[imager.git] / Imager.pm

package Imager;

use strict;
use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS %formats $DEBUG %filters %DSOs $ERRSTR $fontstate %OPCODES $I2P $FORMATGUESS $warn_obsolete);
use IO::File;

use Imager::Color;
use Imager::Font;

@EXPORT_OK = qw(
		init
		init_log
		DSO_open
		DSO_close
		DSO_funclist
		DSO_call

		load_plugin
		unload_plugin

		i_list_formats
		i_has_format

		i_color_new
		i_color_set
		i_color_info

		i_img_empty
		i_img_empty_ch
		i_img_exorcise
		i_img_destroy

		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_init_fonts
		i_t1_new
		i_t1_destroy
		i_t1_set_aa
		i_t1_cp
		i_t1_text
		i_t1_bbox

		i_tt_set_aa
		i_tt_cp
		i_tt_text
		i_tt_bbox

		i_readjpeg_wiol
		i_writejpeg_wiol

		i_readtiff_wiol
		i_writetiff_wiol
		i_writetiff_wiol_faxable

		i_readpng_wiol
		i_writepng_wiol

		i_readgif
		i_readgif_wiol
		i_readgif_callback
		i_writegif
		i_writegifmc
		i_writegif_gen
		i_writegif_callback

		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
);

@EXPORT=qw(
	   init_log
	   i_list_formats
	   i_has_format
	   malloc_state
	   i_color_new

	   i_img_empty
	   i_img_empty_ch
	  );

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

BEGIN {
  require Exporter;
  require DynaLoader;

  $VERSION = '0.41';
  @ISA = qw(Exporter DynaLoader);
  bootstrap Imager $VERSION;
}

BEGIN {
  i_init_fonts(); # Initialize font engines
  Imager::Font::__init();
  for(i_list_formats()) { $formats{$_}++; }

  if ($formats{'t1'}) {
    i_t1_set_aa(1);
  }

  if (!$formats{'t1'} and !$formats{'tt'} 
      && !$formats{'ft2'} && !$formats{'w32'}) {
    $fontstate='no font support';
  }

  %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}); }
			};

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

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

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

  $filters{nearest_color} ={
			    callseq => ['image', 'xo', 'yo', 'colors', 'dist'],
			    defaults => { },
			    callsub => sub { my %hsh=@_; i_nearest_color($hsh{image}, $hsh{xo}, $hsh{yo}, $hsh{colors}, $hsh{dist}); }
			   };
  $filters{gaussian} = {
                        callseq => [ 'image', 'stddev' ],
                        defaults => { },
                        callsub => sub { my %hsh = @_; i_gaussian($hsh{image}, $hsh{stddev}); },
                       };
  $filters{mosaic} =
    {
     callseq => [ qw(image size) ],
     defaults => { size => 20 },
     callsub => sub { my %hsh = @_; i_mosaic($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});
     },
    };
  $filters{bumpmap_complex} =
    {
     callseq => [ qw(image bump channel tx ty Lx Ly Lz cd cs n Ia Il Is) ],
     defaults => {
		  channel => 0,
		  tx => 0,
		  ty => 0,
		  Lx => 0.2,
		  Ly => 0.4,
		  Lz => -1.0,
		  cd => 1.0,
		  cs => 40,
		  n => 1.3,
		  Ia => Imager::Color->new(rgb=>[0,0,0]),
		  Il => Imager::Color->new(rgb=>[255,255,255]),
		  Is => Imager::Color->new(rgb=>[255,255,255]),
		 },
     callsub => sub {
       my %hsh = @_;
       i_bumpmap_complex($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,
                                Imager::Color->new(0,0,0),
                                Imager::Color->new(255, 255, 255),
                                0, 0,
                              ],
                             ],
                 },
     callsub  => 
     sub {
       my %hsh = @_;
       i_fountain($hsh{image}, $hsh{xa}, $hsh{ya}, $hsh{xb}, $hsh{yb},
                  $hsh{ftype}, $hsh{repeat}, $hsh{combine}, $hsh{super_sample},
                  $hsh{ssample_param}, $hsh{segments});
     },
    };
  $filters{unsharpmask} =
    {
     callseq => [ qw(image stddev scale) ],
     defaults => { stddev=>2.0, scale=>1.0 },
     callsub => 
     sub { 
       my %hsh = @_;
       i_unsharp_mask($hsh{image}, $hsh{stddev}, $hsh{scale});
     },
    };

  $FORMATGUESS=\&def_guess_type;

  $warn_obsolete = 1;
}

#
# Non methods
#

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

#sub import {
#  my $pack = shift;
#  (look through @_ for special tags, process, and remove them);   
#  use Data::Dumper;
#  print Dumper($pack);
#  print Dumper(@_);
#}

sub init_log {
	m_init_log($_[0],$_[1]);
	log_entry("Imager $VERSION starting\n", 1);
}


sub init {
  my %parms=(loglevel=>1,@_);
  if ($parms{'log'}) {
    init_log($parms{'log'},$parms{'loglevel'});
  }

