File Coverage

blib/lib/Image/Size.pm

Criterion	Covered	Total	%
statement	243	357	68.0
branch	48	136	35.2
condition	18	41	43.9
subroutine	25	31	80.6
pod	3	22	13.6
total	337	587	57.4

###############################################################################
#
# This file copyright (c) 2015 by Randy J. Ray, all rights reserved
#
# Copying and distribution are permitted under the terms of the Artistic
# License 2.0 (http://www.opensource.org/licenses/artistic-license-2.0.php) or
# the GNU LGPL (http://www.opensource.org/licenses/lgpl-2.1.php).
#
###############################################################################
#
# Once upon a time, this code was lifted almost verbatim from wwwis by Alex
# Knowles, [e-mail]. Since then, even I barely recognize it. It has
# contributions, fixes, additions and enhancements from all over the world.
#
# See the file ChangeLog for change history.
#
###############################################################################

package Image::Size;

require 5.006001;

# These are the Perl::Critic policies that are being turned off globally:
## no critic(RequireBriefOpen)
## no critic(ProhibitAutomaticExportation)

use strict;
use warnings;
use bytes;
use vars qw(
    @EXPORT @EXPORT_OK %EXPORT_TAGS $VERSION $NO_CACHE %CACHE
    $GIF_BEHAVIOR @TYPE_MAP %PCD_MAP $PCD_SCALE $READ_IN $LAST_POS
);

use Exporter 'import';

BEGIN
{
    @EXPORT      = qw(imgsize);
    @EXPORT_OK   = qw(imgsize html_imgsize attr_imgsize
                      %CACHE $NO_CACHE $PCD_SCALE $GIF_BEHAVIOR);
    %EXPORT_TAGS = ('all' => [ @EXPORT_OK ]);

    $VERSION = '3.300';
    $VERSION = eval $VERSION; ## no critic(ProhibitStringyEval)

    # Default behavior for GIFs is to return the "screen" size
    $GIF_BEHAVIOR = 0;
}

# This allows people to specifically request that the cache not be used
$NO_CACHE = 0;

# Package lexicals - invisible to outside world, used only in imgsize
#
# Mapping of patterns to the sizing routines
@TYPE_MAP = (
    qr{^GIF8[79]a}               => \&gifsize,
    qr{^\xFF\xD8}                => \&jpegsize,
    qr{^\x89PNG\x0d\x0a\x1a\x0a} => \&pngsize,
    qr{^P[1-7]}                  => \&ppmsize, # also XVpics
    qr{#define\s+\S+\s+\d+}      => \&xbmsize,
    qr{/[*] XPM [*]/}            => \&xpmsize,
    qr{^MM\x00\x2a}              => \&tiffsize,
    qr{^II\x2a\x00}              => \&tiffsize,
    qr{^BM}                      => \&bmpsize,
    qr{^8BPS}                    => \&psdsize,
    qr{^PCD_OPA}                 => \&pcdsize,
    qr{^FWS}                     => \&swfsize,
    qr{^CWS}                     => \&swfmxsize,
    qr{^\x8aMNG\x0d\x0a\x1a\x0a} => \&mngsize,
    qr{^\x01\x00\x00\x00}        => \&emfsize,
    qr{^RIFF(?s:....)WEBP}       => \&webpsize,
    qr{^\x00\x00\x01\x00}        => \&icosize,
    qr{^\x00\x00\x02\x00}        => \&cursize,
);
# Kodak photo-CDs are weird. Don't ask me why, you really don't want details.
%PCD_MAP = ( 'base/16' => [ 192,  128  ],
             'base/4'  => [ 384,  256  ],
             'base'    => [ 768,  512  ],
             'base4'   => [ 1536, 1024 ],
             'base16'  => [ 3072, 2048 ],
             'base64'  => [ 6144, 4096 ], );
# Default scale for PCD images
$PCD_SCALE = 'base';

# These are lexically-scoped anonymous subroutines for reading the three
# types of input streams. When the input to imgsize() is typed, then the
# lexical "read_in" is assigned one of these, thus allowing the individual
# routines to operate on these streams abstractly.

