Color Style

Table of Contents

• colorAllocate
• getPixel
• rgb
• transparent
• setBrush
• setStyle, GD::Styled
• Brushed
• StyledBrushed
• setTile
• Tiled
• Transparent

• colorAllocate

  function

  allocate colors and return its index

  format

  color = im.colorAllocate(red, green, blue)

  source

  white  = im.colorAllocate(255,255,255)
  black  = im.colorAllocate(0,0,0)
  red    = im.colorAllocate(255,0,0)
  green  = im.colorAllocate(0,255,0)
  blue   = im.colorAllocate(0,0,255)
  yellow = im.colorAllocate(255,250,205)
  

  output

  Nothing

• getPixel

  function

  return the color table index underneath the specified point.

  format

  color_name = im.getPixel(x, y)

  source | getpixel.rb

  im.filledRectangle(10, 10, 50, 50, blue)
  
  STDERR.print im.getPixel(1, 1), "\n"
  STDERR.print im.getPixel(30, 30), "\n"
  

  output

  

  0
  4
  

• rgb

  function

  return a list containing the red, green and blue components of the specified color index

  format

  im.rgb(color)

  source | rgb.rb

  def print_rgb(rgb)
    STDERR.printf "red: %3d  green: %3d  blue: %3d\n",
  	rgb[0], rgb[1], rgb[2]
  end
  
  white = im.colorAllocate(255,255,255)
  black = im.colorAllocate(0,0,0)
  yellow = im.colorAllocate(255,250,205)
  
  rgb = im.rgb(white)
  print_rgb(rgb)
  
  rgb = im.rgb(black)
  print_rgb(rgb)
  
  rgb = im.rgb(yellow)
  print_rgb(rgb)
  

  output

  red: 255  green: 255  blue: 255
  red:   0  green:   0  blue:   0
  red: 255  green: 250  blue: 205
  

• transparent

  function

  make specified color transparent

  format

  im.transparent(color)

  source | transparent.rb

  im.transparent(white)
  im.filledRectangle(10, 10, 50, 50, blue)
  

  output

  no transparent --->

• setBrush

  function

  set brush pattern

  format

  im.setBrush(brush)

  source | setbrush.rb

  brush = GD::Image.new(10,10)
  brush.colorAllocate(255, 255, 255) # white
  brush.colorAllocate(0, 0, 0)       # black
  brush.transparent(white)           # white is transparent
  brush.filledRectangle(0,0,5,2,black) # a black rectangle
  
  im.setBrush(brush)
  im.arc(100, 100, 100, 50, 0, 360, GD::Brushed)
  

  output

  

  source2 | setbrush2.rb

  file = open("setbrush_gif.gif", "rb")
  brush = GD::Image.newFromGif(file)
  file.close
  
  im.setBrush(brush)
  im.arc(100, 100, 100, 50, 0, 360, GD::Brushed)
  

  output

  setbrush_gif.gif is this image --->

• setStyle, GD::Styled

  function

  generate dotted and dashed lines

  format

  GD::Styled

  source | styled.rb

  im.setStyle(red, red, red, white, white, white)
  im.line(10, 10, 50, 10, GD::Styled)
  

  output

  zoom 2x2

• Brushed

  function

  brush pattern

  format

  GD::Brushed

  source | brushed.rb

  # for Brushed
  brush = GD::Image.new(10,10)
  brush.colorAllocate(255, 255, 255) # white
  brush.colorAllocate(0, 0, 0)       # black
  brush.transparent(white)           # white is transparent
  brush.filledRectangle(0,0,5,2,black) # a black rectangle
  im.setBrush(brush)
  
  # for Styled
  im.setStyle(red, red, red, white, white, white)
  

  output

  

• StyledBrushed

  function

  generate dotted and dashed lines

  format

  GD::StyledBrushed

  source

  output

• setTile

  function

  set filled pattern

  format

  im.setTile(tile)

  source | settile.rb

  file = open("settile_gif.gif", "rb")
  tile = GD::Image.newFromGif(file)
  file.close
  
  im.setTile(tile)
  im.filledRectangle(50, 50, 150, 150, GD::Tiled)
  

  output

  settile_gif.gif is this image --->

• Transparent

  function

  Transparent

  format

  GD::Transparent

  source

  output