Class: Cabird::PrettyText

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

Overview

This class represents a rendered text. It provides methods to get the path and the geometry to the generated image. Some parameters of the rendering process can be set using the global Hash PRETTY_TEXT. These are the configuration keys for PRETTY_TEXT:

:image_path

The public path where the plugin stores the rendered images relative to the public path. Defaults to ‘images/pretty_text’

:scale_threshold

Some fonts might look a little bit ugly at smaller sizes. PrettyText tries to fix that by rendering small fonts 5 times bigger and scaling the result down to the original size. You can set a threshold for the font size in pts. All fonts smaller than this threshold will be rendered using this scale hack.

:scale_filter

The ImageMagick filter which is used for resizing. Defaults to Magick::GaussianFilter.

:scale_support

The support argument used by the ImageMagick resize method. Defaults to 0.5.

Constant Summary collapse

SCALE_FACTOR = 
5
@@config = 
Hash.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(text, public_path) ⇒ PrettyText

The constructor is used by the create factory method. You should not use it, but use the create method instead.



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# File 'lib/pretty_text.rb', line 89

def initialize(text, public_path)
  @content = text
  @public_path = public_path
end

Instance Attribute Details

#content ⇒ Object (readonly)

Returns the value of attribute content.



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# File 'lib/pretty_text.rb', line 29

def content
  @content
end

Class Method Details

.create(text, style = nil) ⇒ Object

This class method is used to set up a new PrettyText object. If the requested image is not yet created, it generates the image and returns the approprate PrettyText object.



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# File 'lib/pretty_text.rb', line 34

def self.create(text, style = nil)
  text = text.to_s
  if (style.class.to_s != "Cabird::PrettyTextStyle")
    style = Cabird::PrettyTextStyle.new(style)
  end

  # set up paths
  public_image_path = @@config[:image_path] || File.join('system' , 'pretty_text')
  public_path = File.join(public_image_path, style.generate_filename(text))
  absolute_path = File.join(RAILS_ROOT, 'public', public_path)

  # render small fonts bigger and scale down later
  size = style.size
  scale_hack = size <= (@@config[:scale_threshold] || 12)
  size *= SCALE_FACTOR if scale_hack
  
  if (!File.exist?(absolute_path))
    # create directory
    FileUtils.mkpath(File.dirname(absolute_path)) unless File.exists?(File.dirname(absolute_path))

    gc = Magick::Draw.new
    gc.font = File.join(RAILS_ROOT, 'fonts', style.font) if style.font
    gc.pointsize = size
    #gc.kerning(style.kerning)
    gc.gravity = Magick::NorthWestGravity
    gc.fill = style.color
    text_to_render = style.process_text(text)
    gc.text(style.xoffset, style.yoffset, text_to_render)

    metrics = gc.get_multiline_type_metrics(text_to_render)
    image = Magick::Image.new(metrics.width + style.xextra + style.xoffset, metrics.height + style.yextra + style.yoffset) do
      self.background_color = style.bg_color
    end
    gc.draw(image)

    # scale down to original size
    if scale_hack
      image.resize!(metrics.width / SCALE_FACTOR,
                    metrics.height / SCALE_FACTOR,
                    @@config[:scale_filter]  || Magick::GaussianFilter,
                    @@config[:scale_support] || 0.5)
    end
    # handle gif transparency
    if (style.format == :gif)
      image = image.matte_replace(0, 0)
    end

    image.write(absolute_path)
  end

  return self.new(text, public_path)
end

Instance Method Details

#height ⇒ Object

Returns the height of the image



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# File 'lib/pretty_text.rb', line 106

def height
  get_geometry if @height.nil?
  return @height
end

#path ⇒ Object

Returns the relative path of the image starting at the public directory



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# File 'lib/pretty_text.rb', line 95

def path
  return File.join('', @public_path)
end

#to_s ⇒ Object

Returns the string the image is created from



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# File 'lib/pretty_text.rb', line 112

def to_s
  return @text
end

#width ⇒ Object

Return the width of the image



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# File 'lib/pretty_text.rb', line 100

def width
  get_geometry if @width.nil?
  return @width
end