NAME

PDL::IO::Image - Load/save bitmap from/to PDL (via FreeImage library)

SYNOPSIS

Functional interface:

use 5.010;
use PDL;
use PDL::IO::Image;

my $pdl1 = rimage('picture.tiff');
say $pdl1->info;       # PDL: Byte D [400,300] ... width 400, height 300
# do some hacking with $piddle
wimage($pdl1, 'output.tiff');
# you can also use wimage as PDL's method
$pdl1->wimage('another-output.png');

my ($pixels, $palette) = rimage('picture-256colors.gif', { palette=>1 });
say $pixels->info;     # PDL: Byte D [400,300] ... width 400, height 300
say $palette->info;    # PDL: Byte D [3,256]
# do some hacking with $pixels and $palette
wimage($pixels, 'output.gif', { palette=>$palette });

# load specific image (page) from multi-page file
my $pdl2 = rimage('picture.tiff', { page=>0 });

# load specific image + flit vertically before converting to piddle
my $pdl3 = rimage('picture.tiff', { flip=>'V' });

# random pixels + ramdom colors (RGBA - 35 bits per pixel)
(random(400, 300, 4) * 256)->byte->wimage("random.png");

my $pix1 = (sin(0.25 * rvals(101, 101)) * 128 + 127)->byte;
say $pix1->info;       # PDL: Byte D [101,101]
my $pal1 = yvals(3, 256)->byte;
$pal1->slice("(2),:") .= 0; # set blue part of palette to zero
say $pal1->info;       # PDL: Byte D [3,256]
$pix1->wimage("wave1_grayscale.gif"); # default is grayscale palette
$pix1->wimage("wave2_yellow.gif", { palette=>$pal1 });

# rotate /rescale before saving
my $pix2 = (sin(0.25 * xvals(101, 101)) * 128 + 127)->byte;
$pix2->wimage("wave3_grayscale.gif", { rescale=>[16,16] }); # rescale to 16x16 pixels
$pix2->wimage("wave4_grayscale.gif", { rescale_pct=>50 }); # rescale to 50%
$pix2->wimage("wave5_grayscale.gif", { rotate=>33.33 });

Object oriented (OO) interface:

use 5.010;
use PDL;
use PDL::IO::Image;

# create PDL::IO::Image object from file
my $pimage1 = PDL::IO::Image->new_from_file('picture.gif');
say 'width       = ' . $pimage1->get_width;
say 'height      = ' . $pimage1->get_height;
say 'image_type  = ' . $pimage1->get_image_type;
say 'color_type  = ' . $pimage1->get_color_type;
say 'colors_used = ' . $pimage1->get_colors_used;
say 'bpp         = ' . $pimage1->get_bpp;
# you can do some operations with PDL::IO::Image object
$pimage1->flip_vertical;
# export pixels from PDL::IO::Image object content into a piddle
my $pix_pdl = $pimage1->pixels_to_pdl();
# export palette from PDL::IO::Image object content into a piddle
my $pal_pdl = $pimage1->palette_to_pdl();

# let us have a piddle with pixel data
my $wave_pixels = (sin(0.008 * xvals(2001, 2001)) * 128 + 127)->byte;
# create PDL::IO::Image object from PDL piddle
my $pimage2 = PDL::IO::Image->new_from_pdl($wave_pixels);
# do some transformation with PDL::IO::Image object
$pimage2->rotate(45);
$pimage2->rescale(200, 200);
# export PDL::IO::Image object content into a image file
$pimage2->save("output.jpg");

DESCRIPTION

PDL::IO::Image implements I/O for a number of popular image formats. It is based on "FreeImage library" however there is no need to install FreeImage library on your system because PDL::IO::Image uses Alien::FreeImage module which handles building FreeImage library from sources (works on Windows, Cygwin, Mac OS X, Linux and other UNIXes).

Check also an excellent FreeImage documentation at http://freeimage.sourceforge.net/documentation.html

Supported file formats

This module supports loading ("new_from_file" or "rimage") and saving ("save" or "wimage") of the following formats (note that not all formats support writing - see R/W column).

