我如何在C中使十六进制的颜色变亮/变暗？

#include <stdio.h>

// 函数：将RGB颜色值转换为十六进制颜色值
int rgbToHex(int r, int g, int b) {
    return (r << 16) | (g << 8) | b;
}

// 函数：将十六进制颜色值转换为RGB颜色值
void hexToRgb(int hex, int* r, int* g, int* b) {
    *r = (hex >> 16) & 0xFF;
    *g = (hex >> 8) & 0xFF;
    *b = hex & 0xFF;
}

// 函数：使十六进制颜色变亮
int lightenColor(int hex, int increment) {
    int r, g, b;
    hexToRgb(hex, &r, &g, &b);

    r += increment;
    g += increment;
    b += increment;

    if (r > 255) r = 255;
    if (g > 255) g = 255;
    if (b > 255) b = 255;

    return rgbToHex(r, g, b);
}

// 函数：使十六进制颜色变暗
int darkenColor(int hex, int decrement) {
    int r, g, b;
    hexToRgb(hex, &r, &g, &b);

    r -= decrement;
    g -= decrement;
    b -= decrement;

    if (r < 0) r = 0;
    if (g < 0) g = 0;
    if (b < 0) b = 0;

    return rgbToHex(r, g, b);
}

int main() {
    int color = 0xFF0000; // 红色
    int lightenedColor = lightenColor(color, 50);
    int darkenedColor = darkenColor(color, 50);

    printf("Lightened color: #%06X\n", lightenedColor);
    printf("Darkened color: #%06X\n", darkenedColor);

    return 0;
}