Graphite/node-graph/gcore/src/raster/adjustments.rs

#![allow(clippy::too_many_arguments)]

use crate::raster::curve::{CubicSplines, CurveManipulatorGroup};
use crate::raster::curve::{Curve, ValueMapperNode};
use crate::raster::image::Image;
use crate::raster::{Channel, Color, Pixel};
use crate::raster_types::{CPU, Raster, RasterDataTable};
use crate::registry::types::{Angle, Percentage, SignedPercentage};
use crate::vector::VectorDataTable;
use crate::vector::style::GradientStops;
use crate::{Ctx, Node};
use crate::{GraphicElement, GraphicGroupTable};
use core::cmp::Ordering;
use core::fmt::Debug;
use dyn_any::DynAny;
#[cfg(feature = "serde")]
#[cfg(target_arch = "spirv")]
use spirv_std::num_traits::float::Float;

// TODO: Implement the following:
// Color Balance
// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27blnc%27%20%3D%20Color%20Balance
//
// Photo Filter
// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27phfl%27%20%3D%20Photo%20Filter
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=of%20the%20file.-,Photo%20Filter,-Key%20is%20%27phfl
//
// Color Lookup
// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27clrL%27%20%3D%20Color%20Lookup
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Color%20Lookup%20(Photoshop%20CS6

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq, DynAny, Hash, node_macro::ChoiceType, specta::Type)]
#[widget(Dropdown)]
pub enum LuminanceCalculation {
	#[default]
	#[label("sRGB")]
	SRGB,
	Perceptual,
	AverageChannels,
	MinimumChannels,
	MaximumChannels,
}

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq, DynAny, Hash, specta::Type)]
#[repr(i32)] // TODO: Enable Int8 capability for SPIR-V so that we don't need this?
pub enum BlendMode {
	// Basic group
	#[default]
	Normal,

	// Darken group
	Darken,
	Multiply,
	ColorBurn,
	LinearBurn,
	DarkerColor,

	// Lighten group
	Lighten,
	Screen,
	ColorDodge,
	LinearDodge,
	LighterColor,

	// Contrast group
	Overlay,
	SoftLight,
	HardLight,
	VividLight,
	LinearLight,
	PinLight,
	HardMix,

	// Inversion group
	Difference,
	Exclusion,
	Subtract,
	Divide,

	// Component group
	Hue,
	Saturation,
	Color,
	Luminosity,

	// Other stuff
	Erase,
	Restore,
	MultiplyAlpha,
}

impl BlendMode {
	/// All standard blend modes ordered by group.
	pub fn list() -> [&'static [BlendMode]; 6] {
		use BlendMode::*;
		[
			// Normal group
			&[Normal],
			// Darken group
			&[Darken, Multiply, ColorBurn, LinearBurn, DarkerColor],
			// Lighten group
			&[Lighten, Screen, ColorDodge, LinearDodge, LighterColor],
			// Contrast group
			&[Overlay, SoftLight, HardLight, VividLight, LinearLight, PinLight, HardMix],
			// Inversion group
			&[Difference, Exclusion, Subtract, Divide],
			// Component group
			&[Hue, Saturation, Color, Luminosity],
		]
	}

	/// The subset of [`BlendMode::list()`] that is supported by SVG.
	pub fn list_svg_subset() -> [&'static [BlendMode]; 6] {
		use BlendMode::*;
		[
			// Normal group
			&[Normal],
			// Darken group
			&[Darken, Multiply, ColorBurn],
			// Lighten group
			&[Lighten, Screen, ColorDodge],
			// Contrast group
			&[Overlay, SoftLight, HardLight],
			// Inversion group
			&[Difference, Exclusion],
			// Component group
			&[Hue, Saturation, Color, Luminosity],
		]
	}

	pub fn index_in_list(&self) -> Option<usize> {
		Self::list().iter().flat_map(|x| x.iter()).position(|&blend_mode| blend_mode == *self)
	}

	pub fn index_in_list_svg_subset(&self) -> Option<usize> {
		Self::list_svg_subset().iter().flat_map(|x| x.iter()).position(|&blend_mode| blend_mode == *self)
	}

	/// Convert the enum to the CSS string for the blend mode.
	/// [Read more](https://developer.mozilla.org/en-US/docs/Web/CSS/blend-mode#values)
	pub fn to_svg_style_name(&self) -> Option<&'static str> {
		match self {
			// Normal group
			BlendMode::Normal => Some("normal"),
			// Darken group
			BlendMode::Darken => Some("darken"),
			BlendMode::Multiply => Some("multiply"),
			BlendMode::ColorBurn => Some("color-burn"),
			// Lighten group
			BlendMode::Lighten => Some("lighten"),
			BlendMode::Screen => Some("screen"),
			BlendMode::ColorDodge => Some("color-dodge"),
			// Contrast group
			BlendMode::Overlay => Some("overlay"),
			BlendMode::SoftLight => Some("soft-light"),
			BlendMode::HardLight => Some("hard-light"),
			// Inversion group
			BlendMode::Difference => Some("difference"),
			BlendMode::Exclusion => Some("exclusion"),
			// Component group
			BlendMode::Hue => Some("hue"),
			BlendMode::Saturation => Some("saturation"),
			BlendMode::Color => Some("color"),
			BlendMode::Luminosity => Some("luminosity"),
			_ => None,
		}
	}

