document DEFINE key in return value

[imager.git] / lib / Imager / Files.pod

diff --git a/lib/Imager/Files.pod b/lib/Imager/Files.pod
index 5db54f96bc211d76a95a4e15ad4e7a57fe07619a..244e850d3b06e63ebce5938f9f3a64a0634b2027 100644 (file)
--- a/lib/Imager/Files.pod
+++ b/lib/Imager/Files.pod
@@ -4,14 +4,24 @@ Imager::Files - working with image files
 
 =head1 SYNOPSIS
 
 
 =head1 SYNOPSIS
 

+  use Imager;

   my $img = ...;
   $img->write(file=>$filename, type=>$type)
     or die "Cannot write: ",$img->errstr;
 
   my $img = ...;
   $img->write(file=>$filename, type=>$type)
     or die "Cannot write: ",$img->errstr;
 

+  # type is optional if we can guess the format from the filename
+  $img->write(file => "foo.png")
+    or die "Cannot write: ",$img->errstr;
+

   $img = Imager->new;
   $img->read(file=>$filename, type=>$type)
     or die "Cannot read: ", $img->errstr;
 
   $img = Imager->new;
   $img->read(file=>$filename, type=>$type)
     or die "Cannot read: ", $img->errstr;
 

+  # type is optional if we can guess the type from the file data
+  # and we normally can guess
+  $img->read(file => $filename)
+    or die "Cannot read: ", $img->errstr;
+

   Imager->write_multi({ file=> $filename, ... }, @images)
     or die "Cannot write: ", Imager->errstr;
 
   Imager->write_multi({ file=> $filename, ... }, @images)
     or die "Cannot write: ", Imager->errstr;
 


@@ -20,6 +30,31 @@ Imager::Files - working with image files
 
   Imager->set_file_limits(width=>$max_width, height=>$max_height)
 
 
   Imager->set_file_limits(width=>$max_width, height=>$max_height)
 

+  my @read_types = Imager->read_types;
+  my @write_types = Imager->write_types;
+
+  # we can write/write_multi to things other than filenames
+  my $data;
+  $img->write(data => \$data, type => $type) or die;
+
+  my $fh = ... ; # eg. IO::File
+  $img->write(fh => $fh, type => $type) or die;
+
+  $img->write(fd => fileno($fh), type => $type) or die;
+
+  # some file types need seek callbacks too
+  $img->write(callback => \&write_callback, type => $type) or die;
+
+  # and similarly for read/read_multi
+  $img->read(data => $data) or die;
+  $img->read(fh => $fh) or die;
+  $img->read(fd => fileno($fh)) or die;
+  $img->read(callback => \&read_callback) or die;
+
+  use Imager 0.68;
+  my $img = Imager->new(file => $filename)
+    or die Imager->errstr;
+

 =head1 DESCRIPTION
 
 You can read and write a variety of images formats, assuming you have
 =head1 DESCRIPTION
 
 You can read and write a variety of images formats, assuming you have


@@ -33,7 +68,8 @@ code snippet is sufficient:
   print join " ", keys %Imager::formats;
 
 This will include some other information identifying libraries rather
   print join " ", keys %Imager::formats;
 
 This will include some other information identifying libraries rather

-than file formats.
+than file formats.  For new code you might find the L</read_types> or
+L</write_types> methods useful.

 
 =over 
 
 
 =over 
 


@@ -46,6 +82,24 @@ method to read an image:
   $img->read(file=>$filename, type=>$type)
     or die "Cannot read $filename: ", $img->errstr;
 
   $img->read(file=>$filename, type=>$type)
     or die "Cannot read $filename: ", $img->errstr;
 

+In most cases Imager can auto-detect the file type, so you can just
+supply the file name:
+
+  $img->read(file => $filename)
+    or die "Cannot read $filename: ", $img->errstr;
+
+The read() method accepts the C<allow_partial> parameter.  If this is
+non-zero then read() can return true on an incomplete image and set
+the C<i_incomplete> tag.
+
+From Imager 0.68 you can supply most read() parameters to the new()
+method to read the image file on creation.  If the read fails, check
+Imager->errstr() for the cause:
+
+  use Imager 0.68;
+  my $img = Imager->new(file => $filename)
+    or die "Cannot read $filename: ", Imager->errstr;
+

 =item write
 
 and the C<write()> method to write an image:
 =item write
 
 and the C<write()> method to write an image:


@@ -61,6 +115,9 @@ file, use the C<read_multi()> method:
   my @imgs = Imager->read_multi(file=>$filename, type=>$type)
     or die "Cannot read $filename: ", Imager->errstr;
 
   my @imgs = Imager->read_multi(file=>$filename, type=>$type)
     or die "Cannot read $filename: ", Imager->errstr;
 

+As with the read() method, Imager will normally detect the C<type>
+automatically.
+

 =item write_multi
 
 and if you want to write multiple images to a single file use the
 =item write_multi
 
 and if you want to write multiple images to a single file use the


@@ -69,12 +126,40 @@ C<write_multi()> method:
   Imager->write_multi({ file=> $filename, type=>$type }, @images)
     or die "Cannot write $filename: ", Imager->errstr;
 
   Imager->write_multi({ file=> $filename, type=>$type }, @images)
     or die "Cannot write $filename: ", Imager->errstr;
 

+=item read_types
+
+This is a class method that returns a list of the image file types
+that Imager can read.
+
+  my @types = Imager->read_types;
+
+These types are the possible values for the C<type> parameter, not
+necessarily the extension of the files you're reading.
+
+It is possible for extra file read handlers to be loaded when
+attempting to read a file, which may modify the list of available read
+types.
+
+=item write_types
+
+This is a class method that returns a list of the image file types
+that Imager can write.
+
+  my @types = Imager->write_types;
+
+Note that these are the possible values for the C<type> parameter, not
+necessarily the extension of the files you're writing.
+
+It is possible for extra file write handlers to be loaded when
+attempting to write a file, which may modify the list of available
+write types.
+

 =back
 
 =back
 

-If the I<filename> includes an extension that Imager recognizes, then
-you don't need the I<type>, but you may want to provide one anyway.
-See L</Guessing types> for information on controlling this
-recognition.
+When writing, if the C<filename> includes an extension that Imager
+recognizes, then you don't need the C<type>, but you may want to
+provide one anyway.  See L</Guessing types> for information on
+controlling this recognition.

