Class: MapPrint::LayerHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/map_print/layer_handler.rb

Constant Summary collapse

PROVIDERS = 
{
  'bing' => Providers::Bing,
  'osm'  => Providers::OpenStreetMap
}

Instance Method Summary collapse

Constructor Details

#initialize(layers, south_west, north_east, zoom) ⇒ LayerHandler

Returns a new instance of LayerHandler.



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# File 'lib/map_print/layer_handler.rb', line 8

def initialize(layers, south_west, north_east, zoom)
  @layers = layers.sort_by { |layer| layer[:level] }
  @south_west = LatLng.new(south_west[:lat], south_west[:lng])
  @north_east = LatLng.new(north_east[:lat], north_east[:lng])
  @zoom = zoom
end

Instance Method Details

#process ⇒ Object 



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# File 'lib/map_print/layer_handler.rb', line 15

def process
  @layers.each do |layer|
    provider_class = PROVIDERS[layer[:type]]
    provider = provider_class.new(@south_west, @north_east, @zoom, layer[:urls] && layer[:urls].first)
    layer[:image] = provider.download
  end

  @layers.first[:image].close
  image = MiniMagick::Image.open(@layers.first[:image].path)
  tmp_file = Tempfile.new(['layers', '.png'])

  @layers[1..-1].each do |layer|
    next_image = layer[:image]
    next_image.close
    tmp_image = MiniMagick::Image.open(next_image.path)
    result = image.composite(tmp_image) do |c|
      c.density 300
      c.compose "atop"
      if layer[:opacity] && layer[:opacity] < 1
        c.blend layer[:opacity] * 100
      end
    end
    result.write tmp_file.path
    image = MiniMagick::Image.open(tmp_file.path)
  end
  image.write tmp_file.path
  tmp_file.close
  tmp_file
end