	/// Renders the blend mode CSS style declaration.
	pub fn render(&self) -> String {
		format!(
			r#" mix-blend-mode: {};"#,
			self.to_svg_style_name().unwrap_or_else(|| {
				warn!("Unsupported blend mode {self:?}");
				"normal"
			})
		)
	}
}

impl core::fmt::Display for BlendMode {
	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
		match self {
			// Normal group
			BlendMode::Normal => write!(f, "Normal"),
			// Darken group
			BlendMode::Darken => write!(f, "Darken"),
			BlendMode::Multiply => write!(f, "Multiply"),
			BlendMode::ColorBurn => write!(f, "Color Burn"),
			BlendMode::LinearBurn => write!(f, "Linear Burn"),
			BlendMode::DarkerColor => write!(f, "Darker Color"),
			// Lighten group
			BlendMode::Lighten => write!(f, "Lighten"),
			BlendMode::Screen => write!(f, "Screen"),
			BlendMode::ColorDodge => write!(f, "Color Dodge"),
			BlendMode::LinearDodge => write!(f, "Linear Dodge"),
			BlendMode::LighterColor => write!(f, "Lighter Color"),
			// Contrast group
			BlendMode::Overlay => write!(f, "Overlay"),
			BlendMode::SoftLight => write!(f, "Soft Light"),
			BlendMode::HardLight => write!(f, "Hard Light"),
			BlendMode::VividLight => write!(f, "Vivid Light"),
			BlendMode::LinearLight => write!(f, "Linear Light"),
			BlendMode::PinLight => write!(f, "Pin Light"),
			BlendMode::HardMix => write!(f, "Hard Mix"),
			// Inversion group
			BlendMode::Difference => write!(f, "Difference"),
			BlendMode::Exclusion => write!(f, "Exclusion"),
			BlendMode::Subtract => write!(f, "Subtract"),
			BlendMode::Divide => write!(f, "Divide"),
			// Component group
			BlendMode::Hue => write!(f, "Hue"),
			BlendMode::Saturation => write!(f, "Saturation"),
			BlendMode::Color => write!(f, "Color"),
			BlendMode::Luminosity => write!(f, "Luminosity"),
			// Other utility blend modes (hidden from the normal list)
			BlendMode::Erase => write!(f, "Erase"),
			BlendMode::Restore => write!(f, "Restore"),
			BlendMode::MultiplyAlpha => write!(f, "Multiply Alpha"),
		}
	}
}

#[cfg(feature = "vello")]
impl From<BlendMode> for vello::peniko::Mix {
	fn from(val: BlendMode) -> Self {
		match val {
			// Normal group
			BlendMode::Normal => vello::peniko::Mix::Normal,
			// Darken group
			BlendMode::Darken => vello::peniko::Mix::Darken,
			BlendMode::Multiply => vello::peniko::Mix::Multiply,
			BlendMode::ColorBurn => vello::peniko::Mix::ColorBurn,
			// Lighten group
			BlendMode::Lighten => vello::peniko::Mix::Lighten,
			BlendMode::Screen => vello::peniko::Mix::Screen,
			BlendMode::ColorDodge => vello::peniko::Mix::ColorDodge,
			// Contrast group
			BlendMode::Overlay => vello::peniko::Mix::Overlay,
			BlendMode::SoftLight => vello::peniko::Mix::SoftLight,
			BlendMode::HardLight => vello::peniko::Mix::HardLight,
			// Inversion group
			BlendMode::Difference => vello::peniko::Mix::Difference,
			BlendMode::Exclusion => vello::peniko::Mix::Exclusion,
			// Component group
			BlendMode::Hue => vello::peniko::Mix::Hue,
			BlendMode::Saturation => vello::peniko::Mix::Saturation,
			BlendMode::Color => vello::peniko::Mix::Color,
			BlendMode::Luminosity => vello::peniko::Mix::Luminosity,
			_ => todo!(),
		}
	}
}

#[node_macro::node(category("Raster: Adjustment"))]
fn luminance<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
	luminance_calc: LuminanceCalculation,
) -> T {
	input.adjust(|color| {
		let luminance = match luminance_calc {
			LuminanceCalculation::SRGB => color.luminance_srgb(),
			LuminanceCalculation::Perceptual => color.luminance_perceptual(),
			LuminanceCalculation::AverageChannels => color.average_rgb_channels(),
			LuminanceCalculation::MinimumChannels => color.minimum_rgb_channels(),
			LuminanceCalculation::MaximumChannels => color.maximum_rgb_channels(),
		};
		color.map_rgb(|_| luminance)
	});
	input
}

#[node_macro::node(category("Raster"))]
fn extract_channel<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
	channel: RedGreenBlueAlpha,
) -> T {
	input.adjust(|color| {
		let extracted_value = match channel {
			RedGreenBlueAlpha::Red => color.r(),
			RedGreenBlueAlpha::Green => color.g(),
			RedGreenBlueAlpha::Blue => color.b(),
			RedGreenBlueAlpha::Alpha => color.a(),
		};
		color.map_rgb(|_| extracted_value).with_alpha(1.)
	});
	input
}

#[node_macro::node(category("Raster"))]
fn make_opaque<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
) -> T {
	input.adjust(|color| {
		if color.a() == 0. {
			return color.with_alpha(1.);
		}
		Color::from_rgbaf32(color.r() / color.a(), color.g() / color.a(), color.b() / color.a(), 1.).unwrap()
	});
	input
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27brit%27%20%3D%20Brightness/Contrast
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Padding-,Brightness%20and%20Contrast,-Key%20is%20%27brit
//
// Some further analysis available at:
// https://geraldbakker.nl/psnumbers/brightness-contrast.html
#[node_macro::node(name("Brightness/Contrast"), category("Raster: Adjustment"), properties("brightness_contrast_properties"))]
fn brightness_contrast<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
	Color,
	RasterDataTable<CPU>,
	GradientStops,
)]
	mut input: T,
	brightness: SignedPercentage,
	contrast: SignedPercentage,
	use_classic: bool,
) -> T {
	if use_classic {
		let brightness = brightness as f32 / 255.;

		let contrast = contrast as f32 / 100.;
		let contrast = if contrast > 0. { (contrast * core::f32::consts::FRAC_PI_2 - 0.01).tan() } else { contrast };

		let offset = brightness * contrast + brightness - contrast / 2.;

		input.adjust(|color| color.to_gamma_srgb().map_rgb(|c| (c + c * contrast + offset).clamp(0., 1.)).to_linear_srgb());

		return input;
	}

	const WINDOW_SIZE: usize = 1024;

