DZone Snippets: magick code

Howto resize multiple pictures, graphics, images

Tue, 29 Apr 2008 16:41:33 GMT



for k in $(ls *.jpg); do convert -resize 800 -quality 80 $k r800-$k; done

Batch re-size a collection of images from the command line

27stars (27stars) — Tue, 01 Apr 2008 09:33:24 GMT



for img in $(ls *.png); do convert $img -resize 75% smaller-$img; done;

Generate a graph using Gruff

jrobertson (James Robertson) — Sun, 24 Feb 2008 18:52:14 GMT

This Ruby code produced a graph using gruff. The output shows a line graph [twitxr.com] for the different fruits. Source code origin: Gruff Update With Bar Graphs | Ruby on Rails for Newbies [rubyonrails.com]



require 'gruff'



g = Gruff::Line.new

g.title = "My Graph" 



g.data("Apples", [1, 2, 3, 4, 4, 3])

g.data("Oranges", [4, 8, 7, 9, 8, 9])

g.data("Watermelon", [2, 3, 1, 5, 6, 8])

g.data("Peaches", [9, 9, 10, 8, 7, 9])



g.labels = {0 => '2003', 2 => '2004', 4 => '2005'}



g.write('my_fruity_graph.png')

Note: I executed the code within an irb session on my Gentoo box. With Gentoo, Gruff was installed [gentoo-portage.com] using the command emerge -va gruff. I tried installing it on Ubuntu but ran into some difficulty, even with help from the article install rmagick ubuntu [dzone.com].

*udpate 21:48 24-Feb*

The following code does exactly as the same code above, however it uses XML to separate the data from the process, making it easier and more efficient to build graphs.



#!/usr/bin/ruby

# file: xml2gruff.rb



require 'rexml/document'

require 'gruff'

include REXML



class Xml2Gruff

  

  def initialize(filename)

    file = File.new(filename, 'r')

    doc = Document.new(file)

    # get the title

    @title = doc.root.elements['summary/title'].text

    

    @record = Hash.new

    # get each record

    doc.root.elements.each('records/item') {|item|

      avalues = Array.new

      item.elements.each('values/value') { |value| avalues << value.text.to_i }

      @record[item.elements['label'].text] = avalues

    }

    

    # get the summary labels

    @labels = Hash.new  

    doc.root.elements.each('summary/scale/label') {|l| @labels[l.elements['value'].text.to_i] = l.elements['title'].text} 

    

  end

  

  def save_line_graph(filename)



    g = Gruff::Line.new

    g.title = @title 

    @record.each {|label, data| g.data(label, data) }

    g.labels = @labels

    g.write(filename)



  end

end



if __FILE__ == $0

 x2g = Xml2Gruff.new('my_fruit.xml')

 x2g.save_line_graph('my_fruit2.png')

end

file: my_fruit.xml

Reference: gruff's gruff-0.2.9 Documentation [rubyforge.org]
gruff graphs for ruby by geoffrey grosenbach [topfunky.com]

Avatar Resizer

kedare (Mathieu Poussin) — Mon, 23 Apr 2007 17:13:46 GMT

I go on a lot of Bulletin Board, every has its own limits of size for the avatars, instead of the resize manually I created a script which does it for me with RMagick



#!/usr/bin/ruby

require "RMagick"

$SIZES = [80 , 100 , 110 , 128]



if !ARGV[0]

  puts "Usage: mk_avatars.rb SourceAvatarPath"

  exit

end



image = Magick::Image.read(ARGV[0]).first

$SIZES.each do |sz|

  puts "Generating Avatar : #{sz}"

  out = image.thumbnail(sz,sz)

  file = "out_#{sz}.#{image.format}"

  out.write(file)

end

Resizing images using RMagick

nohmad (Gyoung-Yoon Noh) — Wed, 18 Jan 2006 17:59:56 GMT



require 'rubygems'

require 'RMagick'



include Magick



def append_filename(filename, suffix)

  extrac = filename.split('.')

  extrac[-2] += suffix

  extrac.join('.')

end                                                                                  

ARGV.each do |f|

  ImageList.new(f).resize(800, 600).write(append_filename(f, '_l'))

  ImageList.new(f).resize(400, 300).write(append_filename(f, '_m'))

  ImageList.new(f).resize(40, 30).write(append_filename(f, '_s'))

end