Class: Rubygame::TTF

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

Overview

IMPORTANT: this class only exists if SDL_ttf is available! Your code should check “defined?(Rubygame::TTF) != nil” to see if you can use this class, or be prepared to rescue from NameError.

TTF provides an interface to SDL_ttf, allowing TrueType Font files to be loaded and used to render text to Surfaces.

The TTF class must be initialized with the #setup method before any TTF objects can be created or used.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file, size) ⇒ TTF

Create a new TTF object, which can render text to a Surface with a particular font style and size.

file

filename of the TrueType font to use. Should be a TTF or FON file.

size

point size (based on 72DPI). (That means the height in pixels from the bottom of the descent to the top of the ascent.)



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# File 'lib/rubygame/ttf.rb', line 72

def initialize( file, size )
  if( SDL::TTF.WasInit() == 0 )
    raise( Rubygame::SDLError,
           "You must call TTF.setup before opening a font." )
  end

  @struct = SDL::TTF.OpenFont( file, size )

  if( @struct.pointer.null? )
    raise Rubygame::SDLError, "Could not open font: #{SDL.GetError()}"
  end
end

Class Method Details

.quit ⇒ Object

Clean up and quit SDL_ttf, making the TTF class unusable as a result (until it is setup again). This does not need to be called before Rubygame exits, as it will be done automatically.



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# File 'lib/rubygame/ttf.rb', line 56

def self.quit
  if( SDL::TTF.WasInit() != 0 )
    SDL::TTF.Quit()
  end
end

.setup ⇒ Object

Attempt to setup the TTF class for use by initializing SDL_ttf. This must be called before the TTF class can be used. Raises SDLError if there is a problem initializing SDL_ttf.



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# File 'lib/rubygame/ttf.rb', line 44

def self.setup
  if( SDL::TTF.WasInit() == 0 and SDL::TTF.Init() != 0 )
    raise( Rubygame::SDLError,
           "Could not setup TTF class: #{SDL.GetError()}" )
  end
end

Instance Method Details

#_get_style(style) ⇒ Object

:nodoc:



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# File 'lib/rubygame/ttf.rb', line 90

def _get_style( style )       # :nodoc:
  return (SDL::TTF.GetFontStyle(@struct) & style == style)
end

#_render(text, smooth, color, back, shaded, blended, solid) ⇒ Object

Does the heavy lifting for the render methods.



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# File 'lib/rubygame/ttf.rb', line 222

def _render( text, smooth, color, back, shaded, blended, solid ) # :nodoc;

  color = SDL::Color.new( Rubygame::Color.make_sdl_rgba(color) )

  if back
    back = SDL::Color.new( Rubygame::Color.make_sdl_rgba(back) )
  end

  surf =
    if smooth
      if back
        shaded.call( @struct, text, color, back )
      else
        blended.call( @struct, text, color )
      end
    else
      if back
        s = solid.call( @struct, text, color )
        SDL::SetColors( s, back.pointer, 0, 1 )
        SDL::SetColorKey( s, 0, 0 );
        s
      else
        solid.call( @struct, text, color )
      end
    end

  if surf.pointer.null?
    raise Rubygame::SDLError, "Could not render text: #{SDL.GetError()}"
  end

  return Rubygame::Surface.new( surf )

end

#_set_style(enable, style) ⇒ Object

Sets the style and returns the old value.



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# File 'lib/rubygame/ttf.rb', line 97

def _set_style( enable, style ) # :nodoc:
  old = SDL::TTF.GetFontStyle(@struct)
  if( !enable and (old & style == style ) )
  SDL::TTF.SetFontStyle( @struct, old ^ style )
    return true
  elsif( enable )
    SDL::TTF.SetFontStyle( @struct, old | style )
    return false
  else
    # No change
    return enable;
  end
end

#ascent ⇒ Object

Return the biggest ascent (baseline to top; in pixels) of all glyphs in the font.



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# File 'lib/rubygame/ttf.rb', line 173

def ascent
  SDL::TTF.FontAnscent( @struct )
end

#bold=(enabled) ⇒ Object

Enable or disable bold mode for this font. Returns the old value.



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# File 'lib/rubygame/ttf.rb', line 123

def bold=( enabled )
  _set_style( enabled, SDL::TTF::STYLE_BOLD )
end

#bold? ⇒ Boolean Also known as: bold

True if bold mode is enabled for this font.

Returns:

  • (Boolean) 


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# File 'lib/rubygame/ttf.rb', line 115

def bold?
  _get_style( SDL::TTF::STYLE_BOLD )
end

#descent ⇒ Object

Return the biggest descent (baseline to bottom; in pixels) of all glyphs in the font.



