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# module Magick

### Table Of Contents

- colors
- fonts
- formats
- set_cache_threshold
- set_monitor

## module methods

colors | Magick.colors { |color| block } -> Magick Magick.colors -> anArray

Description

Lists the named colors that ImageMagick knows about. If the optional block is present, calls the block once for each color, passing a Magick::Color object. Otherwise, returns an array of Magick::Color objects, one for each color.

The Magick::Color class is a Struct class with the following attributes:

Attribute | Value
--- | ---
name | The color name. For example, "red".
compliance | A ComplianceType value such as X11Compliance.
color | A Pixel object containing the RGB values.

Arguments | None
Returns | If no block is associated with the call, returns an array of Magick::Color objects.

Example

This is a small sample of `colors.miff`, the complete image created by the example program. .

ImageMagick API | GetColorInfo
fonts | Magick.fonts { |font| block } -> Magick Magick.fonts -> anArray

Description

Lists the fonts that ImageMagick knows about. If the optional block is present, calls the block once for each font, passing a Magick::Font object. Otherwise, returns an array of Magick::Font objects, one for each font.

The Magick::Font class is a Struct class with the following attributes:

Attribute | Value
--- | ---
name | The font name. For example, "Palatino-Roman".
description | The font description. For example, "Palatino Roman".
family | The font family. For example, "Palatino", "Helvetica", or "Courier".
style | A StyleType value such as `NormalStyle`.
stretch | A StretchType value such as `NormalStretch`.
weight | The font weight, one of 100, 200, 300, 400, 500, 600, 700, 800, or 900.
encoding | The font encoding, such as "AppleRoman". May be `nil`.
foundry | The font foundry. "URW", for example. May be `nil`.
format | If the font is a Type1 font, has the value "type1", otherwise `nil`.

Arguments | None
Returns | If no block is associated with the call, returns an array of Magick::Font objects.
Example | fonts.rb
ImageMagick API | GetFontInfo
formats | Magick.formats { |f,v| block } -> Magick Magick.formats -> aHash
Description | Describes the image formats supported by ImageMagick (and therefore RMagick). If the optional block is present, calls the block once for each image format. The first argument, f, is the format name. The second argument, v, is the properties string described below.
Arguments | None

Returns

A hash of ImageMagick image formats and their properties. Each key in the returned hash is the name of a supported ImageMagick image format. Each value is a string in the form "BRWA", where

B | is "*" if the format has native blob support, and "-" otherwise.
R | is "r" if ImageMagick can read the format, and "-" otherwise.
W | is "w" if ImageMagick can write the format, and "-" otherwise.
A | is "+" if the format supports multi-image files, and "-" otherwise.

Example

    p Magick.formats »
       {"TIF"=>"*rw+",
       "H"=>"*rw-",
       "MNG"=>"*rw+",
       "NULL"=>"*rw-",
       ...
       "G"=>"*rw+",
       "GIF"=>"*rw+",
       "PDB"=>"*rw+"}

ImageMagick notes | http://www.imagemagick.org/www/formats.html
Advanced | ImageMagick depends on external programs for some formats. Depending on how ImageMagick was installed on your system, some formats may not be available. If you have questions, ask your system administrator.
set_cache_threshold | Magick.set_cache_threshold(n)
Description | Sets the amount of free memory allocated for the pixel cache.
Arguments | An integer number of megabytes.

Example

    # set the cache threshold to 10Mb
    Magick.set_cache_threshold(10)

ImageMagick notes | Once this threshold is exceeded, all subsequent pixels cache operations are to/from disk.
set_monitor | Magick.set_monitor(aProc)

Description

Establish a monitor exit block. Some (see below) RMagick methods will call the monitor event block, passing parameters that describe how much work there is to be done and how much of that work has already been accomplished.

There can be at most one monitor block defined at a time. To turn off monitoring, call Magick.set_monitor(nil).

The argument is a block. The block should accept 3 arguments:

text
  a String that describes the operation being monitored.
quantum
  a value between 0 and span that represents the number of events that have been performed, images that have been processed, etc.
span
  The total number of events to be performed, images to be processed, etc.

Arguments | A Proc object.

Example

    #! /usr/local/bin/ruby -w
    require 'RMagick'
    img = Magick::Image.read("images/Cheetah.jpg").first
    monitor = Proc.new { |text, quantum, span|
        printf("%s %3.0f%% complete\n", text, ((quantum/span.to_f)*100.0))
        }
    Magick.set_monitor(monitor)
    img.resize!(.50)
    exit

produces:

      Resize image...     0% complete
      Resize image...    29% complete
      Resize image...    57% complete
      Resize image...    86% complete
      Resize image...   100% complete

ImageMagick notes

The list of methods which call the monitor block is difficult to determine. The only sure way to find out is to read the ImageMagick source code. In the Image class the list includes add_noise, blur_image, channel, chop, colorize, crop, colors, despeckle, enhance, equalize, flip, flop, frame, gamma_correct, implode, level, magnify, median_filter, minify, modulate, morph, negate, normalize, oil_paint, opaque, raise, reduce_noise, resize, roll, rotate, sample, scale, segment, shade, sharpen, shear, solarize, spread, stegano, stereo, swirl, texture threshold, transparent, and wave. In the ImageList class, the list includes append, average, and montage.

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