    BMP  R/W  Windows or OS/2 Bitmap [extensions: bmp]
    ICO  R/W  Windows Icon [extensions: ico]
   JPEG  R/W  JPEG - JFIF Compliant [extensions: jpg,jif,jpeg,jpe]
    JNG  R/W  JPEG Network Graphics [extensions: jng]
  KOALA  R/-  C64 Koala Graphics [extensions: koa]
    IFF  R/-  IFF Interleaved Bitmap [extensions: iff,lbm]
    MNG  R/-  Multiple-image Network Graphics [extensions: mng]
    PBM  R/W  Portable Bitmap (ASCII) [extensions: pbm]
 PBMRAW  R/W  Portable Bitmap (RAW) [extensions: pbm]
    PCD  R/-  Kodak PhotoCD [extensions: pcd]
    PCX  R/-  Zsoft Paintbrush [extensions: pcx]
    PGM  R/W  Portable Greymap (ASCII) [extensions: pgm]
 PGMRAW  R/W  Portable Greymap (RAW) [extensions: pgm]
    PNG  R/W  Portable Network Graphics [extensions: png]
    PPM  R/W  Portable Pixelmap (ASCII) [extensions: ppm]
 PPMRAW  R/W  Portable Pixelmap (RAW) [extensions: ppm]
    RAS  R/-  Sun Raster Image [extensions: ras]
  TARGA  R/W  Truevision Targa [extensions: tga,targa]
   TIFF  R/W  Tagged Image File Format [extensions: tif,tiff]
   WBMP  R/W  Wireless Bitmap [extensions: wap,wbmp,wbm]
    PSD  R/-  Adobe Photoshop [extensions: psd]
    CUT  R/-  Dr. Halo [extensions: cut]
    XBM  R/-  X11 Bitmap Format [extensions: xbm]
    XPM  R/W  X11 Pixmap Format [extensions: xpm]
    DDS  R/-  DirectX Surface [extensions: dds]
    GIF  R/W  Graphics Interchange Format [extensions: gif]
    HDR  R/W  High Dynamic Range Image [extensions: hdr]
     G3  R/-  Raw fax format CCITT G.3 [extensions: g3]
    SGI  R/-  SGI Image Format [extensions: sgi,rgb,rgba,bw]
    EXR  R/W  ILM OpenEXR [extensions: exr]
    J2K  R/W  JPEG-2000 codestream [extensions: j2k,j2c]
    JP2  R/W  JPEG-2000 File Format [extensions: jp2]
    PFM  R/W  Portable floatmap [extensions: pfm]
   PICT  R/-  Macintosh PICT [extensions: pct,pict,pic]
    RAW  R/-  RAW camera image [extensions: 3fr,arw,bay,bmq,cap,cine,
                  cr2,crw,cs1,dc2, dcr,drf,dsc,dng,erf,fff,ia,iiq,k25,
                  kc2,kdc,mdc,mef,mos,mrw,nef,nrw,orf,pef, ptx,pxn,qtk,
                  raf,raw,rdc,rw2,rwl,rwz,sr2,srf,srw,sti]
   WEBP  R/W  Google WebP image format [extensions: webp]
JPEG-XR  R/W  JPEG XR image format [extensions: jxr,wdp,hdp]

IMPORTANT the strings in the first column (e.g. 'BMP', 'JPEG', 'PNG') are used as a format identifier in "new_from_file", "save", "rimage", "wimage" (+some other methods).

The supported format may differ depending on FreeImage library version. You can list what exactly you FreeImage library can handle like this:

for (PDL::IO::Image->format_list) {
  my $r = PDL::IO::Image->format_can_read($_) ? 'R' : '-';
  my $w = PDL::IO::Image->format_can_write($_) ? 'W' : '-';
  my $e = PDL::IO::Image->format_extension_list($_);
  my $d = PDL::IO::Image->format_description($_);
  printf("% 7s  %s/%s  %s [extensions: %s]\n", $_, $r, $w, $d, $e);
}

Supported image types

This module can handle the following image types.

