Module: Pura::Image::Operations

Included in:
Wrapper
Defined in:
lib/pura/image/operations.rb

Instance Method Summary collapse

Instance Method Details

#grayscale ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 21

def grayscale
  new_pixels = String.new(encoding: Encoding::BINARY)
  i = 0
  size = @pixels.bytesize
  while i < size
    r = @pixels.getbyte(i)
    g = @pixels.getbyte(i + 1)
    b = @pixels.getbyte(i + 2)
    gray = ((r + g + b) / 3.0).round
    new_pixels << gray << gray << gray
    i += 3
  end
  self.class.new(@width, @height, new_pixels)
end

#resize_and_pad(target_width, target_height, background: [0, 0, 0]) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 56

def resize_and_pad(target_width, target_height, background: [0, 0, 0])
  # First resize_to_fit
  scale = [@width.to_f / target_width, @height.to_f / target_height].max
  new_w = [(@width / scale).round, 1].max
  new_h = [(@height / scale).round, 1].max
  resized = resize(new_w, new_h)

  # Create padded canvas
  r, g, b = background
  bg_row = (String.new(encoding: Encoding::BINARY) << r << g << b) * target_width
  canvas = bg_row * target_height

  # Center the resized image on the canvas
  offset_x = (target_width - resized.width) / 2
  offset_y = (target_height - resized.height) / 2

  resized.height.times do |y|
    src_start = y * resized.width * 3
    dst_start = (((offset_y + y) * target_width) + offset_x) * 3
    canvas[dst_start, resized.width * 3] = resized.pixels[src_start, resized.width * 3]
  end

  self.class.new(target_width, target_height, canvas)
end

#resize_to_cover(cover_width, cover_height) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 81

def resize_to_cover(cover_width, cover_height)
  scale = [@width.to_f / cover_width, @height.to_f / cover_height].min
  new_w = [(@width / scale).round, 1].max
  new_h = [(@height / scale).round, 1].max
  resize(new_w, new_h)
end

#resize_to_fill(fill_width, fill_height) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 52

def resize_to_fill(fill_width, fill_height)
  resize_fill(fill_width, fill_height)
end

#resize_to_fit(max_width, max_height) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 45

def resize_to_fit(max_width, max_height)
  scale = [@width.to_f / max_width, @height.to_f / max_height].max
  new_w = [(@width / scale).round, 1].max
  new_h = [(@height / scale).round, 1].max
  resize(new_w, new_h)
end

#resize_to_limit(max_width, max_height) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 36

def resize_to_limit(max_width, max_height)
  return dup_image if @width <= max_width && @height <= max_height

  scale = [@width.to_f / max_width, @height.to_f / max_height].max
  new_w = [(@width / scale).round, 1].max
  new_h = [(@height / scale).round, 1].max
  resize(new_w, new_h)
end

#rotate(degrees) ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 6

def rotate(degrees)
  case degrees % 360
  when 0
    dup_image
  when 90
    rotate90
  when 180
    rotate180
  when 270
    rotate270
  else
    raise ArgumentError, "Only 90, 180, 270 degree rotations are supported"
  end
end

#strip ⇒ Object 



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# File 'lib/pura/image/operations.rb', line 88

def strip
  dup_image
end