Class: Unmagic::Color::RGB::Gradient::Linear

Inherits:
Gradient::Base show all
Defined in:
lib/unmagic/color/rgb/gradient/linear.rb

Overview

Linear gradient interpolation in RGB color space.

Creates smooth color transitions by interpolating RGB components linearly between color stops. Each color stop has a position (0.0-1.0) that defines where the color appears in the gradient.

## RGB Interpolation

RGB gradients interpolate the red, green, and blue components separately. This can produce different visual results compared to HSL or OKLCH gradients, especially when transitioning through complementary colors.

## Examples

# Simple horizontal gradient
gradient = Unmagic::Color::RGB::Gradient::Linear.build(
  ["#FF0000", "#0000FF"],
  direction: "to right"
)
bitmap = gradient.rasterize(width: 10)
bitmap.pixels[0].map(&:to_hex)
#=> ["#ff0000", "#e60019", ..., "#0000ff"]

# Gradient with intermediate stops
gradient = Unmagic::Color::RGB::Gradient::Linear.build(
  [
    ["#FF0000", 0.0],   # Red at start
    ["#00FF00", 0.5],   # Green at middle
    ["#0000FF", 1.0]    # Blue at end
  ],
  direction: "to bottom"
)
bitmap = gradient.rasterize(width: 1, height: 20)

# Angled gradient
gradient = Unmagic::Color::RGB::Gradient::Linear.build(
  ["#FF0000", "#0000FF"],
  direction: "45deg"
)
bitmap = gradient.rasterize(width: 100, height: 100)

# Use Stop objects directly
stops = [
  Unmagic::Color::Gradient::Stop.new(
    color: Unmagic::Color::RGB.parse("#FF0000"),
    position: 0.0
  ),
  Unmagic::Color::Gradient::Stop.new(
    color: Unmagic::Color::RGB.parse("#0000FF"),
    position: 1.0
  )
]
direction = Unmagic::Color::Units::Degrees::Direction::LEFT_TO_RIGHT
gradient = Unmagic::Color::RGB::Gradient::Linear.new(stops, direction: direction)

Instance Attribute Summary

Attributes inherited from Gradient::Base

#direction, #stops

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Gradient::Base

build, #initialize

Constructor Details

This class inherits a constructor from Unmagic::Color::Gradient::Base

Class Method Details

.color_class ⇒ Class

Get the RGB color class.

Returns:

  • (Class) —

    Unmagic::Color::RGB



67
68
69
 
# File 'lib/unmagic/color/rgb/gradient/linear.rb', line 67

def color_class
  Unmagic::Color::RGB
end

Instance Method Details

#rasterize(width: 1, height: 1) ⇒ Bitmap

Rasterize the gradient to a bitmap.

Generates a bitmap containing the gradient with support for angled directions. The direction is determined by the gradient’s direction parameter.

Parameters:

  • width (Integer) (defaults to: 1) —

    Width of the bitmap (default 1)

  • height (Integer) (defaults to: 1) —

    Height of the bitmap (default 1)

Returns:

  • (Bitmap) —

    A bitmap with the specified dimensions

Raises:

  • (Error) —

    If width or height is less than 1



82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
 
# File 'lib/unmagic/color/rgb/gradient/linear.rb', line 82

def rasterize(width: 1, height: 1)
  raise self.class::Error, "width must be at least 1" if width < 1
  raise self.class::Error, "height must be at least 1" if height < 1

  # Get the angle from the direction's "to" component
  degrees = @direction.to.value

  # Generate pixels row by row
  pixels = Array.new(height) do |y|
    Array.new(width) do |x|
      position = calculate_position(x, y, width, height, degrees)
      color_at_position(position)
    end
  end

  Unmagic::Color::Gradient::Bitmap.new(
    width: width,
    height: height,
    pixels: pixels,
  )
end