BITMAP   Standard image: 1-, 4-, 8-, 16-, 24-, 32-bit
UINT16   Array of unsigned short: unsigned 16-bit
INT16    Array of short: signed 16-bit
UINT32   Array of unsigned long: unsigned 32-bit
INT32    Array of long: signed 32-bit
FLOAT    Array of float: 32-bit IEEE floating point
DOUBLE   Array of double: 64-bit IEEE floating point
RGB16    48-bit RGB image: 3 x 16-bit
RGBA16   64-bit RGBA image: 4 x 16-bit
RGBF     96-bit RGB float image: 3 x 32-bit IEEE floating point
RGBAF    128-bit RGBA float image: 4 x 32-bit IEEE floating point

Currently NOT SUPPORTED:

COMPLEX  Array of FICOMPLEX: 2 x 64-bit IEEE floating point

Image type is important especially when you want to load image data from PDL piddle into a PDL::IO::Image object (and later save to a file). Based on piddle size and piddle type the image type is detected (in "new_from_pdl" and "wimage").

W .. image width
H .. image height
PDL Byte     [W,H]       BITMAP 1-/4-/8-bits per pixel
PDL Byte     [W,H,3]     BITMAP 24-bits per pixel (RGB)
PDL Byte     [W,H,4]     BITMAP 32-bits per pixel (RGBA)
PDL Ushort   [W,H]       UINT16
PDL Short    [W,H]       INT16
PDL LongLong [W,H]       UINT32 (unfortunately there is no PDL Ulong type)
PDL Long     [W,H]       INT32
PDL Float    [W,H]       FLOAT
PDL Double   [W,H]       DOUBLE
PDL Ushort   [W,H,3]     RGB16
PDL Ushort   [W,H,4]     RGBA16
PDL Float    [W,H,3]     RGBf
PDL Float    [W,H,4]     RGBAF

IMPORTANT the strings with type name (e.g. 'BITMAP', 'UINT16', 'RGBAF') are used as a image type identifier in method "convert_image_type" and a return value of method "get_image_type".

Not all file formats support all image formats above (especially those non-BITMAP image types). If you are in doubts use tiff format for storing unusual image types.

FUNCTIONS

The functional interface comprises of two functions "rimage" and "wimage" - both are exported by default.

rimage

Loads image into a PDL piddle (or into two piddles in case of palette-based images).

my $pixels_pdl = rimage($filename);
#or
my $pixels_pdl = rimage($filename, \%options);
#or
my ($pixels_pdl, $palette_pdl) = rimage($filename, { palette=>1 });

Internally it works in these steps:

Create PDL::IO::Image object from the input file.
Do optional transformations (based on %options) with PDL::IO::Image object.
Export PDL::IO::Image object into a piddle(s) via "pixels_to_pdl" and "palette_to_pdl".
IMPORTANT: "rimage" returns piddle(s) not a PDL::IO::Image object

Items supported in options hash:

format

String identifying file format (e.g. 'JPEG' - for valid values see "Supported file formats"), default is 'AUTO' which means that format is auto detected.
format_flag

Optional flag related to loading given file format - see "new_from_file" method for more info.
page

Index (0-based) of a specific page to load from multi-page images (TIFF, ICO or animated GIF).
flip

Values 'H', 'V' or 'HV' specifying horizontal, vertical or horizontal+vertical flipping. Default: do not flip.
rotate

Optional floating point value with rotation angle (in degrees) - see "rotate" method for more info. Default: do not rotate.
convert_image_type

String identifying image type (e.g. 'BITMAP' - for valid values see "Supported image types"). Default: no conversion.
region

An arrayref with a region specification like [$x1,$x2,$y1,$y2] - see "pixels_to_pdl" method for more info. Default: create the output piddle from the whole image.
palette

Values 0 (default) or 1 - whether to load (or not) color lookup table (aka LUT).

wimage

Write PDL piddle(s) into a image file.

$pixels_pdl->wimage($filename);
#or
$pixels_pdl->wimage($filename, \%options);

wimage($pixels_pdl, $filename);
#or
wimage($pixels_pdl, $filename, \%options);

Internally it works in these steps:

Create PDL::IO::Image object from the $pixels_piddle (+ $palette_piddle passed as palette option).
Dimensions and type of $pixels_piddle must comply with "Supported image types".
Do optional transformations (based on %options) with PDL::IO::Image object.
Export PDL::IO::Image object into a image file via "save" method.