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

#    if ($parms{T1LIB_CONFIG}) { $ENV{T1LIB_CONFIG}=$parms{T1LIB_CONFIG}; }
#    if ( $ENV{T1LIB_CONFIG} and ( $fontstate eq 'missing conf' )) {
#	i_init_fonts();
#	$fontstate='ok';
#    }
  if (exists $parms{'t1log'}) {
    i_init_fonts($parms{'t1log'});
  }
}

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 

sub load_plugin {
  my ($filename)=@_;
  my $i;
  my ($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 (!$DSOs{$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\(/) {
        if (grep $_ > 1, @$arg) {
          $result = Imager::Color->new(@$arg);
        }
        else {
          $result = Imager::Color::Float->new(@$arg);
        }
      }
      else {
        $Imager::ERRSTR = "Not a color";
      }
    }
  }
  else {
    # assume Imager::Color::new knows how to handle it
    $result = Imager::Color->new($arg);
  }

  return $result;
}


#
# 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;
  $self->{DEBUG} && print "Initialized Imager\n";
  if ($hsh{xsize} && $hsh{ysize}) { $self->img_set(%hsh); }
  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 $self = shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }

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

# Paste a region

sub paste {
  my $self = shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  my %input=(left=>0, top=>0, @_);
  unless($input{img}) {
    $self->{ERRSTR}="no source image";
    return;
  }
  $input{left}=0 if $input{left} <= 0;
  $input{top}=0 if $input{top} <= 0;
  my $src=$input{img};
  my($r,$b)=i_img_info($src->{IMG});

  i_copyto($self->{IMG}, $src->{IMG}, 
	   0,0, $r, $b, $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 $self=shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  my %hsh=(left=>0,right=>$self->getwidth(),top=>0,bottom=>$self->getheight(),@_);

  my ($w,$h,$l,$r,$b,$t)=($self->getwidth(),$self->getheight(),
				@hsh{qw(left right bottom top)});
  $l=0 if not defined $l;
  $t=0 if not defined $t;

  $r||=$l+delete $hsh{'width'}    if defined $l and exists $hsh{'width'};
  $b||=$t+delete $hsh{'height'}   if defined $t and exists $hsh{'height'};
  $l||=$r-delete $hsh{'width'}    if defined $r and exists $hsh{'width'};
  $t||=$b-delete $hsh{'height'}   if defined $b and exists $hsh{'height'};

  $r=$self->getwidth if not defined $r;
  $b=$self->getheight if not defined $b;

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

  if ($hsh{'width'}) {
    $l=int(0.5+($w-$hsh{'width'})/2);
    $r=$l+$hsh{'width'};
  } else {
    $hsh{'width'}=$r-$l;
  }
  if ($hsh{'height'}) {
    $b=int(0.5+($h-$hsh{'height'})/2);
    $t=$h+$hsh{'height'};
  } else {
    $hsh{'height'}=$b-$t;
  }

#    print "l=$l, r=$r, h=$hsh{'width'}\n";
#    print "t=$t, b=$b, w=$hsh{'height'}\n";

  my $dst=Imager->new(xsize=>$hsh{'width'}, ysize=>$hsh{'height'}, channels=>$self->getchannels());

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

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

sub img_set {
  my $self=shift;

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

  if (defined($self->{IMG})) {
    # let IIM_DESTROY destroy it, it's possible this image is
    # referenced from a virtual image (like masked)
    #i_img_destroy($self->{IMG});
    undef($self->{IMG});
  }

  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 {
    $self->{IMG}=Imager::ImgRaw::new($hsh{'xsize'}, $hsh{'ysize'},
                                     $hsh{'channels'});
  }
}

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

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

  $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;
  }

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

  #print "Type ", i_img_type($result->{IMG}), "\n";

  $result->{IMG} or undef $result;

  return $result;
}

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

  if ($self->{IMG}) {
    $result = Imager->new;
    $result->{IMG} = i_img_to_rgb($self->{IMG})
      or undef $result;
  }

  return $result;
}

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

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

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

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

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

sub getcolors {
  my $self = shift;
  my %opts = @_;
  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;
  }
  
  $self->{IMG} and 
    return i_getcolors($self->{IMG}, $opts{start}, $opts{count});
}

sub colorcount {
  i_colorcount($_[0]{IMG});
}

sub maxcolors {
  i_maxcolors($_[0]{IMG});
}

sub findcolor {
  my $self = shift;
  my %opts = @_;
  $opts{color} or return undef;

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

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

sub type {
  my $self = shift;
  if ($self->{IMG}) {
    return i_img_type($self->{IMG}) ? "paletted" : "direct";
  }
}

sub virtual {
  my $self = shift;
  $self->{IMG} and i_img_virtual($self->{IMG});
}

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

  $self->{IMG} 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 = @_;

  return -1 unless $self->{IMG};
  if ($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 = @_;

  return 0 unless $self->{IMG};

  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) = @_;

