Class: GD2::Image::IndexedColor

Inherits:
GD2::Image show all
Defined in:
lib/gd2/image.rb

Overview

Description

IndexedColor images select pixel colors indirectly through a palette of up to 256 colors. Use Image#palette to access the associated Palette object.

Instance Attribute Summary

Attributes inherited from GD2::Image

#image_ptr, #palette

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from GD2::Image

#==, #[], #[]=, #aspect, #clipping, #clips?, #compare, #copy_from, #copy_from_rotated, create_image_ptr, #crop, #crop!, #draw, #dup, #each, #export, extract_format, #gd, #gd2, #get_pixel, #gif, #height, import, #init_with_image, #init_with_size, #inspect, #interlaced=, #interlaced?, #jpeg, load, new, #png, #polar_transform, #polar_transform!, #resize, #resize!, #rotate, #rotate!, #save_alpha=, #save_alpha?, #set_pixel, #sharpen, #size, #transparent, #transparent=, #true_color?, #uncrop, #uncrop!, #wbmp, #width, #with_clipping

Class Method Details

.create_image_sym ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 724

def self.create_image_sym   #:nodoc:
  :gdImageCreate
end

.palette_class ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 728

def self.palette_class  #:nodoc:
  Palette::IndexedColor
end

Instance Method Details

#alpha_blending=(bool) ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 744

def alpha_blending=(bool)   #:nodoc:
  raise 'Alpha blending mode not available for indexed color images' if bool
end

#alpha_blending? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/gd2/image.rb', line 740

def alpha_blending?   #:nodoc:
  false
end

#color2pixel(color) ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 736

def color2pixel(color)  #:nodoc:
  color.from_palette?(palette) ? color.index : palette.exact!(color).index
end

#merge_from(other, dst_x, dst_y, src_x, src_y, w, h, pct, gray = false) ⇒ Object

Like Image#merge_from except an optional final argument can be specified to preserve the hue of the source by converting the destination pixels to grey scale before the merge.



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# File 'lib/gd2/image.rb', line 781

def merge_from(other, dst_x, dst_y, src_x, src_y, w, h, pct, gray = false)
  return super(other, dst_x, dst_y, src_x, src_y, w, h, pct) unless gray
  ::GD2::GD2FFI.send(:gdImageCopyMergeGray, image_ptr, other.image_ptr,
    dst_x.to_i, dst_y.to_i, src_x.to_i, src_y.to_i, w.to_i, h.to_i, pct.to_percent.round.to_i)
  self
end

#optimize_palette ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 748

def optimize_palette  #:nodoc:
  # first map duplicate colors to a single palette index
  map, cache = palette.inject([{}, Array.new(MAX_COLORS)]) do |ary, color|
    ary.at(0)[color.rgba] = color.index
    ary.at(1)[color.index] = color.rgba
    ary
  end
  each_with_index do |row, y|
    row.each_with_index do |pixel, x|
      set_pixel(x, y, map[cache.at(pixel)])
    end
  end

  # now clean up the palette
  palette.deallocate_unused
end

#pixel2color(pixel) ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 732

def pixel2color(pixel)  #:nodoc:
  palette[pixel]
end

#to_indexed_color(colors = MAX_COLORS, dither = true) ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 774

def to_indexed_color(colors = MAX_COLORS, dither = true)  #:nodoc:
  palette.used <= colors ? self : super
end

#to_true_color ⇒ Object

:nodoc:



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# File 'lib/gd2/image.rb', line 765

def to_true_color   #:nodoc:
  sz = size
  obj = TrueColor.new(*sz)
  obj.alpha_blending = false
  obj.copy_from(self, 0, 0, 0, 0, *sz)
  obj.alpha_blending = true
  obj
end