Class: SilkLayout::Render::FontLibrary

Inherits:
Object
  • Object
show all
Defined in:
lib/silk_layout/render/font_library.rb

Constant Summary collapse

BASE_FONTS = 
{
  helvetica: {
    normal: {
      normal: "Helvetica",
      italic: "Helvetica-Oblique"
    },
    bold: {
      normal: "Helvetica-Bold",
      italic: "Helvetica-BoldOblique"
    }
  },
  times: {
    normal: {
      normal: "Times-Roman",
      italic: "Times-Italic"
    },
    bold: {
      normal: "Times-Bold",
      italic: "Times-BoldItalic"
    }
  },
  courier: {
    normal: {
      normal: "Courier",
      italic: "Courier-Oblique"
    },
    bold: {
      normal: "Courier-Bold",
      italic: "Courier-BoldOblique"
    }
  }
}.freeze
FAMILY_ALIASES = 
{
  "arial" => :helvetica,
  "helvetica" => :helvetica,
  "sans-serif" => :helvetica,
  "sans serif" => :helvetica,
  "times" => :times,
  "times new roman" => :times,
  "serif" => :times,
  "courier" => :courier,
  "courier new" => :courier,
  "monospace" => :courier
}.freeze

Class Method Summary collapse

Class Method Details

.measure_text(text, font_size:, font_family:, font_weight: "normal", font_style: "normal") ⇒ Object 



67
68
69
70
71
72
73
 
# File 'lib/silk_layout/render/font_library.rb', line 67

def measure_text(text, font_size:, font_family:, font_weight: "normal", font_style: "normal")
  return 0 if text.to_s.empty?

  font = metrics(font_family, font_weight: font_weight, font_style: font_style)[:font]
  glyph_width = font.decode_utf8(text.to_s).sum(&:width)
  glyph_width * font_size / 1000.0
end

.metrics(font_family, font_weight: "normal", font_style: "normal") ⇒ Object 



55
56
57
58
59
60
61
62
63
64
65
 
# File 'lib/silk_layout/render/font_library.rb', line 55

def metrics(font_family, font_weight: "normal", font_style: "normal")
  font_name = resolve_font_name(font_family, font_weight: font_weight, font_style: font_style)
  font = font_wrapper(font_name)

  {
    font_name: font_name,
    font: font,
    ascender: normalized_metric(font, :ascender),
    descender: normalized_metric(font, :descender)
  }
end

.resolve_font_name(font_family, font_weight: "normal", font_style: "normal") ⇒ Object 



75
76
77
78
79
80
81
 
# File 'lib/silk_layout/render/font_library.rb', line 75

def resolve_font_name(font_family, font_weight: "normal", font_style: "normal")
  family = normalized_family(font_family)
  weight = bold?(font_weight) ? :bold : :normal
  style = italic?(font_style) ? :italic : :normal

  BASE_FONTS.fetch(family, BASE_FONTS[:helvetica]).fetch(weight).fetch(style)
end