quad01.rb.html

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  <title>RMagick example: quad01.rb</title>
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<h1>quad01.rb</h1>
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<pre class="language-ruby">
# frozen_string_literal: true

require 'rvg/rvg'

Magick::RVG.dpi = 90

rvg = Magick::RVG.new(12.cm, 6.cm).viewbox(0, 0, 1200, 600) do |canvas|
  canvas.title = 'Example quad01 - quadratic Bezier commands in path data'
  canvas.desc = &lt;&lt;-END_DESC
        Picture showing a "Q" a "T" command, along with annotations showing the
        control points and end points
  END_DESC
  canvas.background_fill = 'white'
  canvas.rect(1195, 592, 1, 1).styles(fill: 'none', stroke: 'blue', stroke_width: 1)

  canvas.path('M200,300 Q400,50 600,300 T1000,300')
        .styles(fill: 'none', stroke: 'red', stroke_width: 5)

  # End points
  canvas.g.styles(fill: 'black') do |grp|
    grp.circle(10, 200, 300)
    grp.circle(10, 600, 300)
    grp.circle(10, 1000, 300)
  end

  # Control points and lines from end points to control points
  canvas.g.styles(fill: '#888') do |grp|
    grp.circle(10, 400, 50)
    grp.circle(10, 800, 550)
  end

  canvas.path('M200,300 L400,50 L600,300 L800,550 L1000,300')
        .styles(fill: 'none', stroke: '#888', stroke_width: 2)
end

rvg.draw.write('quad01.gif')
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