 
 The C<type> parameter is a lowercase representation of the file type,
 and can be any of the following:
 
 The C<type> parameter is a lowercase representation of the file type,
 and can be any of the following:


@@ -85,7 +170,7 @@ and can be any of the following:
   png   Portable Network Graphics (PNG)
   pnm   Portable aNyMap (PNM)
   raw   Raw
   png   Portable Network Graphics (PNG)
   pnm   Portable aNyMap (PNM)
   raw   Raw

-  rgb   SGI .rgb files
+  sgi   SGI .rgb files

   tga   TARGA
   tiff  Tagged Image File Format (TIFF)
 
   tga   TARGA
   tiff  Tagged Image File Format (TIFF)
 


@@ -102,11 +187,11 @@ targets:
 
 =over
 
 
 =over
 

-=item file
+=item *

 
 

-The C<file> parameter is the name of the image file to be written to
-or read from.  If Imager recognizes the extension of the file you do
-not need to supply a C<type>.
+C<file> - The C<file> parameter is the name of the image file to be
+written to or read from.  If Imager recognizes the extension of the
+file you do not need to supply a C<type>.

 
   # write in tiff format
   $image->write(file => "example.tif")
 
   # write in tiff format
   $image->write(file => "example.tif")


@@ -119,9 +204,9 @@ not need to supply a C<type>.
   $image->read(file => 'example.tif')
     or die $image->errstr;
 
   $image->read(file => 'example.tif')
     or die $image->errstr;
 

-=item fh
+=item *

 
 

-C<fh> is a file handle, typically either returned from
+C<fh> - C<fh> is a file handle, typically either returned from

 C<<IO::File->new()>>, or a glob from an C<open> call.  You should call
 C<binmode> on the handle before passing it to Imager.
 
 C<<IO::File->new()>>, or a glob from an C<open> call.  You should call
 C<binmode> on the handle before passing it to Imager.
 


@@ -136,9 +221,9 @@ fileno()) rather than writing at the perl level.
   $image->read(fd => $cgi->param('file')) 
     or die $image->errstr;
 
   $image->read(fd => $cgi->param('file')) 
     or die $image->errstr;
 

-=item fd
+=item *

 
 

-C<fd> is a file descriptor.  You can get this by calling the
+C<fd> - C<fd> is a file descriptor.  You can get this by calling the

 C<fileno()> function on a file handle, or by using one of the standard
 file descriptor numbers.
 
 C<fileno()> function on a file handle, or by using one of the standard
 file descriptor numbers.
 


@@ -149,25 +234,26 @@ the image.
   $image->write(fd => file(STDOUT), type => 'gif')
     or die $image->errstr;
 
   $image->write(fd => file(STDOUT), type => 'gif')
     or die $image->errstr;
 

-=item data
+=item *

 
 

-When reading data, C<data> is a scalar containing the image file data,
-when writing, C<data> is a reference to the scalar to save the image
-file data too.  For GIF images you will need giflib 4 or higher, and
-you may need to patch giflib to use this option for writing.
+C<data> - When reading data, C<data> is a scalar containing the image
+file data, when writing, C<data> is a reference to the scalar to save
+the image file data too.  For GIF images you will need C<giflib> 4 or
+higher, and you may need to patch C<giflib> to use this option for
+writing.

 
   my $data;
   $image->write(data => \$data, type => 'tiff')
     or die $image->errstr;
 
   my $data = $row->{someblob}; # eg. from a database
 
   my $data;
   $image->write(data => \$data, type => 'tiff')
     or die $image->errstr;
 
   my $data = $row->{someblob}; # eg. from a database

-  $image->read(data => $data)
-    or die $image->errstr;
+  my @images = Imager->read_multi(data => $data)
+    or die Imager->errstr;

 
 

-=item callback
+=item *

 
 

-Imager will make calls back to your supplied coderefs to read, write
-and seek from/to/through the image file.
+C<callback> - Imager will make calls back to your supplied coderefs to
+read, write and seek from/to/through the image file.

 
 When reading from a file you can use either C<callback> or C<readcb>
 to supply the read callback, and when writing C<callback> or
 
 When reading from a file you can use either C<callback> or C<readcb>
 to supply the read callback, and when writing C<callback> or


@@ -201,8 +287,8 @@ buffered data.
     $data .= unpack("H*", shift);
     1;
   }
     $data .= unpack("H*", shift);
     1;
   }

-  $image->write(callback => \&mywrite, type => 'gif')
-    or die $image->errstr;
+  Imager->write_multi({ callback => \&mywrite, type => 'gif'}, @images)
+    or die Imager->errstr;

 
 Note that for reading you'll almost always need to provide a
 C<seekcb>.
 
 Note that for reading you'll almost always need to provide a
 C<seekcb>.


@@ -212,7 +298,7 @@ C<seekcb>.
 =head2 Guessing types
 
 When writing to a file, if you don't supply a C<type> parameter Imager
 =head2 Guessing types
 
 When writing to a file, if you don't supply a C<type> parameter Imager

-will attempt to guess it from the filename.  This is done by calling
+will attempt to guess it from the file name.  This is done by calling

 the code reference stored in C<$Imager::FORMATGUESS>.  This is only
 done when write() or write_multi() is called with a C<file> parameter.
 
 the code reference stored in C<$Imager::FORMATGUESS>.  This is only
 done when write() or write_multi() is called with a C<file> parameter.
 


@@ -226,7 +312,7 @@ C<\&Imager::def_guess_type>.
 This is the default function Imager uses to derive a file type from a
 file name.  This is a function, not a method.
 
 This is the default function Imager uses to derive a file type from a
 file name.  This is a function, not a method.
 

-Accepts a single parameter, the filename and returns the type or
+Accepts a single parameter, the file name and returns the type or

 undef.
 
 =back
 undef.
 
 =back


@@ -242,10 +328,12 @@ When reading a file Imager examines beginning of the file for
 identifying information.  The current implementation attempts to
 detect the following image types beyond those supported by Imager:
 
 identifying information.  The current implementation attempts to
 detect the following image types beyond those supported by Imager:
 

+=for stopwords Photoshop
+

 =over
 
 =over
 

-xpm, mng, jng, SGI RGB, ilbm, pcx, fits, psd (Photoshop), eps, Utah
-RLE
+C<xpm>, C<mng>, C<jng>, C<ilbm>, C<pcx>, C<fits>, C<psd> (Photoshop), C<eps>, Utah
+C<RLE>.