  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}) {
    my $fd = fileno($input->{fh});
    unless ($fd) {
      $self->_set_error("Handle in fh option not opened");
      return;
    }
    return io_new_fd($fd);
  }
  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, $type) = @_;

  if ($input->{fd}) {
    return io_new_fd($input->{fd});
  }
  elsif ($input->{fh}) {
    my $fd = fileno($input->{fh});
    unless ($fd) {
      $self->_set_error("Handle in fh option not opened");
      return;
    }
    # flush it
    my $oldfh = select($input->{fh});
    # flush anything that's buffered, and make sure anything else is flushed
    $| = 1;
    select($oldfh);
    return io_new_fd($fd);
  }
  elsif ($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;
    return (io_new_fd(fileno($fh)), $fh);
  }
  elsif ($input->{data}) {
    return io_new_bufchain();
  }
  elsif ($input->{callback} || $input->{writecb}) {
    if ($input->{maxbuffer}) {
      return io_new_cb($input->{callback} || $input->{writecb},
                       $input->{readcb},
                       $input->{seekcb}, $input->{closecb},
                       $input->{maxbuffer});
    }
    else {
      return io_new_cb($input->{callback} || $input->{writecb},
                       $input->{readcb},
                       $input->{seekcb}, $input->{closecb});
    }
  }
  else {
    $self->_set_error("file/fd/fh/data/callback parameter missing");
    return;
  }
}

# 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});
  }

  # FIXME: Find the format here if not specified
  # yes the code isn't here yet - next week maybe?
  # Next week?  Are you high or something?  That comment
  # has been there for half a year dude.
  # Look, i just work here, ok?

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

  unless ($input{'type'}) {
		$input{'type'} = i_test_format_probe($IO, -1);
	}

  unless ($input{'type'}) {
	  $self->_set_error('type parameter missing and not possible to guess from extension'); 
    return undef;
  }

  # Setup data source
  if ( $input{'type'} eq 'jpeg' ) {
    ($self->{IMG},$self->{IPTCRAW}) = i_readjpeg_wiol( $IO );
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}='unable to read jpeg image'; return undef;
    }
    $self->{DEBUG} && print "loading a jpeg file\n";
    return $self;
  }

  if ( $input{'type'} eq 'tiff' ) {
    $self->{IMG}=i_readtiff_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 tiff file\n";
    return $self;
  }

  if ( $input{'type'} eq 'pnm' ) {
    $self->{IMG}=i_readpnm_wiol( $IO, -1 ); # Fixme, check if that length parameter is ever needed
    if ( !defined($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 ( $input{'type'} eq 'png' ) {
    $self->{IMG}=i_readpng_wiol( $IO, -1 ); # Fixme, check if that length parameter is ever needed
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}='unable to read png image';
      return undef;
    }
    $self->{DEBUG} && print "loading a png file\n";
  }

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

  if ( $input{'type'} eq 'gif' ) {
    if ($input{colors} && !ref($input{colors})) {
      # must be a reference to a scalar that accepts the colour map
      $self->{ERRSTR} = "option 'colors' must be a scalar reference";
      return undef;
    }
    if ($input{colors}) {
      my $colors;
      ($self->{IMG}, $colors) =i_readgif_wiol( $IO );
      if ($colors) {
	${ $input{colors} } = [ map { NC(@$_) } @$colors ];
      }
    }
    else {
      $self->{IMG} =i_readgif_wiol( $IO );
    }
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}=$self->_error_as_msg();
      return undef;
    }
    $self->{DEBUG} && print "loading a gif file\n";
  }

  if ( $input{'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 ( $input{'type'} eq 'rgb' ) {
    $self->{IMG}=i_readrgb_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 ( $input{'type'} eq 'raw' ) {
    my %params=(datachannels=>3,storechannels=>3,interleave=>1,%input);

    if ( !($params{xsize} && $params{ysize}) ) {
      $self->{ERRSTR}='missing xsize or ysize parameter for raw';
      return undef;
    }

    $self->{IMG} = i_readraw_wiol( $IO,
				   $params{xsize},
				   $params{ysize},
				   $params{datachannels},
				   $params{storechannels},
				   $params{interleave});
    if ( !defined($self->{IMG}) ) {
      $self->{ERRSTR}='unable to read raw image';
      return undef;
    }
    $self->{DEBUG} && print "loading a raw file\n";
  }

  return $self;
}

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',
  );

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

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

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

  if (!$formats{$input{'type'}}) { $self->{ERRSTR}='format not supported'; return undef; }

