Introduction |
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PerlMagick 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 5.4.3 or above and Perl version 5.005_02 or
greater installed on your system for either of these utilities to
work.
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 MagickStudio, 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.
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Installation |
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UNIX
The following instructions for Unix apply only to the
unbundled PerlMagick as obtained from CPAN. PerlMagick is included
as a subdirectory (PerlMagick) of the ImageMagick source
distribution, and may be configured and built using the
instructions provided in the ImageMagick distribution's README.txt
file. It is usually most convenient to install PerlMagick as part
of the ImageMagick distribution.
ImageMagick must already be installed on your system. Next, get
the PerlMagick distribution
corresponding to the installed ImageMagick distribution (e.g.
PerlMagick 5.39 for ImageMagick 5.3.0) and unpack it as shown
below:
gunzip -c PerlMagick-5.39.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 XP / Windows 2000
ImageMagick must already be installed on your system. Also, the
ImageMagick source distribution for Windows
2000 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
See the PerlMagick
Windows HowTo page for further installation instructions.
Running the Regression Tests
To verify a correct installation, type
make test
Use nmake test under Windows. There are a 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 |
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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 $image;
To delete all the images but retain the Image::Magick
object use
@$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,
$ENV{PATH}='/bin:/usr/bin:/usr/local/bin';
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Example Script |
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Here is an example script to get you started:
#!/usr/local/bin/perl use Image::Magick;
my($image, $x);
$image = Image::Magick->new; $x = $image->Read('girl.png', 'logo.png', 'rose.png'); warn "$x" if "$x";
$x = $image->Crop(geometry=>'100x100"+100"+100'); warn "$x" if "$x";
$x = $image->Write('x.png'); warn "$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.png'); $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(stroke=>'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 = 'Works like magick!'; $image->Annotate(font=>'kai.ttf', pointsize=>40, fill=>'green', text=>$text);
Other clever things you can do with a 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 @$p = (); # delete the images but not the object p $p->Convolve([1, 2, 1, 2, 4, 2, 1, 2, 1]); # 3x3 Gaussian kernel
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Read or Write an
Image |
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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', compression=>'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('png:-');
To read an image in the GIF format from a PERL filehandle, use:
$image = Image::Magick->new; open(IMAGE, 'image.gif'); $image->Read(file=>\*IMAGE); close(IMAGE);
To write an image in the PNG format to a PERL filehandle, use:
$filename = "image.png"; open(IMAGE, ">$filename"); $image->Write(file=>\*IMAGE, filename=>$filename); close(IMAGE);
If %0Nd, %0No, or %0Nx appears in the filename, it is
interpreted as a printf format specification and the specification
is replaced with the specified decimal, octal, or hexadecimal
encoding of the scene number. For example,
image%03d.miff
converts files image000.miff, image001.miff, etc.
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 |
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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"+10+20'); $image->[x]->Frame("100x200");
And here is a list of other image manipulation methods you can