 
 =back
 
 
 =back
 


@@ -336,31 +424,69 @@ the C<warn_obsolete> option set to false:
 At some point in the future these obsolete options will no longer be
 supported.
 
 At some point in the future these obsolete options will no longer be
 supported.
 

+=for stopwords aNy PixMaps BitMap
+

 =head2 PNM (Portable aNy Map)
 
 =head2 PNM (Portable aNy Map)
 

-Imager can write PGM (Portable Gray Map) and PPM (Portable PixMaps)
-files, depending on the number of channels in the image.  Currently
-the images are written in binary formats.  Only 1 and 3 channel images
-can be written, including 1 and 3 channel paletted images.
+Imager can write C<PGM> (Portable Gray Map) and C<PPM> (Portable
+PixMaps) files, depending on the number of channels in the image.
+Currently the images are written in binary formats.  Only 1 and 3
+channel images can be written, including 1 and 3 channel paletted
+images.

 
   $img->write(file=>'foo.ppm') or die $img->errstr;
 
 
   $img->write(file=>'foo.ppm') or die $img->errstr;
 

-Imager can read both the ASCII and binary versions of each of the PBM
-(Portable BitMap), PGM and PPM formats.
+Imager can read both the ASCII and binary versions of each of the
+C<PBM> (Portable BitMap), C<PGM> and C<PPM> formats.

 
   $img->read(file=>'foo.ppm') or die $img->errstr;
 
 PNM does not support the spatial resolution tags.
 
 
   $img->read(file=>'foo.ppm') or die $img->errstr;
 
 PNM does not support the spatial resolution tags.
 

+The following tags are set when reading a PNM file:
+
+=over
+
+=item *
+
+X<pnm_maxval>C<pnm_maxval> - the C<maxvals> number from the PGM/PPM header.
+Always set to 2 for a C<PBM> file.
+
+=item *
+
+X<pnm_type>C<pnm_type> - the type number from the C<PNM> header, 1 for ASCII
+C<PBM> files, 2 for ASCII C<PGM> files, 3 for ASCII c<PPM> files, 4 for binary
+C<PBM> files, 5 for binary C<PGM> files, 6 for binary C<PPM> files.
+
+=back
+
+The following tag is checked when writing an image with more than
+8-bits/sample:
+
+=over
+
+=item *
+
+X<pnm_write_wide_data>pnm_write_wide_data - if this is non-zero then
+write() can write C<PGM>/C<PPM> files with 16-bits/sample.  Some
+applications, for example GIMP 2.2, and tools can only read
+8-bit/sample binary PNM files, so Imager will only write a 16-bit
+image when this tag is non-zero.
+
+=back
+

 =head2 JPEG
 
 =head2 JPEG
 

+=for stopwords composited
+

 You can supply a C<jpegquality> parameter (0-100) when writing a JPEG
 You can supply a C<jpegquality> parameter (0-100) when writing a JPEG

-file, which defaults to 75%.  Only 1 and 3 channel images
-can be written, including 1 and 3 channel paletted images.
+file, which defaults to 75%.  If you write an image with an alpha
+channel to a JPEG file then it will be composited against the
+background set by the C<i_background> parameter (or tag).

 
   $img->write(file=>'foo.jpg', jpegquality=>90) or die $img->errstr;
 
 
   $img->write(file=>'foo.jpg', jpegquality=>90) or die $img->errstr;
 

-Imager will read a grayscale JPEG as a 1 channel image and a color
+Imager will read a gray scale JPEG as a 1 channel image and a color

 JPEG as a 3 channel image.
 
   $img->read(file=>'foo.jpg') or die $img->errstr;
 JPEG as a 3 channel image.
 
   $img->read(file=>'foo.jpg') or die $img->errstr;


@@ -370,24 +496,24 @@ to control output:
 
 =over
 
 
 =over
 

-=item jpeg_density_unit
+=item C<jpeg_density_unit>

 
 

-The value of the density unit field in the JFIF header.  This is
-ignored on writing if the i_aspect_only tag is non-zero.
+The value of the density unit field in the C<JFIF> header.  This is
+ignored on writing if the C<i_aspect_only> tag is non-zero.

 
 The C<i_xres> and C<i_yres> tags are expressed in pixels per inch no
 matter the value of this tag, they will be converted to/from the value
 stored in the JPEG file.
 
 
 The C<i_xres> and C<i_yres> tags are expressed in pixels per inch no
 matter the value of this tag, they will be converted to/from the value
 stored in the JPEG file.
 

-=item jpeg_density_unit_name
+=item C<jpeg_density_unit_name>

 
 This is set when reading a JPEG file to the name of the unit given by
 C<jpeg_density_unit>.  Possible results include C<inch>,
 C<centimeter>, C<none> (the C<i_aspect_only> tag is also set reading
 
 This is set when reading a JPEG file to the name of the unit given by
 C<jpeg_density_unit>.  Possible results include C<inch>,
 C<centimeter>, C<none> (the C<i_aspect_only> tag is also set reading

-these files).  If the value of jpeg_density_unit is unknown then this
-tag isn't set.
+these files).  If the value of C<jpeg_density_unit> is unknown then
+this tag isn't set.

 
 

-=item jpeg_comment
+=item C<jpeg_comment>

 
 Text comment.
 
 
 Text comment.
 


@@ -396,8 +522,10 @@ Text comment.
 JPEG supports the spatial resolution tags C<i_xres>, C<i_yres> and
 C<i_aspect_only>.
 
 JPEG supports the spatial resolution tags C<i_xres>, C<i_yres> and
 C<i_aspect_only>.
 

-If an APP1 block containing EXIF information is found, then any of the
-following tags can be set:
+=for stopwords EXIF
+
+If an C<APP1> block containing EXIF information is found, then any of the
+following tags can be set when reading a JPEG image:

 
 =over
 
 
 =over
 


@@ -422,7 +550,7 @@ exif_version exif_white_balance exif_x_resolution exif_y_resolution
 
 =back
 
 
 =back
 

-The following derived tags can also be set:
+The following derived tags can also be set when reading a JPEG image:

 
 =over
 
 
 =over
 


@@ -443,9 +571,28 @@ specification for that value appears in the derived field.  So for
 example if C<exf_metering_mode> is C<5> then
 C<exif_metering_mode_name> is set to C<Pattern>.
 
 example if C<exf_metering_mode> is C<5> then
 C<exif_metering_mode_name> is set to C<Pattern>.
 