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

  if ($input{'type'} eq 'tiff') {
    $self->_set_opts(\%input, "tiff_", $self)
      or return undef;
    $self->_set_opts(\%input, "exif_", $self)
      or return undef;

    if (defined $input{class} && $input{class} eq 'fax') {
      if (!i_writetiff_wiol_faxable($self->{IMG}, $IO, $input{fax_fine})) {
	$self->{ERRSTR}='Could not write to buffer';
	return undef;
      }
    } else {
      if (!i_writetiff_wiol($self->{IMG}, $IO)) {
	$self->{ERRSTR}='Could not write to buffer';
	return undef;
      }
    }
  } elsif ( $input{'type'} eq 'pnm' ) {
    $self->_set_opts(\%input, "pnm_", $self)
      or return undef;
    if ( ! i_writeppm_wiol($self->{IMG},$IO) ) {
      $self->{ERRSTR}='unable to write pnm image';
      return undef;
    }
    $self->{DEBUG} && print "writing a pnm file\n";
  } elsif ( $input{'type'} eq 'raw' ) {
    $self->_set_opts(\%input, "raw_", $self)
      or return undef;
    if ( !i_writeraw_wiol($self->{IMG},$IO) ) {
      $self->{ERRSTR}='unable to write raw image';
      return undef;
    }
    $self->{DEBUG} && print "writing a raw file\n";
  } elsif ( $input{'type'} eq 'png' ) {
    $self->_set_opts(\%input, "png_", $self)
      or return undef;
    if ( !i_writepng_wiol($self->{IMG}, $IO) ) {
      $self->{ERRSTR}='unable to write png image';
      return undef;
    }
    $self->{DEBUG} && print "writing a png file\n";
  } elsif ( $input{'type'} eq 'jpeg' ) {
    $self->_set_opts(\%input, "jpeg_", $self)
      or return undef;
    $self->_set_opts(\%input, "exif_", $self)
      or return undef;
    if ( !i_writejpeg_wiol($self->{IMG}, $IO, $input{jpegquality})) {
      $self->{ERRSTR} = $self->_error_as_msg();
      return undef;
    }
    $self->{DEBUG} && print "writing a jpeg file\n";
  } elsif ( $input{'type'} eq 'bmp' ) {
    $self->_set_opts(\%input, "bmp_", $self)
      or return undef;
    if ( !i_writebmp_wiol($self->{IMG}, $IO) ) {
      $self->{ERRSTR}='unable to write bmp image';
      return undef;
    }
    $self->{DEBUG} && print "writing a bmp file\n";
  } elsif ( $input{'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";
  } elsif ( $input{'type'} eq 'gif' ) {
    $self->_set_opts(\%input, "gif_", $self)
      or return undef;
    # compatibility with the old interfaces
    if ($input{gifquant} eq 'lm') {
      $input{make_colors} = 'addi';
      $input{translate} = 'perturb';
      $input{perturb} = $input{lmdither};
    } elsif ($input{gifquant} eq 'gen') {
      # just pass options through
    } else {
      $input{make_colors} = 'webmap'; # ignored
      $input{translate} = 'giflib';
    }
    $rc = i_writegif_wiol($IO, \%input, $self->{IMG});
  }

  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) = @_;

  if (!$opts->{'type'} && $opts->{'file'}) {
    $opts->{'type'} = $FORMATGUESS->($opts->{'file'});
  }
  unless ($opts->{'type'}) {
    $class->_set_error('type parameter missing and not possible to guess from extension');
    return;
  }
  # translate to ImgRaw
  if (grep !UNIVERSAL::isa($_, 'Imager') || !$_->{IMG}, @images) {
    $class->_set_error('Usage: Imager->write_multi({ options }, @images)');
    return 0;
  }
  $class->_set_opts($opts, "i_", @images)
    or return;
  my @work = map $_->{IMG}, @images;
  my ($IO, $file) = $class->_get_writer_io($opts, $opts->{'type'})
    or return undef;
  if ($opts->{'type'} eq 'gif') {
    $class->_set_opts($opts, "gif_", @images)
      or return;
    my $gif_delays = $opts->{gif_delays};
    local $opts->{gif_delays} = $gif_delays;
    if ($opts->{gif_delays} && !ref $opts->{gif_delays}) {
      # assume the caller wants the same delay for each frame
      $opts->{gif_delays} = [ ($gif_delays) x @images ];
    }
    my $res = i_writegif_wiol($IO, $opts, @work);
    $res or $class->_set_error($class->_error_as_msg());
    return $res;
  }
  elsif ($opts->{'type'} eq 'tiff') {
    $class->_set_opts($opts, "tiff_", @images)
      or return;
    $class->_set_opts($opts, "exif_", @images)
      or return;
    my $res;
    $opts->{fax_fine} = 1 unless exists $opts->{fax_fine};
    if ($opts->{'class'} && $opts->{'class'} eq 'fax') {
      $res = i_writetiff_multi_wiol_faxable($IO, $opts->{fax_fine}, @work);
    }
    else {
      $res = i_writetiff_multi_wiol($IO, @work);
    }
    $res or $class->_set_error($class->_error_as_msg());
    return $res;
  }
  else {
    $ERRSTR = "Sorry, write_multi doesn't support $opts->{'type'} yet";
    return 0;
  }
}