	// Brightness LUT
	let brightness_is_negative = brightness < 0.;
	// We clamp the brightness before the two curve X-axis points `130 - brightness * 26` and `233 - brightness * 48` intersect.
	// Beyond the point of intersection, the cubic spline fitting becomes invalid and fails an assertion, which we need to avoid.
	// See the intersection of the red lines at x = 103/22*100 = 468.18182 in the graph: https://www.desmos.com/calculator/ekvz4zyd9c
	let brightness = (brightness.abs() / 100.).min(103. / 22. - 0.00001) as f32;
	let brightness_curve_points = CubicSplines {
		x: [0., 130. - brightness * 26., 233. - brightness * 48., 255.].map(|x| x / 255.),
		y: [0., 130. + brightness * 51., 233. + brightness * 10., 255.].map(|x| x / 255.),
	};
	let brightness_curve_solutions = brightness_curve_points.solve();
	let mut brightness_lut: [f32; WINDOW_SIZE] = core::array::from_fn(|i| {
		let x = i as f32 / (WINDOW_SIZE as f32 - 1.);
		brightness_curve_points.interpolate(x, &brightness_curve_solutions)
	});
	// Special handling for when brightness is negative
	if brightness_is_negative {
		brightness_lut = core::array::from_fn(|i| {
			let mut x = i;
			while x > 1 && brightness_lut[x] > i as f32 / WINDOW_SIZE as f32 {
				x -= 1;
			}
			x as f32 / WINDOW_SIZE as f32
		});
	}

	// Contrast LUT
	// Unlike with brightness, the X-axis points `64` and `192` don't intersect at any contrast value, because they are constants.
	// So we don't have to worry about clamping the contrast value to avoid invalid cubic spline fitting.
	// See the graph: https://www.desmos.com/calculator/iql9vsca56
	let contrast = contrast as f32 / 100.;
	let contrast_curve_points = CubicSplines {
		x: [0., 64., 192., 255.].map(|x| x / 255.),
		y: [0., 64. - contrast * 30., 192. + contrast * 30., 255.].map(|x| x / 255.),
	};
	let contrast_curve_solutions = contrast_curve_points.solve();
	let contrast_lut: [f32; WINDOW_SIZE] = core::array::from_fn(|i| {
		let x = i as f32 / (WINDOW_SIZE as f32 - 1.);
		contrast_curve_points.interpolate(x, &contrast_curve_solutions)
	});

	// Composed brightness and contrast LUTs
	let combined_lut = brightness_lut.map(|brightness| {
		let index_in_contrast_lut = (brightness * (contrast_lut.len() - 1) as f32).round() as usize;
		contrast_lut[index_in_contrast_lut]
	});
	let lut_max = (combined_lut.len() - 1) as f32;

	input.adjust(|color| color.to_gamma_srgb().map_rgb(|c| combined_lut[(c * lut_max).round() as usize]).to_linear_srgb());

	input
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=levl%27%20%3D%20Levels
//
// Algorithm from:
// https://stackoverflow.com/questions/39510072/algorithm-for-adjustment-of-image-levels
//
// Some further analysis available at:
// https://geraldbakker.nl/psnumbers/levels.html
#[node_macro::node(category("Raster: Adjustment"))]
fn levels<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	#[default(0.)] shadows: Percentage,
	#[default(50.)] midtones: Percentage,
	#[default(100.)] highlights: Percentage,
	#[default(0.)] output_minimums: Percentage,
	#[default(100.)] output_maximums: Percentage,
) -> T {
	image.adjust(|color| {
		let color = color.to_gamma_srgb();

		// Input Range (Range: 0-1)
		let input_shadows = (shadows / 100.) as f32;
		let input_midtones = (midtones / 100.) as f32;
		let input_highlights = (highlights / 100.) as f32;

		// Output Range (Range: 0-1)
		let output_minimums = (output_minimums / 100.) as f32;
		let output_maximums = (output_maximums / 100.) as f32;

		// Midtones interpolation factor between minimums and maximums (Range: 0-1)
		let midtones = output_minimums + (output_maximums - output_minimums) * input_midtones;

		// Gamma correction (Range: 0.01-10)
		let gamma = if midtones < 0.5 {
			// Range: 0-1
			let x = 1. - midtones * 2.;
			// Range: 1-10
			1. + 9. * x
		} else {
			// Range: 0-0.5
			let x = 1. - midtones;
			// Range: 0-1
			let x = x * 2.;
			// Range: 0.01-1
			x.max(0.01)
		};

		// Input levels (Range: 0-1)
		let highlights_minus_shadows = (input_highlights - input_shadows).clamp(f32::EPSILON, 1.);
		let color = color.map_rgb(|c| ((c - input_shadows).max(0.) / highlights_minus_shadows).min(1.));

		// Midtones (Range: 0-1)
		let color = color.gamma(gamma);

		// Output levels (Range: 0-1)
		let color = color.map_rgb(|c| c * (output_maximums - output_minimums) + output_minimums);

		color.to_linear_srgb()
	});
	image
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27blwh%27%20%3D%20Black%20and%20White
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Black%20White%20(Photoshop%20CS3)
//
// Algorithm from:
// https://stackoverflow.com/a/55233732/775283
// Works the same for gamma and linear color
#[node_macro::node(name("Black & White"), category("Raster: Adjustment"))]
async fn black_and_white<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	#[default(Color::BLACK)] tint: Color,
	#[default(40.)]
	#[range((-200., 300.))]
	reds: Percentage,
	#[default(60.)]
	#[range((-200., 300.))]
	yellows: Percentage,
	#[default(40.)]
	#[range((-200., 300.))]
	greens: Percentage,
	#[default(60.)]
	#[range((-200., 300.))]
	cyans: Percentage,
	#[default(20.)]
	#[range((-200., 300.))]
	blues: Percentage,
	#[default(80.)]
	#[range((-200., 300.))]
	magentas: Percentage,
) -> T {
	image.adjust(|color| {
		let color = color.to_gamma_srgb();

		let reds = reds as f32 / 100.;
		let yellows = yellows as f32 / 100.;
		let greens = greens as f32 / 100.;
		let cyans = cyans as f32 / 100.;
		let blues = blues as f32 / 100.;
		let magentas = magentas as f32 / 100.;

		let gray_base = color.r().min(color.g()).min(color.b());

		let red_part = color.r() - gray_base;
		let green_part = color.g() - gray_base;
		let blue_part = color.b() - gray_base;
		let alpha_part = color.a();

		let additional = if red_part == 0. {
			let cyan_part = green_part.min(blue_part);
			cyan_part * cyans + (green_part - cyan_part) * greens + (blue_part - cyan_part) * blues
		} else if green_part == 0. {
			let magenta_part = red_part.min(blue_part);
			magenta_part * magentas + (red_part - magenta_part) * reds + (blue_part - magenta_part) * blues
		} else {
			let yellow_part = red_part.min(green_part);
			yellow_part * yellows + (red_part - yellow_part) * reds + (green_part - yellow_part) * greens
		};

		let luminance = gray_base + additional;

