add new comparison method rgb_difference that resembles arithmetical difference per...

[imager.git] / Imager.pm

package Imager;
use 5.006;

use strict;
use IO::File;
use Scalar::Util;
use Imager::Color;
use Imager::Font;
use Config;

our $ERRSTR;

our @EXPORT_OK = qw(
		init
		init_log
		DSO_open
		DSO_close
		DSO_funclist
		DSO_call

		load_plugin
		unload_plugin

		i_list_formats

		i_color_new
		i_color_set
		i_color_info

		i_img_info

		i_img_setmask
		i_img_getmask

		i_line
		i_line_aa
		i_box
		i_box_filled
		i_arc
		i_circle_aa

		i_bezier_multi
		i_poly_aa
		i_poly_aa_cfill

		i_copyto
		i_rubthru
		i_scaleaxis
		i_scale_nn
		i_haar
		i_count_colors

		i_gaussian
		i_conv

		i_convert
		i_map

		i_img_diff

		i_tt_set_aa
		i_tt_cp
		i_tt_text
		i_tt_bbox

		i_readpnm_wiol
		i_writeppm_wiol

		i_readraw_wiol
		i_writeraw_wiol

		i_contrast
		i_hardinvert
		i_noise
		i_bumpmap
		i_postlevels
		i_mosaic
		i_watermark

		malloc_state

		list_formats

		i_gifquant

		newfont
		newcolor
		newcolour
		NC
		NF
                NCF
);

our @EXPORT=qw(
	  );

our %EXPORT_TAGS=
  (handy => [qw(
		newfont
		newcolor
		NF
		NC
                NCF
	       )],
   all => [@EXPORT_OK],
   default => [qw(
		  load_plugin
		  unload_plugin
		 )]);

# registered file readers
my %readers;

# registered file writers
my %writers;

# modules we attempted to autoload
my %attempted_to_load;

# errors from loading files
my %file_load_errors;

# what happened when we tried to load
my %reader_load_errors;
my %writer_load_errors;

# library keys that are image file formats
my %file_formats = map { $_ => 1 } qw/tiff pnm gif png jpeg raw bmp tga/;

# image pixel combine types
my @combine_types = 
  qw/none normal multiply dissolve add subtract diff lighten darken
     hue saturation value color/;
my %combine_types;
@combine_types{@combine_types} = 0 .. $#combine_types;
$combine_types{mult} = $combine_types{multiply};
$combine_types{'sub'}  = $combine_types{subtract};
$combine_types{sat}  = $combine_types{saturation};

# this will be used to store global defaults at some point
my %defaults;

our $VERSION;

BEGIN {
  require Exporter;
  my $ex_version = eval $Exporter::VERSION;
  if ($ex_version < 5.57) {
    our @ISA = qw(Exporter);
  }
  $VERSION = '1.012';
  require XSLoader;
  XSLoader::load(Imager => $VERSION);
}

my %formats_low;
my %format_classes =
  (
   png => "Imager::File::PNG",
   gif => "Imager::File::GIF",
   tiff => "Imager::File::TIFF",
   jpeg => "Imager::File::JPEG",
   w32 => "Imager::Font::W32",
   ft2 => "Imager::Font::FT2",
   t1 => "Imager::Font::T1",
  );

our %formats;

tie %formats, "Imager::FORMATS", \%formats_low, \%format_classes;

our %filters;

our $DEBUG;
our %OPCODES;
our $FORMATGUESS;
our $warn_obsolete;

BEGIN {
  for(i_list_formats()) { $formats_low{$_}++; }

  %OPCODES=(Add=>[0],Sub=>[1],Mult=>[2],Div=>[3],Parm=>[4],'sin'=>[5],'cos'=>[6],'x'=>[4,0],'y'=>[4,1]);

  $DEBUG=0;

  # the members of the subhashes under %filters are:
  #  callseq - a list of the parameters to the underlying filter in the
  #            order they are passed
  #  callsub - a code ref that takes a named parameter list and calls the
  #            underlying filter
  #  defaults - a hash of default values
  #  names - defines names for value of given parameters so if the names 
  #          field is foo=> { bar=>1 }, and the user supplies "bar" as the
  #          foo parameter, the filter will receive 1 for the foo
  #          parameter
  $filters{contrast}={
		      callseq => ['image','intensity'],
		      callsub => sub { my %hsh=@_; i_contrast($hsh{image},$hsh{intensity}); } 
		     };

  $filters{noise} ={
		    callseq => ['image', 'amount', 'subtype'],
		    defaults => { amount=>3,subtype=>0 },
		    callsub => sub { my %hsh=@_; i_noise($hsh{image},$hsh{amount},$hsh{subtype}); }
		   };

  $filters{hardinvert} ={
			 callseq => ['image'],
			 defaults => { },
			 callsub => sub { my %hsh=@_; i_hardinvert($hsh{image}); }
			};

  $filters{hardinvertall} =
    {
     callseq => ['image'],
     defaults => { },
     callsub => sub { my %hsh=@_; i_hardinvertall($hsh{image}); }
    };

  $filters{autolevels_skew} ={
			 callseq => ['image','lsat','usat','skew'],
			 defaults => { lsat=>0.1,usat=>0.1,skew=>0.0 },
			 callsub => sub { my %hsh=@_; i_autolevels($hsh{image},$hsh{lsat},$hsh{usat},$hsh{skew}); }
			};

  $filters{autolevels} ={
			 callseq => ['image','lsat','usat'],
			 defaults => { lsat=>0.1,usat=>0.1 },
			 callsub => sub { my %hsh=@_; i_autolevels_mono($hsh{image},$hsh{lsat},$hsh{usat}); }
			};

  $filters{turbnoise} ={
			callseq => ['image'],
			defaults => { xo=>0.0,yo=>0.0,scale=>10.0 },
			callsub => sub { my %hsh=@_; i_turbnoise($hsh{image},$hsh{xo},$hsh{yo},$hsh{scale}); }
		       };

  $filters{radnoise} ={
		       callseq => ['image'],
		       defaults => { xo=>100,yo=>100,ascale=>17.0,rscale=>0.02 },
		       callsub => sub { my %hsh=@_; i_radnoise($hsh{image},$hsh{xo},$hsh{yo},$hsh{rscale},$hsh{ascale}); }
		      };

  $filters{conv} =
    {
     callseq => ['image', 'coef'],
     defaults => { },
     callsub => 
     sub { 
       my %hsh=@_;
       i_conv($hsh{image},$hsh{coef})
	 or die Imager->_error_as_msg() . "\n";
     }
    };

  $filters{gradgen} =
    {
     callseq => ['image', 'xo', 'yo', 'colors', 'dist'],
     defaults => { dist => 0 },
     callsub => 
     sub { 
       my %hsh=@_;
       my @colors = @{$hsh{colors}};
       $_ = _color($_)
         for @colors;
       i_gradgen($hsh{image}, $hsh{xo}, $hsh{yo}, \@colors, $hsh{dist});
     }
    };

  $filters{nearest_color} =
    {
     callseq => ['image', 'xo', 'yo', 'colors', 'dist'],
     defaults => { },
     callsub => 
     sub { 
       my %hsh=@_; 
       # make sure the segments are specified with colors
       my @colors;
       for my $color (@{$hsh{colors}}) {
         my $new_color = _color($color) 
           or die $Imager::ERRSTR."\n";
         push @colors, $new_color;
       }

       i_nearest_color($hsh{image}, $hsh{xo}, $hsh{yo}, \@colors, 
                       $hsh{dist})
         or die Imager->_error_as_msg() . "\n";
     },
    };
  $filters{gaussian} = {
                        callseq => [ 'image', 'stddev' ],
                        defaults => { },
                        callsub => sub { my %hsh = @_; i_gaussian($hsh{image}, $hsh{stddev}); },
                       };
  $filters{gaussian2} = {
                        callseq => [ 'image', 'stddevX', 'stddevY' ],
                        defaults => { },
                        callsub => sub { my %hsh = @_; i_gaussian2($hsh{image}, $hsh{stddevX}, $hsh{stddevY}); },
                       };
  $filters{mosaic} =
    {
     callseq => [ qw(image size) ],
     defaults => { size => 20 },
     callsub => sub { my %hsh = @_; i_mosaic($hsh{image}, $hsh{size}) },
    };
  $filters{bumpmap} =
    {
     callseq => [ qw(image bump elevation lightx lighty st) ],
     defaults => { elevation=>0, st=> 2 },
     callsub => sub {
       my %hsh = @_;
       i_bumpmap($hsh{image}, $hsh{bump}{IMG}, $hsh{elevation},
                 $hsh{lightx}, $hsh{lighty}, $hsh{st});
     },
    };
  $filters{bumpmap_complex} =
    {
     callseq => [ qw(image bump channel tx ty Lx Ly Lz cd cs n Ia Il Is) ],
     defaults => {
		  channel => 0,
		  tx => 0,
		  ty => 0,
		  Lx => 0.2,
		  Ly => 0.4,
		  Lz => -1.0,
		  cd => 1.0,
		  cs => 40,
		  n => 1.3,
		  Ia => [0,0,0],
		  Il => [255,255,255],
		  Is => [255,255,255],
		 },
     callsub => sub {
       my %hsh = @_;
       for my $cname (qw/Ia Il Is/) {
	 my $old = $hsh{$cname};
	 my $new_color = _color($old)
	   or die $Imager::ERRSTR, "\n";
	 $hsh{$cname} = $new_color;
       }
       i_bumpmap_complex($hsh{image}, $hsh{bump}{IMG}, $hsh{channel},
                 $hsh{tx}, $hsh{ty}, $hsh{Lx}, $hsh{Ly}, $hsh{Lz},
		 $hsh{cd}, $hsh{cs}, $hsh{n}, $hsh{Ia}, $hsh{Il},
		 $hsh{Is});
     },
    };
  $filters{postlevels} =
    {
     callseq  => [ qw(image levels) ],
     defaults => { levels => 10 },
     callsub  => sub { my %hsh = @_; i_postlevels($hsh{image}, $hsh{levels}); },
    };
  $filters{watermark} =
    {
     callseq  => [ qw(image wmark tx ty pixdiff) ],
     defaults => { pixdiff=>10, tx=>0, ty=>0 },
     callsub  => 
     sub { 
       my %hsh = @_; 
       i_watermark($hsh{image}, $hsh{wmark}{IMG}, $hsh{tx}, $hsh{ty}, 
                   $hsh{pixdiff}); 
     },
    };
  $filters{fountain} =
    {
     callseq  => [ qw(image xa ya xb yb ftype repeat combine super_sample ssample_param segments) ],
     names    => {
                  ftype => { linear         => 0,
                             bilinear       => 1,
                             radial         => 2,
                             radial_square  => 3,
                             revolution     => 4,
                             conical        => 5 },
                  repeat => { none      => 0,
                              sawtooth  => 1,
                              triangle  => 2,
                              saw_both  => 3,
                              tri_both  => 4,
                            },
                  super_sample => {
                                   none    => 0,
                                   grid    => 1,
                                   random  => 2,
                                   circle  => 3,
                                  },
                  combine => {
                              none      => 0,
                              normal    => 1,
                              multiply  => 2, mult => 2,
                              dissolve  => 3,
                              add       => 4,
                              subtract  => 5, 'sub' => 5,
                              diff      => 6,
                              lighten   => 7,
                              darken    => 8,
                              hue       => 9,
                              sat       => 10,
                              value     => 11,
                              color     => 12,
                             },
                 },
     defaults => { ftype => 0, repeat => 0, combine => 0,
                   super_sample => 0, ssample_param => 4,
                   segments=>[ 
                              [ 0, 0.5, 1,
                                [0,0,0],
                                [255, 255, 255],
                                0, 0,
                              ],
                             ],
                 },
     callsub  => 
     sub {
       my %hsh = @_;

       # make sure the segments are specified with colors
       my @segments;
       for my $segment (@{$hsh{segments}}) {
         my @new_segment = @$segment;
         
         $_ = _color($_) or die $Imager::ERRSTR."\n" for @new_segment[3,4];
         push @segments, \@new_segment;
       }

       i_fountain($hsh{image}, $hsh{xa}, $hsh{ya}, $hsh{xb}, $hsh{yb},
                  $hsh{ftype}, $hsh{repeat}, $hsh{combine}, $hsh{super_sample},
                  $hsh{ssample_param}, \@segments)
         or die Imager->_error_as_msg() . "\n";
     },
    };
  $filters{unsharpmask} =
    {
     callseq => [ qw(image stddev scale) ],
     defaults => { stddev=>2.0, scale=>1.0 },
     callsub => 
     sub { 
       my %hsh = @_;
       i_unsharp_mask($hsh{image}, $hsh{stddev}, $hsh{scale});
     },
    };

  $FORMATGUESS=\&def_guess_type;

  $warn_obsolete = 1;
}

#
# Non methods
#

# initialize Imager
# NOTE: this might be moved to an import override later on

sub import {
  my $i = 1;
  while ($i < @_) {
    if ($_[$i] eq '-log-stderr') {
      init_log(undef, 4);
      splice(@_, $i, 1);
    }
    else {
      ++$i;
    }
  }
  goto &Exporter::import;
}

sub init_log {
  Imager->open_log(log => $_[0], level => $_[1]);
}


sub init {
  my %parms=(loglevel=>1,@_);

  if (exists $parms{'warn_obsolete'}) {
    $warn_obsolete = $parms{'warn_obsolete'};
  }

  if ($parms{'log'}) {
    Imager->open_log(log => $parms{log}, level => $parms{loglevel})
      or return;
  }

  if (exists $parms{'t1log'}) {
    if ($formats{t1}) {
      if (Imager::Font::T1::i_init_t1($parms{'t1log'})) {
	Imager->_set_error(Imager->_error_as_msg);
	return;
      }
    }
  }

  return 1;
}

{
  my $is_logging = 0;

  sub open_log {
    my $class = shift;
    my (%opts) = ( loglevel => 1, @_ );

