Color.Blend (Color v0.4.0)

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CSS Compositing and Blending Level 1 blend modes.

blend/3,4 computes B(Cb, Cs) for a source and backdrop colour using one of the sixteen standard CSS blend modes. Both inputs are interpreted in sRGB and the result is returned as a Color.SRGB struct.

Separable blend modes (:multiply, :screen, :overlay, :darken, :lighten, :color_dodge, :color_burn, :hard_light, :soft_light, :difference, :exclusion) operate per-channel.

Non-separable modes (:hue, :saturation, :color, :luminosity) exchange specific colour attributes between source and backdrop and are defined in terms of an sRGB luminance and saturation.

:normal simply returns the source.

Examples

iex> {:ok, c} = Color.Blend.blend("white", "red", :multiply)
iex> Color.SRGB.to_hex(c)
"#ff0000"

iex> {:ok, c} = Color.Blend.blend([0.5, 0.5, 0.5], [0.5, 0.5, 0.5], :screen)
iex> Color.SRGB.to_hex(c)
"#bfbfbf"

Summary

Functions

blend(backdrop, source, mode)

Blends a source over a backdrop using the given blend mode.

Functions

blend(backdrop, source, mode)

@spec blend(Color.input(), Color.input(), atom()) ::
  {:ok, Color.SRGB.t()} | {:error, Exception.t()}

Blends a source over a backdrop using the given blend mode.

Arguments

  • backdrop is the destination colour (Cb) — any colour accepted by Color.new/1.

  • source is the source colour (Cs) — any colour accepted by Color.new/1.

  • mode is one of [:normal, :multiply, :screen, :overlay, :darken, :lighten, :color_dodge, :color_burn, :hard_light, :soft_light, :difference, :exclusion, :hue, :saturation, :color, :luminosity].

Returns

  • {:ok, %Color.SRGB{}} on success.

  • {:error, reason} if the mode is unknown.