SDL2:如何在调整窗口大小时保持纵横比

我正在尝试创建一个SDL窗口，该窗口在发生调整大小事件时保持其纵横比。如果用户加宽窗口，则高度会增加，反之亦然。我捕获SDL_WINDOWEVENT_RESIZED事件，计算保持纵横比的新宽度或高度，然后用计算的值调用SDL_SetWindowSize（）。

问题是在事件轮询循环中调用SDL_SetWindowSize（）函数在屏幕上没有任何作用。SDL确实更新了窗口大小变量（在我的主循环中调用SDL_GetWindowSize（）会返回更新后的窗口尺寸）。但是，实际窗口不会更新。

我能做到这一点的唯一方法是在主循环中不断调用SDL_SetWindowSize（），但我认为这是错误的做法。下面的代码说明了我的问题。有没有更好、更干净的方法让它发挥作用？

我使用的是SDL2.0.3和64位Ubuntu Linux和GNOME桌面。

#include <SDL2/SDL.h>
static const float ASPECT_RATIO = 16.f/9.f;
SDL_Window* window;
SDL_Renderer* renderer;
uint32_t windowID;
SDL_Rect screen;
bool done = false;
bool resizeDone = false;
void handle_events()
{
    SDL_Event e;
    while (SDL_PollEvent(&e)) {
        switch (e.type) {
        case SDL_WINDOWEVENT: 
            if(e.window.windowID == windowID) {
                switch(e.window.event) {
                    case SDL_WINDOWEVENT_RESIZED: { 
                        int width = e.window.data1;
                        int height = e.window.data2;
                        float aspectRatio = (float)width/(float)height;
                        if(aspectRatio != ASPECT_RATIO) {
                            if(aspectRatio > ASPECT_RATIO) {
                                height = (1.f / ASPECT_RATIO) * width; 
                            }
                            else {
                                width = ASPECT_RATIO * height; 
                            }
                            printf("Setting window size to %d, %d, aspect ratio: %fn", 
                                width, height, (float)width/(float)height);
                    }
                    screen.w = width;
                    screen.h = height; 
                    SDL_SetWindowSize(window, width, height); // <-- does not work
                    resizeDone = true;
                    break;
                    }
                }
             }
             break;
        case SDL_QUIT:
            done = true;
            break;
        default:
            break;
        }
    }   
}
void run() {
    while(!done) {
        //SDL_SetWindowSize(window, screen.w, screen.h); // <-- works
        handle_events();
        SDL_RenderClear(renderer);
        SDL_RenderPresent(renderer);
        if(resizeDone) {
            int w, h;
            SDL_GetWindowSize(window, &w, &h);
            printf("SDL_GetWindowSize: %d, %dn", w, h);
            resizeDone = false;
        }
    }
}
int main(int, char**) {
    SDL_Init(SDL_INIT_VIDEO);
    uint32_t window_flags = SDL_WINDOW_SHOWN | SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_RESIZABLE;
    window = SDL_CreateWindow("Test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
    windowID = SDL_GetWindowID(window);
    renderer = SDL_CreateRenderer(window, -1, 0);
    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
    run();
    SDL_Quit();
    return 0;
}