Items supported in options hash:

format

String identifying file format (e.g. 'JPEG' - for valid values see "Supported file formats"), default is 'AUTO' which means that format is auto detected from extension of $filename.
format_flag

Optional flag related to saving given file format - see "save" method for more info.
palette

Optional PDL piddle with color palette (has to be PDL Byte[3,N] where 0 < N <= 256) containing RGB triplets.
flip

Values 'H', 'V' or 'HV' specifying horizontal, vertical or horizontal+vertical flipping. Default: do not flip.
rotate

Optional floating point value with rotation angle (in degrees) - see "rotate" method for more info. Default: do not rotate.
rescale

Optional arrayref with rescale specification (in pixels) e.g. [$new_w, $new_h] - see "rescale" method for more info. Default: do not rescale.
rescale_pct

Optional floating point value with rescale ratio in percent - see "rescale_pct" method for more info. Default: do not rescale.
convert_image_type

String identifying image type (e.g. 'BITMAP' - for valid values see "Supported image types"). Default: no conversion.

METHODS

new_from_file

Create PDL::IO::Image object from image file.

my $pimage = IO::PDL::Image->new_from_file($filename);
#or
my $pimage = IO::PDL::Image->new_from_file($filename, $format);
#or
my $pimage = IO::PDL::Image->new_from_file($filename, $format, $format_flag);
#or
my $pimage = IO::PDL::Image->new_from_file($filename, $format, $format_flag, $page);

#if you have image file content in a scalar variable you can use
my $pimage = IO::PDL::Image->new_from_file(\$variable_with_image_data);

$filename - input image file name or a reference to scalar variable with imiga data.

$format - string identifying file format (e.g. 'JPEG' - for valid values see "Supported file formats"), default is 'AUTO' which means that format is auto detected (based on file header with fall-back to detection based on file extension).

$format_flag - optional flag related to loading given file format, default if 0 (no extra flags). The flag can be created by OR-ing some of available constants:

PDL::IO::Image::GIF_LOAD256        Load the image as a 256 color image with unused
                                   palette entries, if it's 16 or 2 color
PDL::IO::Image::GIF_PLAYBACK       'Play' the GIF to generate each frame (as 32bpp)
                                   instead of returning raw frame data when loading
PDL::IO::Image::ICO_MAKEALPHA      Convert to 32-bit and create an alpha channel from
                                   the ANDmask when loading
PDL::IO::Image::JPEG_FAST          Load the file as fast as possible, sacrificing some quality
PDL::IO::Image::JPEG_ACCURATE      Load the file with the best quality, sacrificing some speed
PDL::IO::Image::JPEG_CMYK          This flag will load CMYK bitmaps as 32-bit separated CMYK
PDL::IO::Image::JPEG_GREYSCALE     Load and convert to a 8-bit greyscale image (faster than
                                   loading as 24-bit and converting to 8-bit)
PDL::IO::Image::JPEG_EXIFROTATE    Load and rotate according to Exif 'Orientation' tag if available
PDL::IO::Image::PCD_BASE           This flag will load the one sized 768 x 512
PDL::IO::Image::PCD_BASEDIV4       This flag will load the bitmap sized 384 x 256
PDL::IO::Image::PCD_BASEDIV16      This flag will load the bitmap sized 192 x 128
PDL::IO::Image::PNG_IGNOREGAMMA    Avoid gamma correction on loading
PDL::IO::Image::PSD_CMYK           Reads tags for separated CMYK (default is conversion to RGB)
PDL::IO::Image::PSD_LAB            Reads tags for CIELab (default is conversion to RGB)
PDL::IO::Image::RAW_PREVIEW        Try to load the embedded JPEG preview with included Exif
                                   data or default to RGB 24-bit
PDL::IO::Image::RAW_DISPLAY        Load the file as RGB 24-bit
PDL::IO::Image::RAW_HALFSIZE       Output a half-size color image
PDL::IO::Image::TARGA_LOAD_RGB888  If set the loader converts RGB555 and ARGB8888 -> RGB888
PDL::IO::Image::TIFF_CMYK          Load CMYK bitmaps as separated CMYK (default is conversion to RGB)

new_from_pdl

Create PDL::IO::Image object from PDL piddle with pixel (+ optional palette) data.

my $pimage = IO::PDL::Image->new_from_pdl($pixels_pdl);
#or
my $pimage = IO::PDL::Image->new_from_pdl($pixels_pdl, $palette_pdl);

$pixels_pdl - PDL piddle containing pixel data, dimensions and type must comply with "Supported image types".