		// TODO: Fix "Color" blend mode implementation so it matches the expected behavior perfectly (it's currently close)
		let color = tint.with_luminance(luminance);

		let color = Color::from_rgbaf32(color.r(), color.g(), color.b(), alpha_part).unwrap();

		color.to_linear_srgb()
	});
	image
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27hue%20%27%20%3D%20Old,saturation%2C%20Photoshop%205.0
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=0%20%3D%20Use%20other.-,Hue/Saturation,-Hue/Saturation%20settings
#[node_macro::node(name("Hue/Saturation"), category("Raster: Adjustment"))]
async fn hue_saturation<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
	hue_shift: Angle,
	saturation_shift: SignedPercentage,
	lightness_shift: SignedPercentage,
) -> T {
	input.adjust(|color| {
		let color = color.to_gamma_srgb();

		let [hue, saturation, lightness, alpha] = color.to_hsla();

		let color = Color::from_hsla(
			(hue + hue_shift as f32 / 360.) % 1.,
			// TODO: Improve the way saturation works (it's slightly off)
			(saturation + saturation_shift as f32 / 100.).clamp(0., 1.),
			// TODO: Fix the way lightness works (it's very off)
			(lightness + lightness_shift as f32 / 100.).clamp(0., 1.),
			alpha,
		);

		color.to_linear_srgb()
	});
	input
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27%20%3D%20Color%20Lookup-,%27nvrt%27%20%3D%20Invert,-%27post%27%20%3D%20Posterize
#[node_macro::node(category("Raster: Adjustment"))]
async fn invert<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
) -> T {
	input.adjust(|color| {
		let color = color.to_gamma_srgb();

		let color = color.map_rgb(|c| color.a() - c);

		color.to_linear_srgb()
	});
	input
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=post%27%20%3D%20Posterize-,%27thrs%27%20%3D%20Threshold,-%27grdm%27%20%3D%20Gradient
#[node_macro::node(category("Raster: Adjustment"))]
async fn threshold<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	#[default(50.)] min_luminance: Percentage,
	#[default(100.)] max_luminance: Percentage,
	luminance_calc: LuminanceCalculation,
) -> T {
	image.adjust(|color| {
		let min_luminance = Color::srgb_to_linear(min_luminance as f32 / 100.);
		let max_luminance = Color::srgb_to_linear(max_luminance as f32 / 100.);

		let luminance = match luminance_calc {
			LuminanceCalculation::SRGB => color.luminance_srgb(),
			LuminanceCalculation::Perceptual => color.luminance_perceptual(),
			LuminanceCalculation::AverageChannels => color.average_rgb_channels(),
			LuminanceCalculation::MinimumChannels => color.minimum_rgb_channels(),
			LuminanceCalculation::MaximumChannels => color.maximum_rgb_channels(),
		};

		if luminance >= min_luminance && luminance <= max_luminance { Color::WHITE } else { Color::BLACK }
	});
	image
}

trait Blend<P: Pixel> {
	fn blend(&self, under: &Self, blend_fn: impl Fn(P, P) -> P) -> Self;
}
impl Blend<Color> for Color {
	fn blend(&self, under: &Self, blend_fn: impl Fn(Color, Color) -> Color) -> Self {
		blend_fn(*self, *under)
	}
}
impl Blend<Color> for Option<Color> {
	fn blend(&self, under: &Self, blend_fn: impl Fn(Color, Color) -> Color) -> Self {
		match (self, under) {
			(Some(a), Some(b)) => Some(blend_fn(*a, *b)),
			(a, None) => *a,
			(None, b) => *b,
		}
	}
}
impl Blend<Color> for RasterDataTable<CPU> {
	fn blend(&self, under: &Self, blend_fn: impl Fn(Color, Color) -> Color) -> Self {
		let mut result_table = self.clone();

		for (over, under) in result_table.instance_mut_iter().zip(under.instance_ref_iter()) {
			let data = over.instance.data.iter().zip(under.instance.data.iter()).map(|(a, b)| blend_fn(*a, *b)).collect();

			*over.instance = Raster::new_cpu(Image {
				data,
				width: over.instance.width,
				height: over.instance.height,
				base64_string: None,
			});
		}

		result_table
	}
}
impl Blend<Color> for GradientStops {
	fn blend(&self, under: &Self, blend_fn: impl Fn(Color, Color) -> Color) -> Self {
		let mut combined_stops = self.iter().map(|(position, _)| position).chain(under.iter().map(|(position, _)| position)).collect::<Vec<_>>();
		combined_stops.dedup_by(|&mut a, &mut b| (a - b).abs() < 1e-6);
		combined_stops.sort_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::Equal));

		let stops = combined_stops
			.into_iter()
			.map(|&position| {
				let over_color = self.evaluate(position);
				let under_color = under.evaluate(position);
				let color = blend_fn(over_color, under_color);
				(position, color)
			})
			.collect::<Vec<_>>();

		GradientStops::new(stops)
	}
}

#[node_macro::node(category("Raster"))]
async fn blend<T: Blend<Color> + Send>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	over: T,
	#[expose]
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	under: T,
	blend_mode: BlendMode,
	#[default(100.)] opacity: Percentage,
) -> T {
	over.blend(&under, |a, b| blend_colors(a, b, blend_mode, opacity / 100.))
}

