Color alpha blending

main.c

#include <stdio.h>
#include <stdint.h>

uint32_t blend(uint32_t base, uint32_t new, float alpha)
{
    uint8_t base_r = (base >> 16) & 0xFF;
    uint8_t base_g = (base >> 8) & 0xFF;
    uint8_t base_b = (base >> 0) & 0xFF;
    
    uint8_t new_r = (new >> 16) & 0xFF;
    uint8_t new_g = (new >> 8) & 0xFF;
    uint8_t new_b = (new >> 0) & 0xFF;
    
    uint8_t final_r = base_r + ((float)new_r - (float)base_r) * alpha;
    uint8_t final_g = base_g + ((float)new_g - (float)base_g) * alpha;
    uint8_t final_b = base_b + ((float)new_b - (float)base_b) * alpha;
    
    return ((uint32_t)final_r << 16) | ((uint32_t)final_g << 8) | ((uint32_t)final_b << 0);
}

int main()
{
    uint32_t base = 0xFFFFFF;
    uint32_t new = 0xFB00FF;
    float alpha = 0.5f;
    
    printf("base: %06X\n", base);
    printf("new: %06X\n", new);
    printf("final: %06X\n", blend(base, new, alpha));

    return 0;
}