my $read_io = sub {
    my $handle = shift;
    my ($length, $offset) = @_;

    if (defined($offset) && ($offset != $LAST_POS))
    {
        $LAST_POS = $offset;
        return q{} if (! seek $handle, $offset, 0);
    }

    my ($buffer, $rtn) = (q{}, 0);
    $rtn = read $handle, $buffer, $length;
    if (! $rtn)
    {
        $buffer = q{};
    }
    $LAST_POS = tell $handle;

    return $buffer;
};

my $read_buf = sub {
    my $buf = shift;
    my ($length, $offset) = @_;

    if (defined($offset) && ($offset != $LAST_POS))
    {
        $LAST_POS = $offset;
        return q{} if ($LAST_POS > length ${$buf});
    }

    my $content = substr ${$buf}, $LAST_POS, $length;
    $LAST_POS += length $content;

    return $content;
};

sub imgsize ## no critic(ProhibitExcessComplexity)
{
    my $stream = shift;

    my ($handle, $header);
    my ($x, $y, $id, $mtime, @list);
    # These only used if $stream is an existing open FH
    my ($save_pos, $need_restore) = (0, 0);
    # This is for when $stream is a locally-opened file
    my $need_close = 0;
    # This will contain the file name, if we got one
    my $file_name = undef;

    $header = q{};

    if (ref($stream) eq 'SCALAR')
    {
        $handle = $stream;
        $READ_IN = $read_buf;
        $header = substr ${$handle} || q{}, 0, 256;
    }
    elsif (ref $stream)
    {
        # I no longer require $stream to be in the IO::* space. So I'm assuming
        # you don't hose yourself by passing a ref that can't do fileops. If
        # you do, you fix it.
        $handle = $stream;
        $READ_IN = $read_io;
        $save_pos = tell $handle;
        $need_restore = 1;

        # First alteration (didn't wait long, did I?) to the existing handle:
        #
        # assist dain-bramaged operating systems -- SWD
        # SWD: I'm a bit uncomfortable with changing the mode on a file
        # that something else "owns" ... the change is global, and there
        # is no way to reverse it.
        # But image files ought to be handled as binary anyway.
        binmode $handle;
        seek $handle, 0, 0;
        read $handle, $header, 256;
        seek $handle, 0, 0;
    }
    else
    {
        if (! $NO_CACHE)
        {
            require Cwd;
            require File::Spec;

            if (! File::Spec->file_name_is_absolute($stream))
            {
                $stream = File::Spec->catfile(Cwd::cwd(), $stream);
            }
            $mtime = (stat $stream)[9];
            if (-e "$stream" and exists $CACHE{$stream})
            {
                @list = split /,/, $CACHE{$stream}, 4;

                # Don't return the cache if the file is newer.
                if ($mtime <= $list[0])
                {
                    return @list[1 .. 3];
                }
                # In fact, clear it
                delete $CACHE{$stream};
            }
        }

        # first try to open the stream
        require Symbol;
        $handle = Symbol::gensym();
        if (! open $handle, '<', $stream)
        {
            return (undef, undef, "Can't open image file $stream: $!");
        }

        $need_close = 1;
        # assist dain-bramaged operating systems -- SWD
        binmode $handle;
        read $handle, $header, 256;
        seek $handle, 0, 0;
        $READ_IN = $read_io;
        $file_name = $stream;
    }
    $LAST_POS = 0;

    # Right now, $x, $y and $id are undef. If the while-loop below doesn't
    # match the header to a file-type and call a subroutine, then the later
    # block that tried Image::Magick will default to setting the id/error to
    # "unknown file type".
    my $tm_idx = 0;
    while ($tm_idx < @TYPE_MAP)
    {
        if ($header =~ $TYPE_MAP[$tm_idx])
        {
            ($x, $y, $id) = $TYPE_MAP[$tm_idx + 1]->($handle);
            last;
        }
        $tm_idx += 2;
    }

    # Added as an afterthought: I'm probably not the only one who uses the
    # same shaded-sphere image for several items on a bulleted list:
    if (! ($NO_CACHE or (ref $stream) or (! defined $x)))
    {
        $CACHE{$stream} = join q{,}, $mtime, $x, $y, $id;
    }

    # If we were passed an existing file handle, we need to restore the
    # old filepos:
    if ($need_restore)
    {
        seek $handle, $save_pos, 0;
    }
    # ...and if we opened the file ourselves, we need to close it
    if ($need_close)
    {
        close $handle; ## no critic(RequireCheckedClose)
    }

    if (! defined $id)
    {
        if ($file_name)
        {
            # Image::Magick operates on file names.
            ($x, $y, $id) = imagemagick_size($file_name);
        }
        else
        {
            $id = 'Data stream is not a known image file format';
        }
    }

