Contents

- Introduction
- Installation
- Overview
- Example Script
- Read or Write an Image
- Manipulate an Image
- Set an Image Attribute
- Get an Image Attribute
- Create an Image Montage
- Miscellaneous Methods
- Handling Errors
- Working with Blobs
- Copyright

Introduction

  PerlMagick, version 4.29, is an objected-oriented Perl interface to ImageMagick. Use the module to read, manipulate, or write an image or image sequence from within a Perl script. This makes it very suitable for Web CGI scripts. You must have ImageMagick 4.2.9 or above and Perl version 5.002 or greater installed on your system for either of these utilities to work. Perl version 5.005_02 or greater is required for PerlMagick to work on an NT system.

There are a number of useful scripts available to show you the value of PerlMagick. You can do Web based image manipulation and conversion with MogrifyMagick, or use L-systems to create images of plants using mathematical constructs, and finally navigate through collections of thumbnail images and select the image to view with the WebMagick Image Navigator.

You can try PerlMagick from your Web browser at the ImageMagick Studio. Or, you can see examples of select PerlMagick functions.

An object-oriented Python interface to ImageMagick is also available, see PythonMagick.

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Installation

  UNIX

ImageMagick must already be installed on your system. Next, get the PerlMagick distribution and unpack it as shown below:

        gunzip -c PerlMagick-4.29.tar.gz | tar -xvf -
        cd PerlMagick

Next, edit `Makefile.PL` and change LIBS and INC to include the appropriate path information to the required `libMagick` library. You will also need paths to JPEG, PNG, TIFF, etc. delegates if they were included with your installed version of ImageMagick. Build and install it like this:

        perl Makefile.PL
        make
        make install

For Unix, you typically need to be `root` to install the software. There are ways around this. Consult the Perl manual pages for more information.

Windows NT / Windows 95

ImageMagick must already be installed on your system. Also, the ImageMagick source distribution for Windows NT is required. You must also have the `nmake` from the Visual C++ or J++ development environment. Copy `\bin\IMagick.dll` and `\bin\X11.dll` to a directory in your dynamic load path such as `c:\perl\site\5.00502`. Next, type

        cd PerlMagick
        copy Makefile.nt Makefile.PL
        perl Makefile.PL
        nmake
        nmake install

Running the Regression Tests

To verify a correct installation, type

        make test

Use `nmake test` under Windows. There are ao few demonstration scripts available to exercise many of the functions PerlMagick can perform. Type

        cd demo
        make

You are now ready to utilize the PerlMagick methods from within your Perl scripts.

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Overview

  Any script that wants to use PerlMagick methods must first define the methods within its namespace and instantiate an image object. Do this with:

        use Image::Magick;

        $image=Image::Magick->new;

The new method takes the same parameters as SetAttribute. For example,

        $image=Image::Magick->new(size=>'384x256');

Next you will want to read an image or image sequence, manipulate it, and then display or write it. The input and output methods for PerlMagick are defined in Read or Write an Image. See Set an Image Attribute for methods that affect the way an image is read or written. Refer to Manipulate an Image for a list of methods to transform an image. Get an Image Attribute describes how to retrieve an attribute for an image. Refer to Create an Image Montage for details about tiling your images as thumbnails on a background. Finally, some methods do not neatly fit into any of the categories just mentioned. Review Miscellaneous Methods for a list of these methods.

Once you are finished with a PerlMagick object you should consider destroying it. Each image in an image sequence is stored in virtual memory. This can potentially add up to mega-bytes of memory. Upon destroying a PerlMagick object, the memory is returned for use by other Perl methods. The recommended way to destroy an object is with `undef`:

        undef $image;

To delete all the images but retain the `Image::Magick` object use

        undef @$image;

and finally, to delete a single image from a multi-image sequence, use

        undef $image->[x];

The next section illustrates how to use various PerlMagick methods to manipulate an image sequence.