    $is_logging = i_init_log($opts{log}, $opts{loglevel});
    unless ($is_logging) {
      Imager->_set_error(Imager->_error_as_msg());
      return;
    }

    Imager->log("Imager $VERSION starting\n", 1);

    return $is_logging;
  }

  sub close_log {
    i_init_log(undef, -1);
    $is_logging = 0;
  }

  sub log {
    my ($class, $message, $level) = @_;

    defined $level or $level = 1;

    i_log_entry($message, $level);
  }

  sub is_logging {
    return $is_logging;
  }
}

END {
  if ($DEBUG) {
    print "shutdown code\n";
    #	for(keys %instances) { $instances{$_}->DESTROY(); }
    malloc_state(); # how do decide if this should be used? -- store something from the import
    print "Imager exiting\n";
  }
}

# Load a filter plugin

our %DSOs;

sub load_plugin {
  my ($filename)=@_;
  my $i;

  if ($^O eq 'android') {
    require File::Spec;
    $filename = File::Spec->rel2abs($filename);
  }

  my ($DSO_handle,$str)=DSO_open($filename);
  if (!defined($DSO_handle)) { $Imager::ERRSTR="Couldn't load plugin '$filename'\n"; return undef; }
  my %funcs=DSO_funclist($DSO_handle);
  if ($DEBUG) { print "loading module $filename\n"; $i=0; for(keys %funcs) { printf("  %2d: %s\n",$i++,$_); } }
  $i=0;
  for(keys %funcs) { if ($filters{$_}) { $ERRSTR="filter '$_' already exists\n"; DSO_close($DSO_handle); return undef; } }

  $DSOs{$filename}=[$DSO_handle,\%funcs];

  for(keys %funcs) { 
    my $evstr="\$filters{'".$_."'}={".$funcs{$_}.'};';
    $DEBUG && print "eval string:\n",$evstr,"\n";
    eval $evstr;
    print $@ if $@;
  }
  return 1;
}

# Unload a plugin

sub unload_plugin {
  my ($filename)=@_;

  if ($^O eq 'android') {
    require File::Spec;
    $filename = File::Spec->rel2abs($filename);
  }

  if (!$DSOs{$filename}) { $ERRSTR="plugin '$filename' not loaded."; return undef; }
  my ($DSO_handle,$funcref)=@{$DSOs{$filename}};
  for(keys %{$funcref}) {
    delete $filters{$_};
    $DEBUG && print "unloading: $_\n";
  }
  my $rc=DSO_close($DSO_handle);
  if (!defined($rc)) { $ERRSTR="unable to unload plugin '$filename'."; return undef; }
  return 1;
}

# take the results of i_error() and make a message out of it
sub _error_as_msg {
  return join(": ", map $_->[0], i_errors());
}

# this function tries to DWIM for color parameters
#  color objects are used as is
#  simple scalars are simply treated as single parameters to Imager::Color->new
#  hashrefs are treated as named argument lists to Imager::Color->new
#  arrayrefs are treated as list arguments to Imager::Color->new iff any
#    parameter is > 1
#  other arrayrefs are treated as list arguments to Imager::Color::Float

sub _color {
  my $arg = shift;
  # perl 5.6.0 seems to do weird things to $arg if we don't make an 
  # explicitly stringified copy
  # I vaguely remember a bug on this on p5p, but couldn't find it
  # through bugs.perl.org (I had trouble getting it to find any bugs)
  my $copy = $arg . "";
  my $result;

  if (ref $arg) {
    if (UNIVERSAL::isa($arg, "Imager::Color")
        || UNIVERSAL::isa($arg, "Imager::Color::Float")) {
      $result = $arg;
    }
    else {
      if ($copy =~ /^HASH\(/) {
        $result = Imager::Color->new(%$arg);
      }
      elsif ($copy =~ /^ARRAY\(/) {
	$result = Imager::Color->new(@$arg);
      }
      else {
        $Imager::ERRSTR = "Not a color";
      }
    }
  }
  else {
    # assume Imager::Color::new knows how to handle it
    $result = Imager::Color->new($arg);
  }

  return $result;
}

sub _combine {
  my ($self, $combine, $default) = @_;

  if (!defined $combine && ref $self) {
    $combine = $self->{combine};
  }
  defined $combine or $combine = $defaults{combine};
  defined $combine or $combine = $default;

  if (exists $combine_types{$combine}) {
    $combine = $combine_types{$combine};
  }
  
  return $combine;
}

sub _valid_image {
  my ($self, $method) = @_;

  ref $self
    or return Imager->_set_error("$method needs an image object");

  $self->{IMG} && Scalar::Util::blessed($self->{IMG}) and return 1;

  my $msg = $self->{IMG} ? "images do not cross threads" : "empty input image";
  $msg = "$method: $msg" if $method;
  $self->_set_error($msg);

  return;
}

# returns first defined parameter
sub _first {
  for (@_) {
    return $_ if defined $_;
  }
  return undef;
}

#
# Methods to be called on objects.
#

# Create a new Imager object takes very few parameters.
# usually you call this method and then call open from
# the resulting object

sub new {
  my $class = shift;
  my $self ={};
  my %hsh=@_;
  bless $self,$class;
  $self->{IMG}=undef;    # Just to indicate what exists
  $self->{ERRSTR}=undef; #
  $self->{DEBUG}=$DEBUG;
  $self->{DEBUG} and print "Initialized Imager\n";
  if (defined $hsh{file} ||
      defined $hsh{fh} ||
      defined $hsh{fd} ||
      defined $hsh{callback} ||
      defined $hsh{readcb} ||
      defined $hsh{data} ||
      defined $hsh{io}) {
    # allow $img = Imager->new(file => $filename)
    my %extras;
    
    # type is already used as a parameter to new(), rename it for the
    # call to read()
    if ($hsh{filetype}) {
      $extras{type} = $hsh{filetype};
    }
    unless ($self->read(%hsh, %extras)) {
      $Imager::ERRSTR = $self->{ERRSTR};
      return;
    }
  }
  elsif (defined $hsh{xsize} || defined $hsh{ysize}) {
    unless ($self->img_set(%hsh)) {
      $Imager::ERRSTR = $self->{ERRSTR};
      return;
    }
  }
  elsif (%hsh) {
    Imager->_set_error("new: supply xsize and ysize or a file access parameter or no parameters");
    return;
  }

  return $self;
}

# Copy an entire image with no changes 
# - if an image has magic the copy of it will not be magical

sub copy {
  my $self = shift;

  $self->_valid_image("copy")
    or return;

  unless (defined wantarray) {
    my @caller = caller;
    warn "copy() called in void context - copy() returns the copied image at $caller[1] line $caller[2]\n";
    return;
  }

  my $newcopy=Imager->new();
  $newcopy->{IMG} = i_copy($self->{IMG});
  return $newcopy;
}

# Paste a region

sub paste {
  my $self = shift;

  $self->_valid_image("paste")
    or return;

  my %input=(left=>0, top=>0, src_minx => 0, src_miny => 0, @_);
  my $src = $input{img} || $input{src};
  unless($src) {
    $self->_set_error("no source image");
    return;
  }
  unless ($src->_valid_image("paste")) {
    $self->{ERRSTR} = $src->{ERRSTR} . " (for src)";
    return;
  }
  $input{left}=0 if $input{left} <= 0;
  $input{top}=0 if $input{top} <= 0;

  my($r,$b)=i_img_info($src->{IMG});
  my ($src_left, $src_top) = @input{qw/src_minx src_miny/};
  my ($src_right, $src_bottom);
  if ($input{src_coords}) {
    ($src_left, $src_top, $src_right, $src_bottom) = @{$input{src_coords}}
  }
  else {
    if (defined $input{src_maxx}) {
      $src_right = $input{src_maxx};
    }
    elsif (defined $input{width}) {
      if ($input{width} <= 0) {
        $self->_set_error("paste: width must me positive");
        return;
      }
      $src_right = $src_left + $input{width};
    }
    else {
      $src_right = $r;
    }
    if (defined $input{src_maxy}) {
      $src_bottom = $input{src_maxy};
    }
    elsif (defined $input{height}) {
      if ($input{height} < 0) {
        $self->_set_error("paste: height must be positive");
        return;
      }
      $src_bottom = $src_top + $input{height};
    }
    else {
      $src_bottom = $b;
    }
  }

  $src_right > $r and $src_right = $r;
  $src_bottom > $b and $src_bottom = $b;

  if ($src_right <= $src_left
      || $src_bottom < $src_top) {
    $self->_set_error("nothing to paste");
    return;
  }

  i_copyto($self->{IMG}, $src->{IMG}, 
	   $src_left, $src_top, $src_right, $src_bottom, 
           $input{left}, $input{top});

  return $self;  # What should go here??
}

# Crop an image - i.e. return a new image that is smaller

sub crop {
  my $self=shift;

  $self->_valid_image("crop")
    or return;
  
  unless (defined wantarray) {
    my @caller = caller;
    warn "crop() called in void context - crop() returns the cropped image at $caller[1] line $caller[2]\n";
    return;
  }

  my %hsh=@_;

  my ($w, $h, $l, $r, $b, $t) =
    @hsh{qw(width height left right bottom top)};

  # work through the various possibilities
  if (defined $l) {
    if (defined $w) {
      $r = $l + $w;
    }
    elsif (!defined $r) {
      $r = $self->getwidth;
    }
  }
  elsif (defined $r) {
    if (defined $w) {
      $l = $r - $w;
    }
    else {
      $l = 0;
    }
  }
  elsif (defined $w) {
    $l = int(0.5+($self->getwidth()-$w)/2);
    $r = $l + $w;
  }
  else {
    $l = 0;
    $r = $self->getwidth;
  }
  if (defined $t) {
    if (defined $h) {
      $b = $t + $h;
    }
    elsif (!defined $b) {
      $b = $self->getheight;
    }
  }
  elsif (defined $b) {
    if (defined $h) {
      $t = $b - $h;
    }
    else {
      $t = 0;
    }
  }
  elsif (defined $h) {
    $t=int(0.5+($self->getheight()-$h)/2);
    $b=$t+$h;
  }
  else {
    $t = 0;
    $b = $self->getheight;
  }

  ($l,$r)=($r,$l) if $l>$r;
  ($t,$b)=($b,$t) if $t>$b;

  $l < 0 and $l = 0;
  $r > $self->getwidth and $r = $self->getwidth;
  $t < 0 and $t = 0;
  $b > $self->getheight and $b = $self->getheight;

  if ($l == $r || $t == $b) {
    $self->_set_error("resulting image would have no content");
    return;
  }
  if( $r < $l or $b < $t ) {
    $self->_set_error("attempting to crop outside of the image");
    return;
  }
  my $dst = $self->_sametype(xsize=>$r-$l, ysize=>$b-$t);

  i_copyto($dst->{IMG},$self->{IMG},$l,$t,$r,$b,0,0);
  return $dst;
}

sub _sametype {
  my ($self, %opts) = @_;

  $self->_valid_image
    or return;

  my $x = $opts{xsize} || $self->getwidth;
  my $y = $opts{ysize} || $self->getheight;
  my $channels = $opts{channels} || $self->getchannels;
  
  my $out = Imager->new;
  if ($channels == $self->getchannels) {
    $out->{IMG} = i_sametype($self->{IMG}, $x, $y);
  }
  else {
    $out->{IMG} = i_sametype_chans($self->{IMG}, $x, $y, $channels);
  }
  unless ($out->{IMG}) {
    $self->{ERRSTR} = $self->_error_as_msg;
    return;
  }
  
  return $out;
}

# Sets an image to a certain size and channel number
# if there was previously data in the image it is discarded

my %model_channels =
  (
   gray => 1,
   graya => 2,
   rgb => 3,
   rgba => 4,
  );

sub img_set {
  my $self=shift;

  my %hsh=(xsize=>100, ysize=>100, channels=>3, bits=>8, type=>'direct', @_);

  undef($self->{IMG});

  if ($hsh{model}) {
    if (my $channels = $model_channels{$hsh{model}}) {
      $hsh{channels} = $channels;
    }
    else {
      $self->_set_error("new: unknown value for model '$hsh{model}'");
      return;
    }
  }

  if ($hsh{type} eq 'paletted' || $hsh{type} eq 'pseudo') {
    $self->{IMG} = i_img_pal_new($hsh{xsize}, $hsh{ysize}, $hsh{channels},
                                 $hsh{maxcolors} || 256);
  }
  elsif ($hsh{bits} eq 'double') {
    $self->{IMG} = i_img_double_new($hsh{xsize}, $hsh{ysize}, $hsh{channels});
  }
  elsif ($hsh{bits} == 16) {
    $self->{IMG} = i_img_16_new($hsh{xsize}, $hsh{ysize}, $hsh{channels});
  }
  else {
    $self->{IMG}= i_img_8_new($hsh{'xsize'}, $hsh{'ysize'},
			      $hsh{'channels'});
  }

  unless ($self->{IMG}) {
    $self->_set_error(Imager->_error_as_msg());
    return;
  }

  $self;
}

# created a masked version of the current image
sub masked {
  my $self = shift;

  $self->_valid_image("masked")
    or return;

  my %opts = (left    => 0, 
              top     => 0, 
              right   => $self->getwidth, 
              bottom  => $self->getheight,
              @_);
  my $mask = $opts{mask} ? $opts{mask}{IMG} : undef;

  my $result = Imager->new;
  $result->{IMG} = i_img_masked_new($self->{IMG}, $mask, $opts{left}, 
                                    $opts{top}, $opts{right} - $opts{left},
                                    $opts{bottom} - $opts{top});
  unless ($result->{IMG}) {
    $self->_set_error(Imager->_error_as_msg);
    return;
  }