+eg.
+
+  my $image = Imager->new;
+  $image->read(file => 'exiftest.jpg')
+    or die "Cannot load image: ", $image->errstr;
+  print $image->tags(name => "exif_image_description"), "\n";
+  print $image->tags(name => "exif_exposure_mode"), "\n";
+  print $image->tags(name => "exif_exposure_mode_name"), "\n";
+
+  # for the exiftest.jpg in the Imager distribution the output would be:
+  Imager Development Notes
+  0
+  Auto exposure
+
+Imager will not write EXIF tags to any type of image, if you need more
+advanced EXIF handling, consider L<Image::ExifTool>.
+
+=for stopwords IPTC
+

 =over
 
 =over
 

-=item parseiptc
+=item parseiptc()

 
 Historically, Imager saves IPTC data when reading a JPEG image, the
 parseiptc() method returns a list of key/value pairs resulting from a
 
 Historically, Imager saves IPTC data when reading a JPEG image, the
 parseiptc() method returns a list of key/value pairs resulting from a


@@ -480,132 +627,137 @@ use most of them when writing to GIF:
 
 =over
 
 
 =over
 

-=item gif_left
+=item *

 
 

-the offset of the image from the left of the "screen" ("Image Left
-Position")
+gif_left - the offset of the image from the left of the "screen"
+("Image Left Position")

 
 

-=item gif_top
+=item *

 
 

-the offset of the image from the top of the "screen" ("Image Top Position")
+gif_top - the offset of the image from the top of the "screen" ("Image
+Top Position")

 
 

-=item gif_interlace
+=item *

 
 

-non-zero if the image was interlaced ("Interlace Flag")
+gif_interlace - non-zero if the image was interlaced ("Interlace
+Flag")

 
 

-=item gif_screen_width
+=item *

 
 

-=item gif_screen_height
+gif_screen_width, gif_screen_height - the size of the logical
+screen. When writing this is used as the minimum.  If any image being
+written would extend beyond this then the screen size is extended.
+("Logical Screen Width", "Logical Screen Height").

 
 

-the size of the logical screen. When writing this is used as the
-minimum.  If any image being written would extend beyond this the
-screen size is extended.  ("Logical Screen Width", "Logical Screen
-Height").
+=item *

 
 

-When writing this is used as a minimum, if the combination of the
-image size and the image's C<gif_left> and C<gif_top> is beyond this
-size then the screen size will be expanded.
+gif_local_map - Non-zero if this image had a local color map.  If set
+for an image when writing the image is quantized separately from the
+other images in the file.

 
 

-=item gif_local_map
+=item *

 
 

-Non-zero if this image had a local color map.  If set for an image
-when writing the image is quantized separately from the other images
-in the file.
+gif_background - The index in the global color map of the logical
+screen's background color.  This is only set if the current image uses
+the global color map.  You can set this on write too, but for it to
+choose the color you want, you will need to supply only paletted
+images and set the C<gif_eliminate_unused> tag to 0.

 
 

-=item gif_background
+=item *

 
 

-The index in the global colormap of the logical screen's background
-color.  This is only set if the current image uses the global
-colormap.  You can set this on write too, but for it to choose the
-color you want, you will need to supply only paletted images and set
-the C<gif_eliminate_unused> tag to 0.
+gif_trans_index - The index of the color in the color map used for
+transparency.  If the image has a transparency then it is returned as
+a 4 channel image with the alpha set to zero in this palette entry.
+This value is not used when writing. ("Transparent Color Index")

 
 

-=item gif_trans_index
+=item *

 
 

-The index of the color in the colormap used for transparency.  If the
-image has a transparency then it is returned as a 4 channel image with
-the alpha set to zero in this palette entry.  This value is not used
-when writing. ("Transparent Color Index")
+gif_trans_color - A reference to an Imager::Color object, which is the
+color to use for the palette entry used to represent transparency in
+the palette.  You need to set the C<transp> option (see L<Quantization
+options>) for this value to be used.

 
 

-=item gif_trans_color
+=item *

 
 

-A reference to an Imager::Color object, which is the colour to use for
-the palette entry used to represent transparency in the palette.  You
-need to set the transp option (see L<Quantization options>) for this
-value to be used.
+gif_delay - The delay until the next frame is displayed, in 1/100 of a
+second.  ("Delay Time").

 
 

-=item gif_delay
+=item *

 
 

-The delay until the next frame is displayed, in 1/100 of a second. 
-("Delay Time").
+gif_user_input - whether or not a user input is expected before
+continuing (view dependent) ("User Input Flag").

 
 

-=item gif_user_input
+=item *

 
 

-whether or not a user input is expected before continuing (view dependent) 
-("User Input Flag").
+gif_disposal - how the next frame is displayed ("Disposal Method")

 
 

-=item gif_disposal
+=item *

 
 

-how the next frame is displayed ("Disposal Method")
+gif_loop - the number of loops from the Netscape Loop extension.  This
+may be zero to loop forever.

 
 

-=item gif_loop
+=item *

 
 

-the number of loops from the Netscape Loop extension.  This may be zero.
+gif_comment - the first block of the first GIF comment before each
+image.

 
 

-=item gif_comment
+=item *

 
 

-the first block of the first gif comment before each image.
+gif_eliminate_unused - If this is true, when you write a paletted
+image any unused colors will be eliminated from its palette.  This is
+set by default.

 
 

-=item gif_eliminate_unused
+=item *

 
 

-If this is true, when you write a paletted image any unused colors
-will be eliminated from its palette.  This is set by default.
+gif_colormap_size - the original size of the color map for the image.
+The color map of the image may have been expanded to include out of
+range color indexes.

 
 =back
 
 
 =back
 

-Where applicable, the ("name") is the name of that field from the GIF89 
+Where applicable, the ("name") is the name of that field from the C<GIF89>

 standard.
 
 standard.
 

-The following gif writing options are obsolete, you should set the
+The following GIF writing options are obsolete, you should set the

 corresponding tag in the image, either by using the tags functions, or
 by supplying the tag and value as options.
 