Some of the PerlMagick methods require external programs such as Ghostscript. This may require an explicit path in your PATH environment variable to work properly. For example,

        $ENV{PATH}='/bin:/usr/bin:/usr/local/bin';

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Example Script

  Here is an example script to get you started:

        #!/usr/local/bin/perl
        use Image::Magick;

        my($image, $x);

        $image = Image::Magick->new;
        $x = $image->Read('girl.gif', 'logo.gif', 'rose.gif');
        warn "$x" if "$x";

        $x = $image->Crop(geometry=>'100x100"+1"00"+1"00');
        warn "$x" if "$x";

        $x = $image->Write('x.gif');
        warn "$x" if "$x";

The script reads three images, crops them, and writes a single image as a GIF animation sequence. In many cases you may want to access individual images of a sequence. The next example illustrates how this is done:

        #!/usr/local/bin/perl
        use Image::Magick;

        my($image, $p, $q);

        $image = new Image::Magick;
        $image->Read('x1.gif');
        $image->Read('j*.jpg');
        $image->Read('k.miff[1, 5, 3]');
        $image->Contrast;
        for ($x = 0; $image->[x]; $x++)
        {
          $image->[x]->Frame('100x200') if $image->[x]->Get('magick') eq 'GIF';
          undef $image->[x] if $image->[x]->Get('columns') < 100;
        }
        $p = $image->[1];
        $p->Draw(pen=>'red', primitive=>'rectangle', points=>20,20 100,100');
        $q = $p->Montage();
        undef $image;
        $q->Write('x.miff');

Suppose you want to start out with a 100 by 100 pixel white canvas with a red pixel in the center. Try

        $image = Image::Magick->new;
        $image->Set(size=>'100x100');
        $image->ReadImage('xc:white');
        $image->Set('pixel[49,49]'=>'red');

Or suppose you want to convert your color image to grayscale:

        $image->Quantize(colorspace=>'gray');

Here we annotate an image with a Taipai TrueType font:

        $text = "\\0x17ef\\0x30ec\\0x25ec\\0x23ef\\0x17ec";
        $image->Annotate(font=>'@kai.ttf', pointsize=>40, pen=>'green', text=>$text);

Other clever things you can do with PerlMagick objects include

        $i = $#$p"+1";     # return the number of images associated with object p
        push(@$q, @$p);  # push the images from object p onto object q
        undef @$p;       # delete the images but not the object p

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Read or Write an Image

  Use the methods listed below to either read, write, or display an image or image sequence.

Read or Write Methods
Method | Parameters | Return Value | Description
--- | --- | --- | ---
Read | one or more filenames | the number of images read | read an image or image sequence
Write | filename | the number of images written | write an image or image sequence
Display | server name | the number of images displayed | display the image or image sequence to an X server
Animate | server name | the number of images animated | animate image sequence to an X server

For convenience, methods `Write`, `Display`, and `Animate` can take any parameter that SetAttribute knows about. For example,

        $image->Write(filename=>'image.png', compress=>'None');

Use `-` as the filename to method `Read` to read from standard in or to method `Write` to write to standard out:

        binmode STDOUT;
        $image->Write('gif:-');

To read an image in the GIF format from a PERL filehandle, use:

        $image = Image::Magick->new(magick=>'GIF');
        open(DATA, 'image.gif');
        $image->Read(file=>DATA);
        close(DATA);

To write an image in the PNG format to a PERL filehandle, use:

        $filename = "image.png";
        open(DATA, ">$filename");
        $image->Write(file=>DATA, filename=>$filename);
        close(DATA);

You can optionally add `Image` to any method name. For example, `ReadImage` is an alias for method `Read`.

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Manipulate an Image

  Once you create an image with, for example, method `ReadImage` you may want to operate on it. Below is a list of all the image manipulations methods available to you with PerlMagick. There are examples of select PerlMagick methods. Here is an example call to an image manipulation method:

        $image->Crop(geometry=>'100x100"+1"0+20');
        $image->[x]->Frame("100x200");

And here is a list of other image manipulation methods you can call:

Image Manipulation Methods
Method | Parameters | Description
--- | --- | ---
AddNoise | noise=>{Uniform, Gaussian, Multiplicative, Impulse, Laplacian, Poisson} | add noise to an image
Annotate | text=>string, font=>string, pointsize=>integer, density=>geometry, box=>colorname, pen=>colorname, geometry=>geometry, server=>{string, @filename}, gravity=>{NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast}, x=>integer, y=>integer, degrees=>double | annotate an image with text.
Blur | factor=>percentage | blurs an image
Border | geometry=>geometry, width=>integer, height=>integer, color=colorname | surround the image with a border of color
Charcoal | factor=>percentage | simulate a charcoal drawing
Chop | geometry=>geometry, width=>integer, height=>integer, x=>integer, y=>integer | chop an image
Clone |  | make a copy an image
Coalesce |  | merge a sequence of images
ColorFloodfill | geometry=>geometry, x=>integer, y=>integer, pen=colorname, bordercolor=colorname | changes the color value of any pixel that matches the color of the target pixel and is a neighbor. If you specify a border color, the color value is changed for any neighbor pixel that is not that color.
Colorize | color=>colorname, pen=>colorname | colorize the image with the pen color
Comment | string | add a comment to your image
Composite | compose=>{Over, In, Out, Atop, Xor, Plus, Minus, Add, Subtract, Difference, Bumpmap, Replace, ReplaceRed, ReplaceGreen, ReplaceBlue, ReplaceMatte, Blend, Displace}, image=>image-handle, geometry=>geometry, x=>integer, y=>integer, gravity=>{NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast} | composite one image onto another
Condense |  | compress image to take up the least amount of memory
Contrast | sharpen=>{True, False} | enhance or reduce the image contrast
Crop | geometry=>geometry, width=>integer, height=>integer, x=>integer, y=>integer | crop an image
CycleColormap | amount=>integer | displace image colormap by amount
Deconstruct |  | break down an image sequence into constituent parts
Despeckle |  | reduce the speckles within an image
Draw | primitive={Point, Line, Rectangle, FillRectangle, Circle, FillCircle, Ellipse, FillEllipse, Polygon, FillPolygon, Color, Matte, Text, Image, @filename}, points=>string, method={Point, Replace, Floodfill, FillToBorder, Reset}, pen=>colorname, bordercolor=>colorname, linewidth=>integer, server=>string, | annotate an image with one or more graphic primitives
Edge | factor=>percentage | detect edges within an image
Emboss |  | emboss the image
Enhance |  | apply a digital filter to enhance a noisy image
Equalize |  | perform histogram equalization to the image
Flip |  | create a mirror image by reflecting the image scanlines in the vertical direction
Flop |  | create a mirror image by reflecting the image scanlines in the horizontal direction
Frame | geometry=>geometry, width=>integer, height=>integer, inner=>integer, outer=>integer, color=>colorname | surround the image with an ornamental border
Gamma | gamma=>double, red=>double, green=>double, blue=>double | gamma correct the image
Implode | factor=>percentage | implode image pixels about the center
Label | string | assign a label to an image
Layer | layer={Red, Green, Blue, Matte} | extract a layer from the image
Magnify |  | double the size of an image
Map | image=>image-handle, dither={True, False} | choose a particular set of colors from this image
MatteFloodfill | geometry=>geometry, x=>integer, y=>integer, matte=integer, bordercolor=colorname | changes the matte value of any pixel that matches the color of the target pixel and is a neighbor. If you specify a border color, the matte value is changed for any neighbor pixel that is not that color.
Minify |  | half the size of an image
Modulate | brightness=>double, saturation=>double, hue=>double | vary the brightness, saturation, and hue of an image
Negate | gray=>{True, False} | replace every pixel with its complementary color (white becomes black, yellow becomes blue, etc.)
Normalize |  | transform image to span the full range of color values
OilPaint | radius=>integer | simulate an oil painting
Opaque | color=>colorname, pen=>colorname | change this color to the pen color within the image
Quantize | colors=>integer, colorspace=>{RGB, Gray, Transparent, OHTA, XYZ, YCbCr, YIQ, YPbPr, YUV, CMYK}, treedepth=> integer, dither=>{True, False}, measure_error=>{True, False}, global_colormap=>{True, False} | preferred number of colors in the image
Raise | geometry=>geometry, width=>integer, height=>integer, x=>integer, y=>integer, raise=>{True, False} | lighten or darken image edges to create a 3-D effect
ReduceNoise |  | add or reduce the noise in an image
Roll | geometry=>geometry, x=>integer, y=>integer | roll an image vertically or horizontally
Rotate | degrees=>double, crop=>{True, False}, sharpen=>{True, False} | roll an image vertically or horizontally
Sample | geometry=>geometry, width=>integer, height=>integer | scale image with pixel sampling
Scale | geometry=>geometry, width=>integer, height=>integer | scale image to desired size
Segment | colorspace=>{RGB, Gray, Transparent, OHTA, XYZ, YCbCr, YCC, YIQ, YPbPr, YUV, CMYK}, verbose={True, False}, cluster=>double, smooth=double | segment an image by analyzing the histograms of the color components and identifying units that are homogeneous
Shade | geometry=>geometry, azimuth=>double, elevation=>double, color=>{true, false} | shade the image using a distant light source
Sharpen | factor=>percentage | sharpen an image
Shear | geometry=>geometry, x=>double, y=>double, crop=>{true, false} | shear the image along the X or Y axis by a positive or negative shear angle
Signature |  | generate an MD5 signature for the image
Solarize | factor=>percentage | negate all pixels above the threshold level
Spread | amount=>integer | displace image pixels by a random amount
Stereo | image=>image-handle | combines two images and produces a single image that is the composite of a left and right image of a stereo pair
Stegano | image=>image-handle, offset=integer | hide a digital watermark within the image
Swirl | degrees=>double | swirl image pixels about the center
Texture | texture=>image-handle | name of texture to tile onto the image background
Threshold | threshold=>integer | threshold the image
Transform | crop=>geometry, geometry=>geometry, filter=>{Point, Box, Triangle, Hermite, Hanning, Hamming, Blackman, Gaussian, Quadratic, Cubic, Catrom, Mitchell, Lanczos, Bessel, Sinc} | crop or resize an image with a fully-qualified geometry specification
Transparent | color=>colorname | make this color transparent within the image
Trim |  | remove edges that are the background color from the image
Wave | geometry=>geometry, amplitude=>double, wavelength=>double | alter an image along a sine wave
Zoom | geometry=>geometry, width=>integer, height=>integer, filter=>{Point, Box, Triangle, Hermite, Hanning, Hamming, Blackman, Gaussian, Quadratic, Cubic, Catrom, Mitchell, Lanczos, Bessel, Sinc}, blur=>double | scale image to desired size. Specify `blur` > 1 for blurry or < 1 for sharp