  # keep references to the mask and base images so they don't
  # disappear on us
  $result->{DEPENDS} = [ $self->{IMG}, $mask ];

  return $result;
}

# convert an RGB image into a paletted image
sub to_paletted {
  my $self = shift;
  my $opts;
  if (@_ != 1 && !ref $_[0]) {
    $opts = { @_ };
  }
  else {
    $opts = shift;
  }

  unless (defined wantarray) {
    my @caller = caller;
    warn "to_paletted() called in void context - to_paletted() returns the converted image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("to_paletted")
    or return;

  my $result = Imager->new;
  unless ($result->{IMG} = i_img_to_pal($self->{IMG}, $opts)) {
    $self->_set_error(Imager->_error_as_msg);
    return;
  }

  return $result;
}

sub make_palette {
  my ($class, $quant, @images) = @_;

  unless (@images) {
    Imager->_set_error("make_palette: supply at least one image");
    return;
  }
  my $index = 1;
  for my $img (@images) {
    unless ($img->{IMG}) {
      Imager->_set_error("make_palette: image $index is empty");
      return;
    }
    ++$index;
  }

  my @cols = i_img_make_palette($quant, map $_->{IMG}, @images);
  unless (@cols) {
      Imager->_set_error(Imager->_error_as_msg);
      return;
  }
  return @cols;
}

# convert a paletted (or any image) to an 8-bit/channel RGB image
sub to_rgb8 {
  my $self = shift;

  unless (defined wantarray) {
    my @caller = caller;
    warn "to_rgb8() called in void context - to_rgb8() returns the converted image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("to_rgb8")
    or return;

  my $result = Imager->new;
  unless ($result->{IMG} = i_img_to_rgb($self->{IMG})) {
    $self->_set_error(Imager->_error_as_msg());
    return;
  }

  return $result;
}

# convert a paletted (or any image) to a 16-bit/channel RGB image
sub to_rgb16 {
  my $self = shift;

  unless (defined wantarray) {
    my @caller = caller;
    warn "to_rgb16() called in void context - to_rgb16() returns the converted image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("to_rgb16")
    or return;

  my $result = Imager->new;
  unless ($result->{IMG} = i_img_to_rgb16($self->{IMG})) {
    $self->_set_error(Imager->_error_as_msg());
    return;
  }

  return $result;
}

# convert a paletted (or any image) to an double/channel RGB image
sub to_rgb_double {
  my $self = shift;

  unless (defined wantarray) {
    my @caller = caller;
    warn "to_rgb16() called in void context - to_rgb_double() returns the converted image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("to_rgb_double")
    or return;

  my $result = Imager->new;
  unless ($result->{IMG} = i_img_to_drgb($self->{IMG})) {
    $self->_set_error(Imager->_error_as_msg());
    return;
  }

  return $result;
}

sub addcolors {
  my $self = shift;
  my %opts = (colors=>[], @_);

  $self->_valid_image("addcolors")
    or return -1;

  my @colors = @{$opts{colors}}
    or return undef;

  for my $color (@colors) {
    $color = _color($color);
    unless ($color) {
      $self->_set_error($Imager::ERRSTR);
      return;
    }  
  }

  return i_addcolors($self->{IMG}, @colors);
}

sub setcolors {
  my $self = shift;
  my %opts = (start=>0, colors=>[], @_);

  $self->_valid_image("setcolors")
    or return;

  my @colors = @{$opts{colors}}
    or return undef;

  for my $color (@colors) {
    $color = _color($color);
    unless ($color) {
      $self->_set_error($Imager::ERRSTR);
      return;
    }  
  }

  return i_setcolors($self->{IMG}, $opts{start}, @colors);
}

sub getcolors {
  my $self = shift;
  my %opts = @_;

  $self->_valid_image("getcolors")
    or return;

  if (!exists $opts{start} && !exists $opts{count}) {
    # get them all
    $opts{start} = 0;
    $opts{count} = $self->colorcount;
  }
  elsif (!exists $opts{count}) {
    $opts{count} = 1;
  }
  elsif (!exists $opts{start}) {
    $opts{start} = 0;
  }

  return i_getcolors($self->{IMG}, $opts{start}, $opts{count});
}

sub colorcount {
  my ($self) = @_;

  $self->_valid_image("colorcount")
    or return -1;

  return i_colorcount($self->{IMG});
}

sub maxcolors {
  my $self = shift;

  $self->_valid_image("maxcolors")
    or return -1;

  i_maxcolors($self->{IMG});
}

sub findcolor {
  my $self = shift;
  my %opts = @_;

  $self->_valid_image("findcolor")
    or return;

  unless ($opts{color}) {
    $self->_set_error("findcolor: no color parameter");
    return;
  }

  my $color = _color($opts{color})
    or return;

  return i_findcolor($self->{IMG}, $color);
}

sub bits {
  my $self = shift;

  $self->_valid_image("bits")
    or return;

  my $bits = i_img_bits($self->{IMG});
  if ($bits && $bits == length(pack("d", 1)) * 8) {
    $bits = 'double';
  }
  return $bits;
}

sub type {
  my $self = shift;

  $self->_valid_image("type")
    or return;

  return i_img_type($self->{IMG}) ? "paletted" : "direct";
}

sub virtual {
  my $self = shift;

  $self->_valid_image("virtual")
    or return;

  return i_img_virtual($self->{IMG});
}

sub is_bilevel {
  my ($self) = @_;

  $self->_valid_image("is_bilevel")
    or return;

  return i_img_is_monochrome($self->{IMG});
}

sub tags {
  my ($self, %opts) = @_;

  $self->_valid_image("tags")
    or return;

  if (defined $opts{name}) {
    my @result;
    my $start = 0;
    my $found;
    while (defined($found = i_tags_find($self->{IMG}, $opts{name}, $start))) {
      push @result, (i_tags_get($self->{IMG}, $found))[1];
      $start = $found+1;
    }
    return wantarray ? @result : $result[0];
  }
  elsif (defined $opts{code}) {
    my @result;
    my $start = 0;
    my $found;
    while (defined($found = i_tags_findn($self->{IMG}, $opts{code}, $start))) {
      push @result, (i_tags_get($self->{IMG}, $found))[1];
      $start = $found+1;
    }
    return @result;
  }
  else {
    if (wantarray) {
      return map { [ i_tags_get($self->{IMG}, $_) ] } 0.. i_tags_count($self->{IMG})-1;
    }
    else {
      return i_tags_count($self->{IMG});
    }
  }
}

sub addtag {
  my $self = shift;
  my %opts = @_;

  $self->_valid_image("addtag")
    or return;

  if ($opts{name}) {
    if (defined $opts{value}) {
      if ($opts{value} =~ /^\d+$/) {
        # add as a number
        return i_tags_addn($self->{IMG}, $opts{name}, 0, $opts{value});
      }
      else {
        return i_tags_add($self->{IMG}, $opts{name}, 0, $opts{value}, 0);
      }
    }
    elsif (defined $opts{data}) {
      # force addition as a string
      return i_tags_add($self->{IMG}, $opts{name}, 0, $opts{data}, 0);
    }
    else {
      $self->{ERRSTR} = "No value supplied";
      return undef;
    }
  }
  elsif ($opts{code}) {
    if (defined $opts{value}) {
      if ($opts{value} =~ /^\d+$/) {
        # add as a number
        return i_tags_addn($self->{IMG}, $opts{code}, 0, $opts{value});
      }
      else {
        return i_tags_add($self->{IMG}, $opts{code}, 0, $opts{value}, 0);
      }
    }
    elsif (defined $opts{data}) {
      # force addition as a string
      return i_tags_add($self->{IMG}, $opts{code}, 0, $opts{data}, 0);
    }
    else {
      $self->{ERRSTR} = "No value supplied";
      return undef;
    }
  }
  else {
    return undef;
  }
}

sub deltag {
  my $self = shift;
  my %opts = @_;

  $self->_valid_image("deltag")
    or return 0;

  if (defined $opts{'index'}) {
    return i_tags_delete($self->{IMG}, $opts{'index'});
  }
  elsif (defined $opts{name}) {
    return i_tags_delbyname($self->{IMG}, $opts{name});
  }
  elsif (defined $opts{code}) {
    return i_tags_delbycode($self->{IMG}, $opts{code});
  }
  else {
    $self->{ERRSTR} = "Need to supply index, name, or code parameter";
    return 0;
  }
}

sub settag {
  my ($self, %opts) = @_;

  $self->_valid_image("settag")
    or return;

  if ($opts{name}) {
    $self->deltag(name=>$opts{name});
    return $self->addtag(name=>$opts{name}, value=>$opts{value});
  }
  elsif (defined $opts{code}) {
    $self->deltag(code=>$opts{code});
    return $self->addtag(code=>$opts{code}, value=>$opts{value});
  }
  else {
    return undef;
  }
}


sub _get_reader_io {
  my ($self, $input) = @_;

  if ($input->{io}) {
    return $input->{io}, undef;
  }
  elsif ($input->{fd}) {
    return io_new_fd($input->{fd});
  }
  elsif ($input->{fh}) {
    unless (Scalar::Util::openhandle($input->{fh})) {
      $self->_set_error("Handle in fh option not opened");
      return;
    }
    return Imager::IO->new_fh($input->{fh});
  }
  elsif ($input->{file}) {
    my $file = IO::File->new($input->{file}, "r");
    unless ($file) {
      $self->_set_error("Could not open $input->{file}: $!");
      return;
    }
    binmode $file;
    return (io_new_fd(fileno($file)), $file);
  }
  elsif ($input->{data}) {
    return io_new_buffer($input->{data});
  }
  elsif ($input->{callback} || $input->{readcb}) {
    if (!$input->{seekcb}) {
      $self->_set_error("Need a seekcb parameter");
    }
    if ($input->{maxbuffer}) {
      return io_new_cb($input->{writecb},
                       $input->{callback} || $input->{readcb},
                       $input->{seekcb}, $input->{closecb},
                       $input->{maxbuffer});
    }
    else {
      return io_new_cb($input->{writecb},
                       $input->{callback} || $input->{readcb},
                       $input->{seekcb}, $input->{closecb});
    }
  }
  else {
    $self->_set_error("file/fd/fh/data/callback parameter missing");
    return;
  }
}

sub _get_writer_io {
  my ($self, $input) = @_;

  my $buffered = exists $input->{buffered} ? $input->{buffered} : 1;

  my $io;
  my @extras;
  if ($input->{io}) {
    $io = $input->{io};
  }
  elsif ($input->{fd}) {
    $io = io_new_fd($input->{fd});
  }
  elsif ($input->{fh}) {
    unless (Scalar::Util::openhandle($input->{fh})) {
      $self->_set_error("Handle in fh option not opened");
      return;
    }
    $io = Imager::IO->new_fh($input->{fh});
  }
  elsif ($input->{file}) {
    my $fh = new IO::File($input->{file},"w+");
    unless ($fh) { 
      $self->_set_error("Could not open file $input->{file}: $!");
      return;
    }
    binmode($fh) or die;
    $io = io_new_fd(fileno($fh));
    push @extras, $fh;
  }
  elsif ($input->{data}) {
    $io = io_new_bufchain();
  }
  elsif ($input->{callback} || $input->{writecb}) {
    if ($input->{maxbuffer} && $input->{maxbuffer} == 1) {
      $buffered = 0;
    }
    $io = io_new_cb($input->{callback} || $input->{writecb},
		    $input->{readcb},
		    $input->{seekcb}, $input->{closecb});
  }
  else {
    $self->_set_error("file/fd/fh/data/callback parameter missing");
    return;
  }

  unless ($buffered) {
    $io->set_buffered(0);
  }

  return ($io, @extras);
}

sub _test_format {
  my ($io) = @_;

  return i_test_format_probe($io, -1);
}

sub add_file_magic {
  my ($class, %opts) = @_;

  my $name = delete $opts{name};
  my $bits = delete $opts{bits};
  my $mask = delete $opts{mask};

  unless (i_add_file_magic($name, $bits, $mask)) {
    Imager->_set_error(Imager->_error_as_msg);
    return;
  }

  1;
}

# Read an image from file

sub read {
  my $self = shift;
  my %input=@_;

  if (defined($self->{IMG})) {
    # let IIM_DESTROY do the destruction, since the image may be
    # referenced from elsewhere
    #i_img_destroy($self->{IMG});
    undef($self->{IMG});
  }

  my ($IO, $fh) = $self->_get_reader_io(\%input) or return;

  my $type = $input{'type'};
  unless ($type) {
    $type = _test_format($IO);
  }

  if ($input{file} && !$type) {
    # guess the type 
    $type = $FORMATGUESS->($input{file});
  }

  unless ($type) {
    my $msg = "type parameter missing and it couldn't be determined from the file contents";
    $input{file} and $msg .= " or file name";
    $self->_set_error($msg);
    return undef;
  }

  _reader_autoload($type);

  if ($readers{$type} && $readers{$type}{single}) {
    return $readers{$type}{single}->($self, $IO, %input);
  }

  unless ($formats_low{$type}) {
    my $read_types = join ', ', sort Imager->read_types();
    $self->_set_error("format '$type' not supported - formats $read_types available for reading - $reader_load_errors{$type}");
    return;
  }

  my $allow_incomplete = $input{allow_incomplete};
  defined $allow_incomplete or $allow_incomplete = 0;

  if ( $type eq 'pnm' ) {
    $self->{IMG}=i_readpnm_wiol( $IO, $allow_incomplete );
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}='unable to read pnm image: '._error_as_msg(); 
      return undef;
    }
    $self->{DEBUG} && print "loading a pnm file\n";
    return $self;
  }

  if ( $type eq 'bmp' ) {
    $self->{IMG}=i_readbmp_wiol( $IO, $allow_incomplete );
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}=$self->_error_as_msg();
      return undef;
    }
    $self->{DEBUG} && print "loading a bmp file\n";
  }

  if ( $type eq 'tga' ) {
    $self->{IMG}=i_readtga_wiol( $IO, -1 ); # Fixme, check if that length parameter is ever needed
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}=$self->_error_as_msg();
      return undef;
    }
    $self->{DEBUG} && print "loading a tga file\n";
  }

  if ( $type eq 'raw' ) {
    unless ( $input{xsize} && $input{ysize} ) {
      $self->_set_error('missing xsize or ysize parameter for raw');
      return undef;
    }

    my $interleave = _first($input{raw_interleave}, $input{interleave});
    unless (defined $interleave) {
      my @caller = caller;
      warn "read(type => 'raw') $caller[2] line $caller[1]: supply interleave or raw_interleave for future compatibility\n";
      $interleave = 1;
    }
    my $data_ch = _first($input{raw_datachannels}, $input{datachannels}, 3);
    my $store_ch = _first($input{raw_storechannels}, $input{storechannels}, 3);

