Class: GD2::Font::TrueType

Inherits:
Object
  • Object
show all
Defined in:
lib/gd2/font.rb

Defined Under Namespace

Classes: FontconfigError, FreeTypeError

Constant Summary collapse

CHARMAP_UNICODE = 
0
CHARMAP_SHIFT_JIS = 
1
CHARMAP_BIG5 = 
2
FTEX_LINESPACE = 
1
FTEX_CHARMAP = 
2
FTEX_RESOLUTION = 
4
FTEX_DISABLE_KERNING = 
8
FTEX_XSHOW = 
16
FTEX_FONTPATHNAME = 
32
FTEX_FONTCONFIG = 
64
FTEX_RETURNFONTPATHNAME = 
128
@@fontcount = 
0
@@fontconfig = 
false

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fontname, ptsize, options = {}) ⇒ TrueType

Instantiate a TrueType font given by fontname (either a pathname or a fontconfig pattern if fontconfig is enabled) and ptsize (a point size given as a floating point number).

The possible options are:

  • :linespacing => The desired line spacing for multiline text, expressed as a multiple of the font height. A line spacing of 1.0 is the minimum to guarantee that lines of text do not collide. The default according to GD is 1.05.

  • :charmap => Specify a preference for Unicode, Shift_JIS, or Big5 character encoding. Use one of the constants Font::TrueType::CHARMAP_UNICODE, Font::TrueType::CHARMAP_SHIFT_JIS, or Font::TrueType::CHARMAP_BIG5.

  • :hdpi => The horizontal resolution hint for the rendering engine. The default according to GD is 96 dpi.

  • :vdpi => The vertical resolution hint for the rendering engine. The default according to GD is 96 dpi.

  • :dpi => A shortcut to specify both :hdpi and :vdpi.

  • :kerning => A boolean to specify whether kerning tables should be used, if fontconfig is available. The default is true.

Raises:



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# File 'lib/gd2/font.rb', line 215

def initialize(fontname, ptsize, options = {})
  @fontname, @ptsize = fontname, ptsize.to_f
  @linespacing = options.delete(:linespacing)
  @linespacing = @linespacing.to_f if @linespacing
  @charmap = options.delete(:charmap)
  @hdpi = options.delete(:hdpi)
  @vdpi = options.delete(:vdpi)
  if dpi = options.delete(:dpi)
    @hdpi ||= dpi
    @vdpi ||= dpi
  end
  @kerning = options.delete(:kerning)
  @kerning = true if @kerning.nil?

  self.class.register(self)

  # Get the font path (and verify existence of file)

  strex = strex(false, true)
  r, rs = SYM[:gdImageStringFTEx].call(nil,
    Array.new(8) { 0 }, 0, @fontname, @ptsize, 0.0, 0, 0, '', strex)
  raise FreeTypeError, r if r

  strex[:fontpath].free = SYM[:gdFree]
  @fontpath = strex[:fontpath].to_s
end

Instance Attribute Details

#charmap ⇒ Object (readonly)

The chosen charmap



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# File 'lib/gd2/font.rb', line 177

def charmap
  @charmap
end

#fontpath ⇒ Object (readonly)

The effective path to this TrueType font



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# File 'lib/gd2/font.rb', line 171

def fontpath
  @fontpath
end

#hdpi ⇒ Object (readonly)

The chosen horizontal resolution hint



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# File 'lib/gd2/font.rb', line 180

def hdpi
  @hdpi
end

#kerning ⇒ Object (readonly)

Whether kerning is desired



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# File 'lib/gd2/font.rb', line 186

def kerning
  @kerning
end

#linespacing ⇒ Object (readonly)

The chosen linespacing



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# File 'lib/gd2/font.rb', line 174

def linespacing
  @linespacing
end

#vdpi ⇒ Object (readonly)

The chosen vertical resolution hint



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# File 'lib/gd2/font.rb', line 183

def vdpi
  @vdpi
end

Class Method Details

.fontconfig ⇒ Object

:nodoc:



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# File 'lib/gd2/font.rb', line 147

def self.fontconfig   #:nodoc:
  @@fontconfig
end

.fontconfig=(want) ⇒ Object

Set whether fontconfig support should be enabled. To use this, the GD library must have been built with fontconfig support. Raises an error if fontconfig support is unavailable.