#[node_macro::node(category(""), skip_impl)]
fn blend_color_pair<BlendModeNode, OpacityNode>(input: (Color, Color), blend_mode: &'n BlendModeNode, opacity: &'n OpacityNode) -> Color
where
	BlendModeNode: Node<'n, (), Output = BlendMode> + 'n,
	OpacityNode: Node<'n, (), Output = Percentage> + 'n,
{
	let blend_mode = blend_mode.eval(());
	let opacity = opacity.eval(());
	blend_colors(input.0, input.1, blend_mode, opacity / 100.)
}

pub fn apply_blend_mode(foreground: Color, background: Color, blend_mode: BlendMode) -> Color {
	match blend_mode {
		// Normal group
		BlendMode::Normal => background.blend_rgb(foreground, Color::blend_normal),
		// Darken group
		BlendMode::Darken => background.blend_rgb(foreground, Color::blend_darken),
		BlendMode::Multiply => background.blend_rgb(foreground, Color::blend_multiply),
		BlendMode::ColorBurn => background.blend_rgb(foreground, Color::blend_color_burn),
		BlendMode::LinearBurn => background.blend_rgb(foreground, Color::blend_linear_burn),
		BlendMode::DarkerColor => background.blend_darker_color(foreground),
		// Lighten group
		BlendMode::Lighten => background.blend_rgb(foreground, Color::blend_lighten),
		BlendMode::Screen => background.blend_rgb(foreground, Color::blend_screen),
		BlendMode::ColorDodge => background.blend_rgb(foreground, Color::blend_color_dodge),
		BlendMode::LinearDodge => background.blend_rgb(foreground, Color::blend_linear_dodge),
		BlendMode::LighterColor => background.blend_lighter_color(foreground),
		// Contrast group
		BlendMode::Overlay => foreground.blend_rgb(background, Color::blend_hardlight),
		BlendMode::SoftLight => background.blend_rgb(foreground, Color::blend_softlight),
		BlendMode::HardLight => background.blend_rgb(foreground, Color::blend_hardlight),
		BlendMode::VividLight => background.blend_rgb(foreground, Color::blend_vivid_light),
		BlendMode::LinearLight => background.blend_rgb(foreground, Color::blend_linear_light),
		BlendMode::PinLight => background.blend_rgb(foreground, Color::blend_pin_light),
		BlendMode::HardMix => background.blend_rgb(foreground, Color::blend_hard_mix),
		// Inversion group
		BlendMode::Difference => background.blend_rgb(foreground, Color::blend_difference),
		BlendMode::Exclusion => background.blend_rgb(foreground, Color::blend_exclusion),
		BlendMode::Subtract => background.blend_rgb(foreground, Color::blend_subtract),
		BlendMode::Divide => background.blend_rgb(foreground, Color::blend_divide),
		// Component group
		BlendMode::Hue => background.blend_hue(foreground),
		BlendMode::Saturation => background.blend_saturation(foreground),
		BlendMode::Color => background.blend_color(foreground),
		BlendMode::Luminosity => background.blend_luminosity(foreground),
		// Other utility blend modes (hidden from the normal list) - do not have alpha blend
		_ => panic!("Used blend mode without alpha blend"),
	}
}

trait Adjust<P> {
	fn adjust(&mut self, map_fn: impl Fn(&P) -> P);
}
impl Adjust<Color> for Color {
	fn adjust(&mut self, map_fn: impl Fn(&Color) -> Color) {
		*self = map_fn(self);
	}
}
impl Adjust<Color> for Option<Color> {
	fn adjust(&mut self, map_fn: impl Fn(&Color) -> Color) {
		if let Some(v) = self {
			*v = map_fn(v)
		}
	}
}
impl Adjust<Color> for GradientStops {
	fn adjust(&mut self, map_fn: impl Fn(&Color) -> Color) {
		for (_pos, c) in self.iter_mut() {
			*c = map_fn(c);
		}
	}
}
impl Adjust<Color> for RasterDataTable<CPU>
where
	GraphicElement: From<Image<Color>>,
{
	fn adjust(&mut self, map_fn: impl Fn(&Color) -> Color) {
		for instance in self.instance_mut_iter() {
			for c in instance.instance.data_mut().data.iter_mut() {
				*c = map_fn(c);
			}
		}
	}
}

#[inline(always)]
pub fn blend_colors(foreground: Color, background: Color, blend_mode: BlendMode, opacity: f64) -> Color {
	let target_color = match blend_mode {
		// Other utility blend modes (hidden from the normal list) - do not have alpha blend
		BlendMode::Erase => return background.alpha_subtract(foreground),
		BlendMode::Restore => return background.alpha_add(foreground),
		BlendMode::MultiplyAlpha => return background.alpha_multiply(foreground),
		blend_mode => apply_blend_mode(foreground, background, blend_mode),
	};

	background.alpha_blend(target_color.to_associated_alpha(opacity as f32))
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27grdm%27%20%3D%20Gradient%20Map
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Gradient%20settings%20(Photoshop%206.0)
#[node_macro::node(category("Raster: Adjustment"))]
async fn gradient_map<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	gradient: GradientStops,
	reverse: bool,
) -> T {
	image.adjust(|color| {
		let intensity = color.luminance_srgb();
		let intensity = if reverse { 1. - intensity } else { intensity };
		gradient.evaluate(intensity as f64).to_linear_srgb()
	});

	image
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27-,vibA%27%20%3D%20Vibrance,-%27hue%20%27%20%3D%20Old
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Vibrance%20(Photoshop%20CS3)
//
// Algorithm based on:
// https://stackoverflow.com/questions/33966121/what-is-the-algorithm-for-vibrance-filters
// The results of this implementation are very close to correct, but not quite perfect.
//
// Some further analysis available at:
// https://www.photo-mark.com/notes/analyzing-photoshop-vibrance-and-saturation/
//
// This algorithm is currently lacking a "Saturation" parameter which is needed for interoperability.
// It's not the same as the saturation component of Hue/Saturation/Value. Vibrance and Saturation are both separable.
// When both parameters are set, it is equivalent to running this adjustment twice, with only vibrance set and then only saturation set.
// (Except for some noise probably due to rounding error.)
#[node_macro::node(category("Raster: Adjustment"))]
async fn vibrance<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	vibrance: SignedPercentage,
) -> T {
	image.adjust(|color| {
		let vibrance = vibrance as f32 / 100.;
		// Slow the effect down by half when it's negative, since artifacts begin appearing past -50%.
		// So this scales the 0% to -50% range to 0% to -100%.
		let slowed_vibrance = if vibrance >= 0. { vibrance } else { vibrance * 0.5 };