    $self->{IMG} = i_readraw_wiol( $IO,
				   $input{xsize},
				   $input{ysize},
				   $data_ch,
				   $store_ch,
				   $interleave);
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}=$self->_error_as_msg();
      return undef;
    }
    $self->{DEBUG} && print "loading a raw file\n";
  }

  return $self;
}

sub register_reader {
  my ($class, %opts) = @_;

  defined $opts{type}
    or die "register_reader called with no type parameter\n";

  my $type = $opts{type};

  defined $opts{single} || defined $opts{multiple}
    or die "register_reader called with no single or multiple parameter\n";

  $readers{$type} = {  };
  if ($opts{single}) {
    $readers{$type}{single} = $opts{single};
  }
  if ($opts{multiple}) {
    $readers{$type}{multiple} = $opts{multiple};
  }

  return 1;
}

sub register_writer {
  my ($class, %opts) = @_;

  defined $opts{type}
    or die "register_writer called with no type parameter\n";

  my $type = $opts{type};

  defined $opts{single} || defined $opts{multiple}
    or die "register_writer called with no single or multiple parameter\n";

  $writers{$type} = {  };
  if ($opts{single}) {
    $writers{$type}{single} = $opts{single};
  }
  if ($opts{multiple}) {
    $writers{$type}{multiple} = $opts{multiple};
  }

  return 1;
}

sub read_types {
  my %types =
    (
     map { $_ => 1 }
     keys %readers,
     grep($file_formats{$_}, keys %formats),
     qw(ico sgi), # formats not handled directly, but supplied with Imager
    );

  return keys %types;
}

sub write_types {
  my %types =
    (
     map { $_ => 1 }
     keys %writers,
     grep($file_formats{$_}, keys %formats),
     qw(ico sgi), # formats not handled directly, but supplied with Imager
    );

  return keys %types;
}

sub _load_file {
  my ($file, $error) = @_;

  if ($attempted_to_load{$file}) {
    if ($file_load_errors{$file}) {
      $$error = $file_load_errors{$file};
      return 0;
    }
    else {
      return 1;
    }
  }
  else {
    local $SIG{__DIE__};
    my $loaded = eval {
      local @INC = @INC;
      pop @INC if $INC[-1] eq '.';
      ++$attempted_to_load{$file};
      require $file;
      return 1;
    };
    if ($loaded) {
      return 1;
    }
    else {
      my $work = $@ || "Unknown error";
      chomp $work;
      $work =~ s/\n?Compilation failed in require at .*Imager\.pm line .*\z//m;
      $work =~ s/\n/\\n/g;
      $work =~ s/\s*\.?\z/ loading $file/;
      $file_load_errors{$file} = $work;
      $$error = $work;
      return 0;
    }
  }
}

# probes for an Imager::File::whatever module
sub _reader_autoload {
  my $type = shift;

  return if $formats_low{$type} || $readers{$type};

  return unless $type =~ /^\w+$/;

  my $file = "Imager/File/\U$type\E.pm";

  my $error;
  my $loaded = _load_file($file, \$error);
  if (!$loaded && $error =~ /^Can't locate /) {
    my $filer = "Imager/File/\U$type\EReader.pm";
    $loaded = _load_file($filer, \$error);
    if ($error =~ /^Can't locate /) {
      $error = "Can't locate $file or $filer";
    }
  }
  unless ($loaded) {
    $reader_load_errors{$type} = $error;
  }
}

# probes for an Imager::File::whatever module
sub _writer_autoload {
  my $type = shift;

  return if $formats_low{$type} || $writers{$type};

  return unless $type =~ /^\w+$/;

  my $file = "Imager/File/\U$type\E.pm";

  my $error;
  my $loaded = _load_file($file, \$error);
  if (!$loaded && $error =~ /^Can't locate /) {
    my $filew = "Imager/File/\U$type\EWriter.pm";
    $loaded = _load_file($filew, \$error);
    if ($error =~ /^Can't locate /) {
      $error = "Can't locate $file or $filew";
    }
  }
  unless ($loaded) {
    $writer_load_errors{$type} = $error;
  }
}

sub _fix_gif_positions {
  my ($opts, $opt, $msg, @imgs) = @_;

  my $positions = $opts->{'gif_positions'};
  my $index = 0;
  for my $pos (@$positions) {
    my ($x, $y) = @$pos;
    my $img = $imgs[$index++];
    $img->settag(name=>'gif_left', value=>$x);
    $img->settag(name=>'gif_top', value=>$y) if defined $y;
  }
  $$msg .= "replaced with the gif_left and gif_top tags";
}

my %obsolete_opts =
  (
   gif_each_palette=>'gif_local_map',
   interlace       => 'gif_interlace',
   gif_delays => 'gif_delay',
   gif_positions => \&_fix_gif_positions,
   gif_loop_count => 'gif_loop',
  );

# options that should be converted to colors
my %color_opts = map { $_ => 1 } qw/i_background/;

sub _set_opts {
  my ($self, $opts, $prefix, @imgs) = @_;

  for my $opt (keys %$opts) {
    my $tagname = $opt;
    if ($obsolete_opts{$opt}) {
      my $new = $obsolete_opts{$opt};
      my $msg = "Obsolete option $opt ";
      if (ref $new) {
        $new->($opts, $opt, \$msg, @imgs);
      }
      else {
        $msg .= "replaced with the $new tag ";
        $tagname = $new;
      }
      $msg .= "line ".(caller(2))[2]." of file ".(caller(2))[1];
      warn $msg if $warn_obsolete && $^W;
    }
    next unless $tagname =~ /^\Q$prefix/;
    my $value = $opts->{$opt};
    if ($color_opts{$opt}) {
      $value = _color($value);
      unless ($value) {
	$self->_set_error($Imager::ERRSTR);
	return;
      }
    }
    if (ref $value) {
      if (UNIVERSAL::isa($value, "Imager::Color")) {
        my $tag = sprintf("color(%d,%d,%d,%d)", $value->rgba);
        for my $img (@imgs) {
          $img->settag(name=>$tagname, value=>$tag);
        }
      }
      elsif (ref($value) eq 'ARRAY') {
        for my $i (0..$#$value) {
          my $val = $value->[$i];
          if (ref $val) {
            if (UNIVERSAL::isa($val, "Imager::Color")) {
              my $tag = sprintf("color(%d,%d,%d,%d)", $value->rgba);
              $i < @imgs and
                $imgs[$i]->settag(name=>$tagname, value=>$tag);
            }
            else {
              $self->_set_error("Unknown reference type " . ref($value) . 
                                " supplied in array for $opt");
              return;
            }
          }
          else {
            $i < @imgs
              and $imgs[$i]->settag(name=>$tagname, value=>$val);
          }
        }
      }
      else {
        $self->_set_error("Unknown reference type " . ref($value) . 
                          " supplied for $opt");
        return;
      }
    }
    else {
      # set it as a tag for every image
      for my $img (@imgs) {
        $img->settag(name=>$tagname, value=>$value);
      }
    }
  }

  return 1;
}

# Write an image to file
sub write {
  my $self = shift;
  my %input=(jpegquality=>75,
	     gifquant=>'mc',
	     lmdither=>6.0,
	     lmfixed=>[],
	     idstring=>"",
	     compress=>1,
	     wierdpack=>0,
	     fax_fine=>1, @_);
  my $rc;

  $self->_valid_image("write")
    or return;

  $self->_set_opts(\%input, "i_", $self)
    or return undef;

  my $type = $input{'type'};
  if (!$type and $input{file}) { 
    $type = $FORMATGUESS->($input{file});
  }
  unless ($type) { 
    $self->{ERRSTR}='type parameter missing and not possible to guess from extension';
    return undef;
  }

  _writer_autoload($type);

  my ($IO, $fh);
  if ($writers{$type} && $writers{$type}{single}) {
    ($IO, $fh) = $self->_get_writer_io(\%input)
      or return undef;

    $writers{$type}{single}->($self, $IO, %input, type => $type)
      or return undef;
  }
  else {
    if (!$formats_low{$type}) { 
      my $write_types = join ', ', sort Imager->write_types();
      $self->_set_error("format '$type' not supported - formats $write_types available for writing - $writer_load_errors{$type}");
      return undef;
    }
    
    ($IO, $fh) = $self->_get_writer_io(\%input, $type)
      or return undef;
  
    if ( $type eq 'pnm' ) {
      $self->_set_opts(\%input, "pnm_", $self)
        or return undef;
      if ( ! i_writeppm_wiol($self->{IMG},$IO) ) {
        $self->{ERRSTR} = $self->_error_as_msg();
        return undef;
      }
      $self->{DEBUG} && print "writing a pnm file\n";
    }
    elsif ( $type eq 'raw' ) {
      $self->_set_opts(\%input, "raw_", $self)
        or return undef;
      if ( !i_writeraw_wiol($self->{IMG},$IO) ) {
        $self->{ERRSTR} = $self->_error_as_msg();
        return undef;
      }
      $self->{DEBUG} && print "writing a raw file\n";
    }
    elsif ( $type eq 'bmp' ) {
      $self->_set_opts(\%input, "bmp_", $self)
        or return undef;
      if ( !i_writebmp_wiol($self->{IMG}, $IO) ) {
	$self->{ERRSTR} = $self->_error_as_msg;
        return undef;
      }
      $self->{DEBUG} && print "writing a bmp file\n";
    }
    elsif ( $type eq 'tga' ) {
      $self->_set_opts(\%input, "tga_", $self)
        or return undef;
      
      if ( !i_writetga_wiol($self->{IMG}, $IO, $input{wierdpack}, $input{compress}, $input{idstring}) ) {
        $self->{ERRSTR}=$self->_error_as_msg();
        return undef;
      }
      $self->{DEBUG} && print "writing a tga file\n";
    }
  }

  if (exists $input{'data'}) {
    my $data = io_slurp($IO);
    if (!$data) {
      $self->{ERRSTR}='Could not slurp from buffer';
      return undef;
    }
    ${$input{data}} = $data;
  }
  return $self;
}

sub write_multi {
  my ($class, $opts, @images) = @_;

  my $type = $opts->{type};

  if (!$type && $opts->{'file'}) {
    $type = $FORMATGUESS->($opts->{'file'});
  }
  unless ($type) {
    $class->_set_error('type parameter missing and not possible to guess from extension');
    return;
  }
  # translate to ImgRaw
  my $index = 1;
  for my $img (@images) {
    unless (ref $img && Scalar::Util::blessed($img) && $img->isa("Imager")) {
      $class->_set_error("write_multi: image $index is not an Imager image object");
      return;
    }
    unless ($img->_valid_image("write_multi")) {
      $class->_set_error($img->errstr . " (image $index)");
      return;
    }
    ++$index;
  }
  $class->_set_opts($opts, "i_", @images)
    or return;
  my @work = map $_->{IMG}, @images;

  _writer_autoload($type);

  my ($IO, $file);
  if ($writers{$type} && $writers{$type}{multiple}) {
    ($IO, $file) = $class->_get_writer_io($opts, $type)
      or return undef;

    $writers{$type}{multiple}->($class, $IO, $opts, @images)
      or return undef;
  }
  else {
    if (!$formats{$type}) { 
      my $write_types = join ', ', sort Imager->write_types();
      $class->_set_error("format '$type' not supported - formats $write_types available for writing");
      return undef;
    }
    
    ($IO, $file) = $class->_get_writer_io($opts, $type)
      or return undef;
    
    if (0) { # eventually PNM in here, now that TIFF/GIF are elsewhere
    }
    else {
      if (@images == 1) {
	unless ($images[0]->write(%$opts, io => $IO, type => $type)) {
	  return 1;
	}
      }
      else {
	$ERRSTR = "Sorry, write_multi doesn't support $type yet";
	return 0;
      }
    }
  }

  if (exists $opts->{'data'}) {
    my $data = io_slurp($IO);
    if (!$data) {
      Imager->_set_error('Could not slurp from buffer');
      return undef;
    }
    ${$opts->{data}} = $data;
  }
  return 1;
}

# read multiple images from a file
sub read_multi {
  my ($class, %opts) = @_;

  my ($IO, $file) = $class->_get_reader_io(\%opts, $opts{'type'})
    or return;

  my $type = $opts{'type'};
  unless ($type) {
    $type = _test_format($IO);
  }

  if ($opts{file} && !$type) {
    # guess the type 
    $type = $FORMATGUESS->($opts{file});
  }

  unless ($type) {
    my $msg = "type parameter missing and it couldn't be determined from the file contents";
    $opts{file} and $msg .= " or file name";
    Imager->_set_error($msg);
    return;
  }

  _reader_autoload($type);

  if ($readers{$type} && $readers{$type}{multiple}) {
    return $readers{$type}{multiple}->($IO, %opts);
  }

  unless ($formats{$type}) {
    my $read_types = join ', ', sort Imager->read_types();
    Imager->_set_error("format '$type' not supported - formats $read_types available for reading");
    return;
  }

  my @imgs;
  if ($type eq 'pnm') {
    @imgs = i_readpnm_multi_wiol($IO, $opts{allow_incomplete}||0);
  }
  else {
    my $img = Imager->new;
    if ($img->read(%opts, io => $IO, type => $type)) {
      return ( $img );
    }
    Imager->_set_error($img->errstr);
    return;
  }

  if (!@imgs) {
    $ERRSTR = _error_as_msg();
  return;
  }
  return map { 
        bless { IMG=>$_, DEBUG=>$DEBUG, ERRSTR=>undef }, 'Imager' 
      } @imgs;
}

