Class: Dragonfly::Generation::RMagickGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/dragonfly/generation/r_magick_generator.rb

Constant Summary collapse

FONT_STYLES = 
{
  'normal' => Magick::NormalStyle,
  'italic' => Magick::ItalicStyle,
  'oblique' => Magick::ObliqueStyle
}
FONT_STRETCHES = 
{
  'normal'          => Magick::NormalStretch,
  'semi-condensed'  => Magick::SemiCondensedStretch,
  'condensed'       => Magick::CondensedStretch,
  'extra-condensed' => Magick::ExtraCondensedStretch,
  'ultra-condensed' => Magick::UltraCondensedStretch,
  'semi-expanded'   => Magick::SemiExpandedStretch,
  'expanded'        => Magick::ExpandedStretch,
  'extra-expanded'  => Magick::ExtraExpandedStretch,
  'ultra-expanded'  => Magick::UltraExpandedStretch
}
FONT_WEIGHTS = 
{
  'normal'  => Magick::NormalWeight,
  'bold'    => Magick::BoldWeight,
  'bolder'  => Magick::BolderWeight,
  'lighter' => Magick::LighterWeight,
  '100'     => 100,
  '200'     => 200,
  '300'     => 300,
  '400'     => 400,
  '500'     => 500,
  '600'     => 600,
  '700'     => 700,
  '800'     => 800,
  '900'     => 900
}

Instance Method Summary collapse

Instance Method Details

#plasma(width, height, format = 'png') ⇒ Object 



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# File 'lib/dragonfly/generation/r_magick_generator.rb', line 45

def plasma(width, height, format='png')
  image = Magick::Image.read("plasma:fractal"){self.size = "#{width}x#{height}"}.first
  image.format = format.to_s
  content = use_filesystem ? write_to_tempfile(image) : image.to_blob
  image.destroy!
  [
    content,
    {:format => format.to_sym, :name => "plasma.#{format}"}
  ]
end

#text(text_string, opts = {}) ⇒ Object 



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# File 'lib/dragonfly/generation/r_magick_generator.rb', line 56

def text(text_string, opts={})
  opts = HashWithCssStyleKeys[opts]

  draw = Magick::Draw.new
  draw.gravity = Magick::CenterGravity
  draw.text_antialias = true

  # Font size
  font_size = (opts[:font_size] || 12).to_i

  # Scale up the text for better quality -
  #  it will be reshrunk at the end
  s = scale_factor_for(font_size)

  # Settings
  draw.pointsize    = font_size * s
  draw.font         = opts[:font] if opts[:font]
  draw.font_family  = opts[:font_family] if opts[:font_family]
  draw.fill         = opts[:color] if opts[:color]
  draw.stroke       = opts[:stroke_color] if opts[:stroke_color]
  draw.font_style   = FONT_STYLES[opts[:font_style]] if opts[:font_style]
  draw.font_stretch = FONT_STRETCHES[opts[:font_stretch]] if opts[:font_stretch]
  draw.font_weight  = FONT_WEIGHTS[opts[:font_weight]] if opts[:font_weight]

  # Padding
  # NB the values are scaled up by the scale factor
  pt, pr, pb, pl = parse_padding_string(opts[:padding]) if opts[:padding]
  padding_top    = (opts[:padding_top]    || pt || 0) * s
  padding_right  = (opts[:padding_right]  || pr || 0) * s
  padding_bottom = (opts[:padding_bottom] || pb || 0) * s
  padding_left   = (opts[:padding_left]   || pl || 0) * s

  # Calculate (scaled up) dimensions
  metrics = draw.get_type_metrics(text_string)
  width, height = metrics.width, metrics.height

  scaled_up_width = padding_left + width + padding_right
  scaled_up_height = padding_top + height + padding_bottom

  # Draw the background
  image = Magick::Image.new(scaled_up_width, scaled_up_height){
    self.background_color = opts[:background_color] || 'transparent'
  }
  # Draw the text
  draw.annotate(image, width, height, padding_left, padding_top, text_string)

  # Scale back down again
  image.scale!(1/s)

  format = opts[:format] || :png
  image.format = format.to_s

  # Output image either as a string or a tempfile
  content = use_filesystem ? write_to_tempfile(image) : image.to_blob
  image.destroy!
  [
    content,
    {:format => format, :name => "text.#{format}"}
  ]
end