Raises:



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# File 'lib/gd2/font.rb', line 160

def self.fontconfig=(want)
  avail = !SYM[:gdFTUseFontConfig].call(want ? 1 : 0)[0].zero?
  raise FontconfigError, 'Fontconfig not available' if want && !avail
  @@fontconfig = want
end

.fontconfig? ⇒ Boolean

Return a boolean indicating whether fontconfig support has been enabled. The default is false.

Returns:

  • (Boolean) 


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# File 'lib/gd2/font.rb', line 153

def self.fontconfig?
  fontconfig
end

.register(font) ⇒ Object

:nodoc:



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# File 'lib/gd2/font.rb', line 116

def self.register(font)   #:nodoc:
  Thread.critical = true

  count = @@fontcount
  @@fontcount += 1

  if count.zero?
    raise FreeTypeError, 'FreeType library failed to initialize' unless
      SYM[:gdFontCacheSetup].call[0].zero?
  end

  ObjectSpace.define_finalizer(font, font_finalizer)
ensure
  Thread.critical = false
end

Instance Method Details

#bounding_rectangle(string, angle = 0.0) ⇒ Object

Return a hash describing the rectangle that would enclose the given string rendered in this font at the given angle. The returned hash contains the following keys:

  • :lower_left => The [x, y] coordinates of the lower left corner.

  • :lower_right => The [x, y] coordinates of the lower right corner.

  • :upper_right => The [x, y] coordinates of the upper right corner.

  • :upper_left => The [x, y] coordinates of the upper left corner.

  • :position => An array of floating point character position offsets for each character of the string, beginning with 0.0. The array also includes a final position indicating where the last character ends.

The upper, lower, left, and right references are relative to the text of the string, regardless of the angle.



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# File 'lib/gd2/font.rb', line 308

def bounding_rectangle(string, angle = 0.0)
  data = draw(nil, 0, 0, angle, string, 0)

  if string.length == 1
    # gd annoyingly fails to provide xshow data for strings of length 1
    position = draw(nil, 0, 0, angle, string + ' ', 0)[:position]
    data[:position] = position[0...-1]
  end

  data
end

#draw(image_ptr, x, y, angle, string, fg) ⇒ Object

:nodoc:

Raises:



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# File 'lib/gd2/font.rb', line 252

def draw(image_ptr, x, y, angle, string, fg)  #:nodoc:
  brect = Array.new(8) { 0 }
  strex = strex(true)
  r, rs = SYM[:gdImageStringFTEx].call(image_ptr,
    brect, fg, @fontname, @ptsize, angle.to_f, x, y,
    string.gsub('&', '&'), strex)
  raise FreeTypeError, r if r

  brect = rs[1].to_a('I', 8)

  if xshow = strex[:xshow]
    xshow.free = SYM[:gdFree]
    xshow = xshow.to_s.split(' ').map { |e| e.to_f }
  else
    xshow = []
  end

  sum = 0.0
  position = Array.new(xshow.length + 1)
  xshow.each_with_index do |advance, i|
    position[i] = sum
    sum += advance
  end
  position[-1] = sum

  { :lower_left   => [brect[0], brect[1]],
    :lower_right  => [brect[2], brect[3]],
    :upper_right  => [brect[4], brect[5]],
    :upper_left   => [brect[6], brect[7]],
    :position     => position
  }
end

#draw_circle(image_ptr, cx, cy, radius, text_radius, fill_portion, top, bottom, fgcolor) ⇒ Object

Raises:



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# File 'lib/gd2/font.rb', line 285

def draw_circle(image_ptr, cx, cy, radius, text_radius, fill_portion,
    top, bottom, fgcolor)   #:nodoc:
  r, rs = SYM[:gdImageStringFTCircle].call(image_ptr, cx, cy,
    radius.to_f, text_radius.to_f, fill_portion.to_f, @fontname, @ptsize,
    top || '', bottom || '', fgcolor)
  raise FreeTypeError, r if r
  nil
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/gd2/font.rb', line 242

def inspect   #:nodoc:
  result  = "#<#{self.class} #{@fontpath.inspect}, #{@ptsize}"
  result += ", :linespacing => #{@linespacing}" if @linespacing
  result += ", :charmap => #{@charmap}" if @charmap
  result += ", :hdpi => #{@hdpi}" if @hdpi
  result += ", :vdpi => #{@vdpi}" if @vdpi
  result += ", :kerning => #{@kerning}" unless @kerning
  result += '>'
end