    # results:
    return (wantarray) ? ($x, $y, $id) : ();
}

sub imagemagick_size
{
    my $file_name = shift;

    my $module_name;
    # First see if we have already loaded Graphics::Magick or Image::Magick
    # If so, just use whichever one is already loaded.
    if (exists $INC{'Graphics/Magick.pm'})
    {
        $module_name = 'Graphics::Magick';
    }
    elsif (exists $INC{'Image/Magick.pm'})
    {
        $module_name = 'Image::Magick';
    }
    # If neither are already loaded, try loading either one.
    elsif (_load_magick_module('Graphics::Magick'))
    {
       $module_name = 'Graphics::Magick';
    }
    elsif (_load_magick_module('Image::Magick'))
    {
       $module_name = 'Image::Magick';
    }

    if ($module_name)
    {
        my $img = $module_name->new();
        my $x = $img->Read($file_name);
        # Image::Magick error handling is a bit weird, see
        #
        if("$x") {
            return (undef, undef, "$x");
        } else {
            return ($img->Get('width', 'height', 'format'));
        }

    }
    else {
        return (undef, undef, 'Data stream is not a known image file format');
    }
}

# load Graphics::Magick or Image::Magick if one is not already loaded.
sub _load_magick_module {
    my $module_name = shift;
    my $retval = eval {
        local $SIG{__DIE__} = q{};
        require $module_name;
        1;
    };
    return $retval ? 1 : 0;
}


sub html_imgsize
{
    my @args = @_;
    @args = imgsize(@args);

    # Use lowercase and quotes so that it works with xhtml.
    return ((defined $args[0]) ?
            sprintf('width="%d" height="%d"', @args[0,1]) :
            undef);
}

sub attr_imgsize
{
    my @args = @_;
    @args = imgsize(@args);

    return ((defined $args[0]) ?
            (('-width', '-height', @args)[0, 2, 1, 3]) :
            undef);
}

# This used only in gifsize:
sub img_eof
{
    my $stream = shift;

    if (ref($stream) eq 'SCALAR')
    {
        return ($LAST_POS >= length ${$stream});
    }

    return eof $stream;
}

# Simple converter-routine used by SWF and CWS code
sub _bin2int
{
    my $val = shift;
    # "no critic" because I want it clear which args are being used by
    # substr() versus unpack().
    ## no critic (ProhibitParensWithBuiltins)
    return unpack 'N', pack 'B32', substr(('0' x 32) . $val, -32);
}

###########################################################################
# Subroutine gets the size of the specified GIF
###########################################################################
sub gifsize ## no critic(ProhibitExcessComplexity)
{
    my $stream = shift;

    my ($cmapsize, $buf, $sh, $sw, $x, $y, $type);

    my $gif_blockskip = sub {
        my ($skip, $blocktype) = @_;
        my ($lbuf);

        $READ_IN->($stream, $skip);        # Skip header (if any)
        while (1)
        {
            if (img_eof($stream))
            {
                return (undef, undef,
                        "Invalid/Corrupted GIF (at EOF in GIF $blocktype)");
            }
            $lbuf = $READ_IN->($stream, 1);  # Block size
            last if ord($lbuf) == 0;         # Block terminator
            $READ_IN->($stream, ord $lbuf);  # Skip data
        }
    };

    if ($GIF_BEHAVIOR > 2)
    {
        return (undef, undef,
                "\$Image::Size::GIF_BEHAVIOR out of range: $GIF_BEHAVIOR");
    }

    # Skip over the identifying string, since we already know this is a GIF
    $type = $READ_IN->($stream, 6);
    if (length($buf = $READ_IN->($stream, 7)) != 7 )
    {
        return (undef, undef, 'Invalid/Corrupted GIF (bad header)');
    }
    ($sw, $sh, $x) = unpack 'vv C', $buf;
    if ($GIF_BEHAVIOR == 0)
    {
        return ($sw, $sh, 'GIF');
    }

    if ($x & 0x80)
    {
        $cmapsize = 3 * (2**(($x & 0x07) + 1));
        if (! $READ_IN->($stream, $cmapsize))
        {
            return (undef, undef,
                    'Invalid/Corrupted GIF (global color map too small?)');
        }
    }