$palette_pdl - Optional PDL piddle with color palette (has to be PDL Byte[3,N] where 0 < N <= 256) containing RGB triplets.

clone

Create a copy (clone) of PDL::IO::Image object.

my $pimage_copy = $pimage->clone();

pixels_to_pdl

Export pixel data from PDL::IO::Image object into a piddle.

my $pixels_pdl = $pimage->pixels_to_pdl;
#or
my $pixels_pdl = $pimage->pixels_to_pdl($x1, $x2, $y1, $y2);

$x1, $x2, $y1, $y2 - Optional specification of image sub-region to be exported. All values are 0-based, negative values can be used to specify boundary "from the end".

palette_to_pdl

Export palette (aka LUT - color lookup table) data from PDL::IO::Image object into a piddle.

my $palette_pdl = $pimage->palette_to_pdl;

The output piddle is ususally PDL Byte [3, 256]. Returns undef if image represented by $pimage does not use palette.

save

Export PDL::IO::Image object into a image file.

$pimage->save($filename, $format, $flags);
#or
$pimage->save($filename, $format);
#or
$pimage->save($filename);

#you can save the image data to a variable like this
my $output_image;
$pimage->save(\$output_image, $format);
#NOTE: $format is mandatory in this case

Returns $pimage (self).

$filename - output image file name or a reference to perl scalar variable.

$format - string identifying file format (e.g. 'JPEG' - for valid values see "Supported file formats"), default is 'AUTO' which means that format is auto detected from extension of $filename.

$format_flag - optional flag related to saving given file format, default if 0 (no extra flags). The flag can be created by OR-ing some of available constants:

PDL::IO::Image::BMP_SAVE_RLE              Compress the bitmap using RLE when saving
PDL::IO::Image::EXR_FLOAT                 Save data as float instead of as half (not recommended)
PDL::IO::Image::EXR_NONE                  Save with no compression
PDL::IO::Image::EXR_ZIP                   Save with zlib compression, in blocks of 16 scan lines
PDL::IO::Image::EXR_PIZ                   Save with piz-based wavelet compression
PDL::IO::Image::EXR_PXR24                 Save with lossy 24-bit float compression
PDL::IO::Image::EXR_B44                   Save with lossy 44% float compression
PDL::IO::Image::EXR_LC                    Save with one luminance and two chroma channels, rather than RGB (lossy)
  for J2K format: integer X in [1..512]   Save with a X:1 rate (default = 16)
  for JP2 format: integer X in [1..512]   Save with a X:1 rate (default = 16)
PDL::IO::Image::JPEG_QUALITYSUPERB        Saves with superb quality (100:1)
PDL::IO::Image::JPEG_QUALITYGOOD          Saves with good quality (75:1 - default)
PDL::IO::Image::JPEG_QUALITYNORMAL        Saves with normal quality (50:1)
PDL::IO::Image::JPEG_QUALITYAVERAGE       Saves with average quality (25:1)
PDL::IO::Image::JPEG_QUALITYBAD           Saves with bad quality (10:1)
  for JPEG format: integer X in [0..100]  Save with quality X:1
PDL::IO::Image::JPEG_PROGRESSIVE          Saves as a progressive JPEG file
PDL::IO::Image::JPEG_SUBSAMPLING_411      Save with high 4x1 chroma subsampling (4:1:1)
PDL::IO::Image::JPEG_SUBSAMPLING_420      Save with medium 2x2 chroma subsampling (4:2:0) - default value
PDL::IO::Image::JPEG_SUBSAMPLING_422      Save with low 2x1 chroma subsampling (4:2:2)
PDL::IO::Image::JPEG_SUBSAMPLING_444      Save with no chroma subsampling (4:4:4)
PDL::IO::Image::JPEG_OPTIMIZE             On saving, compute optimal Huffman coding tables
PDL::IO::Image::JPEG_BASELINE             Save basic JPEG, without metadata or any markers
  for JXR format: integer X in [1..100)   Save with quality X:1 (default = 80), using X=100 means lossless
PDL::IO::Image::JXR_LOSSLESS              Save lossless (quality = 100)
PDL::IO::Image::JXR_PROGRESSIVE           Saves as a progressive JPEG-XR file
PDL::IO::Image::PNG_Z_BEST_SPEED          Save using ZLib level 1 compression (default value is 6)
PDL::IO::Image::PNG_Z_DEFAULT_COMPRESSION Save using ZLib level 6 compression (default)
PDL::IO::Image::PNG_Z_BEST_COMPRESSION    Save using ZLib level 9 compression (default value is 6)
PDL::IO::Image::PNG_Z_NO_COMPRESSION      Save without ZLib compression
PDL::IO::Image::PNG_INTERLACED            Save using Adam7 interlacing
PDL::IO::Image::PNM_SAVE_RAW              Saves the bitmap as a binary file
PDL::IO::Image::PNM_SAVE_ASCII            Saves the bitmap as an ASCII file
PDL::IO::Image::TIFF_CMYK                 Stores tags for separated CMYK
PDL::IO::Image::TIFF_PACKBITS             Save using PACKBITS compression
PDL::IO::Image::TIFF_DEFLATE              Save using DEFLATE compression (also known as ZLIB compression)
PDL::IO::Image::TIFF_ADOBE_DEFLATE        Save using ADOBE DEFLATE compression
PDL::IO::Image::TIFF_NONE                 Save without any compression
PDL::IO::Image::TIFF_CCITTFAX3            Save using CCITT Group 3 fax encoding
PDL::IO::Image::TIFF_CCITTFAX4            Save using CCITT Group 4 fax encoding
PDL::IO::Image::TIFF_LZW                  Save using LZW compression
PDL::IO::Image::TIFF_JPEG                 Save using JPEG compression (8-bit greyscale and 24-bit only)
PDL::IO::Image::TIFF_LOGLUV               Save using LogLuv compression (only available with RGBF images
PDL::IO::Image::TARGA_SAVE_RLE            Save with RLE compression

dump_bitmap

Extract raw bitmap data (+ do necessary image type and/or bpp conversions).

my ($width, $height, $bpp, $pixels, $palette) = $pimage->dump_bitmap;
#or
my ($width, $height, $bpp, $pixels, $palette) = $pimage->dump_bitmap($required_bpp);

$pixels and $palette are raw data buffers containg sequence of RGB (RGBA) byte values.

$required_bpp can be 8, 24 or 32 - before dumping the image is converted to BITMAP image type + colors depth is converted to given value. Default is autodetect the lowest sufficient bpp (from 8, 24, 32).

get_image_type

Returns the data type of a bitmap (e.g. 'BITMAP', 'UINT16') - see "Supported image types".

my $imtype = $pimage->get_image_type;

get_colors_used

Returns the palette size for palletised bitmaps (usually 256), and 0 for high-colour bitmaps.

my $colors = $pimage->get_colors_used;

get_bpp

Returns the size of one pixel in the bitmap in bits (aka bits per pixel).

my $bpp = $pimage->get_bpp;

get_width

Returns the width of the bitmap in pixels.

my $w = $pimage->get_width;

get_height

Returns the height of the bitmap in pixels.

my $h = $pimage->get_height;

get_dots_per_meter_x

Returns the horizontal resolution, in pixels-per-meter.

my $dpmx = $pimage->get_dots_per_meter_x;

set_dots_per_meter_x

Set the horizontal resolution, in pixels-per-meter.

$pimage->set_dots_per_meter_x($res);

Returns $pimage (self).

get_dots_per_meter_y

Returns the vertical resolution, in pixels-per-meter.

my $dpmy = $pimage->get_dots_per_meter_y;

set_dots_per_meter_y

Set the vertical resolution, in pixels-per-meter.