# Destroy an Imager object

sub DESTROY {
  my $self=shift;
  #    delete $instances{$self};
  if (defined($self->{IMG})) {
    # the following is now handled by the XS DESTROY method for
    # Imager::ImgRaw object
    # Re-enabling this will break virtual images
    # tested for in t/t020masked.t
    # i_img_destroy($self->{IMG});
    undef($self->{IMG});
  } else {
#    print "Destroy Called on an empty image!\n"; # why did I put this here??
  }
}

# Perform an inplace filter of an image
# that is the image will be overwritten with the data

sub filter {
  my $self=shift;
  my %input=@_;
  my %hsh;

  $self->_valid_image("filter")
    or return;

  if (!$input{'type'}) { $self->{ERRSTR}='type parameter missing'; return undef; }

  if ( (grep { $_ eq $input{'type'} } keys %filters) != 1) {
    $self->{ERRSTR}='type parameter not matching any filter'; return undef;
  }

  if ($filters{$input{'type'}}{names}) {
    my $names = $filters{$input{'type'}}{names};
    for my $name (keys %$names) {
      if (defined $input{$name} && exists $names->{$name}{$input{$name}}) {
        $input{$name} = $names->{$name}{$input{$name}};
      }
    }
  }
  if (defined($filters{$input{'type'}}{defaults})) {
    %hsh=( image => $self->{IMG},
           imager => $self,
           %{$filters{$input{'type'}}{defaults}},
           %input );
  } else {
    %hsh=( image => $self->{IMG},
           imager => $self,
           %input );
  }

  my @cs=@{$filters{$input{'type'}}{callseq}};

  for(@cs) {
    if (!defined($hsh{$_})) {
      $self->{ERRSTR}="missing parameter '$_' for filter ".$input{'type'}; return undef;
    }
  }

  eval {
    local $SIG{__DIE__}; # we don't want this processed by confess, etc
    &{$filters{$input{'type'}}{callsub}}(%hsh);
  };
  if ($@) {
    chomp($self->{ERRSTR} = $@);
    return;
  }

  my @b=keys %hsh;

  $self->{DEBUG} && print "callseq is: @cs\n";
  $self->{DEBUG} && print "matching callseq is: @b\n";

  return $self;
}

sub register_filter {
  my $class = shift;
  my %hsh = ( defaults => {}, @_ );

  defined $hsh{type}
    or die "register_filter() with no type\n";
  defined $hsh{callsub}
    or die "register_filter() with no callsub\n";
  defined $hsh{callseq}
    or die "register_filter() with no callseq\n";

  exists $filters{$hsh{type}}
    and return;

  $filters{$hsh{type}} = \%hsh;

  return 1;
}

sub scale_calculate {
  my $self = shift;

  my %opts = ('type'=>'max', @_);

  # none of these should be references
  for my $name (qw/xpixels ypixels xscalefactor yscalefactor width height/) {
    if (defined $opts{$name} && ref $opts{$name}) {
      $self->_set_error("scale_calculate: $name parameter cannot be a reference");
      return;
    }
  }

  my ($x_scale, $y_scale);
  my $width = $opts{width};
  my $height = $opts{height};
  if (ref $self) {
    defined $width or $width = $self->getwidth;
    defined $height or $height = $self->getheight;
  }
  else {
    unless (defined $width && defined $height) {
      $self->_set_error("scale_calculate: width and height parameters must be supplied when called as a class method");
      return;
    }
  }

  if ($opts{'xscalefactor'} && $opts{'yscalefactor'}) {
    $x_scale = $opts{'xscalefactor'};
    $y_scale = $opts{'yscalefactor'};
  }
  elsif ($opts{'xscalefactor'}) {
    $x_scale = $opts{'xscalefactor'};
    $y_scale = $opts{'scalefactor'} || $x_scale;
  }
  elsif ($opts{'yscalefactor'}) {
    $y_scale = $opts{'yscalefactor'};
    $x_scale = $opts{'scalefactor'} || $y_scale;
  }
  else {
    $x_scale = $y_scale = $opts{'scalefactor'} || 0.5;
  }

  # work out the scaling
  if ($opts{xpixels} and $opts{ypixels} and $opts{'type'}) {
    my ($xpix, $ypix)=( $opts{xpixels} / $width , 
			$opts{ypixels} / $height );
    if ($opts{'type'} eq 'min') { 
      $x_scale = $y_scale = _min($xpix,$ypix); 
    }
    elsif ($opts{'type'} eq 'max') {
      $x_scale = $y_scale = _max($xpix,$ypix);
    }
    elsif ($opts{'type'} eq 'nonprop' || $opts{'type'} eq 'non-proportional') {
      $x_scale = $xpix;
      $y_scale = $ypix;
    }
    else {
      $self->_set_error('invalid value for type parameter');
      return;
    }
  } elsif ($opts{xpixels}) { 
    $x_scale = $y_scale = $opts{xpixels} / $width;
  }
  elsif ($opts{ypixels}) { 
    $x_scale = $y_scale = $opts{ypixels}/$height;
  }
  elsif ($opts{constrain} && ref $opts{constrain}
	 && $opts{constrain}->can('constrain')) {
    # we've been passed an Image::Math::Constrain object or something
    # that looks like one
    my $scalefactor;
    (undef, undef, $scalefactor)
      = $opts{constrain}->constrain($self->getwidth, $self->getheight);
    unless ($scalefactor) {
      $self->_set_error('constrain method failed on constrain parameter');
      return;
    }
    $x_scale = $y_scale = $scalefactor;
  }

  my $new_width = int($x_scale * $width + 0.5);
  $new_width > 0 or $new_width = 1;
  my $new_height = int($y_scale * $height + 0.5);
  $new_height > 0 or $new_height = 1;

  return ($x_scale, $y_scale, $new_width, $new_height);
  
}

# Scale an image to requested size and return the scaled version

sub scale {
  my $self=shift;
  my %opts = (qtype=>'normal' ,@_);
  my $img = Imager->new();
  my $tmp = Imager->new();

  unless (defined wantarray) {
    my @caller = caller;
    warn "scale() called in void context - scale() returns the scaled image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("scale")
    or return;

  my ($x_scale, $y_scale, $new_width, $new_height) = 
    $self->scale_calculate(%opts)
      or return;

  if ($opts{qtype} eq 'normal') {
    $tmp->{IMG} = i_scaleaxis($self->{IMG}, $x_scale, 0);
    if ( !defined($tmp->{IMG}) ) { 
      $self->{ERRSTR} = 'unable to scale image: ' . $self->_error_as_msg;
      return undef;
    }
    $img->{IMG}=i_scaleaxis($tmp->{IMG}, $y_scale, 1);
    if ( !defined($img->{IMG}) ) { 
      $self->{ERRSTR}='unable to scale image: ' . $self->_error_as_msg; 
      return undef;
    }

    return $img;
  }
  elsif ($opts{'qtype'} eq 'preview') {
    $img->{IMG} = i_scale_nn($self->{IMG}, $x_scale, $y_scale); 
    if ( !defined($img->{IMG}) ) { 
      $self->{ERRSTR}='unable to scale image'; 
      return undef;
    }
    return $img;
  }
  elsif ($opts{'qtype'} eq 'mixing') {
    $img->{IMG} = i_scale_mixing($self->{IMG}, $new_width, $new_height);
    unless ($img->{IMG}) {
      $self->_set_error(Imager->_error_as_msg);
      return;
    }
    return $img;
  }
  else {
    $self->_set_error('invalid value for qtype parameter');
    return undef;
  }
}

# Scales only along the X axis

sub scaleX {
  my $self = shift;
  my %opts = ( scalefactor=>0.5, @_ );

  unless (defined wantarray) {
    my @caller = caller;
    warn "scaleX() called in void context - scaleX() returns the scaled image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("scaleX")
    or return;

  my $img = Imager->new();

  my $scalefactor = $opts{scalefactor};

  if ($opts{pixels}) { 
    $scalefactor = $opts{pixels} / $self->getwidth();
  }

  unless ($self->{IMG}) { 
    $self->{ERRSTR}='empty input image'; 
    return undef;
  }

  $img->{IMG} = i_scaleaxis($self->{IMG}, $scalefactor, 0);

  if ( !defined($img->{IMG}) ) { 
    $self->{ERRSTR} = 'unable to scale image'; 
    return undef;
  }

  return $img;
}

# Scales only along the Y axis

sub scaleY {
  my $self = shift;
  my %opts = ( scalefactor => 0.5, @_ );

  unless (defined wantarray) {
    my @caller = caller;
    warn "scaleY() called in void context - scaleY() returns the scaled image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("scaleY")
    or return;

  my $img = Imager->new();

  my $scalefactor = $opts{scalefactor};

  if ($opts{pixels}) { 
    $scalefactor = $opts{pixels} / $self->getheight();
  }

  unless ($self->{IMG}) { 
    $self->{ERRSTR} = 'empty input image'; 
    return undef;
  }
  $img->{IMG}=i_scaleaxis($self->{IMG}, $scalefactor, 1);

  if ( !defined($img->{IMG}) ) {
    $self->{ERRSTR} = 'unable to scale image';
    return undef;
  }

  return $img;
}

# Transform returns a spatial transformation of the input image
# this moves pixels to a new location in the returned image.
# NOTE - should make a utility function to check transforms for
# stack overruns

our $I2P;

sub transform {
  my $self=shift;
  my %opts=@_;
  my (@op,@ropx,@ropy,$iop,$or,@parm,$expr,@xt,@yt,@pt,$numre);

#  print Dumper(\%opts);
#  xopcopdes

  $self->_valid_image("transform")
    or return;

  if ( $opts{'xexpr'} and $opts{'yexpr'} ) {
    if (!$I2P) {
      {
	local @INC = @INC;
	pop @INC if $INC[-1] eq '.';
	eval ("use Affix::Infix2Postfix;");
      }

      if ( $@ ) {
	$self->{ERRSTR}='transform: expr given and Affix::Infix2Postfix is not avaliable.'; 
	return undef;
      }
      $I2P=Affix::Infix2Postfix->new('ops'=>[{op=>'+',trans=>'Add'},
					     {op=>'-',trans=>'Sub'},
					     {op=>'*',trans=>'Mult'},
					     {op=>'/',trans=>'Div'},
					     {op=>'-','type'=>'unary',trans=>'u-'},
					     {op=>'**'},
					     {op=>'func','type'=>'unary'}],
				     'grouping'=>[qw( \( \) )],
				     'func'=>[qw( sin cos )],
				     'vars'=>[qw( x y )]
				    );
    }

    @xt=$I2P->translate($opts{'xexpr'});
    @yt=$I2P->translate($opts{'yexpr'});

    $numre=$I2P->{'numre'};
    @pt=(0,0);

    for(@xt) { if (/$numre/) { push(@pt,$_); push(@{$opts{'xopcodes'}},'Parm',$#pt); } else { push(@{$opts{'xopcodes'}},$_); } }
    for(@yt) { if (/$numre/) { push(@pt,$_); push(@{$opts{'yopcodes'}},'Parm',$#pt); } else { push(@{$opts{'yopcodes'}},$_); } }
    @{$opts{'parm'}}=@pt;
  }

#  print Dumper(\%opts);

  if ( !exists $opts{'xopcodes'} or @{$opts{'xopcodes'}}==0) {
    $self->{ERRSTR}='transform: no xopcodes given.';
    return undef;
  }

  @op=@{$opts{'xopcodes'}};
  for $iop (@op) { 
    if (!defined ($OPCODES{$iop}) and ($iop !~ /^\d+$/) ) {
      $self->{ERRSTR}="transform: illegal opcode '$_'.";
      return undef;
    }
    push(@ropx,(exists $OPCODES{$iop}) ? @{$OPCODES{$iop}} : $iop );
  }


# yopcopdes

  if ( !exists $opts{'yopcodes'} or @{$opts{'yopcodes'}}==0) {
    $self->{ERRSTR}='transform: no yopcodes given.';
    return undef;
  }

  @op=@{$opts{'yopcodes'}};
  for $iop (@op) { 
    if (!defined ($OPCODES{$iop}) and ($iop !~ /^\d+$/) ) {
      $self->{ERRSTR}="transform: illegal opcode '$_'.";
      return undef;
    }
    push(@ropy,(exists $OPCODES{$iop}) ? @{$OPCODES{$iop}} : $iop );
  }

#parameters

  if ( !exists $opts{'parm'}) {
    $self->{ERRSTR}='transform: no parameter arg given.';
    return undef;
  }

#  print Dumper(\@ropx);
#  print Dumper(\@ropy);
#  print Dumper(\@ropy);

  my $img = Imager->new();
  $img->{IMG}=i_transform($self->{IMG},\@ropx,\@ropy,$opts{'parm'});
  if ( !defined($img->{IMG}) ) { $self->{ERRSTR}='transform: failed'; return undef; }
  return $img;
}


sub transform2 {
  my ($opts, @imgs) = @_;
  
  require "Imager/Expr.pm";

  $opts->{variables} = [ qw(x y) ];
  my ($width, $height) = @{$opts}{qw(width height)};
  if (@imgs) {
    my $index = 1;
    for my $img (@imgs) {
      unless ($img->_valid_image("transform2")) {
	Imager->_set_error($img->errstr . " (input image $index)");
	return;
      }
      ++$index;
    }

