The Gruff Graphing Library is a project to make beautiful graphs with Ruby easily.

It relies on ImageMagick and RMagick.

Installation on Red Hat/Centos systems

The package ImageMagick is in the standard OS repository.

The package ruby-RMagick is available on EPEL.

yum -y install ImageMagick
yum -y install ruby-RMagick # needs EPEL
yum -y install liberation-fonts # RHEL 5
yum -y install liberation-fonts-common liberation-sans-fonts # RHEL 6
gem install gruff

You can download the gem on http://www.rubygems.org

Alternatively you can use a rpm package for gruff, rubygem-gruff, available on http://www.kermit.fr/custom/

Use the font like this :

g = Gruff::Line.new()
g.font = '/usr/share/fonts/liberation/LiberationSans-Regular.ttf'

Installation on Windows

I followed the video tutorial RMagick 2.13.1 Gem Install for Ruby 1.9.3 on Windows 7

Here is a summary with some extra details.

Tested on Windows 2003 and Windows Seven.

Download Ruby for Windows from http://www.rubyinstaller.org/downloads/

Install in c:\Ruby193 :

  • rubyinstaller-1.9.3-p194.exe

During the installation, select Add Ruby executables to you PATH and Associate .rb files with this Ruby installation.

Download Development Kit from http://www.rubyinstaller.org/downloads/

  • DevKit-tdm-32-4.5.2-20111229-1559-sfx.exe

Check the installation procedure from https://github.com/oneclick/rubyinstaller/wiki/Development-Kit

Unzip in C:\DevKit

Then at a command prompt :

C:
cd \DevKit
ruby dk.rb init
ruby dk.rb install

Download MinGW from http://sourceforge.net/projects/mingw/files/

  • x86-mingw32-build-1.0-sh.tar.bz2

Install in C:\MinGW

During the installation, select MinGW Developer Toolkit.

Add C:\MinGW\bin; at the beginning of the PATH environment variable.

Download ImageMagick from http://imagemagick.org/script/binary-releases.php#windows

Install in C:\ImageMagick :

  • ImageMagick-6.7.9-4-Q16-windows-static.exe

AND

  • ImageMagick-6.7.9-4-Q16-windows-dll.exe

During the installation, select Install development headers for C and C++.

Download the source code from http://www.imagemagick.org/script/download.php

  • ImageMagick-6.7.9-4.zip

Extract as C:\ImageMagick\SourceCode

Get the rmagick gem from http://www.rubygems.org

Build it in a command prompt :

gem install rmagick-2.13.1.gem --platform=ruby -- "--with-opt-include=C:/ImageMagick/SourceCode" "--with-opt-lib=C:/ImageMagick"

Get the gruff gem from http://www.rubygems.org

Install it :

gem install gruff-0.3.6.gem

In your programs with Gruff 0.3.6, you get a "ZeroDivisionError".

Patch with information from https://github.com/topfunky/gruff/issues/21

In lib/gruff/base.rb (C:\Ruby193\lib\ruby\gems\1.9.1\gems\gruff-0.3.6\lib\gruff\base.rb),

replace :

     def label(value)
       label = if (@spread.to_f % @marker_count.to_f == 0) || !@y_axis_increment.nil?

With :

     def label(value)
       label = if (@spread.to_f % (@marker_count.to_f==0 ? 1 : @marker_count.to_f) == 0) || !@y_axis_increment.nil?

Or force maker_count just after instantiation :

g = Gruff::Line.new()
g.marker_count = 10

Monkey patch for displaying labels vertically

For Gruff 0.3.6.

Just add at the top of your program :

# Monkey patch for displaying labels vertically in Gruff 0.3.6

class Gruff::Base
    def draw_label(x_offset, index)
          return if @hide_line_markers

          if !@labels[index].nil? && @labels_seen[index].nil?
            y_offset = @graph_bottom + LABEL_MARGIN

            @d.fill = @font_color
            @d.font = @font if @font
            @d.stroke('transparent')
            @d.rotation = 90 # patch
            @d.text_align( LeftAlign ) # patch
            @d.font_weight = NormalWeight
            @d.pointsize = scale_fontsize(@marker_font_size)
            @d.gravity = NorthWestGravity # patch
            @d = @d.annotate_scaled(@base_image,
                                    1.0, 1.0,
                                    x_offset, y_offset,
                                    @labels[index], @scale)
            @d.rotation = -90 # patch
            @labels_seen[index] = 1
            debug { @d.line 0.0, y_offset, @raw_columns, y_offset }
          end
    end

    def bmargin=(margin)
        @bottom_margin = margin
    end
end

You may need also to reduce the font size for the labels and adjust the margin :

g = Gruff::Line.new()
g.marker_font_size = 11
g.bmargin = 60          # check the method in the monkey patch above

Additional tags : graph, chart, rmagick, imagemagick