#include <a_samp>

new RainbowGradient[25] = {
0xFF0000FF, 0xFF2C00FF, 0xFF5000FF, 0xFF8700FF, 0xFFA700FF,
0xFFDC00FF, 0xFFFB00FF, 0xC4FF00FF, 0x7BFF00FF, 0x00FF00FF,
0x00FF1EFF, 0x00FF3BFF, 0x00FF7CFF, 0x00FFAEFF, 0x00FFD5FF,
0x00FFFFFF, 0x00CCFFFF, 0x00ACFFFF, 0x0083FFFF, 0x0054FFFF,
0x0000FFFF, 0x2C00FFFF, 0x5F00FFFF, 0x9B00FFFF, 0xCB00FFFF
};

public OnPlayerUpdate(playerid)
{
    for(new i = 25; i >= 0; i--)
    {
        SetPlayerColor(playerid, RainbowGradient[i]);
        if(RainbowGradient[i] == 0) i = 26;
    }
    return 1;
}