Class: Fleximage::Operator::Text

Inherits:
Base
  • Object
show all
Defined in:
lib/fleximage/operator/text.rb

Overview

Draw text on the image. Customize size, position, color, dropshadow, and font.

image.text(string_to_write, options = {})

Use the following keys in the options hash:

  • alignment: symbol like in ImageOverlay

  • offset: size string

  • antialias: true or false

  • color: string or color(r, g, b)

  • font_size: integer

  • font: path to a font file relative to Rails.root

  • rotate: degrees as an integer

  • shadow: {:blur => 1, :opacity => 1.0}

  • font_weight: RMagick font weight constant or value. See: www.imagemagick.org/RMagick/doc/draw.html#font_weight

  • stroke: hash that, if present, will stroke the text. The hash should have both :width (integer) and :color (string or color object).

Example:

@photo.operate do |image|
  image.text('I like Cheese',
    :alignment => :top_left,
    :offset => '300x150',
    :antialias => true,
    :color => 'pink',
    :font_size => 24,
    :font => 'path/to/myfont.ttf',
    :rotate => -15,
    :shadow => {
      :blur => 1,
      :opacity => 0.5,
    },
    :stroke => {
      :width => 3,
      :color => color(0, 0, 0),
    }
  )
end

Instance Method Summary collapse

Methods inherited from Base

#color, color, #execute, #initialize, #scale, #scale_and_crop, size_to_xy, #size_to_xy, #stretch, #symbol_to_blending_mode, #symbol_to_gravity

Constructor Details

This class inherits a constructor from Fleximage::Operator::Base

Instance Method Details

#operate(string_to_write, options = {}) ⇒ Object 



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# File 'lib/fleximage/operator/text.rb', line 43

def operate(string_to_write, options = {})
  options = {
    :alignment  => :top_left,
    :offset     => '0x0',
    :antialias  => true,
    :color      => 'black',
    :font_size  => '12',
    :font       => nil,
    :text_align => :left,
    :rotate     => 0,
    :shadow     => nil,
    :stroke     => {
      :width => 0,
      :color => 'white',
    }
  }.merge(options)
  options[:offset] = size_to_xy(options[:offset])

  # prepare drawing surface
  text                = Magick::Draw.new
  text.gravity        = symbol_to_gravity(options[:alignment])
  text.fill           = options[:color]
  text.text_antialias = options[:antialias]
  text.pointsize      = options[:font_size].to_i
  text.rotation       = options[:rotate]
  text.font_weight    = options[:font_weight] if options[:font_weight]
  
  if options[:stroke][:width] > 0
    text.stroke_width   = options[:stroke][:width]
    text.stroke         = options[:stroke][:color]
  end

  # assign font path with to rails root unless the path is absolute
  if options[:font]
    font = options[:font]
    font = "#{Rails.root}/#{font}" unless font =~ %r{^(~?|[A-Za-z]:)/}
    text.font = font
  end

  # draw text on transparent image
  temp_image = Magick::Image.new(@image.columns, @image.rows) { self.background_color = 'none' }
  temp_image = temp_image.annotate(text, 0, 0, options[:offset][0], options[:offset][1], string_to_write)

  # add drop shadow to text image
  if options[:shadow]
    shadow_args = [2, 2, 1, 1]
    if options[:shadow].is_a?(Hash)
      #shadow_args[0], shadow_args[1] = size_to_xy(options[:shadow][:offset]) if options[:shadow][:offset]
      shadow_args[2] = options[:shadow][:blur]                               if options[:shadow][:blur]
      shadow_args[3] = options[:shadow][:opacity]                            if options[:shadow][:opacity]
    end
    shadow = temp_image.shadow(*shadow_args)
    temp_image = shadow.composite(temp_image, 0, 0, symbol_to_blending_mode(:over))
  end

  # composite text on original image
  @image.composite!(temp_image, 0, 0, symbol_to_blending_mode(:over))
end