call:
Image Manipulation Methods
Method |
Parameters |
Description |
AdaptiveThreshold |
geometry=>geometry, width=>integer,
height=>integer, offset=>integer |
local adaptive thresholding. |
AddNoise |
noise=>{Uniform, Gaussian, Multiplicative, Impulse,
Laplacian, Poisson} |
add noise to an image |
AffineTransform |
affine=>array of float values,
translate=>float, float, scale=> float, float,
rotate=>float, skewX=>float,
skewY=>float |
affine transform image |
Annotate |
text=>string, font=>string,
family=>string, style=>{Normal, Italic, Oblique, Any},
stretch=>{Normal, UltraCondensed, ExtraCondensed, Condensed,
SemiCondensed, SemiExpanded, Expanded, ExtraExpanded,
UltraExpanded}, weight=>integer,
pointsize=>integer, density=>geometry,
stroke=> color name,
strokewidth=>integer,
fill=>color name,
undercolor=>color name,
geometry=>geometry, gravity=>{NorthWest, North,
NorthEast, West, Center, East, SouthWest, South, SouthEast},
antialias=>{true, false}, x=>integer,
y=>integer, affine=>array of float values,
translate=>float, float, scale=>float, float,
rotate=>float. skewX=>float, skewY=>
float, align=>{Left, Center, Right},
encoding=>{UTF-8} |
annotate an image with text. See
QueryFontMetrics to get font metrics without
rendering any text. |
BlackThreshold |
threshold=>string |
force all pixels below the threshold intensity into
black |
Blur |
geometry=>geometry, radius=>double,
sigma=>double, channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
blur the image with a Gaussian operator of the given radius and
standard deviation (sigma). |
Border |
geometry=>geometry, width=>integer,
height=>integer, fill=>color
name |
surround the image with a border of color |
Charcoal |
geometry=>geometry, radius=>double,
sigma=>double |
simulate a charcoal drawing |
Chop |
geometry=>geometry, width=>integer,
height=>integer, x=>integer,
y=>integer |
chop an image |
Clip |
id=>name, inside=>{true, false}, |
apply along a named path from the 8BIM profile. |
Coalesce |
|
merge a sequence of images |
ColorFloodfill |
geometry=>geometry, x=>integer,
y=>integer , fill=>color
name, bordercolor=>color
name, fuzz=>double |
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 |
fill=>color name,
opacity=>string |
colorize the image with the fill color |
Comment |
string |
add a comment to your image |
Compare |
image=>image-handle |
compare image to a reference image |
Composite |
image=>image-handle, compose=>{Over, In, Out,
Atop, Xor, Plus, Minus, Difference, Multiply, Bumpmap, Dissolve,
Clear, Displace, Modulate, Threshold},
mask=>image-handle, geometry=>geometry,
x=>integer, y=>integer, gravity=>{NorthWest,
North, NorthEast, West, Center, East, SouthWest, South, SouthEast},
opacity=>integer, tile=>{True, False},
rotate=>double, color=>color
name |
composite one image onto another |
Contrast |
sharpen=>{True, False} |
enhance or reduce the image contrast |
Convolve |
coefficients=>array of float values,
channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
apply a convolution kernel to the image. Given a kernel
order , you would supply order*order float values
(e.g. 3x3 implies 9 values). |
Crop |
geometry=>geometry, width=>integer,
height=>integer, x=>integer,
y=>integer, fuzz=>double |
crop an image |
CycleColormap |
amount=>integer |
displace image colormap by amount |
Deconstruct |
|
break down an image sequence into constituent parts |
Describe |
file=>file |
describe in detail the attributes of an image |
Despeckle |
|
reduce the speckles within an image |
Draw |
primitive=>{point, line, rectangle, arc, ellipse, circle,
path, polyline, polygon, bezier, color, matte, text,
@filename}, points=>string , method=>{Point,
Replace, Floodfill, FillToBorder, Reset},
stroke=>color name,
fill=>color name,
tile=>image-handle, strokewidth=>float,
antialias=>{true, false},
bordercolor=>color name,
x=>float, y=>float, affine=>array of
float values, translate=>float, float,
scale=>float, float, rotate=>float.