    # Before we start this loop, set $sw and $sh to 0s and use them to track
    # the largest sub-image in the overall GIF.
    $sw = $sh = 0;

  FINDIMAGE:
    while (1)
    {
        if (img_eof($stream))
        {
            # At this point, if we haven't returned then the user wants the
            # largest of the sub-images. So, if $sh and $sw are still 0s, then
            # we didn't see even one Image Descriptor block. Otherwise, return
            # those two values.
            if ($sw and $sh)
            {
                return ($sw, $sh, 'GIF');
            }
            else
            {
                return (undef, undef,
                        'Invalid/Corrupted GIF (no Image Descriptors)');
            }
        }
        $buf = $READ_IN->($stream, 1);
        ($x) = unpack 'C', $buf;
        if ($x == 0x2c)
        {
            # Image Descriptor (GIF87a, GIF89a 20.c.i)
            if (length($buf = $READ_IN->($stream, 8)) != 8)
            {
                return (undef, undef,
                        'Invalid/Corrupted GIF (missing image header?)');
            }
            ($x, $y) = unpack 'x4 vv', $buf;
            return ($x, $y, 'GIF') if ($GIF_BEHAVIOR == 1);
            if ($x > $sw and $y > $sh)
            {
                $sw = $x;
                $sh = $y;
            }
        }
        if ($x == 0x21)
        {
            # Extension Introducer (GIF89a 23.c.i, could also be in GIF87a)
            $buf = $READ_IN->($stream, 1);
            ($x) = unpack 'C', $buf;
            if ($x == 0xF9)
            {
                # Graphic Control Extension (GIF89a 23.c.ii)
                $READ_IN->($stream, 6);    # Skip it
                next FINDIMAGE;       # Look again for Image Descriptor
            }
            elsif ($x == 0xFE)
            {
                # Comment Extension (GIF89a 24.c.ii)
                $gif_blockskip->(0, 'Comment');
                next FINDIMAGE;       # Look again for Image Descriptor
            }
            elsif ($x == 0x01)
            {
                # Plain Text Label (GIF89a 25.c.ii)
                $gif_blockskip->(13, 'text data');
                next FINDIMAGE;       # Look again for Image Descriptor
            }
            elsif ($x == 0xFF)
            {
                # Application Extension Label (GIF89a 26.c.ii)
                $gif_blockskip->(12, 'application data');
                next FINDIMAGE;       # Look again for Image Descriptor
            }
            else
            {
                return (undef, undef,
                        sprintf 'Invalid/Corrupted GIF (Unknown ' .
                                'extension %#x)', $x);
            }
        }
        else
        {
            return (undef, undef,
                    sprintf 'Invalid/Corrupted GIF (Unknown code %#x)', $x);
        }
    }

    return (undef, undef, 'gifsize fell through to the end, error');
}

sub xbmsize
{
    my $stream = shift;

    my $input;
    my ($x, $y, $id) = (undef, undef, 'Could not determine XBM size');

    $input = $READ_IN->($stream, 1024);
    if ($input =~ /^\#define\s*\S*\s*(\d+)\s*\n\#define\s*\S*\s*(\d+)/ix)
    {
        ($x, $y) = ($1, $2);
        $id = 'XBM';
    }

    return ($x, $y, $id);
}

# Added by Randy J. Ray, 30 Jul 1996
# Size an XPM file by looking for the "X Y N W" line, where X and Y are
# dimensions, N is the total number of colors defined, and W is the width of
# a color in the ASCII representation, in characters. We only care about X & Y.
sub xpmsize
{
    my $stream = shift;

    my $line;
    my ($x, $y, $id) = (undef, undef, 'Could not determine XPM size');

    while ($line = $READ_IN->($stream, 1024))
    {
        if ($line =~ /"\s*(\d+)\s+(\d+)(\s+\d+\s+\d+){1,2}\s*"/)
        {
            ($x, $y) = ($1, $2);
            $id = 'XPM';
            last;
        }
    }

    return ($x, $y, $id);
}

# pngsize : gets the width & height (in pixels) of a png file
# cor this program is on the cutting edge of technology! (pity it's blunt!)
#
# Re-written and tested by [e-mail]
sub pngsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Could not determine PNG size');
    my ($offset, $length);

