Progress bar with fmt

progress_bar.cpp

#include <fmt/core.h>
#include <fmt/color.h>
#include <chrono>
#include <thread>

void update_bar(int percent)
{
    int total = 100;
    int done = (percent / 100.0) * total;
    fmt::print("\r[");
    fmt::print(fg(fmt::rgb(5, 16, 57)) | bg(fmt::rgb(78, 66, 193)) | fmt::emphasis::bold, "{:>>{}}", "", done);
    fmt::print(fg(fmt::color::dark_blue) | bg(fmt::color::black), "{:->{}}", "", total - done);
    fmt::print("]");
    fmt::print(fg(fmt::color::sky_blue) | fmt::emphasis::bold, " {:>2}%", percent);
    fflush(stdout);
}

void update_transition_bar(int percent, 
        const fmt::rgb& start = fmt::color::white, 
        const fmt::rgb &finish = fmt::color::black)
{
    int total = 100;
    float alpha = percent / 100.0;
    int done = alpha * total;
    fmt::rgb bg_color = fmt::rgb((1 - alpha) * start.r + alpha * finish.r,
                               (1 - alpha) * start.g + alpha * finish.g,
                               (1 - alpha) * start.b + alpha * finish.b);
    fmt::print("\r[");
    fmt::print(fg(fmt::rgb(5, 16, 57)) | bg(bg_color) | fmt::emphasis::bold, "{:>>{}}", "", done);
    fmt::print(fg(fmt::color::dark_blue) | bg(fmt::color::black), "{:->{}}", "", total - done);
    fmt::print("]");
    fmt::print(fg(fmt::color::sky_blue) | fmt::emphasis::bold, " {:>2}%", percent);
    fflush(stdout);
}

void update_gradient_bar(int percent, 
        const fmt::rgb& start = fmt::color::white, 
        const fmt::rgb &finish = fmt::rgb(72, 184, 79))
{
    int total = 100;
    int done = (percent / 100.0) * total;
    fmt::print("\r[");
    for(int i = 1; i <= done; i++)
    {
        float alpha = i / 100.0;
        fmt::rgb bg_color = fmt::rgb((1 - alpha) * start.r + alpha * finish.r,
                (1 - alpha) * start.g + alpha * finish.g,
                (1 - alpha) * start.b + alpha * finish.b);
        fmt::print(fg(fmt::rgb(5, 16, 57)) | bg(bg_color) | fmt::emphasis::bold, ">");
    }
    fmt::print(fg(fmt::color::dark_blue) | bg(fmt::color::black), "{:->{}}", "", total - done);
    fmt::print("]");
    fmt::print(fg(fmt::color::sky_blue) | fmt::emphasis::bold, " {:>2}%", percent);
    fflush(stdout);
}

int main(int argc, char **argv)
{
    char ch = 0;
    if(argc > 1)
        ch = argv[1][0];
    int done = 0, total = 100;
    while(done <= total)
    {
        if(ch == 0 || ch == 'n')
        {
            update_bar((done++ / (float)total) * 100);
        }
        else if(ch == 't')
        {
            update_transition_bar((done++ / (float)total) * 100);
        }
        else if(ch == 'g')
        {
            update_gradient_bar((done++ / (float)total) * 100);
        }
        std::this_thread::sleep_for(std::chrono::milliseconds(17));
    }
    fmt::print("\n");
}