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

  if ($opts{file} && !exists $opts{'type'}) {
    # guess the type 
    my $type = $FORMATGUESS->($opts{file});
    $opts{'type'} = $type;
  }
  unless ($opts{'type'}) {
    $ERRSTR = "No type parameter supplied and it couldn't be guessed";
    return;
  }

  my ($IO, $file) = $class->_get_reader_io(\%opts, $opts{'type'})
    or return;
  if ($opts{'type'} eq 'gif') {
    my @imgs;
    @imgs = i_readgif_multi_wiol($IO);
    if (@imgs) {
      return map { 
        bless { IMG=>$_, DEBUG=>$DEBUG, ERRSTR=>undef }, 'Imager' 
      } @imgs;
    }
    else {
      $ERRSTR = _error_as_msg();
      return;
    }
  }
  elsif ($opts{'type'} eq 'tiff') {
    my @imgs = i_readtiff_multi_wiol($IO, -1);
    if (@imgs) {
      return map { 
        bless { IMG=>$_, DEBUG=>$DEBUG, ERRSTR=>undef }, 'Imager' 
      } @imgs;
    }
    else {
      $ERRSTR = _error_as_msg();
      return;
    }
  }

  $ERRSTR = "Cannot read multiple images from $opts{'type'} files";
  return;
}

# 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 $self=shift;
  my %input=@_;
  my %hsh;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }

  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',$self->{IMG},%{$filters{$input{'type'}}{defaults}},%input);
  } else {
    %hsh=('image',$self->{IMG},%input);
  }

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

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

  &{$filters{$input{'type'}}{callsub}}(%hsh);

  my @b=keys %hsh;

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

  return $self;
}

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

sub scale {
  my $self=shift;
  my %opts=(scalefactor=>0.5,'type'=>'max',qtype=>'normal',@_);
  my $img = Imager->new();
  my $tmp = Imager->new();

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

  if ($opts{xpixels} and $opts{ypixels} and $opts{'type'}) {
    my ($xpix,$ypix)=( $opts{xpixels}/$self->getwidth() , $opts{ypixels}/$self->getheight() );
    if ($opts{'type'} eq 'min') { $opts{scalefactor}=min($xpix,$ypix); }
    if ($opts{'type'} eq 'max') { $opts{scalefactor}=max($xpix,$ypix); }
  } elsif ($opts{xpixels}) { $opts{scalefactor}=$opts{xpixels}/$self->getwidth(); }
  elsif ($opts{ypixels}) { $opts{scalefactor}=$opts{ypixels}/$self->getheight(); }

  if ($opts{qtype} eq 'normal') {
    $tmp->{IMG}=i_scaleaxis($self->{IMG},$opts{scalefactor},0);
    if ( !defined($tmp->{IMG}) ) { $self->{ERRSTR}='unable to scale image'; return undef; }
    $img->{IMG}=i_scaleaxis($tmp->{IMG},$opts{scalefactor},1);
    if ( !defined($img->{IMG}) ) { $self->{ERRSTR}='unable to scale image'; return undef; }
    return $img;
  }
  if ($opts{'qtype'} eq 'preview') {
    $img->{IMG}=i_scale_nn($self->{IMG},$opts{'scalefactor'},$opts{'scalefactor'}); 
    if ( !defined($img->{IMG}) ) { $self->{ERRSTR}='unable to scale image'; return undef; }
    return $img;
  }
  $self->{ERRSTR}='scale: invalid value for qtype'; return undef;
}

# Scales only along the X axis

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

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

  my $img = Imager->new();

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

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

  my $img = Imager->new();

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

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

sub transform {
  my $self=shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  my %opts=@_;
  my (@op,@ropx,@ropy,$iop,$or,@parm,$expr,@xt,@yt,@pt,$numre);

#  print Dumper(\%opts);
#  xopcopdes

  if ( $opts{'xexpr'} and $opts{'yexpr'} ) {
    if (!$I2P) {
      eval ("use Affix::Infix2Postfix;");
      print $@;
      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) {
    $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 $img = Imager->new();
  $img->{IMG} = i_transform2($opts->{width}, $opts->{height}, $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=(tx=>0,ty=>0,@_);

  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  unless ($opts{src} && $opts{src}->{IMG}) { $self->{ERRSTR}='empty input image for source'; return undef; }

  unless (i_rubthru($self->{IMG}, $opts{src}->{IMG}, $opts{tx},$opts{ty})) {
    $self->{ERRSTR} = $self->_error_as_msg();
    return undef;
  }
  return $self;
}


sub flip {
  my $self  = shift;
  my %opts  = @_;
  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 = @_;
  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} * 3.1415926535 / 180;

    my $result = Imager->new;
    if ($result->{IMG} = i_rotate_exact($self->{IMG}, $amount)) {
      return $result;
    }
    else {
      $self->{ERRSTR} = $self->_error_as_msg();
      return undef;
    }
  }
  else {
    $self->{ERRSTR} = "Only the 'right' parameter is available";
    return undef;
  }
}

