pollEvent(event)) {
            if (event.type == sf::Event::Closed)
                window.close();

//Can only resize as 16:9 ratio
            else if (event.type == sf::Event::Resized) {
                window.draw(devTool1);

//if width resized, do this
                if (lastW != event.size.width) {
                    std::cout << event.size.width;
                    std::cout << "---";
                    std::cout << RHtexture.getSize().x;
                    std::cout << "---";
                    devTool1.setScale(
                        event.size.width / RHtexture.getSize().x / 10,
                        lastH / RHtexture.getSize().y / 10);
                    window.setSize(sf::Vector2u(RHtexture.getSize().x * event.size.width, event.size.height));
                    lastW = event.size.width;
                    break;
                }