skewX=>float, skewY=>float |
annotate an image with one or more graphic primitives |
Edge |
radius=>double |
enhance edges within the image with a convolution filter of the
given radius. |
Emboss |
geometry=>geometry, radius=>double,
sigma=>double |
emboss the image with a convolution filter of the given radius
and standard deviation (sigma). |
Enhance |
|
apply a digital filter to enhance a noisy image |
Equalize |
|
perform histogram equalization to the image |
Evaluate |
value=>double,
operator=>;{Add, And, Divide, LeftShift, Max, Min, Multiply,
Or, Rightshift, Subtract, Xor}, channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
apply an arithmetic, relational, or logical expression to the image |
Flatten |
|
flatten a sequence of images |
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, fill=>color
name |
surround the image with an ornamental border |
Gamma |
gamma=>string, channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
gamma correct the image |
GaussianBlur |
geometry=>geometry, radius=>double,
sigma=>double, channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
blur the image with a Gaussian operator of the given radius and
standard deviation (sigma). |
GetPixels |
geometry=>geometry, width=>integer,
height=>integer, x=>integer,
y=>integer, map=>string |
get normalized image pixels as defined by the map
(e.g. "RGB", "RGBA", etc.) |
Implode |
amount=>double |
implode image pixels about the center |
Label |
string |
assign a label to an image |
Level |
level=>string, 'black-point'=>double,
'gamma'=>double, 'white-point'=>double,
channel=>{Red, Cyan, Green, Magenta, Blue, Yellow, Opacity,
Black, or All} |
adjust the level of image contrast |
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=>color name,
fuzz=>double |
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. |
MedianFilter |
radius=>double |
replace each pixel with the median intensity pixel of a
neighborhood. |
Minify |
|
half the size of an image |
Modulate |
brightness=>double, saturation=>double,
hue=>double |
vary the brightness, saturation, and hue of an image by the
specified percentage |
MotionBlur |
geometry=>geometry, radius=>double,
sigma=>double, angle=>double |
blur the image with a Gaussian operator of the given radius and
standard deviation (sigma) at the given angle to simulate the
effect of motion |
Negate |
gray=>{True, False}, channel=>{Red, Cyan, Green, Magenta,
Blue, Yellow, Alpha, Black, or All} |
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=>color name,
fill=>color name |
change this color to the fill color within the image |
Posterize |
levels=>integer, dither=>{True, False} |
reduce the image to a limited number of color level |
Profile |
name=>string, profile=>blob |
add or remove ICC or IPTC image profile; name is formal name
(e.g. ICC or filename; set profile to undef to remove
profile |
Quantize |
colors=>integer, colorspace=>{RGB, Gray,
Transparent, OHTA, XYZ, YCbCr, YIQ, YPbPr, YUV, CMYK, sRGB, HSL,
HSB}, treedepth=> integer, dither=>{True, False},
measure_error=>{True, False}, global_colormap=>{True,
False} |
preferred number of colors in the image |
RadialBlur |
angle=>double |
radial blur 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 |
radius=>double |
reduce noise in the image with a noise peak elimination
filter |
Resample |
density=>geometry, x=>double,
y=>double, filter=>{Point, Box, Triangle, Hermite,
Hanning, Hamming, Blackman, Gaussian, Quadratic, Cubic, Catrom,
Mitchell, Lanczos, Bessel, Sinc}, blur=>double |
resample image to desired resolution. Specify blur
> 1 for blurry or < 1 for sharp |
Resize |
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 |
Roll |
geometry=>geometry, x=>integer,
y=>integer |
roll an image vertically or horizontally |
Rotate |
degrees=>double,
color=>color name |
rotate an image |
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 |
Separate |
channel=>{Red, Cyan, Green, Magenta, Blue, Yellow, Opacity,
Black, or All} |
separate a channel from the image into a grayscale
image |
Shade |
geometry=>geometry, azimuth=>double,
elevation=>double, gray=>{true, false} |
shade the image using a distant light source |
Sharpen |
geometry=>geometry, radius=>double,
sigma=>double, channel=>{Red, Cyan, Green, Magenta, Blue, Yellow,
Alpha, Black, or All} |
sharpen the image with a Gaussian operator of the given radius
and standard deviation (sigma). |
Shave |
geometry=>geometry, width=>integer,
height=>integer |
