24 bit color test with qsort animation

24bit-color-qsort.sh

#!/bin/bash

COLS=${1:-16}
ROWS=${2:-15}
DELAY=${3:-0.005}
TOTAL=$((COLS * ROWS))

declare -a R G B ORD

init() {
    for ((i=0; i<TOTAL; i++)); do
        hue=$((i * 360 / TOTAL))
        sec=$((hue / 60))
        f=$((hue % 60))
        q=$((255 * (60 - f) / 60))
        t=$((255 * f / 60))

        case $sec in
            0) R[i]=255; G[i]=$t; B[i]=0 ;;
            1) R[i]=$q; G[i]=255; B[i]=0 ;;
            2) R[i]=0; G[i]=255; B[i]=$t ;;
            3) R[i]=0; G[i]=$q; B[i]=255 ;;
            4) R[i]=$t; G[i]=0; B[i]=255 ;;
            *) R[i]=255; G[i]=0; B[i]=$q ;;
        esac
        ORD[i]=$i
    done
}

swap() {
    local a=$1 b=$2 tmp
    tmp=${R[a]}; R[a]=${R[b]}; R[b]=$tmp
    tmp=${G[a]}; G[a]=${G[b]}; G[b]=$tmp
    tmp=${B[a]}; B[a]=${B[b]}; B[b]=$tmp
    tmp=${ORD[a]}; ORD[a]=${ORD[b]}; ORD[b]=$tmp
}

shuffle() {
    for ((i=TOTAL-1; i>0; i--)); do
        swap "$i" "$((RANDOM % (i + 1)))"
    done
}

draw_all() {
    local n=0
    for ((row=0; row<ROWS; row++)); do
        for ((col=0; col<COLS; col++)); do
            printf "\e[48;2;%d;%d;%dm  " "${R[n]}" "${G[n]}" "${B[n]}"
            ((n++))
        done
        printf "\e[0m\n"
    done
    printf "\e[0mENTER=sorted | Ctrl+C=exit\n"
}

draw_cell() {
    local idx=$1 r g b
    local row_up=$((ROWS + 1 - idx / COLS))
    local col=$((idx % COLS * 2 + 1))

    if (($# == 4)); then
        r=$2; g=$3; b=$4
    else
        r=${R[idx]}; g=${G[idx]}; b=${B[idx]}
    fi

    printf "\e[%dA\e[%dG\e[48;2;%d;%d;%dm  \e[0m\e[%dB\e[1G" "$row_up" "$col" "$r" "$g" "$b" "$row_up"
}

restore_original() {
    for ((i=0; i<TOTAL; i++)); do
        for ((j=i; j<TOTAL; j++)); do
            if ((ORD[j] == i)); then
                swap "$i" "$j"
                break
            fi
        done
    done
}

sort_animate() {
    for ((i=0; i<TOTAL-1; i++)); do
        min=$i
        for ((j=i+1; j<TOTAL; j++)); do
            ((ORD[j] < ORD[min])) && min=$j
        done

        if ((min != i)); then
            draw_cell "$i" 255 255 0
            draw_cell "$min" 255 255 0
            swap "$i" "$min"

            IFS= read -t "$DELAY" -r key 2>/dev/null && {
                restore_original
                printf "\e[%dA" "$((ROWS + 1))"
                draw_all
                return 1
            }

            draw_cell "$i"
            draw_cell "$min"
        fi
    done
}

main() {
    printf "\e[?25l"

    init
    shuffle
    draw_all
    sleep 0.3

    stty -echo -icanon time 0 min 0 2>/dev/null
    sort_animate
    stty sane 2>/dev/null

    printf "\e[?25h\e[0m\n"
}

main