Note, that the `geometry` parameter is a short cut for the `width` and `height` parameters (e.g. `geometry=>'106x80'` is equivalent to `width=>106, height=>80`).

You can specify `@filename` in both `Annotate` and `Draw`. This reads the text or graphic primitive instructions from a file on disk. For example,

       $image->Draw(pen=>'red', primitive=>'rectangle',
         points=>'20,20 100,100  40,40 200,200  60,60 300,300');

Is eqivalent to

       $image->Draw(pen=>'red', primitive=>'@draw.txt');

Where `draw.txt` is a file on disk that contains this:

      rectangle 20, 20 100, 100
      rectangle 40, 40 200, 200
      rectangle 60, 60 300, 300

The text parameter for methods, `Annotate`, `Comment`, `Draw`, and `Label` can include the image filename, type, width, height, or other image attribute by embedding these special format characters:

        %b   file size
        %d   directory
        %e   filename extension
        %f   filename
        %h   height
        %m   magick
        %p   page number
        %s   scene number
        %t   top of filename
        %w   width
        %x   x resolution
        %y   y resolution
        \n   newline
        \r   carriage return

For example,

      text=>"%m:%f %wx%h"

  produces an annotation of MIFF:bird.miff 512x480 for an image titled bird.miff and whose width is 512 and height is 480.

You can optionally add `Image` to any method name. For example, `TrimImage` is an alias for method `Trim`.

Most of the attributes listed above have an analog in convert. See the documentation for a more detailed description of these attributes.

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Set an Image Attribute

  Use method `Set` to set an image attribute. For example,

        $image->Set(dither=>'True');
        $image->[$x]->Set(delay=>3);

And here is a list of all the image attributes you can set:

Image Attributes
Attribute | Values | Description
--- | --- | ---
adjoin | {True, False} | join images into a single multi-image file
antialias | {True, False} | remove pixel aliasing
background | string | image background color
blue_primary | x-value, y-value | chromaticity blue primary point (e.g. 0.15, 0.06)
bordercolor | string | set the image border color
colormap[i] | string | color name (e.g. red) or hex value (e.g. #ccc) at position i
colorspace | {RGB, CMYK} | type of colorspace
compress | None, BZip, Fax, Group4, JPEG, LZW, Runlength, Zip | type of image compression
delay | integer | this many 1/100ths of a second\fP must expire before displaying the next image in a sequence
density | geometry | vertical and horizontal resolution in pixels of the image
dispose | {0, 1, 2, 3, 4} | GIF disposal method
dither | {True, False} | apply error diffusion to the image
display | string | specifies the X server to contact
file | filehandle | set the image filehandle
filename | string | set the image filename
font | string | use this font when annotating the image with text
fuzz | integer | colors within this distance are considered equal
green_primary | x-value, y-value | chromaticity green primary point (e.g. 0.3, 0.6)
interlace | {None, Line, Plane, Partition} | the type of interlacing scheme
iterations | integer | add Netscape loop extension to your GIF animation
loop | integer | add Netscape loop extension to your GIF animation
magick | string | set the image format
matte | {True, False} | True if the image has transparency
mattecolor | string | set the image matte color
monochrome | {True, False} | transform the image to black and white
page | { Letter, Tabloid, Ledger, Legal, Statement, Executive, A3, A4, A5, B4, B5, Folio, Quarto, 10x14} or geometry | preferred size and location of an image canvas
pen | color | color name (e.g. red) or hex value (e.g. #ccc) for annotating or changing opaque color
pixel[x, y] | string | color name (e.g. red) or hex value (e.g. #ccc) at position (x, y)
pointsize | integer | pointsize of the Postscript or TrueType font
preview | { Rotate, Shear, Roll, Hue, Saturation, Brightness, Gamma, Spiff, Dull, Grayscale, Quantize, Despeckle, ReduceNoise, AddNoise, Sharpen, Blur, Threshold, EdgeDetect, Spread, Solarize, Shade, Raise, Segment, Swirl, Implode, Wave, OilPaint, CharcoalDrawing, JPEG} | type of preview for the Preview image format
quality | integer | JPEG/MIFF/PNG compression level
red_primary | x-value, y-value | chromaticity red primary point (e.g. 0.64, 0.33)
rendering_intent | {Undefined, Saturation, Perceptual, Absolute, Relative} | the type of rendering intent
scene | integer | image scene number
subimage | integer | subimage of an image sequence
subrange | integer | number of images relative to the base image
server | string | specifies the X server to contact
size | string | width and height of a raw image
tile | string | tile name
texture | string | name of texture to tile onto the image background
units | { Undefined, PixelsPerInch, PixelsPerCentimeters} | units of image resolution
verbose | {True, False} | print detailed information about the image
view | string | FlashPix viewing parameters
white_point | x-value, y-value | chromaticity white point (e.g. 0.3127, 0.329)

Note, that the `geometry` parameter is a short cut for the `width` and `height` parameters (e.g. `geometry=>'106x80'` is equivalent to `width=>106, height=>80`).

`SetAttribute` is an alias for method `Set`.

Most of the attributes listed above have an analog in convert. See the documentation for a more detailed description of these attributes.

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Get an Image Attribute

  Use method `Get` to get an image attribute. For example,

        ($a, $b, $c) = $image->Get('colorspace', 'magick', 'adjoin');
        $width = $image->[3]->Get('columns');

In addition to all the attributes listed in Set an Image Attribute, you can get these additional attributes:

Image Attributes
Attribute | Values | Description
--- | --- | ---
base_columns | integer | base image width (before transformations)
base_filename | string | base image filename (before transformations)
base_rows | integer | base image height (before transformations)
class | {Direct, Pseudo} | image class
colors | integer | number of unique colors in the image
comment | string | image comment
columns | integer | image width
depth | integer | image depth
directory | string | tile names from within an image montage
filesize | integer | number of bytes of the image on disk
format | string | get the descriptive image format
gamma | double | gamma level of the image
geometry | string | image geometry
height | integer | the number of rows or height of an image
label | string | image label
mean | double | the mean error per pixel computed when an image is color reduced
montage | geometry | tile size and offset within an image montage
normalized_max | double | the normalized max error per pixel computed when an image is color reduced
normalized_mean | double | the normalized mean error per pixel computed when an image is color reduced
packetsize | integer | the number of bytes in each pixel packet
packets | integer | the number of runlength-encoded packets in the image
rows | integer | the number of rows or height of an image
signature | string | MD5 signature associated with the image
tainted | {True, False} | True if the image has been modified
text | string | any text associated with the image
type | {Bilevel, Grayscale, Palette, TrueColor, MatteType, ColorSeparation } | image type
width | integer | the number of columns or width of an image
x-resolution | integer | x resolution of the image
y-resolution | integer | y resolution of the image

`GetAttribute` is an alias for method `Get`.