shave pixels from the image edges |
Shear |
geometry=>geometry, x=>double,
y=>double color=>color
name |
shear the image along the X or Y axis by a positive or negative
shear angle |
Signature |
|
generate an SHA-256 message digest for the image pixel
stream |
Solarize |
threshold=>double |
negate all pixels above the threshold level |
Spread |
amount=>double |
displace image pixels by a random amount |
Stegano |
image=>image-handle, offset=>integer |
hide a digital watermark within the image |
Stereo |
image=>image-handle |
composites two images and produces a single image that is the
composite of a left and right image of a stereo pair |
Strip |
|
strip an image of all profiles and comments. |
Swirl |
degrees=>double |
swirl image pixels about the center |
Texture |
texture=>image-handle |
name of texture to tile onto the image background |
Thumbnail |
geometry=>geometry, width=>integer,
height=>integer |
changes the size of an image to the given dimensions and
removes any associated profiles. |
Threshold |
threshold=>string, channel=>{Red, Cyan, Green,
Magenta, Blue, Yellow, Alpha, Black, or All} |
threshold the image |
Tint |
fill=>color name,
opacity=>string |
tint the image with the fill color. |
Transparent |
color=>color name |
make this color transparent within the image |
Trim |
|
remove edges that are the background color from the
image |
UnsharpMask |
geometry=>geometry, radius=>double,
sigma=>double, amount=>double,
threshold=>double |
sharpen the image with the unsharp mask algorithm. |
Wave |
geometry=>geometry, amplitude=>double,
wavelength=>double |
alter an image along a sine wave |
WhiteThreshold |
threshold=>string |
force all pixels above the threshold intensity into
white |
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(fill=>'red', primitive=>'rectangle', points=>'20,20 100,100 40,40 200,200 60,60 300,300');
Is equivalent to
$image->Draw(fill=>'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 comment %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 %z image depth \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 |
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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 |
area-limit |
integer |
set pixel area resource limit in megabytes. |
authenticate |
string |
decrypt image with this password. |
background |
color name |
image background color |
blue-primary |
x-value, y-value |
chromaticity blue primary point (e.g. 0.15, 0.06) |
bordercolor |
color name |
set the image border color |
clip-mask |
image |
Associate a clip mask with the image. |
colormap[i] |
color name |
color name (e.g. red) or hex value (e.g. #ccc) at position
i |
colorspace |
{RGB, CMYK} |
type of colorspace |
compression |
{None, BZip, Fax, Group4, JPEG, LosslessJPEG, LZW, RLE,
Zip} |
type of image compression |
debug |
{All, Annotate, Blob, Cache, Coder, Configure, Deprecate, Draw,
Exception, Locale, None, Resource, Transform, X11} |
display copious debugging information |
delay |
integer |
this many 1/100ths of a second must expire before displaying
the next image in a sequence |
density |
geometry |
vertical and horizontal resolution in pixels of the
image |
depth |
integer |
image depth |
disk-limit |
integer |
set disk resource limit in megabytes |
dispose |
{Undefined, None, Background, Previous} |
GIF disposal method |
dither |
{True, False} |
apply error diffusion to the image |
display |
string |
specifies the X server to contact |
extract |
geometry |
extract area from image |
file |
filehandle |
set the image filehandle |
filename |
string |
set the image filename |
fill |
color |
The fill color paints any areas inside the outline of drawn
shape. |
font |
string |
use this font when annotating the image with text |
fuzz |
integer |
colors within this distance are considered equal |
gamma |
double |
gamma level of the image |
Gravity |
{Forget, NorthWest, North, NorthEast, West, Center, East,
SouthWest, South, SouthEast} |
type of image gravity |
green-primary |
x-value, y-value |
chromaticity green primary point (e.g. 0.3, 0.6) |
index[x, y] |
string |
colormap index at position (x, y) |
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 |
color name |
set the image matte color |
map-limit |
integer |
set map resource limit in megabytes |
memory-limit |
integer |
set memory resource limit in megabytes |
monochrome |
{True, False} |
transform the image to black and white |
option |
string |
associate an option with an image format (e.g.