		let channel_max = color.r().max(color.g()).max(color.b());
		let channel_min = color.r().min(color.g()).min(color.b());
		let channel_difference = channel_max - channel_min;

		let scale_multiplier = if channel_max == color.r() {
			let green_blue_difference = (color.g() - color.b()).abs();
			let t = (green_blue_difference / channel_difference).min(1.);
			t * 0.5 + 0.5
		} else {
			1.
		};
		let scale = slowed_vibrance * scale_multiplier * (2. - channel_difference);
		let channel_reduction = channel_min * scale;
		let scale = 1. + scale * (1. - channel_difference);

		let luminance_initial = color.to_linear_srgb().luminance_srgb();
		let altered_color = color.map_rgb(|c| c * scale - channel_reduction).to_linear_srgb();
		let luminance = altered_color.luminance_srgb();
		let altered_color = altered_color.map_rgb(|c| c * luminance_initial / luminance);

		let channel_max = altered_color.r().max(altered_color.g()).max(altered_color.b());
		let altered_color = if Color::linear_to_srgb(channel_max) > 1. {
			let scale = (1. - luminance) / (channel_max - luminance);
			altered_color.map_rgb(|c| (c - luminance) * scale + luminance)
		} else {
			altered_color
		};
		let altered_color = altered_color.to_gamma_srgb();

		if vibrance >= 0. {
			altered_color
		} else {
			// TODO: The result ends up a bit darker than it should be, further investigation is needed
			let luminance = color.luminance_rec_601();

			// Near -0% vibrance we mostly use `altered_color`.
			// Near -100% vibrance, we mostly use half the desaturated luminance color and half `altered_color`.
			let factor = -slowed_vibrance;
			altered_color.map_rgb(|c| c * (1. - factor) + luminance * factor)
		}
	});
	image
}

/// Color Channel
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
#[widget(Radio)]
pub enum RedGreenBlue {
	#[default]
	Red,
	Green,
	Blue,
}

/// Color Channel
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
#[widget(Radio)]
pub enum RedGreenBlueAlpha {
	#[default]
	Red,
	Green,
	Blue,
	Alpha,
}

/// Style of noise pattern
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
#[widget(Dropdown)]
pub enum NoiseType {
	#[default]
	Perlin,
	#[label("OpenSimplex2")]
	OpenSimplex2,
	#[label("OpenSimplex2S")]
	OpenSimplex2S,
	Cellular,
	ValueCubic,
	Value,
	WhiteNoise,
}

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
/// Style of layered levels of the noise pattern
pub enum FractalType {
	#[default]
	None,
	#[label("Fractional Brownian Motion")]
	FBm,
	Ridged,
	PingPong,
	#[label("Progressive (Domain Warp Only)")]
	DomainWarpProgressive,
	#[label("Independent (Domain Warp Only)")]
	DomainWarpIndependent,
}

/// Distance function used by the cellular noise
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
pub enum CellularDistanceFunction {
	#[default]
	Euclidean,
	#[label("Euclidean Squared (Faster)")]
	EuclideanSq,
	Manhattan,
	Hybrid,
}

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
pub enum CellularReturnType {
	CellValue,
	#[default]
	#[label("Nearest (F1)")]
	Nearest,
	#[label("Next Nearest (F2)")]
	NextNearest,
	#[label("Average (F1 / 2 + F2 / 2)")]
	Average,
	#[label("Difference (F2 - F1)")]
	Difference,
	#[label("Product (F2 * F1 / 2)")]
	Product,
	#[label("Division (F1 / F2)")]
	Division,
}

/// Type of domain warp
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
#[widget(Dropdown)]
pub enum DomainWarpType {
	#[default]
	None,
	#[label("OpenSimplex2")]
	OpenSimplex2,
	#[label("OpenSimplex2 Reduced")]
	OpenSimplex2Reduced,
	BasicGrid,
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27mixr%27%20%3D%20Channel%20Mixer
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Lab%20color%20only-,Channel%20Mixer,-Key%20is%20%27mixr
#[node_macro::node(category("Raster: Adjustment"), properties("channel_mixer_properties"))]
async fn channel_mixer<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,

	monochrome: bool,
	#[default(40.)]
	#[name("Red")]
	monochrome_r: f64,
	#[default(40.)]
	#[name("Green")]
	monochrome_g: f64,
	#[default(20.)]
	#[name("Blue")]
	monochrome_b: f64,
	#[default(0.)]
	#[name("Constant")]
	monochrome_c: f64,

	#[default(100.)]
	#[name("(Red) Red")]
	red_r: f64,
	#[default(0.)]
	#[name("(Red) Green")]
	red_g: f64,
	#[default(0.)]
	#[name("(Red) Blue")]
	red_b: f64,
	#[default(0.)]
	#[name("(Red) Constant")]
	red_c: f64,

	#[default(0.)]
	#[name("(Green) Red")]
	green_r: f64,
	#[default(100.)]
	#[name("(Green) Green")]
	green_g: f64,
	#[default(0.)]
	#[name("(Green) Blue")]
	green_b: f64,
	#[default(0.)]
	#[name("(Green) Constant")]
	green_c: f64,

	#[default(0.)]
	#[name("(Blue) Red")]
	blue_r: f64,
	#[default(0.)]
	#[name("(Blue) Green")]
	blue_g: f64,
	#[default(100.)]
	#[name("(Blue) Blue")]
	blue_b: f64,
	#[default(0.)]
	#[name("(Blue) Constant")]
	blue_c: f64,