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# File 'lib/rubygame/ttf.rb', line 181

def descent
  SDL::TTF.FontDescent( @struct )
end

#height ⇒ Object

Return the biggest height (bottom to top; in pixels) of all glyphs in the font.



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# File 'lib/rubygame/ttf.rb', line 165

def height
  SDL::TTF.FontHeight( @struct )
end

#italic=(enabled) ⇒ Object

Enable or disable italic mode for this font. Returns the old value.



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# File 'lib/rubygame/ttf.rb', line 140

def italic=( enabled )
  _set_style( enabled, SDL::TTF::STYLE_ITALIC )
end

#italic? ⇒ Boolean Also known as: italic

True if italic mode is enabled for this font.

Returns:

  • (Boolean) 


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# File 'lib/rubygame/ttf.rb', line 131

def italic?
  _get_style( SDL::TTF::STYLE_ITALIC )
end

#line_skip ⇒ Object

Return the recommended distance (in pixels) from a point on a line of text to the same point on the line of text below it.



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# File 'lib/rubygame/ttf.rb', line 189

def line_skip
  SDL::TTF.FontLineSkip( @struct )
end

#render(text, smooth, color, back = nil) ⇒ Object

Renders a string to a Surface with the font’s style and the given color(s).

text

the text string to render

smooth

Use anti-aliasing if true. Enabling this makes the text look much nicer (smooth curves), but is much slower.

color

the color to render the text, in the form [r,g,b]

back

the color to use as a background for the text. This option can be omitted to have a transparent background.



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# File 'lib/rubygame/ttf.rb', line 267

def render( text, smooth, color, back=nil )
  _render( text, smooth, color, back,
           SDL::TTF.method(:RenderText_Shaded),
           SDL::TTF.method(:RenderText_Blended),
           SDL::TTF.method(:RenderText_Solid) )
end

#render_unicode(text, smooth, color, back = nil) ⇒ Object

Renders a Unicode string to a Surface with the font’s style and the given color(s).

text

the text string to render

smooth

Use anti-aliasing if true. Enabling this makes the text look much nicer (smooth curves), but is much slower.

color

the color to render the text, in the form [r,g,b]

back

the color to use as a background for the text. This option can be omitted to have a transparent background.



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# File 'lib/rubygame/ttf.rb', line 303

def render_unicode( text, smooth, color, back=nil )
  _render( text, smooth, color, back,
           SDL::TTF.method(:RenderUNICODE_Shaded),
           SDL::TTF.method(:RenderUNICODE_Blended),
           SDL::TTF.method(:RenderUNICODE_Solid) )
end

#render_utf8(text, smooth, color, back = nil) ⇒ Object

Renders a UTF-8 string to a Surface with the font’s style and the given color(s).

text

the text string to render

smooth

Use anti-aliasing if true. Enabling this makes the text look much nicer (smooth curves), but is much slower.

color

the color to render the text, in the form [r,g,b]

back

the color to use as a background for the text. This option can be omitted to have a transparent background.



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# File 'lib/rubygame/ttf.rb', line 285

def render_utf8( text, smooth, color, back=nil )
  _render( text, smooth, color, back,
           SDL::TTF.method(:RenderUTF8_Shaded),
           SDL::TTF.method(:RenderUTF8_Blended),
           SDL::TTF.method(:RenderUTF8_Solid) )
end

#size_text(text) ⇒ Object

The width and height the text would be if it were rendered, without the overhead of actually rendering it.



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# File 'lib/rubygame/ttf.rb', line 198

def size_text( text )
  SDL::TTF.SizeText(@struct, text)
end

#size_unicode(text) ⇒ Object

The width and height the Unicode text would be if it were rendered, without the overhead of actually rendering it.



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# File 'lib/rubygame/ttf.rb', line 214

def size_unicode( text )
  SDL::TTF.SizeUNICODE(@struct, text)
end

#size_utf8(text) ⇒ Object

The width and height the UTF-8 encoded text would be if it were rendered, without the overhead of actually rendering it.



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# File 'lib/rubygame/ttf.rb', line 206

def size_utf8( text )
  SDL::TTF.SizeUTF8(@struct, text)
end

#underline=(enabled) ⇒ Object

Enable or disable underline mode for this font. Returns the old value.



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# File 'lib/rubygame/ttf.rb', line 157

def underline=( enabled )
  _set_style( enabled, SDL::TTF::STYLE_UNDERLINE )
end

#underline? ⇒ Boolean Also known as: underline

True if underline mode is enabled for this font.

Returns:

  • (Boolean) 


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# File 'lib/rubygame/ttf.rb', line 148

def underline?
  _get_style( SDL::TTF::STYLE_UNDERLINE )
end