option=>'ps:imagemask' |
orientation |
{top-left, top-right, bottom-right, bottom-left, left-top,
right-top, right-bottom, left-bottom} |
image orientation |
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 |
pixel[x, y] |
string |
hex value (e.g. #ccc) at position (x,
y) |
pointsize |
integer |
pointsize of the Postscript or TrueType font |
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 |
sampling-factor |
geometry |
horizontal and vertical sampling factor |
scene |
integer |
image scene number |
server |
string |
specifies the X server to contact |
size |
string |
width and height of a raw image |
stroke |
color |
The stroke color paints along the outline of a shape. |
texture |
string |
name of texture to tile onto the image background |
type |
{Bilevel, Grayscale, GrayscaleMatte, Palette, PaletteMatte,
TrueColor, TrueColorMatte, ColorSeparation, ColorSeparationMatte,
Optimize } |
image type |
units |
{ Undefined, PixelsPerInch, PixelsPerCentimeters} |
units of image resolution |
verbose |
{True, False} |
print detailed information about the image |
virtual-pixel |
{Constant, Edge, Mirror, Tile} |
the virtual pixel method |
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 |
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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 |
get the image comment |
columns |
integer |
image width |
directory |
string |
tile names from within an image montage |
elapsed-time |
double |
elapsed time in seconds since the image was created |
error |
double |
the mean error per pixel computed with methods Compare() or
Quantize() |
bounding-box |
string |
image bounding box |
filesize |
integer |
number of bytes of the image on disk |
format |
string |
get the descriptive image format |
geometry |
string |
image geometry |
height |
integer |
the number of rows or height of an image |
id |
integer |
ImageMagick registry id |
label |
string |
image label |
mean-error |
double |
the normalized mean error per pixel computed with methods
Compare() or Quantize() |
maximum-error |
double |
the normalized max error per pixel computed with methods
Compare() or Quantize() |
MIME |
string |
get the image MIME type |
mime |
string |
MIME of the image format |
montage |
geometry |
tile size and offset within an image montage |
rows |
integer |
the number of rows or height of an image |
signature |
string |
SHA-256 message digest associated with the image pixel
stream |
taint |
{True, False} |
True if the image has been modified |
user-time |
double |
user time in seconds since the image was created |
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 |
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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 name |
background color name |
borderwidth |
integer |
image border width |
compose |
{Over, In, Out, Atop, Xor, Plus, Minus, Add, Subtract,
Difference, Bumpmap, Copy, Mask, Dissolve, Clear, Displace} |
composite operator |
filename |
string |
name of montage image |
fill |
color name |
fill color for annotations |
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 (e.g. 120x120+4+3>) |
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 |
pointsize |
integer |
pointsize of the Postscript or TrueType font |
shadow |
{True, False} |
add a shadow beneath a tile to simulate depth |
stroke |
color name |
stroke color for annotations |
texture |
string |
name of texture to tile onto the image background |
tile |
geometry |
the number of tiles per row and page (e.g. 6x4) |
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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Working with
Blobs |
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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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Miscellaneous
Methods |
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The Append() method append a set of images. For example,
$p = $image->Append(stack=>{true,false});
appends all the images associated with object $image. By
default, images are stacked left-to-right. Set stack to
True to stack them top-to-bottom.
The Average() method averages a set of images. For example,
$p = $image->Average();
averages all the images associated with object
$image.
The Clone() method copies a set of images. For example,
$p = $image->Clone();
copies all the images from object $q to $p. You
can use this method for single or multi-image sequences.
The Fx() method applies a mathematical expression to a set of
images. For example,
$p = $image->Fx(expression=>'(g+b)/2.0',channel=>'red');
replaces the red channel with the average of the green and blue
channels.
Histogram() returns the unique colors in the image and a count
for each one. The returned values are an array of red, green, blue,
opacity, and count values.
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:
$p = $image->Morph(frames=>integer);
where frames is the number of in-between images to generate.
The default is 1.
Mosaic() creates an mosaic from an image sequence.
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 similar 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):
$image->MogrifyRegion('100x100+40+50', 'modulate', brightness=>50);
Ping() is a convenience method that returns information about an
image without having to read the image into memory. It returns the
width, height, file size in bytes, and the file format of the
image. You can specify more than one filename but only one
filehandle:
($width, $height, $size, $format) = $image->Ping('logo.png');
($width, $height, $size, $format) = $image->Ping(file=>\*IMAGE);
($width, $height, $size, $format) = $image->Ping(blob=>$blob);
This is a more efficient and less memory intensive way to query if
an image exists and what its characteristics are.
