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{{topTenTips}}
An introduction to computer programming using Ruby. Comprising
*[[ruby:Tutorials| Tutorials]] which present problems and their solutions.
*[[ruby:Guides| How to...]] guides to completing common tasks.
*[[ruby:Assessments| Assessments]] graded problems with solutions.
==An Example: drawing the French tricolour ==
You can create images using the GD2 library. The first tutorial [[{{NAMESPACE}}:Flags Tutorial|Flags]] looks at drawing flags of the world, from simple flags such as Libya to more complicated flags such as the Stars and Stripes of the USA.

With GD2 you can set the canvas color and draw a rectangle to create simple images.        
<question height="100" width="150" imgOut="flag.png" className="Raster" title="France" rows="9" cols="40" lang='rb'> 
[[Image:Flag_guide_france.png|border|right]] 
Notice that the blue rectangle has corners at (0,0) and (50,100) and has color [1,0,0]
<div style='clear:right'>
 g.color = image.palette.resolve Color[1.0, 0, 0]
 g.rectangle(0,0,50,100,filled=true)
</div>
<shell lang="rb" className="Flag" import="shells.xml#rasterrb"/>
<prog>
image.draw do |g|
  g.color = image.palette.resolve Color[0,0,1.0]
  g.rectangle(0,0,50,100,filled=true)
  g.color = image.palette.resolve Color[1.0,1.0,1.0]
  g.rectangle(50,0,100,100,filled=true)
  g.color = image.palette.resolve Color[1.0,0,0]
  g.rectangle(100,0,150,100,filled=true)
end
</prog>
</question>

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