 =over
 
 corresponding tag in the image, either by using the tags functions, or
 by supplying the tag and value as options.
 
 =over
 

-=item gif_each_palette
+=item *

 
 

-Each image in the gif file has it's own palette if this is non-zero.
-All but the first image has a local colour table (the first uses the
-global colour table.
+gif_each_palette - Each image in the GIF file has it's own palette if
+this is non-zero.  All but the first image has a local color table
+(the first uses the global color table.

 
 Use C<gif_local_map> in new code.
 
 
 Use C<gif_local_map> in new code.
 

-=item interlace
+=item *

 
 

-The images are written interlaced if this is non-zero.
+interlace - The images are written interlaced if this is non-zero.

 
 Use C<gif_interlace> in new code.
 
 
 Use C<gif_interlace> in new code.
 

-=item gif_delays
+=item *

 
 

-A reference to an array containing the delays between images, in 1/100
-seconds.
+gif_delays - A reference to an array containing the delays between
+images, in 1/100 seconds.

 
 Use C<gif_delay> in new code.
 
 
 Use C<gif_delay> in new code.
 

-=item gif_positions
+=item *

 
 

-A reference to an array of references to arrays which represent screen
-positions for each image.
+gif_positions - A reference to an array of references to arrays which
+represent screen positions for each image.

 
 New code should use the C<gif_left> and C<gif_top> tags.
 
 
 New code should use the C<gif_left> and C<gif_top> tags.
 

-=item gif_loop_count
+=item *

 
 

-If this is non-zero the Netscape loop extension block is generated,
-which makes the animation of the images repeat.
+gif_loop_count - If this is non-zero the Netscape loop extension block
+is generated, which makes the animation of the images repeat.

 
 

-This is currently unimplemented due to some limitations in giflib.
+This is currently unimplemented due to some limitations in C<giflib>.

 
 =back
 
 
 =back
 


@@ -616,115 +768,222 @@ some page other than the first.  The page is 0 based:
   $image->read(file=>"example.gif", page=>1)
     or die "Cannot read second page: ",$image->errstr,"\n";
 
   $image->read(file=>"example.gif", page=>1)
     or die "Cannot read second page: ",$image->errstr,"\n";
 

-Before release 0.46, Imager would read multi-image GIF image files
+Before release 0.46, Imager would read multiple image GIF image files

 into a single image, overlaying each of the images onto the virtual
 GIF screen.
 
 As of 0.46 the default is to read the first image from the file, as if
 called with C<< page => 0 >>.
 
 into a single image, overlaying each of the images onto the virtual
 GIF screen.
 
 As of 0.46 the default is to read the first image from the file, as if
 called with C<< page => 0 >>.
 

-You can return to the previous behaviour by calling read with the
+You can return to the previous behavior by calling read with the

 C<gif_consolidate> parameter set to a true value:
 
   $img->read(file=>$some_gif_file, gif_consolidate=>1);
 
 C<gif_consolidate> parameter set to a true value:
 
   $img->read(file=>$some_gif_file, gif_consolidate=>1);
 

+As with the to_paletted() method, if you supply a colors parameter as
+a reference to an array, this will be filled with Imager::Color
+objects of the color table generated for the image file.
+

 =head2 TIFF (Tagged Image File Format)
 
 Imager can write images to either paletted or RGB TIFF images,
 =head2 TIFF (Tagged Image File Format)
 
 Imager can write images to either paletted or RGB TIFF images,

-depending on the type of the source image.  Currently if you write a
-16-bit/sample or double/sample image it will be written as an
-8-bit/sample image.  Only 1 or 3 channel images can be written.
+depending on the type of the source image.
+
+When writing direct color images to TIFF the sample size of the
+output file depends on the input:
+
+=over
+
+=item *
+
+double/sample - written as 32-bit/sample TIFF
+
+=item *
+
+16-bit/sample - written as 16-bit/sample TIFF
+
+=item *
+
+8-bit/sample - written as 8-bit/sample TIFF
+
+=back
+
+For paletted images:
+
+=over
+
+=item *
+
+C<< $img->is_bilevel >> is true - the image is written as bi-level
+
+=item *
+
+otherwise - image is written as paletted.
+
+=back

 
 If you are creating images for faxing you can set the I<class>
 parameter set to C<fax>.  By default the image is written in fine
 mode, but this can be overridden by setting the I<fax_fine> parameter
 to zero.  Since a fax image is bi-level, Imager uses a threshold to
 decide if a given pixel is black or white, based on a single channel.
 
 If you are creating images for faxing you can set the I<class>
 parameter set to C<fax>.  By default the image is written in fine
 mode, but this can be overridden by setting the I<fax_fine> parameter
 to zero.  Since a fax image is bi-level, Imager uses a threshold to
 decide if a given pixel is black or white, based on a single channel.

-For greyscale images channel 0 is used, for color images channel 1
+For gray scale images channel 0 is used, for color images channel 1

 (green) is used.  If you want more control over the conversion you can
 use $img->to_paletted() to product a bi-level image.  This way you can
 use dithering:
 
 (green) is used.  If you want more control over the conversion you can
 use $img->to_paletted() to product a bi-level image.  This way you can
 use dithering:
 

-  my $bilevel = $img->to_paletted(colors=>[ NC(0,0,0), NC(255,255,255) ],
-                                  make_colors => 'none',
+  my $bilevel = $img->to_paletted(make_colors => 'mono',

                                   translate => 'errdiff',
                                   errdiff => 'stucki');
 
 =over
 
                                   translate => 'errdiff',
                                   errdiff => 'stucki');
 
 =over
 

-=item class
+=item *

 
 

-If set to 'fax' the image will be written as a bi-level fax image.
+C<class> - If set to 'fax' the image will be written as a bi-level fax
+image.

 
 

-=item fax_fine
+=item *

 
 

-By default when I<class> is set to 'fax' the image is written in fine
-mode, you can select normal mode by setting I<fax_fine> to 0.
+C<fax_fine> - By default when C<class> is set to 'fax' the image is
+written in fine mode, you can select normal mode by setting
+C<fax_fine> to 0.