    # Offset to first Chunk Type code = 8-byte ident + 4-byte chunk length + 1
    $offset = 12; $length = 4;
    if ($READ_IN->($stream, $length, $offset) eq 'IHDR')
    {
        # IHDR = Image Header
        $length = 8;
        ($x, $y) = unpack 'NN', $READ_IN->($stream, $length);
        $id = 'PNG';
    }

    return ($x, $y, $id);
}

# mngsize: gets the width and height (in pixels) of an MNG file.
# See  for the specification.
#
# Basically a copy of pngsize.
sub mngsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Could not determine MNG size');
    my ($offset, $length);

    # Offset to first Chunk Type code = 8-byte ident + 4-byte chunk length + 1
    $offset = 12; $length = 4;
    if ($READ_IN->($stream, $length, $offset) eq 'MHDR')
    {
        # MHDR = Image Header
        $length = 8;
        ($x, $y) = unpack 'NN', $READ_IN->($stream, $length);
        $id = 'MNG';
    }

    return ($x, $y, $id);
}

# jpegsize: gets the width and height (in pixels) of a jpeg file
# Andrew Tong, [e-mail]           February 14, 1995
# modified slightly by [e-mail]
# and further still by [e-mail]
# optimization and general re-write from [e-mail]
sub jpegsize
{
    my $stream = shift;

    my $MARKER     = chr 0xff; # Section marker

    my $SIZE_FIRST = 0xC0;   # Range of segment identifier codes
    my $SIZE_LAST  = 0xC3;   #  that hold size info.

    my ($x, $y, $id) = (undef, undef, 'Could not determine JPEG size');

    my ($marker, $code, $length);
    my $segheader;

    # Dummy read to skip header ID
    $READ_IN->($stream, 2);
    while (1)
    {
        $segheader = $READ_IN->($stream, 2);

        # Extract the segment header.
        ($marker, $code) = unpack 'a a', $segheader;

        while ( $code eq $MARKER && ($marker = $code) ) {
            $segheader = $READ_IN->($stream, 1);
            ($code) = unpack 'a', $segheader;
        }
        $segheader = $READ_IN->($stream, 2);
        $length = unpack 'n', $segheader;

        # Verify that it's a valid segment.
        if ($marker ne $MARKER)
        {
            # Was it there?
            $id = 'JPEG marker not found';
            last;
        }
        elsif ((ord($code) >= $SIZE_FIRST) && (ord($code) <= $SIZE_LAST))
        {
            # Segments that contain size info
            $length = 5;
            my $buf = $READ_IN->($stream, $length);
            # unpack dies on truncated data
            last if (length($buf) < $length);
            ($y, $x) = unpack 'xnn', $buf;
            $id = 'JPG';
            last;
        }
        else
        {
            # Dummy read to skip over data
            $READ_IN->($stream, ($length - 2));
        }
    }

    return ($x, $y, $id);
}

# ppmsize: gets data on the PPM/PGM/PBM family.
#
# Contributed by Carsten Dominik
sub ppmsize
{
    my $stream = shift;

    my ($x, $y, $id) =
        (undef, undef, 'Unable to determine size of PPM/PGM/PBM data');
    my $n;
    my @table = qw(nil PBM PGM PPM PBM PGM PPM);

    my $header = $READ_IN->($stream, 1024);

    # PPM file of some sort
    $header =~ s/^\#.*//mg;
    if ($header =~ /^(?:P([1-7]))\s+(\d+)\s+(\d+)/)
    {
        ($n, $x, $y) = ($1, $2, $3);

        if ($n == 7)
        {
            # John Bradley's XV thumbnail pics (from [e-mail])
            $id = 'XV';
            ($x, $y) = ($header =~ /IMGINFO:(\d+)x(\d+)/s);
        }
        else
        {
            $id = $table[$n];
        }
    }

    return ($x, $y, $id);
}

# tiffsize: size a TIFF image
#
# Contributed by Cloyce Spradling
sub tiffsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Unable to determine size of TIFF data');

    my $endian = 'n';           # Default to big-endian; I like it better
    my $header = $READ_IN->($stream, 4);
    if ($header =~ /II\x2a\x00/o)
    {
        # little-endian
        $endian = 'v';
    }

