Module: Pixels::HasAlphaChannel

Included in:

Targa16, Targa32

Defined in:

lib/pixels.rb

Overview

Mix-in module for image types having an alpha channel.

It makes has_alpha? return true, and it emulates rgb_from_color and color_from_rgb.

Instance Method Summary

• #color_from_rgb(r, g, b) ⇒ Object

  Given separate [r, g, b] values, return the integer colour value.

• #has_alpha? ⇒ Boolean

  Return true of the image has an alpha channel.

• #rgb_from_color(color) ⇒ Object

  Given an integer colour value, return separate [r, g, b] values.

Instance Method Details

#color_from_rgb(r, g, b) ⇒ Object

Given separate [r, g, b] values, return the integer colour value.

This is a wrapper around color_from_rgba. The alpha channel is always set fully opaque.

# File 'lib/pixels.rb', line 445

def color_from_rgb(r, g, b)
  return color_from_rgba(r, g, b, 255)
end

#has_alpha? ⇒ Boolean

Return true of the image has an alpha channel. Otherwise, return false.

Returns:

• (Boolean)

# File 'lib/pixels.rb', line 430

def has_alpha?
  true
end

#rgb_from_color(color) ⇒ Object

Given an integer colour value, return separate [r, g, b] values.

This is a wrapper around rgba_from_color. The alpha channel is ignored.

# File 'lib/pixels.rb', line 437

def rgb_from_color(color)
  return rgba_from_color(color)[0..2]
end