	// Display-only properties (not used within the node)
	_output_channel: RedGreenBlue,
) -> T {
	image.adjust(|color| {
		let color = color.to_gamma_srgb();

		let (r, g, b, a) = color.components();

		let color = if monochrome {
			let (monochrome_r, monochrome_g, monochrome_b, monochrome_c) = (monochrome_r as f32 / 100., monochrome_g as f32 / 100., monochrome_b as f32 / 100., monochrome_c as f32 / 100.);

			let gray = (r * monochrome_r + g * monochrome_g + b * monochrome_b + monochrome_c).clamp(0., 1.);

			Color::from_rgbaf32_unchecked(gray, gray, gray, a)
		} else {
			let (red_r, red_g, red_b, red_c) = (red_r as f32 / 100., red_g as f32 / 100., red_b as f32 / 100., red_c as f32 / 100.);
			let (green_r, green_g, green_b, green_c) = (green_r as f32 / 100., green_g as f32 / 100., green_b as f32 / 100., green_c as f32 / 100.);
			let (blue_r, blue_g, blue_b, blue_c) = (blue_r as f32 / 100., blue_g as f32 / 100., blue_b as f32 / 100., blue_c as f32 / 100.);

			let red = (r * red_r + g * red_g + b * red_b + red_c).clamp(0., 1.);
			let green = (r * green_r + g * green_g + b * green_b + green_c).clamp(0., 1.);
			let blue = (r * blue_r + g * blue_g + b * blue_b + blue_c).clamp(0., 1.);

			Color::from_rgbaf32_unchecked(red, green, blue, a)
		};

		color.to_linear_srgb()
	});
	image
}

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
#[widget(Radio)]
pub enum RelativeAbsolute {
	#[default]
	Relative,
	Absolute,
}

#[repr(C)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, DynAny, node_macro::ChoiceType, specta::Type)]
pub enum SelectiveColorChoice {
	#[default]
	Reds,
	Yellows,
	Greens,
	Cyans,
	Blues,
	Magentas,

	#[menu_separator]
	Whites,
	Neutrals,
	Blacks,
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=%27selc%27%20%3D%20Selective%20color
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=from%20%2D100...100.%20.-,Selective%20Color,-Selective%20Color%20settings
//
// Algorithm based on:
// https://blog.pkh.me/p/22-understanding-selective-coloring-in-adobe-photoshop.html
#[node_macro::node(category("Raster: Adjustment"), properties("selective_color_properties"))]
async fn selective_color<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	mode: RelativeAbsolute,
	#[name("(Reds) Cyan")] r_c: f64,
	#[name("(Reds) Magenta")] r_m: f64,
	#[name("(Reds) Yellow")] r_y: f64,
	#[name("(Reds) Black")] r_k: f64,
	#[name("(Yellows) Cyan")] y_c: f64,
	#[name("(Yellows) Magenta")] y_m: f64,
	#[name("(Yellows) Yellow")] y_y: f64,
	#[name("(Yellows) Black")] y_k: f64,
	#[name("(Greens) Cyan")] g_c: f64,
	#[name("(Greens) Magenta")] g_m: f64,
	#[name("(Greens) Yellow")] g_y: f64,
	#[name("(Greens) Black")] g_k: f64,
	#[name("(Cyans) Cyan")] c_c: f64,
	#[name("(Cyans) Magenta")] c_m: f64,
	#[name("(Cyans) Yellow")] c_y: f64,
	#[name("(Cyans) Black")] c_k: f64,
	#[name("(Blues) Cyan")] b_c: f64,
	#[name("(Blues) Magenta")] b_m: f64,
	#[name("(Blues) Yellow")] b_y: f64,
	#[name("(Blues) Black")] b_k: f64,
	#[name("(Magentas) Cyan")] m_c: f64,
	#[name("(Magentas) Magenta")] m_m: f64,
	#[name("(Magentas) Yellow")] m_y: f64,
	#[name("(Magentas) Black")] m_k: f64,
	#[name("(Whites) Cyan")] w_c: f64,
	#[name("(Whites) Magenta")] w_m: f64,
	#[name("(Whites) Yellow")] w_y: f64,
	#[name("(Whites) Black")] w_k: f64,
	#[name("(Neutrals) Cyan")] n_c: f64,
	#[name("(Neutrals) Magenta")] n_m: f64,
	#[name("(Neutrals) Yellow")] n_y: f64,
	#[name("(Neutrals) Black")] n_k: f64,
	#[name("(Blacks) Cyan")] k_c: f64,
	#[name("(Blacks) Magenta")] k_m: f64,
	#[name("(Blacks) Yellow")] k_y: f64,
	#[name("(Blacks) Black")] k_k: f64,
	_colors: SelectiveColorChoice,
) -> T {
	image.adjust(|color| {
		let color = color.to_gamma_srgb();

		let (r, g, b, a) = color.components();

		let min = |a: f32, b: f32, c: f32| a.min(b).min(c);
		let max = |a: f32, b: f32, c: f32| a.max(b).max(c);
		let med = |a: f32, b: f32, c: f32| a + b + c - min(a, b, c) - max(a, b, c);

		let max_channel = max(r, g, b);
		let min_channel = min(r, g, b);

		let pixel_color_range = |choice| match choice {
			SelectiveColorChoice::Reds => max_channel == r,
			SelectiveColorChoice::Yellows => min_channel == b,
			SelectiveColorChoice::Greens => max_channel == g,
			SelectiveColorChoice::Cyans => min_channel == r,
			SelectiveColorChoice::Blues => max_channel == b,
			SelectiveColorChoice::Magentas => min_channel == g,
			SelectiveColorChoice::Whites => r > 0.5 && g > 0.5 && b > 0.5,
			SelectiveColorChoice::Neutrals => r > 0. && g > 0. && b > 0. && r < 1. && g < 1. && b < 1.,
			SelectiveColorChoice::Blacks => r < 0.5 && g < 0.5 && b < 0.5,
		};

		let color_parameter_group_scale_factor_rgb = max(r, g, b) - med(r, g, b);
		let color_parameter_group_scale_factor_cmy = med(r, g, b) - min(r, g, b);