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

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

    my $result = Imager->new;
    $result->{IMG} = i_matrix_transform($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 $self=shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  my $dflcl=i_color_new(255,255,255,255);
  my %opts=(color=>$dflcl,xmin=>0,ymin=>0,xmax=>$self->getwidth()-1,ymax=>$self->getheight()-1,@_);

  if (exists $opts{'box'}) { 
    $opts{'xmin'} = min($opts{'box'}->[0],$opts{'box'}->[2]);
    $opts{'xmax'} = max($opts{'box'}->[0],$opts{'box'}->[2]);
    $opts{'ymin'} = min($opts{'box'}->[1],$opts{'box'}->[3]);
    $opts{'ymax'} = max($opts{'box'}->[1],$opts{'box'}->[3]);
  }

  if ($opts{filled}) { 
    my $color = _color($opts{'color'});
    unless ($color) { 
      $self->{ERRSTR} = $Imager::ERRSTR; 
      return; 
    }
    i_box_filled($self->{IMG},$opts{xmin},$opts{ymin},$opts{xmax},
                 $opts{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} = $Imager::ERRSTR;
        return undef;
      }
    }
    i_box_cfill($self->{IMG},$opts{xmin},$opts{ymin},$opts{xmax},
                $opts{ymax},$opts{fill}{fill});
  }
  else {
    my $color = _color($opts{'color'});
    unless ($color) { 
      $self->{ERRSTR} = $Imager::ERRSTR;
      return;
    }
    i_box($self->{IMG},$opts{xmin},$opts{ymin},$opts{xmax},$opts{ymax},
          $color);
  }
  return $self;
}

# Draws an arc - this routine SUCKS and is buggy - it sometimes doesn't work when the arc is a convex polygon

sub arc {
  my $self=shift;
  unless ($self->{IMG}) { $self->{ERRSTR}='empty input image'; return undef; }
  my $dflcl=i_color_new(255,255,255,255);
  my %opts=(color=>$dflcl,
	    'r'=>min($self->getwidth(),$self->getheight())/3,
	    'x'=>$self->getwidth()/2,
	    'y'=>$self->getheight()/2,
	    'd1'=>0, 'd2'=>361, @_);
  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{d1} == 0 && $opts{d2} == 361 && $opts{aa}) {
      i_circle_aa($self->{IMG}, $opts{'x'}, $opts{'y'}, $opts{'r'}, 
                  $color);
    }
    else {
      if ($opts{'d1'} <= $opts{'d2'}) { 
        i_arc($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},
              $opts{'d1'}, $opts{'d2'}, $color); 
      }
      else {
        i_arc($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},
              $opts{'d1'}, 361,         $color);
        i_arc($self->{IMG},$opts{'x'},$opts{'y'},$opts{'r'},
              0,           $opts{'d2'}, $color); 
      }
    }
  }

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

  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,@_);

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

  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, @_);

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

  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;
  }

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

  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,@_);

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

  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;

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

  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) { $self; } else { $self->{ERRSTR} = $self->_error_as_msg(); return (); }
}

sub setpixel {
  my $self = shift;

  my %opts = ( color=>$self->{fg} || NC(255, 255, 255), @_);

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

  my $x = $opts{'x'};
  my $y = $opts{'y'};
  my $color = _color($opts{color})
    or return undef;
  if (ref $x && ref $y) {
    unless (@$x == @$y) {
      $self->{ERRSTR} = 'length of x and y mismatch';
      return undef;
    }
    if ($color->isa('Imager::Color')) {
      for my $i (0..$#{$opts{'x'}}) {
        i_ppix($self->{IMG}, $x->[$i], $y->[$i], $color);
      }
    }
    else {
      for my $i (0..$#{$opts{'x'}}) {
        i_ppixf($self->{IMG}, $x->[$i], $y->[$i], $color);
      }
    }
  }
  else {
    if ($color->isa('Imager::Color')) {
      i_ppix($self->{IMG}, $x, $y, $color);
    }
    else {
      i_ppixf($self->{IMG}, $x, $y, $color);
    }
  }

  $self;
}

sub getpixel {
  my $self = shift;

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

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

  my $x = $opts{'x'};
  my $y = $opts{'y'};
  if (ref $x && ref $y) {
    unless (@$x == @$y) {
      $self->{ERRSTR} = 'length of x and y mismatch';
      return undef;
    }
    my @result;
    if ($opts{"type"} eq '8bit') {
      for my $i (0..$#{$opts{'x'}}) {
        push(@result, i_get_pixel($self->{IMG}, $x->[$i], $y->[$i]));
      }
    }
    else {
      for my $i (0..$#{$opts{'x'}}) {
        push(@result, i_gpixf($self->{IMG}, $x->[$i], $y->[$i]));
      }
    }
    return wantarray ? @result : \@result;
  }
  else {
    if ($opts{"type"} eq '8bit') {
      return i_get_pixel($self->{IMG}, $x, $y);
    }
    else {
      return i_gpixf($self->{IMG}, $x, $y);
    }
  }

