Module: Pixels::NoAlphaChannel

Included in:

Targa15, Targa24

Defined in:

lib/pixels.rb

Overview

Mix-in module for image types having no alpha channel.

It makes has_alpha? return false, and it emulates rgba_from_color and color_from_rgba.

Instance Method Summary

• #color_from_rgba(r, g, b, a) ⇒ Object

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

• #has_alpha? ⇒ Boolean

  Return true of the image has an alpha channel.

• #rgba_from_color(color) ⇒ Object

  Given an integer colour value, return separate [r, g, b, 255] values.

Instance Method Details

#color_from_rgba(r, g, b, a) ⇒ Object

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

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

# File 'lib/pixels.rb', line 419

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

#has_alpha? ⇒ Boolean

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

Returns:

• (Boolean)

# File 'lib/pixels.rb', line 404

def has_alpha?
  false
end

#rgba_from_color(color) ⇒ Object

Given an integer colour value, return separate [r, g, b, 255] values.

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

# File 'lib/pixels.rb', line 412

def rgba_from_color(color)
  return rgb_from_color(color) + [255]
end