    $width ||= $imgs[0]->getwidth();
    $height ||= $imgs[0]->getheight();
    my $img_num = 1;
    for my $img (@imgs) {
      $opts->{constants}{"w$img_num"} = $img->getwidth();
      $opts->{constants}{"h$img_num"} = $img->getheight();
      $opts->{constants}{"cx$img_num"} = $img->getwidth()/2;
      $opts->{constants}{"cy$img_num"} = $img->getheight()/2;
      ++$img_num;
    }
  }
  if ($width) {
    $opts->{constants}{w} = $width;
    $opts->{constants}{cx} = $width/2;
  }
  else {
    $Imager::ERRSTR = "No width supplied";
    return;
  }
  if ($height) {
    $opts->{constants}{h} = $height;
    $opts->{constants}{cy} = $height/2;
  }
  else {
    $Imager::ERRSTR = "No height supplied";
    return;
  }
  my $code = Imager::Expr->new($opts);
  if (!$code) {
    $Imager::ERRSTR = Imager::Expr::error();
    return;
  }
  my $channels = $opts->{channels} || 3;
  unless ($channels >= 1 && $channels <= 4) {
    return Imager->_set_error("channels must be an integer between 1 and 4");
  }

  my $img = Imager->new();
  $img->{IMG} = i_transform2($opts->{width}, $opts->{height}, 
			     $channels, $code->code(),
                             $code->nregs(), $code->cregs(),
                             [ map { $_->{IMG} } @imgs ]);
  if (!defined $img->{IMG}) {
    $Imager::ERRSTR = Imager->_error_as_msg();
    return;
  }

  return $img;
}

sub rubthrough {
  my $self=shift;
  my %opts= @_;

  $self->_valid_image("rubthrough")
    or return;

  unless ($opts{src} && $opts{src}->_valid_image("rubthrough")) {
    $self->{ERRSTR} = $opts{src}{ERRSTR} . ' (for src)';
    return;
  }

  %opts = (src_minx => 0,
	   src_miny => 0,
	   src_maxx => $opts{src}->getwidth(),
	   src_maxy => $opts{src}->getheight(),
	   %opts);

  my $tx = $opts{tx};
  defined $tx or $tx = $opts{left};
  defined $tx or $tx = 0;

  my $ty = $opts{ty};
  defined $ty or $ty = $opts{top};
  defined $ty or $ty = 0;

  unless (i_rubthru($self->{IMG}, $opts{src}->{IMG}, $tx, $ty,
                    $opts{src_minx}, $opts{src_miny}, 
                    $opts{src_maxx}, $opts{src_maxy})) {
    $self->_set_error($self->_error_as_msg());
    return undef;
  }

  return $self;
}

sub compose {
  my $self = shift;
  my %opts =
    ( 
     opacity => 1.0,
     mask_left => 0,
     mask_top => 0,
     @_
    );

  $self->_valid_image("compose")
    or return;

  unless ($opts{src}) {
    $self->_set_error("compose: src parameter missing");
    return;
  }
  
  unless ($opts{src}->_valid_image("compose")) {
    $self->_set_error($opts{src}->errstr . " (for src)");
    return;
  }
  my $src = $opts{src};

  my $left = $opts{left};
  defined $left or $left = $opts{tx};
  defined $left or $left = 0;

  my $top = $opts{top};
  defined $top or $top = $opts{ty};
  defined $top or $top = 0;

  my $src_left = $opts{src_left};
  defined $src_left or $src_left = $opts{src_minx};
  defined $src_left or $src_left = 0;

  my $src_top = $opts{src_top};
  defined $src_top or $src_top = $opts{src_miny};
  defined $src_top or $src_top = 0;

  my $width = $opts{width};
  if (!defined $width && defined $opts{src_maxx}) {
    $width = $opts{src_maxx} - $src_left;
  }
  defined $width or $width = $src->getwidth() - $src_left;

  my $height = $opts{height};
  if (!defined $height && defined $opts{src_maxy}) {
    $height = $opts{src_maxy} - $src_top;
  }
  defined $height or $height = $src->getheight() - $src_top;

  my $combine = $self->_combine($opts{combine}, 'normal');

  if ($opts{mask}) {
    unless ($opts{mask}->_valid_image("compose")) {
      $self->_set_error($opts{mask}->errstr . " (for mask)");
      return;
    }

    my $mask_left = $opts{mask_left};
    defined $mask_left or $mask_left = $opts{mask_minx};
    defined $mask_left or $mask_left = 0;
    
    my $mask_top = $opts{mask_top};
    defined $mask_top or $mask_top = $opts{mask_miny};
    defined $mask_top or $mask_top = 0;

    unless (i_compose_mask($self->{IMG}, $src->{IMG}, $opts{mask}{IMG}, 
		   $left, $top, $src_left, $src_top,
		   $mask_left, $mask_top, $width, $height, 
			   $combine, $opts{opacity})) {
      $self->_set_error(Imager->_error_as_msg);
      return;
    }
  }
  else {
    unless (i_compose($self->{IMG}, $src->{IMG}, $left, $top, $src_left, $src_top,
		      $width, $height, $combine, $opts{opacity})) {
      $self->_set_error(Imager->_error_as_msg);
      return;
    }
  }

  return $self;
}

sub flip {
  my $self  = shift;
  my %opts  = @_;

  $self->_valid_image("flip")
    or return;

  my %xlate = (h=>0, v=>1, hv=>2, vh=>2);
  my $dir;
  return () unless defined $opts{'dir'} and defined $xlate{$opts{'dir'}};
  $dir = $xlate{$opts{'dir'}};
  return $self if i_flipxy($self->{IMG}, $dir);
  return ();
}

sub rotate {
  my $self = shift;
  my %opts = @_;

  unless (defined wantarray) {
    my @caller = caller;
    warn "rotate() called in void context - rotate() returns the rotated image at $caller[1] line $caller[2]\n";
    return;
  }

  $self->_valid_image("rotate")
    or return;

  if (defined $opts{right}) {
    my $degrees = $opts{right};
    if ($degrees < 0) {
      $degrees += 360 * int(((-$degrees)+360)/360);
    }
    $degrees = $degrees % 360;
    if ($degrees == 0) {
      return $self->copy();
    }
    elsif ($degrees == 90 || $degrees == 180 || $degrees == 270) {
      my $result = Imager->new();
      if ($result->{IMG} = i_rotate90($self->{IMG}, $degrees)) {
        return $result;
      }
      else {
        $self->{ERRSTR} = $self->_error_as_msg();
        return undef;
      }
    }
    else {
      $self->{ERRSTR} = "Parameter 'right' must be a multiple of 90 degrees";
      return undef;
    }
  }
  elsif (defined $opts{radians} || defined $opts{degrees}) {
    my $amount = $opts{radians} || $opts{degrees} * 3.14159265358979 / 180;

    my $back = $opts{back};
    my $result = Imager->new;
    if ($back) {
      $back = _color($back);
      unless ($back) {
        $self->_set_error(Imager->errstr);
        return undef;
      }

      $result->{IMG} = i_rotate_exact($self->{IMG}, $amount, $back);
    }
    else {
      $result->{IMG} = i_rotate_exact($self->{IMG}, $amount);
    }
    if ($result->{IMG}) {
      return $result;
    }
    else {
      $self->{ERRSTR} = $self->_error_as_msg();
      return undef;
    }
  }
  else {
    $self->{ERRSTR} = "Only the 'right', 'radians' and 'degrees' parameters are available";
    return undef;
  }
}

sub matrix_transform {
  my $self = shift;
  my %opts = @_;

  $self->_valid_image("matrix_transform")
    or return;

  unless (defined wantarray) {
    my @caller = caller;
    warn "copy() called in void context - copy() returns the copied image at $caller[1] line $caller[2]\n";
    return;
  }

  if ($opts{matrix}) {
    my $xsize = $opts{xsize} || $self->getwidth;
    my $ysize = $opts{ysize} || $self->getheight;

    my $result = Imager->new;
    if ($opts{back}) {
      $result->{IMG} = i_matrix_transform($self->{IMG}, $xsize, $ysize, 
					  $opts{matrix}, $opts{back})
	or return undef;
    }
    else {
      $result->{IMG} = i_matrix_transform($self->{IMG}, $xsize, $ysize, 
					  $opts{matrix})
	or return undef;
    }

    return $result;
  }
  else {
    $self->{ERRSTR} = "matrix parameter required";
    return undef;
  }
}

# blame Leolo :)
*yatf = \&matrix_transform;

# These two are supported for legacy code only

sub i_color_new {
  return Imager::Color->new(@_);
}

sub i_color_set {
  return Imager::Color::set(@_);
}

# Draws a box between the specified corner points.
sub box {
  my $self=shift;
  my $raw = $self->{IMG};

  $self->_valid_image("box")
    or return;

  my %opts = @_;

  my ($xmin, $ymin, $xmax, $ymax);
  if (exists $opts{'box'}) { 
    $xmin = _min($opts{'box'}->[0],$opts{'box'}->[2]);
    $xmax = _max($opts{'box'}->[0],$opts{'box'}->[2]);
    $ymin = _min($opts{'box'}->[1],$opts{'box'}->[3]);
    $ymax = _max($opts{'box'}->[1],$opts{'box'}->[3]);
  }
  else {
    defined($xmin = $opts{xmin}) or $xmin = 0;
    defined($xmax = $opts{xmax}) or $xmax = $self->getwidth()-1;
    defined($ymin = $opts{ymin}) or $ymin = 0;
    defined($ymax = $opts{ymax}) or $ymax = $self->getheight()-1;
  }

  if ($opts{filled}) { 
    my $color = $opts{'color'};

    if (defined $color) {
      unless (_is_color_object($color)) {
	$color = _color($color);
	unless ($color) { 
	  $self->{ERRSTR} = $Imager::ERRSTR; 
	  return;
	}
      }
    }
    else {
      $color = i_color_new(255,255,255,255);
    }

    if ($color->isa("Imager::Color")) {
      i_box_filled($raw, $xmin, $ymin,$xmax, $ymax, $color);
    }
    else {
      i_box_filledf($raw, $xmin, $ymin,$xmax, $ymax, $color);
    }
  }
  elsif ($opts{fill}) {
    unless (UNIVERSAL::isa($opts{fill}, 'Imager::Fill')) {
      # assume it's a hash ref
      require 'Imager/Fill.pm';
      unless ($opts{fill} = Imager::Fill->new(%{$opts{fill}})) {
        $self->{ERRSTR} = $Imager::ERRSTR;
        return undef;
      }
    }
    i_box_cfill($raw, $xmin, $ymin, $xmax, $ymax, $opts{fill}{fill});
  }
  else {
    my $color = $opts{'color'};
    if (defined $color) {
      unless (_is_color_object($color)) {
	$color = _color($color);
	unless ($color) { 
	  $self->{ERRSTR} = $Imager::ERRSTR;
	  return;
	}
      }
    }
    else {
      $color = i_color_new(255, 255, 255, 255);
    }
    unless ($color) { 
      $self->{ERRSTR} = $Imager::ERRSTR;
      return;
    }
    i_box($raw, $xmin, $ymin, $xmax, $ymax, $color);
  }

  return $self;
}

sub arc {
  my $self=shift;

  $self->_valid_image("arc")
    or return;

  my $dflcl= [ 255, 255, 255, 255];
  my $good = 1;
  my %opts=
    (
     color=>$dflcl,
     'r'=>_min($self->getwidth(),$self->getheight())/3,
     'x'=>$self->getwidth()/2,
     'y'=>$self->getheight()/2,
     'd1'=>0, 'd2'=>361, 
     filled => 1,
     @_,
    );
  if ($opts{aa}) {
    if ($opts{fill}) {
      unless (UNIVERSAL::isa($opts{fill}, 'Imager::Fill')) {
	# assume it's a hash ref
	require 'Imager/Fill.pm';
	unless ($opts{fill} = Imager::Fill->new(%{$opts{fill}})) {
	  $self->{ERRSTR} = $Imager::ERRSTR;
	  return;
	}
      }
      if ($opts{d1} == 0 && $opts{d2} == 361) {
	i_circle_aa_fill($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{'r'},
			 $opts{fill}{fill});
      }
      else {
	i_arc_aa_cfill($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},$opts{'d1'},
		       $opts{'d2'}, $opts{fill}{fill});
      }
    }
    elsif ($opts{filled}) {
      my $color = _color($opts{'color'});
      unless ($color) { 
	$self->{ERRSTR} = $Imager::ERRSTR; 
	return; 
      }
      if ($opts{d1} == 0 && $opts{d2} == 361 && $opts{aa}) {
	i_circle_aa($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{'r'}, 
		    $color);
      }
      else {
	i_arc_aa($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},
		 $opts{'d1'}, $opts{'d2'}, $color); 
      }
    }
    else {
      my $color = _color($opts{'color'});
      if ($opts{d2} - $opts{d1} >= 360) {
	$good = i_circle_out_aa($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{'r'}, $color);
      }
      else {
	$good = i_arc_out_aa($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{'r'}, $opts{'d1'}, $opts{'d2'}, $color);
      }
    }
  }
  else {
    if ($opts{fill}) {
      unless (UNIVERSAL::isa($opts{fill}, 'Imager::Fill')) {
	# assume it's a hash ref
	require 'Imager/Fill.pm';
	unless ($opts{fill} = Imager::Fill->new(%{$opts{fill}})) {
	  $self->{ERRSTR} = $Imager::ERRSTR;
	  return;
	}
      }
      i_arc_cfill($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},$opts{'d1'},
		  $opts{'d2'}, $opts{fill}{fill});
    }
    else {
      my $color = _color($opts{'color'});
      unless ($color) { 
	$self->{ERRSTR} = $Imager::ERRSTR; 
	return;
      }
      if ($opts{filled}) {
	i_arc($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},
	      $opts{'d1'}, $opts{'d2'}, $color); 
      }
      else {
	if ($opts{d1} == 0 && $opts{d2} == 361) {
	  $good = i_circle_out($self->{IMG}, $opts{x}, $opts{y}, $opts{r}, $color);
	}
	else {
	  $good = i_arc_out($self->{IMG}, $opts{x}, $opts{y}, $opts{r}, $opts{d1}, $opts{d2}, $color);
	}
      }
    }
  }
  unless ($good) {
    $self->_set_error($self->_error_as_msg);
    return;
  }

  return $self;
}

# Draws a line from one point to the other
# the endpoint is set if the endp parameter is set which it is by default.
# to turn of the endpoint being set use endp=>0 when calling line.