  $self;
}

# 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;

  # 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();
  $new->{IMG} = i_img_new();
  unless (i_convert($new->{IMG}, $self->{IMG}, $matrix)) {
    # most likely a bad matrix
    $self->{ERRSTR} = _error_as_msg();
    return undef;
  }
  return $new;
}


# general function to map an image through lookup tables

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

  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) = @_;

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

  defined $opts{other}
    or return $self->_set_error("No 'other' parameter supplied");
  defined $opts{other}{IMG}
    or return $self->_set_error("No image data in 'other' image");

  $self->{IMG}
    or return $self->_set_error("No image data");

  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;
}

# 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 $self = shift;
  if (!defined($self->{IMG})) { $self->{ERRSTR} = 'image is empty'; return undef; }
  return (i_img_info($self->{IMG}))[0];
}

# Get the height of an image

sub getheight {
  my $self = shift;
  if (!defined($self->{IMG})) { $self->{ERRSTR} = 'image is empty'; return undef; }
  return (i_img_info($self->{IMG}))[1];
}

# Get number of channels in an image

sub getchannels {
  my $self = shift;
  if (!defined($self->{IMG})) { $self->{ERRSTR} = 'image is empty'; return undef; }
  return i_img_getchannels($self->{IMG});
}

# Get channel mask

sub getmask {
  my $self = shift;
  if (!defined($self->{IMG})) { $self->{ERRSTR} = 'image is empty'; return undef; }
  return i_img_getmask($self->{IMG});
}

# Set channel mask

sub setmask {
  my $self = shift;
  my %opts = @_;
  if (!defined($self->{IMG})) { $self->{ERRSTR} = 'image is empty'; return undef; }
  i_img_setmask( $self->{IMG} , $opts{mask} );
}

# Get number of colors in an image

sub getcolorcount {
  my $self=shift;
  my %opts=('maxcolors'=>2**30,@_);
  if (!defined($self->{IMG})) { $self->{ERRSTR}='image is empty'; return undef; }
  my $rc=i_count_colors($self->{IMG},$opts{'maxcolors'});
  return ($rc==-1? undef : $rc);
}

# draw string to an image

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

  my %input=('x'=>0, 'y'=>0, @_);
  $input{string}||=$input{text};

  unless(exists $input{string}) {
    $self->{ERRSTR}="missing required parameter 'string'";
    return;
  }

  unless($input{font}) {
    $self->{ERRSTR}="missing required parameter 'font'";
    return;
  }

  unless ($input{font}->draw(image=>$self, %input)) {
    $self->{ERRSTR} = $self->_error_as_msg();
    return;
  }

  return $self;
}

# Shortcuts that can be exported

sub newcolor { Imager::Color->new(@_); }
sub newfont  { Imager::Font->new(@_); }

*NC=*newcolour=*newcolor;
*NF=*newfont;

*open=\&read;
*circle=\&arc;


#### Utility routines

sub errstr { 
  ref $_[0] ? $_[0]->{ERRSTR} : $ERRSTR
}

sub _set_error {
  my ($self, $msg) = @_;

  if (ref $self) {
    $self->{ERRSTR} = $msg;
  }
  else {
    $ERRSTR = $msg;
  }
  return;
}

# Default guess for the type of an image from extension

sub def_guess_type {
  my $name=lc(shift);
  my $ext;
  $ext=($name =~ m/\.([^\.]+)$/)[0];
  return 'tiff' if ($ext =~ m/^tiff?$/);
  return 'jpeg' if ($ext =~ m/^jpe?g$/);
  return 'pnm'  if ($ext =~ m/^p[pgb]m$/);
  return 'png'  if ($ext eq "png");
  return 'bmp'  if ($ext eq "bmp" || $ext eq "dib");
  return 'tga'  if ($ext eq "tga");
  return 'rgb'  if ($ext eq "rgb");
  return 'gif'  if ($ext eq "gif");
  return 'raw'  if ($ext eq "raw");
  return ();
}

# get the minimum of a list

sub min {
  my $mx=shift;
  for(@_) { if ($_<$mx) { $mx=$_; }}
  return $mx;
}

# get the maximum of a list

sub max {
  my $mx=shift;
  for(@_) { if ($_>$mx) { $mx=$_; }}
  return $mx;
}

# string stuff for iptc headers

sub clean {
  my($str)=$_[0];
  $str = substr($str,3);
  $str =~ s/[\n\r]//g;
  $str =~ s/\s+/ /g;
  $str =~ s/^\s//;
  $str =~ s/\s$//;
  return $str;
}

# A little hack to parse iptc headers.

sub parseiptc {
  my $self=shift;
  my(@sar,$item,@ar);
  my($caption,$photogr,$headln,$credit);

  my $str=$self->{IPTCRAW};

  #print $str;

  @ar=split(/8BIM/,$str);

  my $i=0;
  foreach (@ar) {
    if (/^\004\004/) {
      @sar=split(/\034\002/);
      foreach $item (@sar) {
	if ($item =~ m/^x/) {
	  $caption=&clean($item);
	  $i++;
	}
	if ($item =~ m/^P/) {
	  $photogr=&clean($item);
	  $i++;
	}
	if ($item =~ m/^i/) {
	  $headln=&clean($item);
	  $i++;
	}
	if ($item =~ m/^n/) {
	  $credit=&clean($item);
	  $i++;
	}
      }
    }
  }
  return (caption=>$caption,photogr=>$photogr,headln=>$headln,credit=>$credit);
}

# Autoload methods go after =cut, and are processed by the autosplit program.

1;
__END__
# Below is the stub of documentation for your module. You better edit it!