PreviewImage() tiles 9 thumbnails of the specified image with an
image processing operation applied at varying strengths. This may
be helpful pin-pointing an appropriate parameter for a particular
image processing operation. Choose from these operations:
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. Here is an example:
$preview = $image->Preview('Gamma');
$preview->Display();
To have full control over text positioning you need font metric
information. Use
($x_ppem, $y_ppem, $ascender, $descender, $width, $height, $max_advance) = $image->QueryFontMetrics(parameters);
Where parameters is any parameter of the
Annotate method. The return values are:
- character width
- character height
- ascender
- descender
- text width
- text height
- maximum horizontal advance
Call QueryColor() with no parameters to return a list of known
colors names or specify one or more color names to get these
attributes: red, green, blue, and opacity value.
@colors = $image->QueryColor(); ($red, $green, $blue, $opacity) = $image->QueryColor('cyan'); ($red, $green, $blue, $opacity) = $image->QueryColor('#716bae');
QueryColorname() accepts a color value and returns its respective
name or hex value;
$name = $image->QueryColorname('rgba(80,60,0,0)');
Call QueryFont() with no parameters to return a list of known
fonts or specify one or more font names to get these attributes:
font name, description, family, style, stretch, weight, encoding,
foundry, format, metrics, and glyphs values.
@fonts = $image->QueryFont(); $weight = ($image->QueryFont('Helvetica'))[5];
Call QueryFormat() with no parameters to return a list of known
image formats or specify one or more format names to get these
attributes: adjoin, blob support, raw, decoder, encoder,
description, and module.
@formats = $image->QueryFormat();
($adjoin, $blob_support, $raw, $decoder, $encoder,
$description, $module) = $image->QueryFormat('gif');
Call MagickToMime() with the image format name to get its MIME type
such as image/tiff from tif.
$mime = $image->MagickToMime('tif');
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, the Transform() method accepts a fully-qualified
geometry specification for cropping or resizing one or more images.
For example,
$p = $image->Transform(crop=>'100x100');
You can optionally add Image to any method name above. For
example, PingImage() is an alias for method Ping().
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Handling Errors |
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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. Resize(), 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 |
TypeWarning |
A font is unavailable; a substitution may have
occurred |
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 |
335 |
BlobWarning |
a binary large object could not be allocated |
340 |
StreamWarning |
there was a problem reading or writing from a stream |
345 |
CacheWarning |
pixels could not be saved to the pixel cache |
350 |
CoderWarning |
there was a problem with an image coder |
355 |
ModuleWarning |
there was a problem with an image module |
360 |
DrawWarning |
a drawing operation failed |
365 |
ImageWarning |
the operation could not complete due to an incompatible
image |
380 |
XServerWarning |
an X resource is unavailable |
385 |
MonitorWarning |
there was a problem with prgress monitor |
390 |
RegistryWarning |
there was a problem getting or setting the registry |
395 |
ConfigureWarning |
there was a problem getting a configuration file |
400 |
ResourceLimitError |
a program resource is exhausted (e.g. not enough
memory) |
405 |
TypeError |
A font is unavailable; a substitution may have
occurred |
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 |
435 |
BlobError |
a binary large object could not be allocated |
440 |
StreamError |
there was a problem reading or writing from a stream |
445 |
CacheError |
pixels could not be saved to the pixel cache |
450 |
CoderError |
there was a problem with an image coder |
455 |
ModuleError |
there was a problem with an image module |
460 |
DrawError |
a drawing operation failed |
465 |
ImageError |
the operation could not complete due to an incompatible
image |
480 |
XServerError |
an X resource is unavailable |
480 |
MonitorError |
there was a progress monitor error |
490 |
RegistryError |
there was a problem getting or setting the registry |
495 |
ConfigureError |
there was a problem getting a configuration
file |
The following illustrates how you can use a numeric status
code:
$x = $image->Read('rose.png'); $x =~ /(\d+)/; die "unable to continue" if ($1 == ResourceLimitError);
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