sub line {
  my $self=shift;
  my $dflcl=i_color_new(0,0,0,0);
  my %opts=(color=>$dflcl,
	    endp => 1,
	    @_);

  $self->_valid_image("line")
    or return;

  unless (exists $opts{x1} and exists $opts{y1}) { $self->{ERRSTR}='missing begining coord'; return undef; }
  unless (exists $opts{x2} and exists $opts{y2}) { $self->{ERRSTR}='missing ending coord'; return undef; }

  my $color = _color($opts{'color'});
  unless ($color) {
    $self->{ERRSTR} = $Imager::ERRSTR;
    return;
  }

  $opts{antialias} = $opts{aa} if defined $opts{aa};
  if ($opts{antialias}) {
    i_line_aa($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},
              $color, $opts{endp});
  } else {
    i_line($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},
           $color, $opts{endp});
  }
  return $self;
}

# Draws a line between an ordered set of points - It more or less just transforms this
# into a list of lines.

sub polyline {
  my $self=shift;
  my ($pt,$ls,@points);
  my $dflcl=i_color_new(0,0,0,0);
  my %opts=(color=>$dflcl,@_);

  $self->_valid_image("polyline")
    or return;

  if (exists($opts{points})) { @points=@{$opts{points}}; }
  if (!exists($opts{points}) and exists($opts{'x'}) and exists($opts{'y'}) ) {
    @points=map { [ $opts{'x'}->[$_],$opts{'y'}->[$_] ] } (0..(scalar @{$opts{'x'}}-1));
    }

#  print Dumper(\@points);

  my $color = _color($opts{'color'});
  unless ($color) { 
    $self->{ERRSTR} = $Imager::ERRSTR; 
    return; 
  }
  $opts{antialias} = $opts{aa} if defined $opts{aa};
  if ($opts{antialias}) {
    for $pt(@points) {
      if (defined($ls)) { 
        i_line_aa($self->{IMG},$ls->[0],$ls->[1],$pt->[0],$pt->[1],$color, 1);
      }
      $ls=$pt;
    }
  } else {
    for $pt(@points) {
      if (defined($ls)) { 
        i_line($self->{IMG},$ls->[0],$ls->[1],$pt->[0],$pt->[1],$color,1);
      }
      $ls=$pt;
    }
  }
  return $self;
}

sub polygon {
  my $self = shift;
  my ($pt,$ls,@points);
  my $dflcl = i_color_new(0,0,0,0);
  my %opts = (color=>$dflcl, @_);

  $self->_valid_image("polygon")
    or return;

  if (exists($opts{points})) {
    $opts{'x'} = [ map { $_->[0] } @{$opts{points}} ];
    $opts{'y'} = [ map { $_->[1] } @{$opts{points}} ];
  }

  if (!exists $opts{'x'} or !exists $opts{'y'})  {
    $self->{ERRSTR} = 'no points array, or x and y arrays.'; return undef;
  }

  my $mode = _first($opts{mode}, 0);

  if ($opts{'fill'}) {
    unless (UNIVERSAL::isa($opts{'fill'}, 'Imager::Fill')) {
      # assume it's a hash ref
      require 'Imager/Fill.pm';
      unless ($opts{'fill'} = Imager::Fill->new(%{$opts{'fill'}})) {
        $self->{ERRSTR} = $Imager::ERRSTR;
        return undef;
      }
    }
    unless (i_poly_aa_cfill_m($self->{IMG}, $opts{'x'}, $opts{'y'},
			      $mode, $opts{'fill'}{'fill'})) {
      return $self->_set_error($self->_error_as_msg);
    }
  }
  else {
    my $color = _color($opts{'color'});
    unless ($color) { 
      $self->{ERRSTR} = $Imager::ERRSTR; 
      return;
    }
    unless (i_poly_aa_m($self->{IMG}, $opts{'x'}, $opts{'y'}, $mode, $color)) {
      return $self->_set_error($self->_error_as_msg);
    }
  }

  return $self;
}

sub polypolygon {
  my ($self, %opts) = @_;

  $self->_valid_image("polypolygon")
    or return;

  my $points = $opts{points};
  $points
    or return $self->_set_error("polypolygon: missing required points");

  my $mode = _first($opts{mode}, "evenodd");

  if ($opts{filled}) {
    my $color = _color(_first($opts{color}, [ 0, 0, 0, 0 ]))
      or return $self->_set_error($Imager::ERRSTR);

    i_poly_poly_aa($self->{IMG}, $points, $mode, $color)
      or return $self->_set_error($self->_error_as_msg);
  }
  elsif ($opts{fill}) {
    my $fill = $opts{fill};
    $self->_valid_fill($fill, "polypolygon")
      or return;

    i_poly_poly_aa_cfill($self->{IMG}, $points, $mode, $fill->{fill})
      or return $self->_set_error($self->_error_as_msg);
  }
  else {
    my $color = _color(_first($opts{color}, [ 0, 0, 0, 255 ]))
      or return $self->_set_error($Imager::ERRSTR);

    my $rimg = $self->{IMG};

    if (_first($opts{aa}, 1)) {
      for my $poly (@$points) {
	my $xp = $poly->[0];
	my $yp = $poly->[1];
	for my $i (0 .. $#$xp - 1) {
	  i_line_aa($rimg, $xp->[$i], $yp->[$i], $xp->[$i+1], $yp->[$i+1],
		    $color, 0);
	}
	i_line_aa($rimg, $xp->[$#$xp], $yp->[$#$yp], $xp->[0], $yp->[0],
		  $color, 0);
      }
    }
    else {
      for my $poly (@$points) {
	my $xp = $poly->[0];
	my $yp = $poly->[1];
	for my $i (0 .. $#$xp - 1) {
	  i_line($rimg, $xp->[$i], $yp->[$i], $xp->[$i+1], $yp->[$i+1],
		 $color, 0);
	}
	i_line($rimg, $xp->[$#$xp], $yp->[$#$yp], $xp->[0], $yp->[0],
	       $color, 0);
      }
    }
  }

  return $self;
}

# this the multipoint bezier curve
# this is here more for testing that actual usage since
# this is not a good algorithm.  Usually the curve would be
# broken into smaller segments and each done individually.

sub polybezier {
  my $self=shift;
  my ($pt,$ls,@points);
  my $dflcl=i_color_new(0,0,0,0);
  my %opts=(color=>$dflcl,@_);

  $self->_valid_image("polybezier")
    or return;

  if (exists $opts{points}) {
    $opts{'x'}=map { $_->[0]; } @{$opts{'points'}};
    $opts{'y'}=map { $_->[1]; } @{$opts{'points'}};
  }

  unless ( @{$opts{'x'}} and @{$opts{'x'}} == @{$opts{'y'}} ) {
    $self->{ERRSTR}='Missing or invalid points.';
    return;
  }

  my $color = _color($opts{'color'});
  unless ($color) { 
    $self->{ERRSTR} = $Imager::ERRSTR; 
    return; 
  }
  i_bezier_multi($self->{IMG},$opts{'x'},$opts{'y'},$color);
  return $self;
}

sub flood_fill {
  my $self = shift;
  my %opts = ( color=>Imager::Color->new(255, 255, 255), @_ );
  my $rc;

  $self->_valid_image("flood_fill")
    or return;

  unless (exists $opts{'x'} && exists $opts{'y'}) {
    $self->{ERRSTR} = "missing seed x and y parameters";
    return undef;
  }

  if ($opts{border}) {
    my $border = _color($opts{border});
    unless ($border) {
      $self->_set_error($Imager::ERRSTR);
      return;
    }
    if ($opts{fill}) {
      unless (UNIVERSAL::isa($opts{fill}, 'Imager::Fill')) {
	# assume it's a hash ref
	require Imager::Fill;
	unless ($opts{fill} = Imager::Fill->new(%{$opts{fill}})) {
	  $self->{ERRSTR} = $Imager::ERRSTR;
	  return;
	}
      }
      $rc = i_flood_cfill_border($self->{IMG}, $opts{'x'}, $opts{'y'}, 
				 $opts{fill}{fill}, $border);
    }
    else {
      my $color = _color($opts{'color'});
      unless ($color) {
	$self->{ERRSTR} = $Imager::ERRSTR;
	return;
      }
      $rc = i_flood_fill_border($self->{IMG}, $opts{'x'}, $opts{'y'}, 
				$color, $border);
    }
    if ($rc) { 
      return $self; 
    } 
    else { 
      $self->{ERRSTR} = $self->_error_as_msg(); 
      return;
    }
  }
  else {
    if ($opts{fill}) {
      unless (UNIVERSAL::isa($opts{fill}, 'Imager::Fill')) {
	# assume it's a hash ref
	require 'Imager/Fill.pm';
	unless ($opts{fill} = Imager::Fill->new(%{$opts{fill}})) {
	  $self->{ERRSTR} = $Imager::ERRSTR;
	  return;
	}
      }
      $rc = i_flood_cfill($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{fill}{fill});
    }
    else {
      my $color = _color($opts{'color'});
      unless ($color) {
	$self->{ERRSTR} = $Imager::ERRSTR;
	return;
      }
      $rc = i_flood_fill($self->{IMG}, $opts{'x'}, $opts{'y'}, $color);
    }
    if ($rc) { 
      return $self; 
    } 
    else { 
      $self->{ERRSTR} = $self->_error_as_msg(); 
      return;
    }
  } 
}

sub setpixel {
  my ($self, %opts) = @_;

  $self->_valid_image("setpixel")
    or return;

  my $color = $opts{color};
  unless (defined $color) {
    $color = $self->{fg};
    defined $color or $color = NC(255, 255, 255);
  }

  unless (ref $color && UNIVERSAL::isa($color, "Imager::Color")) {
    unless ($color = _color($color, 'setpixel')) {
      $self->_set_error("setpixel: " . Imager->errstr);
      return;
    }
  }

  unless (exists $opts{'x'} && exists $opts{'y'}) {
    $self->_set_error('setpixel: missing x or y parameter');
    return;
  }

  my $x = $opts{'x'};
  my $y = $opts{'y'};
  if (ref $x || ref $y) {
    $x = ref $x ? $x : [ $x ];
    $y = ref $y ? $y : [ $y ];
    unless (@$x) {
      $self->_set_error("setpixel: x is a reference to an empty array");
      return;
    }
    unless (@$y) {
      $self->_set_error("setpixel: y is a reference to an empty array");
      return;
    }

    # make both the same length, replicating the last element
    if (@$x < @$y) {
      $x = [ @$x, ($x->[-1]) x (@$y - @$x) ];
    }
    elsif (@$y < @$x) {
      $y = [ @$y, ($y->[-1]) x (@$x - @$y) ];
    }

    my $set = 0;
    if ($color->isa('Imager::Color')) {
      for my $i (0..$#$x) {
        i_ppix($self->{IMG}, $x->[$i], $y->[$i], $color)
	  or ++$set;
      }
    }
    else {
      for my $i (0..$#$x) {
        i_ppixf($self->{IMG}, $x->[$i], $y->[$i], $color)
	  or ++$set;
      }
    }

    return $set;
  }
  else {
    if ($color->isa('Imager::Color')) {
      i_ppix($self->{IMG}, $x, $y, $color)
	and return "0 but true";
    }
    else {
      i_ppixf($self->{IMG}, $x, $y, $color)
	and return "0 but true";
    }

    return 1;
  }
}

sub getpixel {
  my $self = shift;

  my %opts = ( "type"=>'8bit', @_);

  $self->_valid_image("getpixel")
    or return;

  unless (exists $opts{'x'} && exists $opts{'y'}) {
    $self->_set_error('getpixel: missing x or y parameter');
    return;
  }

  my $x = $opts{'x'};
  my $y = $opts{'y'};
  my $type = $opts{'type'};
  if (ref $x || ref $y) {
    $x = ref $x ? $x : [ $x ];
    $y = ref $y ? $y : [ $y ];
    unless (@$x) {
      $self->_set_error("getpixel: x is a reference to an empty array");
      return;
    }
    unless (@$y) {
      $self->_set_error("getpixel: y is a reference to an empty array");
      return;
    }

    # make both the same length, replicating the last element
    if (@$x < @$y) {
      $x = [ @$x, ($x->[-1]) x (@$y - @$x) ];
    }
    elsif (@$y < @$x) {
      $y = [ @$y, ($y->[-1]) x (@$x - @$y) ];
    }

    my @result;
    if ($type eq '8bit') {
      for my $i (0..$#$x) {
        push(@result, i_get_pixel($self->{IMG}, $x->[$i], $y->[$i]));
      }
    }
    elsif ($type eq 'float' || $type eq 'double') {
      for my $i (0..$#$x) {
        push(@result, i_gpixf($self->{IMG}, $x->[$i], $y->[$i]));
      }
    }
    else {
      $self->_set_error("getpixel: type must be '8bit' or 'float'");
      return;
    }
    return wantarray ? @result : \@result;
  }
  else {
    if ($type eq '8bit') {
      return i_get_pixel($self->{IMG}, $x, $y);
    }
    elsif ($type eq 'float' || $type eq 'double') {
      return i_gpixf($self->{IMG}, $x, $y);
    }
    else {
      $self->_set_error("getpixel: type must be '8bit' or 'float'");
      return;
    }
  }
}

sub getscanline {
  my $self = shift;
  my %opts = ( type => '8bit', x=>0, @_);