$pimage->set_dots_per_meter_y($res);

Returns $pimage (self).

get_color_type

Returns color type.

my $coltype = $pimage->get_color_type;

The return value is a string:

'MINISBLACK'   Monochrome bitmap (1-bit): first palette entry is black.
               Palletised bitmap (4 or 8-bit) and single channel non standard bitmap: greyscale palette
'MINISWHITE'   Monochrome bitmap (1-bit): first palette entry is white.
               Palletised bitmap (4 or 8-bit): inverted greyscale palette
'PALETTE'      Palettized bitmap (1, 4 or 8 bit)
'RGB'          High-color bitmap (16, 24 or 32 bit), RGB16 or RGBF
'RGBALPHA'     High-color bitmap with an alpha channel (32 bit bitmap, RGBA16 or RGBAF)
'CMYK'         CMYK bitmap (32 bit only)

is_transparent

Returns 1 when the transparency table is enabled (1-, 4- or 8-bit images) or when the input dib contains alpha values (32-bit images, RGBA16 or RGBAF images). Returns 0 otherwise.

my $bool = $pimage->is_transparent;

get_transparent_index

Returns the palette entry used as transparent color for the image specified. Works for palletised images only and returns -1 for high color images or if the image has no color set to be transparent.

my $idx = $pimage->get_transparent_index;

set_transparent_index

Sets the index of the palette entry to be used as transparent color for the image specified. Does nothing on high color images.

$pimage->set_transparent_index($index);

Returns $pimage (self).

flip_horizontal

Flip the image horizontally along the vertical axis.

$pimage->flip_horizontal;

Returns $pimage (self).

flip_vertical

Flip the image vertically along the horizontal axis.

$pimage->flip_vertical;

Returns $pimage (self).

rotate

Rotates image, the angle of counter clockwise rotation is specified by the $angle parameter in degrees.

$pimage->rotate($angle);
#or
$pimage->rotate($angle, $bg_r, $bg_g, $bg_b, $bg_a);   # RGBA(F|16) images
$pimage->rotate($angle, $bg_r, $bg_g, $bg_b);          # RGB(F|16) images
$pimage->rotate($angle, $bg);                          # palette-based images

You can specify optional backgroung color via $bg_r, $bg_g, $bg_b, $bg_a or $bg.

Returns $pimage (self).

rescale

Performs resampling (scaling/zooming) of a greyscale or RGB(A) image to the desired destination width and height.

$pimage->rescale($dst_width, $dst_height, $filter);
#or
$pimage->rescale($dst_width, 0);  # destination height is computed
#or
$pimage->rescale(0, $dst_height); # destination width is computed

Returns $pimage (self).

$filter - resampling filter identifier:

0 .. Box, pulse, Fourier window, 1st order (constant) b-spline
1 .. Mitchell & Netravali's two-param cubic filter
2 .. Bilinear filter
3 .. 4th order (cubic) b-spline
4 .. Catmull-Rom spline, Overhauser spline
5 .. Lanczos3 filter

rescale_pct

Performs resampling by given percentage ratio.

$pimage->rescale($dst_width_pct, $dst_height_pct, $filter);
#or
$pimage->rescale($dst_pct);

Returns $pimage (self).

$filter - see "rescale"

convert_image_type

Converts an image to destination $image_type.

$pimage->convert_image_type($image_type, $scale_linear);
#or
$pimage->convert_image_type($image_type);

Returns $pimage (self).

$image_type - string identifying image type (e.g. 'BITMAP', 'UINT16' - for valid values see "Supported image types").

adjust_colors

Adjusts an image's brightness, contrast and gamma as well as it may optionally invert the image within a single operation.

$pimage->adjust_colors($brightness, $contrast, $gamma, $invert);

Returns $pimage (self).

$brightness - real value from range [-100..100], value 0 means no change, less than 0 will make the image darker and greater than 0 will make the image brighter

$contrast - real value from range [-100..100], value 0 means no change, less than 0 will decrease the contrast and greater than 0 will increase the contrast of the image

$gamma - real value greater than 0, value of 1.0 leaves the image alone, less than one darkens it, and greater than one lightens it

$invert - 0 or 1 invert (or not) all pixels

color_to_4bpp

Converts a bitmap to 4 bits. If the bitmap was a high-color bitmap (16, 24 or 32-bit) or if it was a monochrome or greyscale bitmap (1 or 8-bit), the end result will be a greyscale bitmap, otherwise (1-bit palletised bitmaps) it will be a palletised bitmap.

