use warnings;
use strict;
use Win32::API;

printf(
    "width: %d, height: %d, bits per pixel: %d, frequency: %d Hz\n",
    getDisplayMetrics()
);

sub getDisplayMetrics { # per EnumDisplaySettings
    my $ENUM_CURRENT_SETTINGS = 0xFFFFFFFF;

    my $devmode = pack(
        "B" x 32 . "SSSSLsssssssssssss" . "B" x 32 . "SLLLLL",
        (0 x 32),       # dmDeviceName
        0,              # dmSpecVersion
        0,              # dmDriverVersion
        124,            # dmSize
        0,              # dmDriverExtra
        0,              # dmFields
        0,              # dmOrientation
        0,              # dmPaperSize
        0,              # dmPaperLength
        0,              # dmPaperWidth
        0,              # dmScale
        0,              # dmCopies
        0,              # dmDefaultSource
        0,              # dmPrintQuality
        0,              # dmColor
        0,              # dmDuplex
        0,              # dmYResolution
        0,              # dmTTOption
        0,              # dmCollate
        (0 x 32),       # dmFormName
        0,              # dmLogPixels
        0,              # dmBitsPerPel
        0,              # dmPelsWidth
        0,              # dmPelsHeight
        0,              # dmDisplayFlags
        0,              # dmDisplayFrequency
    );

    my $EnumDisplaySettings =   new Win32::API(
        "user32", "EnumDisplaySettings",   "PNP",  "N"
    );

    my $res = $EnumDisplaySettings->Call(0, $ENUM_CURRENT_SETTINGS, $devmode);
    my ($bpp, $x, $y, undef, $hz) = unpack("x104 LLLLL", $devmode);
    return ($x, $y, $bpp, $hz);
}