=head1 NAME

Imager - Perl extension for Generating 24 bit Images

=head1 SYNOPSIS

  # Thumbnail example

  #!/usr/bin/perl -w
  use strict;
  use Imager;

  die "Usage: thumbmake.pl filename\n" if !-f $ARGV[0];
  my $file = shift;

  my $format;

  my $img = Imager->new();
  $img->open(file=>$file) or die $img->errstr();

  $file =~ s/\.[^.]*$//;

  # Create smaller version
  my $thumb = $img->scale(scalefactor=>.3);

  # Autostretch individual channels
  $thumb->filter(type=>'autolevels');

  # try to save in one of these formats
  SAVE:

  for $format ( qw( png gif jpg tiff ppm ) ) {
    # Check if given format is supported
    if ($Imager::formats{$format}) {
      $file.="_low.$format";
      print "Storing image as: $file\n";
      $thumb->write(file=>$file) or
        die $thumb->errstr;
      last SAVE;
    }
  }


=head1 DESCRIPTION

Imager is a module for creating and altering images.  It can read and
write various image formats, draw primitive shapes like lines,and
polygons, blend multiple images together in various ways, scale, crop,
render text and more.

=head2 Overview of documentation

=over

=item Imager

This document - Synopsis Example, Table of Contents and Overview.

=item Imager::ImageTypes

Basics of constructing image objects with C<new()>:
Direct type/virtual images, RGB(A)/paletted images, 8/16/double
bits/channel, color maps, channel masks, image tags, color
quantization.  Also discusses basic image information methods.

=item Imager::Files

IO interaction, reading/writing images, format specific tags.

=item Imager::Draw

Drawing Primitives, lines, boxes, circles, arcs, flood fill.

=item Imager::Color

Color specification.

=item Imager::Fill

Fill pattern specification.

=item Imager::Font

General font rendering, bounding boxes and font metrics.

=item Imager::Transformations

Copying, scaling, cropping, flipping, blending, pasting, convert and
map.

=item Imager::Engines

Programmable transformations through C<transform()>, C<transform2()>
and C<matrix_transform()>.

=item Imager::Filters

Filters, sharpen, blur, noise, convolve etc. and filter plugins.

=item Imager::Expr

Expressions for evaluation engine used by transform2().

=item Imager::Matrix2d

Helper class for affine transformations.

=item Imager::Fountain

Helper for making gradient profiles.

=back


=head2 Basic Overview

An Image object is created with C<$img = Imager-E<gt>new()>.
Examples:

  $img=Imager->new();                         # create empty image
  $img->open(file=>'lena.png',type=>'png') or # read image from file
     die $img->errstr();                      # give an explanation
                                              # if something failed

or if you want to create an empty image:

  $img=Imager->new(xsize=>400,ysize=>300,channels=>4);

This example creates a completely black image of width 400 and height
300 and 4 channels.

When an operation fails which can be directly associated with an image
the error message is stored can be retrieved with
C<$img-E<gt>errstr()>.

In cases where no image object is associated with an operation
C<$Imager::ERRSTR> is used to report errors not directly associated
with an image object.

The C<Imager-E<gt>new> method is described in detail in the 
Imager::ImageTypes manpage.

=head1 SUPPORT

You can ask for help, report bugs or express your undying love for
Imager on the Imager-devel mailing list.

To subscribe send a message with C<subscribe> in the body to:

   imager-devel+request@molar.is

or use the form at:

   http://www.molar.is/en/lists/imager-devel/
   (annonymous is temporarily off due to spam)

where you can also find the mailing list archive.

If you're into IRC, you can typically find the developers in #Imager
on irc.rhizomatic.net.  As with any IRC channel, the participants
could be occupied or asleep, so please be patient.

=head1 BUGS

Bugs are listed individually for relevant pod pages.

=head1 AUTHOR

Arnar M. Hrafnkelsson (addi@imager.perl.org) and Tony Cook
(tony@imager.perl.org) See the README for a complete list.

=head1 SEE ALSO

perl(1), Imager::ImageTypes(3), Imager::Files(3), Imager::Draw(3),
Imager::Color(3), Imager::Fill(3), Imager::Font(3),
Imager::Transformations(3), Imager::Engines(3), Imager::Filters(3),
Imager::Expr(3), Imager::Matrix2d(3), Imager::Fountain(3)

Affix::Infix2Postfix(3), Parse::RecDescent(3)
http://www.eecs.umich.edu/~addi/perl/Imager/

=cut