$pimage->color_to_4bpp();

Returns $pimage (self).

color_to_8bpp

Converts a bitmap to 8 bits. If the bitmap was a high-color bitmap (16, 24 or 32-bit) or if it was a monochrome or greyscale bitmap (1 or 4-bit), the end result will be a greyscale bitmap, otherwise (1 or 4-bit palletised bitmaps) it will be a palletised bitmap.

$pimage->color_to_8bpp();

Returns $pimage (self).

color_to_8bpp_grey

Converts a bitmap to a 8-bit greyscale image with a linear ramp. Contrary to the FreeImage_ConvertTo8Bits function, 1-, 4- and 8-bit palletised images are correctly converted, as well as images with a FIC_MINISWHITE color type.

$pimage->color_to_8bpp_grey();

Returns $pimage (self).

color_to_16bpp_555

Converts a bitmap to 16 bits, where each pixel has a color pattern of 5 bits red, 5 bits green and 5 bits blue. One bit in each pixel is unused.

$pimage->color_to_16bpp_555();

Returns $pimage (self).

color_to_16bpp_565

Converts a bitmap to 16 bits, where each pixel has a color pattern of 5 bits red, 6 bits green and 5 bits blue.

$pimage->color_to_16bpp_565();

Returns $pimage (self).

color_to_24bpp

Converts a bitmap to 24 bits per pixel.

$pimage->color_to_24bpp();

Returns $pimage (self).

color_to_32bpp

Converts a bitmap to 32 bits per pixel.

$pimage->color_to_32bpp();

Returns $pimage (self).

color_dither

Converts a bitmap to 1-bit monochrome bitmap using a dithering algorithm.

$pimage->color_dither($algorithm);
#or
$pimage->color_dither();

Returns $pimage (self).

Possible $algorithm values:

0 .. Floyd & Steinberg error diffusion (DEFAULT)
1 .. Bayer ordered dispersed dot dithering (order 2 dithering matrix)
2 .. Bayer ordered dispersed dot dithering (order 3 dithering matrix)
3 .. Ordered clustered dot dithering (order 3 - 6x6 matrix)
4 .. Ordered clustered dot dithering (order 4 - 8x8 matrix)
5 .. Ordered clustered dot dithering (order 8 - 16x16 matrix)
6 .. Bayer ordered dispersed dot dithering (order 4 dithering matrix)

color_threshhold

Converts a bitmap to 1-bit monochrome bitmap using a $threshold between [0..255] (default is 127).

$pimage->color_threshhold($threshold);
#or
$pimage->color_threshhold();

Returns $pimage (self).

color_quantize

$pimage->color_quantize($quantize);
#or
$pimage->color_quantize();

Returns $pimage (self).

Possible $quantize values:

0 .. Xiaolin Wu color quantization algorithm
1 .. NeuQuant neural-net quantization algorithm by Anthony Dekker

tone_mapping

Converts a High Dynamic Range image (48-bit RGB or 96-bit RGBF) to a 24-bit RGB image, suitable for display.

$pimage->tone_mapping($tone_mapping_operator, $param1, $param2);

Returns $pimage (self).

$tone_mapping_operator - tone mapping operator identifier:

0 .. Adaptive logarithmic mapping (F. Drago, 2003)
1 .. Dynamic range reduction inspired by photoreceptor physiology (E. Reinhard, 2005)
2 .. Gradient domain high dynamic range compression (R. Fattal, 2002)

Optional parameters:

$pimage->tone_mapping(0, $gamma, $exposure);
#or
$pimage->tone_mapping(1, $intensity, $contrast);
#or
$pimage->tone_mapping(2, $color_saturation, $attenuation);

free_image_version

Returns a string containing the current version of the library.

my $v = PDL::IO::Image->free_image_version();

format_list

Returns a list of all supported file formats.

my @f = PDL::IO::Image->format_list();