Most of the attributes listed above have an analog in convert. See the documentation for a more detailed description of these attributes.

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Create an Image Montage

  Use method `Montage` to create a composite image by combining several separate images. The images are tiled on the composite image with the name of the image optionally appearing just below the individual tile. For example,

        $image->Montage(geometry=>'160x160', tile=>'2x2', texture=>'granite:');

And here is a list of `Montage` parameters you can set:

Montage Parameters
Parameter | Values | Description
--- | --- | ---
background | color | X11 color name
borderwidth | integer | image border width
compose | {Over, In, Out, Atop, Xor, Plus, Minus, Add, Subtract, Difference, Bumpmap, Replace, MatteReplace, Mask, Blend, Displace} | composite operator
filename | string | name of montage image
font | string | X11 font name
frame | geometry | surround the image with an ornamental border
geometry | geometry | preferred tile and border size of each tile of the composite image
gravity | {NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast} | direction image gravitates to within a tile
label | string | assign a label to an image
mode | {Frame, Unframe, Concatenate} | thumbnail framing options
pen | string | color for annotation text
pointsize | integer | pointsize of the Postscript or TrueType font
shadow | {True, False} | add a shadow beneath a tile to simulate depth
texture | string | name of texture to tile onto the image background
tile | geometry | number of tiles per row and column
title | string | assign a title to the image montage
transparent | string | make this color transparent within the image

Note, that the `geometry` parameter is a short cut for the `width` and `height` parameters (e.g. `geometry=>'106x80'` is equivalent to `width=>106, height=>80`).

`MontageImage` is an alias for method `Montage`.

Most of the attributes listed above have an analog in montage. See the documentation for a more detailed description of these attributes.

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Miscellaneous Methods

  The `Append` method append a set of images. For example,

        $x = $image->Append(stack=>{true,false});

appends all the images associated with object `$image`. All the input images must have the same width or height. Images of the same width are stacked top-to-bottom. Images of the same height are stacked left-to-right. If the stack parameter is false, rectangular images are stacked left-to-right otherwise top-to-bottom.

  The `Average` method averages a set of images. For example,

        $x = $image->Average();

averages all the images associated with object `$image`.

  The `Morph` method morphs a set of images. Both the image pixels and size are linearly interpolated to give the appearance of a meta-morphosis from one image to the next:

        $x = $image->Morph(frames=>integer);

where frames is the number of in-between images to generate. The default is 1.

Method `Mogrify` is a single entry point for the image manipulation methods (Manipulate an Image). The parameters are the name of a method followed by any parameters the method may require. For example, these calls are equivalent:

        $image->Crop('340x256+0+0');
        $image->Mogrify('crop', '340x256+0+0');

Method `MogrifyRegion` applies a transform to a region of the image. It is similiar to `Mogrify` but begins with the region geometry. For example, suppose you want to brighten a 100x100 region of your image at location (40, 50):

        $image->MogrifyRegion('100x100+40+50', 'modulate', brightness=>50);

  The `Clone` method copies a set of images. For example,

        $p = $image->Clone();

copies all the images from object `$q` to `$p`. Use this method for multi-image sequences. PerlMagick transparently creates a linked list from an image array. If two locations in the array point to the same object, the linked list goes into an infinite loop and your script will run forever until interrupted. Instead of

        push(@$images, $image);
        push(@$images, $image);  # warning duplicate object

use cloning to prevent an infinite loop:

        push(@$images, $image);
        $clone=$image->Clone();
        push(@$images, $clone);  # same image but different object

`Ping` accepts one or more image file names and returns their respective width, height, size in bytes, and format (e.g. GIF, JPEG, etc.). For example,

        ($width, $height, $size, $format) = split(',', $image->Ping('logo.gif'));

This is a more efficient and less memory intensive way to query if an image exists and what its characteristics are. Note, only information about the first image in a multi-frame image file is returned.

You can optionally add `Image` to any method name above. For example, `PingImage` is an alias for method `Ping`.

Use `RemoteCommand` to send a command to an already running display or animate application. The only parameter is the name of the image file to display or animate.