 
 =back
 
 Imager should be able to read any TIFF image you supply.  Paletted
 TIFF images are read as paletted Imager images, since paletted TIFF
 images have 16-bits/sample (48-bits/color) this means the bottom
 
 =back
 
 Imager should be able to read any TIFF image you supply.  Paletted
 TIFF images are read as paletted Imager images, since paletted TIFF
 images have 16-bits/sample (48-bits/color) this means the bottom

-8-bits are lost, but this shouldn't be a big deal.  Currently all
-direct color images are read at 8-bits/sample.
+8-bits are lost, but this shouldn't be a big deal.

 
 TIFF supports the spatial resolution tags.  See the
 C<tiff_resolutionunit> tag for some extra options.
 
 
 TIFF supports the spatial resolution tags.  See the
 C<tiff_resolutionunit> tag for some extra options.
 

+As of Imager 0.62 Imager reads:
+
+=over
+
+=item *
+
+8-bit/sample gray, RGB or CMYK images, including a possible alpha
+channel as an 8-bit/sample image.
+
+=item *
+
+16-bit gray, RGB, or CMYK image, including a possible alpha channel as
+a 16-bit/sample image.
+
+=item *
+
+32-bit gray, RGB image, including a possible alpha channel as a
+double/sample image.
+
+=item *
+
+bi-level images as paletted images containing only black and white,
+which other formats will also write as bi-level.
+
+=item *
+
+tiled paletted images are now handled correctly
+
+=item *
+
+other images are read using C<tifflib>'s RGBA interface as
+8-bit/sample images.
+
+=back
+

 The following tags are set in a TIFF image when read, and can be set
 to control output:
 
 =over
 
 The following tags are set in a TIFF image when read, and can be set
 to control output:
 
 =over
 

-=item tiff_resolutionunit
+=item *
+
+C<tiff_compression> - When reading an image this is set to the numeric
+value of the TIFF compression tag.
+
+On writing you can set this to either a numeric compression tag value,
+or one of the following values:
+
+  Ident     Number  Description
+  none         1    No compression
+  packbits   32773  Macintosh RLE
+  ccittrle     2    CCITT RLE
+  fax3         3    CCITT Group 3 fax encoding (T.4)
+  t4           3    As above
+  fax4         4    CCITT Group 4 fax encoding (T.6)
+  t6           4    As above
+  lzw          5    LZW
+  jpeg         7    JPEG
+  zip          8    Deflate (GZIP) Non-standard
+  deflate      8    As above.
+  oldzip     32946  Deflate with an older code.
+  ccittrlew  32771  Word aligned CCITT RLE
+
+In general a compression setting will be ignored where it doesn't make
+sense, eg. C<jpeg> will be ignored for compression if the image is
+being written as bilevel.
+
+=for stopwords LZW
+
+Imager attempts to check that your build of C<libtiff> supports the
+given compression, and will fallback to C<packbits> if it isn't
+enabled.  eg. older distributions didn't include LZW compression, and
+JPEG compression is only available if C<libtiff> is configured with
+C<libjpeg>'s location.
+
+  $im->write(file => 'foo.tif', tiff_compression => 'lzw')
+    or die $im->errstr;
+
+=item *

 
 

-The value of the ResolutionUnit tag.  This is ignored on writing if
-the i_aspect_only tag is non-zero.
+C<tags, tiff_jpegquality>C<tiff_jpegquality> - If C<tiff_compression>
+is C<jpeg> then this can be a number from 1 to 100 giving the JPEG
+compression quality.  High values are better quality and larger files.
+
+=item *
+
+X<tags, tiff_resolutionunit>C<tiff_resolutionunit> - The value of the
+C<ResolutionUnit> tag.  This is ignored on writing if the
+i_aspect_only tag is non-zero.

 
 The C<i_xres> and C<i_yres> tags are expressed in pixels per inch no
 matter the value of this tag, they will be converted to/from the value
 stored in the TIFF file.
 
 
 The C<i_xres> and C<i_yres> tags are expressed in pixels per inch no
 matter the value of this tag, they will be converted to/from the value
 stored in the TIFF file.
 

-=item tiff_resolutionunit_name
+=item *

 
 

-This is set when reading a TIFF file to the name of the unit given by
+X<tags, tiff_resolutionunit_name>C<tiff_resolutionunit_name> - This is
+set when reading a TIFF file to the name of the unit given by

 C<tiff_resolutionunit>.  Possible results include C<inch>,
 C<centimeter>, C<none> (the C<i_aspect_only> tag is also set reading
 these files) or C<unknown>.
 
 C<tiff_resolutionunit>.  Possible results include C<inch>,
 C<centimeter>, C<none> (the C<i_aspect_only> tag is also set reading
 these files) or C<unknown>.
 

-=item tiff_bitspersample
-
-Bits per sample from the image.  This value is not used when writing
-an image, it is only set on a read image.
-
-=item tiff_photometric
-
-Value of the PhotometricInterpretation tag from the image.  This value
-is not used when writing an image, it is only set on a read image.
-
-=item tiff_documentname
-
-=item tiff_imagedescription
-
-=item tiff_make
-
-=item tiff_model
+=item *

 
 

-=item tiff_pagename
+X<tags, tiff_bitspersample>C<tiff_bitspersample> - Bits per sample
+from the image.  This value is not used when writing an image, it is
+only set on a read image.

 
 

-=item tiff_software
+=item *

 
 

-=item tiff_datetime
+X<tags, tiff_photometric>C<tiff_photometric> - Value of the
+C<PhotometricInterpretation> tag from the image.  This value is not
+used when writing an image, it is only set on a read image.

 
 

-=item tiff_artist
+=item *

 
 

-=item tiff_hostcomputer
+C<tiff_documentname>, C<tiff_imagedescription>, C<tiff_make>,
+C<tiff_model>, C<tiff_pagename>, C<tiff_software>, C<tiff_datetime>,
+C<tiff_artist>, C<tiff_hostcomputer> - Various strings describing the
+image.  C<tiff_datetime> must be formatted as "YYYY:MM:DD HH:MM:SS".
+These correspond directly to the mixed case names in the TIFF
+specification.  These are set in images read from a TIFF and saved
+when writing a TIFF image.