    # Set up an association between data types and their corresponding
    # pack/unpack specification.  Don't take any special pains to deal with
    # signed numbers; treat them as unsigned because none of the image
    # dimensions should ever be negative. (I hope.)
    my @packspec = ( undef,      # nothing (shouldn't happen)
                     'C',        # BYTE (8-bit unsigned integer)
                     undef,      # ASCII
                     $endian,    # SHORT (16-bit unsigned integer)
                     uc $endian, # LONG (32-bit unsigned integer)
                     undef,      # RATIONAL
                     'c',        # SBYTE (8-bit signed integer)
                     undef,      # UNDEFINED
                     $endian,    # SSHORT (16-bit unsigned integer)
                     uc $endian, # SLONG (32-bit unsigned integer)
                     );

    my $offset = $READ_IN->($stream, 4, 4); # Get offset to IFD
    $offset = unpack uc $endian, $offset; # Fix it so we can use it

    my $ifd = $READ_IN->($stream, 2, $offset); # Get num. of directory entries
    my $num_dirent = unpack $endian, $ifd; # Make it useful
    $offset += 2;
    $num_dirent = $offset + ($num_dirent * 12); # Calc. maximum offset of IFD

    # Do all the work
    $ifd = q{};
    my $tag = 0;
    my $type = 0;
    while ((! defined $x) || (! defined$y)) {
        $ifd = $READ_IN->($stream, 12, $offset);   # Get first directory entry
        last if (($ifd eq q{}) || ($offset > $num_dirent));
        $offset += 12;
        $tag = unpack $endian, $ifd;               # ...and decode its tag
        $type = unpack $endian, substr $ifd, 2, 2; # ...and the data type
        # Check the type for sanity.
        next if (($type > @packspec+0) || (! defined $packspec[$type]));
        if ($tag == 0x0100)    # ImageWidth (x)
        {
            # Decode the value
            $x = unpack $packspec[$type], substr $ifd, 8, 4;
        }
        elsif ($tag == 0x0101) # ImageLength (y)
        {
            # Decode the value
            $y = unpack $packspec[$type], substr $ifd, 8, 4;
        }
    }

    # Decide if we were successful or not
    if (defined $x and defined $y)
    {
        $id = 'TIF';
    }
    else
    {
        $id = q{};
        if (! defined $x)
        {
            $id = 'ImageWidth ';
        }
        if (! defined $y)
        {
            if ($id ne q{})
            {
                $id .= 'and ';
            }
            $id .= 'ImageLength ';
        }
        $id .= 'tag(s) could not be found';
    }

    return ($x, $y, $id);
}

# bmpsize: size a Windows-ish BitMaP image
#
# Adapted from code contributed by Aldo Calpini
sub bmpsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Unable to determine size of BMP data');
    my $buffer;

    $buffer = $READ_IN->($stream, 26);
    my $header_size = unpack 'x14V', $buffer;
    if ($header_size == 12)
    {
        ($x, $y) = unpack 'x18vv', $buffer;     # old OS/2 header
    }
    else
    {
        ($x, $y) = unpack 'x18VV', $buffer;     # modern Windows header
    }
    if (defined $x and defined $y)
    {
        $id = 'BMP';
    }

    return ($x, $y, $id);
}

# psdsize: determine the size of a PhotoShop save-file (*.PSD)
sub psdsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Unable to determine size of PSD data');
    my $buffer;

    $buffer = $READ_IN->($stream, 26);
    ($y, $x) = unpack 'x14NN', $buffer;
    if (defined $x and defined $y)
    {
        $id = 'PSD';
    }

    return ($x, $y, $id);
}

# swfsize: determine size of ShockWave/Flash files. Adapted from code sent by
# Dmitry Dorofeev
sub swfsize
{
    my $image  = shift;
    my $header = $READ_IN->($image, 33);

    my $ver = _bin2int(unpack 'B8', substr $header, 3, 1);
    my $bs = unpack 'B133', substr $header, 8, 17;
    my $bits = _bin2int(substr $bs, 0, 5);
    my $x = int _bin2int(substr $bs, 5+$bits, $bits)/20;
    my $y = int _bin2int(substr $bs, 5+$bits*3, $bits)/20;

    return ($x, $y, 'SWF');
}

# Suggested by Matt Mueller , and based on a piece of
# sample Perl code by a currently-unknown author. Credit will be placed here
# once the name is determined.
sub pcdsize
{
    my $stream = shift;

    my ($x, $y, $id) = (undef, undef, 'Unable to determine size of PCD data');
    my $buffer = $READ_IN->($stream, 0xf00);