Finally, for convenience, method `QueryColor` accepts one or more color names or hex value and returns their respective red, green, and blue color values:

        ($red, $green, $blue) = split(', ', $image->QueryColor('cyan'));
        ($red, $green, $blue) = split(', ', $image->QueryColor('#716bae'));

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Handling Errors

  All PerlMagick methods return an undefined string context upon success. If any problems occur, the error is returned as a string with an embedded numeric status code. A status code less than 400 is a warning. This means that the operation did not complete but was recoverable to some degree. A numeric code greater or equal to 400 is an error and indicates the operation failed completely. Here is how errors are returned for the different methods:

- Methods which return a number (e.g. `Read`, `Write`):

        $x = $image->Read(...);
        warn "$x" if "$x";      # print the error message
        $x =~ /(\d+)/;
        print $1;               # print the error number
        print 0+$x;             # print the number of images read

- Methods which operate on an image (e.g. `Zoom`, `Crop`):

        $x = $image->Crop(...);
        warn "$x" if "$x";      # print the error message
        $x =~ /(\d+)/;
        print $1;               # print the error number

- Methods which return images (`Average`, `Montage`, `Clone`) should be checked for errors this way:

        $x = $image->Montage(...);
        warn "$x" if !ref($x);  # print the error message
        $x =~ /(\d+)/;
        print $1;               # print the error number

Here is an example error message:

        Error 400: Memory allocation failed

Below is a list of error and warning codes:

Error and Warning Codes
Code | Mnemonic | Description
--- | --- | ---
0 | Success | method completed without an error or warning
300 | ResourceLimitWarning | a program resource is exhausted (e.g. not enough memory)
305 | XServerWarning | an X resource is unavailable
310 | OptionWarning | a command-line option was malformed
315 | DelegateWarning | an ImageMagick delegate returned a warning
320 | MissingDelegateWarning | the image type can not be read or written because the appropriate Delegate is missing
325 | CorruptImageWarning | the image file may be corrupt
330 | FileOpenWarning | the image file could not be opened
400 | ResourceLimitError | a program resource is exhausted (e.g. not enough memory)
405 | XServerError | an X resource is unavailable
410 | OptionError | a command-line option was malformed
415 | DelegateError | an ImageMagick delegate returned a warning
420 | MissingDelegateError | the image type can not be read or written because the appropriate Delegate is missing
425 | CorruptImageError | the image file may be corrupt
430 | FileOpenError | the image file could not be opened

The following illustrates how you can use a numeric status code:

        $x = $image->Read('rose.gif');
        $x =~ /(\d+)/;
        die "unable to continue" if ($1 == ResourceLimitError);

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Working with Blobs

  A blob contains data that directly represent a particular image format in memory instead of on disk. PerlMagick supports blobs in any of these image formats and provides methods to convert a blob to or from a particular image format.

Blob Methods
Method | Parameters | Return Value | Description
--- | --- | --- | ---
ImageToBlob | any image attribute | an array of image data in the respective image format | convert an image or image sequence to an array of blobs
BlobToImage | one or more blobs | the number of blobs converted to an image | convert one or more blobs to an image

`ImageToBlob` returns the image data in their respective formats. You can then print it, save it to an ODBC database, write it to a file, or pipe it to a display program:

        @blobs = $image->ImageToBlob();
        open(DISPLAY,"| display -") || die;
        binmode DISPLAY;
        print DISPLAY $blobs[0];
        close DISPLAY;

Method `BlobToImage` returns an image or image sequence converted from the supplied blob:

        $blob=$db->GetImage();
        $image=Image::Magick->new(magick=>'jpg');
        $image->BlobToImage($blob);

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Copyright

  Copyright 1999 E. I. du Pont de Nemours and Company

  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files ("PerlMagick"), to deal in PerlMagick without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of PerlMagick, and to permit persons to whom the PerlMagick is furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all copies or substantial portions of PerlMagick.

  The software is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement.In no event shall E. I. du Pont de Nemours and Company be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with PerlMagick or the use or other dealings in PerlMagick.

  Except as contained in this notice, the name of the E. I. du Pont de Nemours and Company shall not be used in advertising or otherwise to promote the sale, use or other dealings in PerlMagick without prior written authorization from the E. I. du Pont de Nemours and Company.

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Image manipulation software that works like magic.