 
 

-Various strings describing the image.  tiff_datetime must be formatted
-as "YYYY:MM:DD HH:MM:SS".  These correspond directly to the mixed case
-names in the TIFF specification.  These are set in images read from a
-TIFF and saved when writing a TIFF image.
+=back

 
 You can supply a C<page> parameter to the C<read()> method to read
 some page other than the first.  The page is 0 based:
 
 You can supply a C<page> parameter to the C<read()> method to read
 some page other than the first.  The page is 0 based:


@@ -733,27 +992,10 @@ some page other than the first.  The page is 0 based:
   $image->read(file=>"example.tif", page=>1)
     or die "Cannot read second page: ",$image->errstr,"\n";
 
   $image->read(file=>"example.tif", page=>1)
     or die "Cannot read second page: ",$image->errstr,"\n";
 

-=back
-
-Note: Imager uses the TIFF*RGBA* family of libtiff functions,
-unfortunately these don't support alpha channels on CMYK images.  This
-will result in a full coverage alpha channel on CMYK images with an
-alpha channel, until this is implemented in libtiff (or Imager's TIFF
-implementation changes.)
-

 If you read an image with multiple alpha channels, then only the first
 alpha channel will be read.
 
 If you read an image with multiple alpha channels, then only the first
 alpha channel will be read.
 

-Currently Imager's TIFF support reads all direct color images as 8-bit
-RGB images, this may change in the future to reading 16-bit/sample
-images.
-
-Currently tags that control the output color type and compression are
-ignored when writing, this may change in the future.  If you have
-processes that rely upon Imager always producing packbits compressed
-RGB images, you should strip any tags before writing.
-
-=head2 BMP (BitMaP)
+=head2 BMP (Windows Bitmap)

 
 Imager can write 24-bit RGB, and 8, 4 and 1-bit per pixel paletted
 Windows BMP files.  Currently you cannot write compressed BMP files
 
 Imager can write 24-bit RGB, and 8, 4 and 1-bit per pixel paletted
 Windows BMP files.  Currently you cannot write compressed BMP files


@@ -763,7 +1005,7 @@ Imager can read 24-bit RGB, and 8, 4 and 1-bit perl pixel paletted
 Windows BMP files.  There is some support for reading 16-bit per pixel
 images, but I haven't found any for testing.
 
 Windows BMP files.  There is some support for reading 16-bit per pixel
 images, but I haven't found any for testing.
 

-BMP has no support for multi-image files.
+BMP has no support for multiple image files.

 
 BMP files support the spatial resolution tags, but since BMP has no
 support for storing only an aspect ratio, if C<i_aspect_only> is set
 
 BMP files support the spatial resolution tags, but since BMP has no
 support for storing only an aspect ratio, if C<i_aspect_only> is set


@@ -779,6 +1021,8 @@ The following tags are set when you read an image from a BMP file:
 The type of compression, if any.  This can be any of the following
 values:
 
 The type of compression, if any.  This can be any of the following
 values:
 

+=for stopwords RLE
+

 =over
 
 =item BI_RGB (0)
 =over
 
 =item BI_RGB (0)


@@ -821,17 +1065,18 @@ Number of bits stored per pixel. (24, 8, 4 or 1)
 
 =back
 
 
 =back
 

-=head2 TGA (TarGA)
+=for stopwords Targa
+
+=head2 TGA (Targa)

 
 

-When storing targa images rle compression can be activated with the
-'compress' parameter, the 'idstring' parameter can be used to set the
-targa comment field and the 'wierdpack' option can be used to use the
-15 and 16 bit targa formats for rgb and rgba data.  The 15 bit format
+When storing Targa images RLE compression can be activated with the
+C<compress> parameter, the C<idstring> parameter can be used to set the
+Targa comment field and the C<wierdpack> option can be used to use the
+15 and 16 bit Targa formats for RGB and RGBA data.  The 15 bit format

 has 5 of each red, green and blue.  The 16 bit format in addition
 allows 1 bit of alpha.  The most significant bits are used for each
 channel.
 
 has 5 of each red, green and blue.  The 16 bit format in addition
 allows 1 bit of alpha.  The most significant bits are used for each
 channel.
 

-

 Tags:
 
 =over
 Tags:
 
 =over


@@ -847,14 +1092,14 @@ Tags:
 =head2 RAW
 
 When reading raw images you need to supply the width and height of the
 =head2 RAW
 
 When reading raw images you need to supply the width and height of the

-image in the xsize and ysize options:
+image in the C<xsize> and C<ysize> options:

 
   $img->read(file=>'foo.raw', xsize=>100, ysize=>100)
     or die "Cannot read raw image\n";
 
 If your input file has more channels than you want, or (as is common),
 
   $img->read(file=>'foo.raw', xsize=>100, ysize=>100)
     or die "Cannot read raw image\n";
 
 If your input file has more channels than you want, or (as is common),

-junk in the fourth channel, you can use the datachannels and
-storechannels options to control the number of channels in your input
+junk in the fourth channel, you can use the C<datachannels> and
+C<storechannels> options to control the number of channels in your input

 file and the resulting channels in your image.  For example, if your
 input image uses 32-bits per pixel with red, green, blue and junk
 values for each pixel you could do:
 file and the resulting channels in your image.  For example, if your
 input image uses 32-bits per pixel with red, green, blue and junk
 values for each pixel you could do:


@@ -863,13 +1108,62 @@ values for each pixel you could do:
             storechannels=>3)
     or die "Cannot read raw image\n";
 
             storechannels=>3)
     or die "Cannot read raw image\n";
 

-Normally the raw image is expected to have the value for channel 1
-immediately following channel 0 and channel 2 immediately following
-channel 1 for each pixel.  If your input image has all the channel 0
-values for the first line of the image, followed by all the channel 1
-values for the first line and so on, you can use the interleave option:
+Read parameters:
+
+=over
+
+=item *
+
+raw_interleave - controls the ordering of samples within the image.
+Default: 1.  Alternatively and historically spelled C<interleave>.
+Possible values:
+
+=over
+
+=item *
+
+0 - samples are pixel by pixel, so all samples for the first pixel,
+then all samples for the second pixel and so on.  eg. for a four pixel
+scan line the channels would be laid out as:
+
+  012012012012
+
+=item *
+
+1 - samples are line by line, so channel 0 for the entire scan line is
+followed by channel 1 for the entire scan line and so on.  eg. for a
+four pixel scan line the channels would be laid out as:
+
+  000011112222
+
+This is the default.
+
+=back
+
+Unfortunately, historically, the default C<raw_interleave> for read
+has been 1, while writing only supports the C<raw_interleave> = 0
+format.