    # Second-tier sanity check
    if (substr($buffer, 0x800, 3) ne 'PCD')
    {
        return ($x, $y, $id);
    }

    my $orient = ord(substr $buffer, 0x0e02, 1) & 1; # Clear down to one bit
    ($x, $y) = @{$Image::Size::PCD_MAP{lc $Image::Size::PCD_SCALE}}
        [($orient ? (0, 1) : (1, 0))];

    return ($x, $y, 'PCD');
}

# swfmxsize: determine size of compressed ShockWave/Flash MX files. Adapted
# from code sent by Victor Kuriashkin
sub swfmxsize
{
    my $image = shift;

    my $retval = eval {
        local $SIG{__DIE__} = q{};
        require Compress::Zlib;
        1;
    };
    if (! $retval)
    {
        return (undef, undef, "Error loading Compress::Zlib: $@");
    }

    my $header = $READ_IN->($image, 1058);
    my $ver = _bin2int(unpack 'B8', substr $header, 3, 1);

    my ($d, $status) = Compress::Zlib::inflateInit();
    $header = substr $header, 8, 1024;
    $header = $d->inflate($header);

    my $bs = unpack 'B133', substr $header, 0, 17;
    my $bits = _bin2int(substr $bs, 0, 5);
    my $x = int _bin2int(substr $bs, 5+$bits, $bits)/20;
    my $y = int _bin2int(substr $bs, 5+$bits*3, $bits)/20;

    return ($x, $y, 'CWS');
}

# Windows EMF files, requested by Jan v/d Zee
sub emfsize
{
    my $image = shift;

    my ($x, $y);
    my $buffer = $READ_IN->($image, 24);

    my ($topleft_x, $topleft_y, $bottomright_x, $bottomright_y) =
        unpack 'x8V4', $buffer;

    # The four values describe a box *around* the image, not *of* the image.
    # In other words, the dimensions are not inclusive.
    $x = $bottomright_x - $topleft_x - 1;
    $y = $bottomright_y - $topleft_y - 1;

    return ($x, $y, 'EMF');
}

# WEBP files, see https://developers.google.com/speed/webp/docs/riff_container
# Added by Baldur Kristinsson, github.com/bk
sub webpsize {
    my $img = shift;

    # There are 26 bytes of lead-in, before the width and height info:
    # 1. WEBP container
    #    - 'RIFF', 4 bytes
    #    - filesize, 4 bytes
    #    - 'WEBP', 4 bytes
    # 2. VP8 frame
    #    - 'VP8', 3 bytes
    #    - frame meta, 8 bytes
    #    - marker, 3 bytes
    my $buf = $READ_IN->($img, 4, 26);
    my ($raw_w, $raw_h) = unpack 'SS', $buf;
    my $b14 = 2**14 - 1;

    # The width and height values contain a 2-bit scaling factor,
    # which is left-shifted by 14 bits. We ignore this, since it seems
    # not to be relevant for our purposes. WEBP images in actual use
    # all seem to have a scaling factor of 0, anyway. (The meaning
    # of the scaling factor is as follows: 0=no upscale, 1=upscale by 5/4,
    # 2=upscale by 5/3, 3=upscale by 2).
    #
    # my $wscale = $raw_w >> 14;
    # my $hscale = $raw_h >> 14;
    my $x = $raw_w & $b14;
    my $y = $raw_h & $b14;

    return ($x, $y, 'WEBP');
}

# ICO files, originally contributed by Thomas Walloschke ,
# see https://rt.cpan.org/Public/Bug/Display.html?id=46279
# (revised by Baldur Kristinsson, github.com/bk)
sub icosize {
    my $img = shift;
    my ($x, $y) = unpack 'CC', $READ_IN->($img, 2, 6);
    if ($x == 0) { $x = 256; }
    if ($y == 0) { $y = 256; }
    return ($x, $y, 'ICO');
}

# CUR files, originally contributed by Thomas Walloschke ,
# see https://rt.cpan.org/Public/Bug/Display.html?id=46279
# (revised by Baldur Kristinsson, github.com/bk)
sub cursize {
    my ($x, $y, $ico) = icosize(shift);
    return ($x, $y, 'CUR');
}


1;

__END__