Class: Fontisan::Pipeline::FormatDetector

Inherits:
Object
  • Object
show all
Defined in:
lib/fontisan/pipeline/format_detector.rb

Overview

Detects font format and capabilities

This class analyzes font files to determine:

  • Format: TTF, OTF, TTC, OTC, WOFF, WOFF2, SVG
  • Variation type: static, gvar (TrueType variable), CFF2 (OpenType variable)
  • Capabilities: outline type, variation support, collection support

Used by the universal transformation pipeline to determine conversion strategies and validate compatibility.

Examples:

Detecting a font's format

detector = FormatDetector.new("font.ttf")
info = detector.detect
puts info[:format]        # => :ttf
puts info[:variation_type] # => :gvar
puts info[:capabilities][:outline] # => :truetype

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path) ⇒ FormatDetector

Initialize detector

Parameters:

  • file_path (String) —

    Path to font file



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# File 'lib/fontisan/pipeline/format_detector.rb', line 31

def initialize(file_path)
  @file_path = file_path
  @font = nil
end

Instance Attribute Details

#file_path ⇒ String (readonly)

Returns Path to font file.

Returns:

  • (String) —

    Path to font file



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# File 'lib/fontisan/pipeline/format_detector.rb', line 23

def file_path
  @file_path
end

#font ⇒ TrueTypeFont, ... (readonly)

Returns Loaded font.

Returns:



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# File 'lib/fontisan/pipeline/format_detector.rb', line 26

def font
  @font
end

Instance Method Details

#collection? ⇒ Boolean

Check if font is a collection

Returns:

  • (Boolean) —

    True if the loaded object is a font collection



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# File 'lib/fontisan/pipeline/format_detector.rb', line 103

def collection?
  return false unless @font

  @font.collection?
end

#compatible_with?(target_format) ⇒ Boolean

Check if format is compatible with target

Parameters:

  • target_format (Symbol) —

    Target format (:ttf, :otf, etc.)

Returns:

  • (Boolean) —

    True if conversion is possible



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# File 'lib/fontisan/pipeline/format_detector.rb', line 120

def compatible_with?(target_format)
  current_format = detect_format
  variation_type = detect_variation

  # Same format is always compatible
  return true if current_format == target_format

  # Collection formats
  if %i[ttc otc].include?(current_format)
    return %i[ttc otc].include?(target_format)
  end

  # Variable font constraints
  if variation_type == :static
    # Static fonts can convert to any format
    true
  else
    case variation_type
    when :gvar
      # TrueType variable can convert to TrueType formats
      %i[ttf ttc woff woff2].include?(target_format)
    when :cff2
      # OpenType variable can convert to OpenType formats
      %i[otf otc woff woff2].include?(target_format)
    end
  end
end

#detect ⇒ Hash

Detect format and capabilities

Returns:

  • (Hash) —

    Detection results with :format, :variation_type, :capabilities



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# File 'lib/fontisan/pipeline/format_detector.rb', line 39

def detect
  load_font

  {
    format: detect_format,
    variation_type: detect_variation,
    capabilities: detect_capabilities,
  }
end

#detect_capabilities ⇒ Hash

Detect font capabilities

Aggregates four pieces of self-knowledge owned by the font class: outline representation, variation support, collection status, and the table directory. Each is exposed as a method on the font object so this method stays free of class-specific branching.

Returns:

  • (Hash) —

    Capabilities hash



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# File 'lib/fontisan/pipeline/format_detector.rb', line 89

def detect_capabilities
  return default_capabilities unless @font

  {
    outline: @font.outline_type,
    variation: @font.variation_type != :static,
    collection: @font.collection?,
    tables: @font.table_names,
  }
end

#detect_format ⇒ Symbol

Detect font format

Delegates to the loaded font object's own #format method. Each font class (TrueTypeFont, OpenTypeFont, WoffFont, Woff2Font, Type1Font, *Collection) is the single source of truth for its format identifier. This keeps FormatDetector closed for modification when new font classes are added (OCP): no case statement to edit.

Returns:

  • (Symbol) —

    One of :ttf, :otf, :ttc, :otc, :woff, :woff2, :type1, :dfont, or :unknown



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# File 'lib/fontisan/pipeline/format_detector.rb', line 59

def detect_format
  # SVG fonts are an export-only target; no font object exists yet.
  return :svg if @file_path.end_with?(".svg")

  return :unknown unless @font

  @font.format
end

#detect_variation ⇒ Symbol

Detect variation type

Delegates to the loaded font object's own #variation_type method. Each font class is the single source of truth for its variation profile, so this method needs no class-specific branching.

Returns:

  • (Symbol) —

    :static, :gvar (TrueType variable), or :cff2



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# File 'lib/fontisan/pipeline/format_detector.rb', line 75

def detect_variation
  return :static unless @font

  @font.variation_type
end

#variable? ⇒ Boolean

Check if font is variable

Returns:

  • (Boolean) —

    True if variable font



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# File 'lib/fontisan/pipeline/format_detector.rb', line 112

def variable?
  detect_variation != :static
end