 
 

-  $img->read(file=>'foo.raw', xsize=100, ysize=>100, interleave=>1)
+For future compatibility, you should always supply the
+C<raw_interleave> (or C<interleave>) parameter.  As of 0.68, Imager
+will warn if you attempt to read a raw image without a
+C<raw_interleave> parameter.
+
+=item *
+
+raw_storechannels - the number of channels to store in the image.
+Range: 1 to 4.  Default: 3.  Alternatively and historically spelled
+C<storechannels>.
+
+=item *
+
+raw_datachannels - the number of channels to read from the file.
+Range: 1 or more.  Default: 3.  Alternatively and historically spelled
+C<datachannels>.
+
+=back
+
+  $img->read(file=>'foo.raw', xsize=100, ysize=>100, raw_interleave=>1)

     or die "Cannot read raw image\n";
 
 =head2 PNG
     or die "Cannot read raw image\n";
 
 =head2 PNG


@@ -879,7 +1173,7 @@ There are no PNG specific tags.
 =head2 ICO (Microsoft Windows Icon) and CUR (Microsoft Windows Cursor)
 
 Icon and Cursor files are very similar, the only differences being a
 =head2 ICO (Microsoft Windows Icon) and CUR (Microsoft Windows Cursor)
 
 Icon and Cursor files are very similar, the only differences being a

-number in the header and the storage of the cursor hotspot.  I've
+number in the header and the storage of the cursor hot spot.  I've

 treated them separately so that you're not messing with tags to
 distinguish between them.
 
 treated them separately so that you're not messing with tags to
 distinguish between them.
 


@@ -905,7 +1199,7 @@ newline.
 
 =item *
 
 
 =item *
 

-following lines which contain 0 and 1 placeholders for each scanline
+following lines which contain 0 and 1 placeholders for each scan line

 of the image, starting from the top of the image.
 
 =back
 of the image, starting from the top of the image.
 
 =back


@@ -978,6 +1272,27 @@ clipped to the size of the image when written to the file.
 
 =back
 
 
 =back
 

+The following parameters can be supplied to read() or read_multi() to
+control reading of ICO/CUR files:
+
+=over
+
+=item *
+
+ico_masked - if true, the default, then the icon/cursors mask is
+applied as an alpha channel to the image.  This may result in a
+paletted image being returned as a direct color image.  Default: 1
+
+  # retrieve the image as stored, without using the mask as an alpha
+  # channel
+  $img->read(file => 'foo.ico', ico_masked => 0)
+    or die $img->errstr;
+
+This was introduced in Imager 0.60.  Previously reading ICO images
+acted as if C<ico_masked =E<gt> 0>.
+
+=back
+

 C<cur_bits> is set when reading a cursor.
 
 Examples:
 C<cur_bits> is set when reading a cursor.
 
 Examples:


@@ -990,6 +1305,45 @@ Examples:
   $im->settag(name => 'cur_hotspoty', value => 16);
   $im->write(file => 'box.cur');
 
   $im->settag(name => 'cur_hotspoty', value => 16);
   $im->write(file => 'box.cur');
 

+=for stopwords BW
+
+=head2 SGI (RGB, BW)
+
+SGI images, often called by the extensions, RGB or BW, can be stored
+either uncompressed or compressed using an RLE compression.
+
+By default, when saving to an extension of C<rgb>, C<bw>, C<sgi>,
+C<rgba> the file will be saved in SGI format.  The file extension is
+otherwise ignored, so saving a 3-channel image to a C<.bw> file will
+result in a 3-channel image on disk.
+
+The following tags are set when reading a SGI image:
+
+=over
+
+=item *
+
+i_comment - the C<IMAGENAME> field from the image.  Also written to
+the file when writing.
+
+=item *
+
+sgi_pixmin, sgi_pixmax - the C<PIXMIN> and C<PIXMAX> fields from the
+image.  On reading image data is expanded from this range to the full
+range of samples in the image.
+
+=item *
+
+sgi_bpc - the number of bytes per sample for the image.  Ignored when
+writing.
+
+=item *
+
+sgi_rle - whether or not the image is compressed.  If this is non-zero
+when writing the image will be compressed.
+
+=back
+

 =head1 ADDING NEW FORMATS
 
 To support a new format for reading, call the register_reader() class
 =head1 ADDING NEW FORMATS
 
 To support a new format for reading, call the register_reader() class


@@ -1175,6 +1529,8 @@ to autoload it.
 
 Once you have an image the basic mechanism is:
 
 
 Once you have an image the basic mechanism is:
 

+=for stopwords STDOUT
+

 =over
 
 =item 1.
 =over
 
 =item 1.


@@ -1225,7 +1581,7 @@ The basic idea is simple, just use write_multi():
 
 If your images are RGB images the default quantization mechanism will
 produce a very good result, but can take a long time to execute.  You
 
 If your images are RGB images the default quantization mechanism will
 produce a very good result, but can take a long time to execute.  You

-could either use the standard webmap:
+could either use the standard web color map:

 
   Imager->write_multi({ file=>$filename, 
                         type=>'gif',
 
   Imager->write_multi({ file=>$filename, 
                         type=>'gif',


@@ -1239,7 +1595,7 @@ or use a median cut algorithm to built a fairly optimal color map:
                         make_colors=>'mediancut' },
                       @imgs);
 
                         make_colors=>'mediancut' },
                       @imgs);
 

-By default all of the images will use the same global colormap, which
+By default all of the images will use the same global color map, which

 will produce a smaller image.  If your images have significant color
 differences, you may want to generate a new palette for each image:
 
 will produce a smaller image.  If your images have significant color
 differences, you may want to generate a new palette for each image:
 


@@ -1282,9 +1638,9 @@ This is pretty simple:
 
 =head1 BUGS
 
 
 =head1 BUGS
 

-When saving Gif images the program does NOT try to shave of extra
+When saving GIF images the program does NOT try to shave off extra

 colors if it is possible.  If you specify 128 colors and there are
 colors if it is possible.  If you specify 128 colors and there are

-only 2 colors used - it will have a 128 colortable anyway.
+only 2 colors used - it will have a 128 color table anyway.

 
 =head1 SEE ALSO
 
 
 =head1 SEE ALSO