  $self->_valid_image("getscanline")
    or return;

  defined $opts{width} or $opts{width} = $self->getwidth - $opts{x};

  unless (defined $opts{'y'}) {
    $self->_set_error("missing y parameter");
    return;
  }

  if ($opts{type} eq '8bit') {
    return i_glin($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
		  $opts{'y'});
  }
  elsif ($opts{type} eq 'float') {
    return i_glinf($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
		  $opts{'y'});
  }
  elsif ($opts{type} eq 'index') {
    unless (i_img_type($self->{IMG})) {
      $self->_set_error("type => index only valid on paletted images");
      return;
    }
    return i_gpal($self->{IMG}, $opts{x}, $opts{x} + $opts{width},
                  $opts{'y'});
  }
  else {
    $self->_set_error("invalid type parameter - must be '8bit' or 'float'");
    return;
  }
}

sub setscanline {
  my $self = shift;
  my %opts = ( x=>0, @_);

  $self->_valid_image("setscanline")
    or return;

  unless (defined $opts{'y'}) {
    $self->_set_error("missing y parameter");
    return;
  }

  if (!$opts{type}) {
    if (ref $opts{pixels} && @{$opts{pixels}}) {
      # try to guess the type
      if ($opts{pixels}[0]->isa('Imager::Color')) {
	$opts{type} = '8bit';
      }
      elsif ($opts{pixels}[0]->isa('Imager::Color::Float')) {
	$opts{type} = 'float';
      }
      else {
	$self->_set_error("missing type parameter and could not guess from pixels");
	return;
      }
    }
    else {
      # default
      $opts{type} = '8bit';
    }
  }

  if ($opts{type} eq '8bit') {
    if (ref $opts{pixels}) {
      return i_plin($self->{IMG}, $opts{x}, $opts{'y'}, @{$opts{pixels}});
    }
    else {
      return i_plin($self->{IMG}, $opts{x}, $opts{'y'}, $opts{pixels});
    }
  }
  elsif ($opts{type} eq 'float') {
    if (ref $opts{pixels}) {
      return i_plinf($self->{IMG}, $opts{x}, $opts{'y'}, @{$opts{pixels}});
    }
    else {
      return i_plinf($self->{IMG}, $opts{x}, $opts{'y'}, $opts{pixels});
    }
  }
  elsif ($opts{type} eq 'index') {
    if (ref $opts{pixels}) {
      return i_ppal($self->{IMG}, $opts{x}, $opts{'y'}, @{$opts{pixels}});
    }
    else {
      return i_ppal_p($self->{IMG}, $opts{x}, $opts{'y'}, $opts{pixels});
    }
  }
  else {
    $self->_set_error("invalid type parameter - must be '8bit' or 'float'");
    return;
  }
}

sub getsamples {
  my $self = shift;
  my %opts = ( type => '8bit', x=>0, offset => 0, @_);

  $self->_valid_image("getsamples")
    or return;

  defined $opts{width} or $opts{width} = $self->getwidth - $opts{x};

  unless (defined $opts{'y'}) {
    $self->_set_error("missing y parameter");
    return;
  }
  
  if ($opts{target}) {
    my $target = $opts{target};
    my $offset = $opts{offset};
    if ($opts{type} eq '8bit') {
      my @samples = i_gsamp($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
			    $opts{y}, $opts{channels})
	or return;
      @{$target}[$offset .. $offset + @samples - 1] = @samples;
      return scalar(@samples);
    }
    elsif ($opts{type} eq 'float') {
      my @samples = i_gsampf($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
			     $opts{y}, $opts{channels});
      @{$target}[$offset .. $offset + @samples - 1] = @samples;
      return scalar(@samples);
    }
    elsif ($opts{type} =~ /^(\d+)bit$/) {
      my $bits = $1;

      my @data;
      my $count = i_gsamp_bits($self->{IMG}, $opts{x}, $opts{x}+$opts{width}, 
			       $opts{y}, $bits, $target, 
			       $offset, $opts{channels});
      unless (defined $count) {
	$self->_set_error(Imager->_error_as_msg);
	return;
      }

      return $count;
    }
    else {
      $self->_set_error("invalid type parameter - must be '8bit' or 'float'");
      return;
    }
  }
  else {
    if ($opts{type} eq '8bit') {
      return i_gsamp($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
		     $opts{y}, $opts{channels});
    }
    elsif ($opts{type} eq 'float') {
      return i_gsampf($self->{IMG}, $opts{x}, $opts{x}+$opts{width},
		      $opts{y}, $opts{channels});
    }
    elsif ($opts{type} =~ /^(\d+)bit$/) {
      my $bits = $1;

      my @data;
      i_gsamp_bits($self->{IMG}, $opts{x}, $opts{x}+$opts{width}, 
		   $opts{y}, $bits, \@data, 0, $opts{channels})
	or return;
      return @data;
    }
    else {
      $self->_set_error("invalid type parameter - must be '8bit' or 'float'");
      return;
    }
  }
}

sub setsamples {
  my $self = shift;

  $self->_valid_image("setsamples")
    or return;

  my %opts = ( x => 0, offset => 0 );
  my $data_index;
  # avoid duplicating the data parameter, it may be a large scalar
  my $i = 0;
  while ($i < @_ -1) {
    if ($_[$i] eq 'data') {
      $data_index = $i+1;
    }
    else {
      $opts{$_[$i]} = $_[$i+1];
    }

    $i += 2;
  }

  unless(defined $data_index) {
    $self->_set_error('setsamples: data parameter missing');
    return;
  }
  unless (defined $_[$data_index]) {
    $self->_set_error('setsamples: data parameter not defined');
    return;
  }

  my $type = $opts{type};
  defined $type or $type = '8bit';

  my $width = defined $opts{width} ? $opts{width}
    : $self->getwidth() - $opts{x};

  my $count;
  if ($type eq '8bit') {
    $count = i_psamp($self->{IMG}, $opts{x}, $opts{y}, $opts{channels},
		     $_[$data_index], $opts{offset}, $width);
  }
  elsif ($type eq 'float') {
    $count = i_psampf($self->{IMG}, $opts{x}, $opts{y}, $opts{channels},
		      $_[$data_index], $opts{offset}, $width);
  }
  elsif ($type =~ /^([0-9]+)bit$/) {
    my $bits = $1;

    unless (ref $_[$data_index]) {
      $self->_set_error("setsamples: data must be an array ref for type not 8bit or float");
      return;
    }

    $count = i_psamp_bits($self->{IMG}, $opts{x}, $opts{y}, $bits,
			  $opts{channels}, $_[$data_index], $opts{offset}, 
			  $width);
  }
  else {
    $self->_set_error('setsamples: type parameter invalid');
    return;
  }

  unless (defined $count) {
    $self->_set_error(Imager->_error_as_msg);
    return;
  }

  return $count;
}

# make an identity matrix of the given size
sub _identity {
  my ($size) = @_;

  my $matrix = [ map { [ (0) x $size ] } 1..$size ];
  for my $c (0 .. ($size-1)) {
    $matrix->[$c][$c] = 1;
  }
  return $matrix;
}

# general function to convert an image
sub convert {
  my ($self, %opts) = @_;
  my $matrix;

  $self->_valid_image("convert")
    or return;

  unless (defined wantarray) {
    my @caller = caller;
    warn "convert() called in void context - convert() returns the converted image at $caller[1] line $caller[2]\n";
    return;
  }

  # the user can either specify a matrix or preset
  # the matrix overrides the preset
  if (!exists($opts{matrix})) {
    unless (exists($opts{preset})) {
      $self->{ERRSTR} = "convert() needs a matrix or preset";
      return;
    }
    else {
      if ($opts{preset} eq 'gray' || $opts{preset} eq 'grey') {
	# convert to greyscale, keeping the alpha channel if any
	if ($self->getchannels == 3) {
	  $matrix = [ [ 0.222, 0.707, 0.071 ] ];
	}
	elsif ($self->getchannels == 4) {
	  # preserve the alpha channel
	  $matrix = [ [ 0.222, 0.707, 0.071, 0 ],
		      [ 0,     0,     0,     1 ] ];
	}
	else {
	  # an identity
	  $matrix = _identity($self->getchannels);
	}
      }
      elsif ($opts{preset} eq 'noalpha') {
	# strip the alpha channel
	if ($self->getchannels == 2 or $self->getchannels == 4) {
	  $matrix = _identity($self->getchannels);
	  pop(@$matrix); # lose the alpha entry
	}
	else {
	  $matrix = _identity($self->getchannels);
	}
      }
      elsif ($opts{preset} eq 'red' || $opts{preset} eq 'channel0') {
	# extract channel 0
	$matrix = [ [ 1 ] ];
      }
      elsif ($opts{preset} eq 'green' || $opts{preset} eq 'channel1') {
	$matrix = [ [ 0, 1 ] ];
      }
      elsif ($opts{preset} eq 'blue' || $opts{preset} eq 'channel2') {
	$matrix = [ [ 0, 0, 1 ] ];
      }
      elsif ($opts{preset} eq 'alpha') {
	if ($self->getchannels == 2 or $self->getchannels == 4) {
	  $matrix = [ [ (0) x ($self->getchannels-1), 1 ] ];
	}
	else {
	  # the alpha is just 1 <shrug>
	  $matrix = [ [ (0) x $self->getchannels, 1 ] ];
	}
      }
      elsif ($opts{preset} eq 'rgb') {
	if ($self->getchannels == 1) {
	  $matrix = [ [ 1 ], [ 1 ], [ 1 ] ];
	}
	elsif ($self->getchannels == 2) {
	  # preserve the alpha channel
	  $matrix = [ [ 1, 0 ], [ 1, 0 ], [ 1, 0 ], [ 0, 1 ] ];
	}
	else {
	  $matrix = _identity($self->getchannels);
	}
      }
      elsif ($opts{preset} eq 'addalpha') {
	if ($self->getchannels == 1) {
	  $matrix = _identity(2);
	}
	elsif ($self->getchannels == 3) {
	  $matrix = _identity(4);
	}
	else {
	  $matrix = _identity($self->getchannels);
	}
      }
      else {
	$self->{ERRSTR} = "Unknown convert preset $opts{preset}";
	return undef;
      }
    }
  }
  else {
    $matrix = $opts{matrix};
  }

  my $new = Imager->new;
  $new->{IMG} = i_convert($self->{IMG}, $matrix);
  unless ($new->{IMG}) {
    # most likely a bad matrix
    i_push_error(0, "convert");
    $self->{ERRSTR} = _error_as_msg();
    return undef;
  }
  return $new;
}

# combine channels from multiple input images, a class method
sub combine {
  my ($class, %opts) = @_;

  my $src = delete $opts{src};
  unless ($src) {
    $class->_set_error("src parameter missing");
    return;
  }
  my @imgs;
  my $index = 0;
  for my $img (@$src) {
    unless (eval { $img->isa("Imager") }) {
      $class->_set_error("src must contain image objects");
      return;
    }
    unless ($img->_valid_image("combine")) {
      $Imager::ERRSTR = $img->{ERRSTR} . " (src->[$index])";
      return;
    }
    push @imgs, $img->{IMG};
  }
  my $result;
  if (my $channels = delete $opts{channels}) {
    $result = i_combine(\@imgs, $channels);
  }
  else {
    $result = i_combine(\@imgs);
  }
  unless ($result) {
    $class->_set_error($class->_error_as_msg);
    return;
  }

  my $img = $class->new;
  $img->{IMG} = $result;

  return $img;
}


# general function to map an image through lookup tables

sub map {
  my ($self, %opts) = @_;
  my @chlist = qw( red green blue alpha );

  $self->_valid_image("map")
    or return;

  if (!exists($opts{'maps'})) {
    # make maps from channel maps
    my $chnum;
    for $chnum (0..$#chlist) {
      if (exists $opts{$chlist[$chnum]}) {
	$opts{'maps'}[$chnum] = $opts{$chlist[$chnum]};
      } elsif (exists $opts{'all'}) {
	$opts{'maps'}[$chnum] = $opts{'all'};
      }
    }
  }
  if ($opts{'maps'} and $self->{IMG}) {
    i_map($self->{IMG}, $opts{'maps'} );
  }
  return $self;
}

sub difference {
  my ($self, %opts) = @_;

  $self->_valid_image("difference")
    or return;

  defined $opts{mindist} or $opts{mindist} = 0;

  defined $opts{other}
    or return $self->_set_error("No 'other' parameter supplied");
  unless ($opts{other}->_valid_image("difference")) {
    $self->_set_error($opts{other}->errstr . " (other image)");
    return;
  }

  my $result = Imager->new;
  $result->{IMG} = i_diff_image($self->{IMG}, $opts{other}{IMG}, 
                                $opts{mindist})
    or return $self->_set_error($self->_error_as_msg());

  return $result;
}

sub rgb_difference {
  my ($self, %opts) = @_;

  $self->_valid_image("rgb_difference")
    or return;

  defined $opts{other}
    or return $self->_set_error("No 'other' parameter supplied");
  unless ($opts{other}->_valid_image("rgb_difference")) {
    $self->_set_error($opts{other}->errstr . " (other image)");
    return;
  }

  my $result = Imager->new;
  $result->{IMG} = i_rgbdiff_image($self->{IMG}, $opts{other}{IMG})
    or return $self->_set_error($self->_error_as_msg());

  return $result;
}

# destructive border - image is shrunk by one pixel all around

sub border {
  my ($self,%opts)=@_;
  my($tx,$ty)=($self->getwidth()-1,$self->getheight()-1);
  $self->polyline('x'=>[0,$tx,$tx,0,0],'y'=>[0,0,$ty,$ty,0],%opts);
}


# Get the width of an image

sub getwidth {
  my $self = shift;

  $self->_valid_image("getwidth")
    or return;

  return i_img_get_width($self->{IMG});
}

# Get the height of an image

sub getheight {
  my $self = shift;

  $self->_valid_image("getheight")
    or return;

  return i_img_get_height($self->{IMG});