		// Used to apply the r, g, or b channel slope (by multiplying it by 1) in relative mode, or no slope (by multiplying it by 0) in absolute mode
		let (slope_r, slope_g, slope_b) = match mode {
			RelativeAbsolute::Relative => (r - 1., g - 1., b - 1.),
			RelativeAbsolute::Absolute => (-1., -1., -1.),
		};

		let (sum_r, sum_g, sum_b) = [
			(SelectiveColorChoice::Reds, (r_c as f32, r_m as f32, r_y as f32, r_k as f32)),
			(SelectiveColorChoice::Yellows, (y_c as f32, y_m as f32, y_y as f32, y_k as f32)),
			(SelectiveColorChoice::Greens, (g_c as f32, g_m as f32, g_y as f32, g_k as f32)),
			(SelectiveColorChoice::Cyans, (c_c as f32, c_m as f32, c_y as f32, c_k as f32)),
			(SelectiveColorChoice::Blues, (b_c as f32, b_m as f32, b_y as f32, b_k as f32)),
			(SelectiveColorChoice::Magentas, (m_c as f32, m_m as f32, m_y as f32, m_k as f32)),
			(SelectiveColorChoice::Whites, (w_c as f32, w_m as f32, w_y as f32, w_k as f32)),
			(SelectiveColorChoice::Neutrals, (n_c as f32, n_m as f32, n_y as f32, n_k as f32)),
			(SelectiveColorChoice::Blacks, (k_c as f32, k_m as f32, k_y as f32, k_k as f32)),
		]
		.into_iter()
		.fold((0., 0., 0.), |acc, (color_parameter_group, (c, m, y, k))| {
			// Skip this color parameter group...
			// ...if it's unchanged from the default of zero offset on all CMYK parameters, or...
			// ...if this pixel's color isn't in the range affected by this color parameter group
			if (c < f32::EPSILON && m < f32::EPSILON && y < f32::EPSILON && k < f32::EPSILON) || (!pixel_color_range(color_parameter_group)) {
				return acc;
			}

			let (c, m, y, k) = (c / 100., m / 100., y / 100., k / 100.);

			let color_parameter_group_scale_factor = match color_parameter_group {
				SelectiveColorChoice::Reds | SelectiveColorChoice::Greens | SelectiveColorChoice::Blues => color_parameter_group_scale_factor_rgb,
				SelectiveColorChoice::Cyans | SelectiveColorChoice::Magentas | SelectiveColorChoice::Yellows => color_parameter_group_scale_factor_cmy,
				SelectiveColorChoice::Whites => min(r, g, b) * 2. - 1.,
				SelectiveColorChoice::Neutrals => 1. - ((max(r, g, b) - 0.5).abs() + (min(r, g, b) - 0.5).abs()),
				SelectiveColorChoice::Blacks => 1. - max(r, g, b) * 2.,
			};

			let offset_r = ((c + k * (c + 1.)) * slope_r).clamp(-r, -r + 1.) * color_parameter_group_scale_factor;
			let offset_g = ((m + k * (m + 1.)) * slope_g).clamp(-g, -g + 1.) * color_parameter_group_scale_factor;
			let offset_b = ((y + k * (y + 1.)) * slope_b).clamp(-b, -b + 1.) * color_parameter_group_scale_factor;

			(acc.0 + offset_r, acc.1 + offset_g, acc.2 + offset_b)
		});

		let color = Color::from_rgbaf32_unchecked((r + sum_r).clamp(0., 1.), (g + sum_g).clamp(0., 1.), (b + sum_b).clamp(0., 1.), a);

		color.to_linear_srgb()
	});
	image
}

pub(super) trait MultiplyAlpha {
	fn multiply_alpha(&mut self, factor: f64);
}

impl MultiplyAlpha for Color {
	fn multiply_alpha(&mut self, factor: f64) {
		*self = Color::from_rgbaf32_unchecked(self.r(), self.g(), self.b(), (self.a() * factor as f32).clamp(0., 1.))
	}
}
impl MultiplyAlpha for VectorDataTable {
	fn multiply_alpha(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.opacity *= factor as f32;
		}
	}
}
impl MultiplyAlpha for GraphicGroupTable {
	fn multiply_alpha(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.opacity *= factor as f32;
		}
	}
}
impl MultiplyAlpha for RasterDataTable<CPU>
where
	GraphicElement: From<Image<Color>>,
{
	fn multiply_alpha(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.opacity *= factor as f32;
		}
	}
}

pub(super) trait MultiplyFill {
	fn multiply_fill(&mut self, factor: f64);
}
impl MultiplyFill for Color {
	fn multiply_fill(&mut self, factor: f64) {
		*self = Color::from_rgbaf32_unchecked(self.r(), self.g(), self.b(), (self.a() * factor as f32).clamp(0., 1.))
	}
}
impl MultiplyFill for VectorDataTable {
	fn multiply_fill(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.fill *= factor as f32;
		}
	}
}
impl MultiplyFill for GraphicGroupTable {
	fn multiply_fill(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.fill *= factor as f32;
		}
	}
}
impl MultiplyFill for RasterDataTable<CPU> {
	fn multiply_fill(&mut self, factor: f64) {
		for instance in self.instance_mut_iter() {
			instance.alpha_blending.fill *= factor as f32;
		}
	}
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=nvrt%27%20%3D%20Invert-,%27post%27%20%3D%20Posterize,-%27thrs%27%20%3D%20Threshold
//
// Algorithm based on:
// https://www.axiomx.com/posterize.htm
// This algorithm produces fully accurate output in relation to the industry standard.
#[node_macro::node(category("Raster: Adjustment"))]
async fn posterize<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
	#[default(4)]
	#[hard_min(2.)]
	levels: u32,
) -> T {
	input.adjust(|color| {
		let color = color.to_gamma_srgb();

		let levels = levels as f32;
		let number_of_areas = levels.recip();
		let size_of_areas = (levels - 1.).recip();
		let channel = |channel: f32| (channel / number_of_areas).floor() * size_of_areas;
		let color = color.map_rgb(channel);

		color.to_linear_srgb()
	});
	input
}

// Aims for interoperable compatibility with:
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=curv%27%20%3D%20Curves-,%27expA%27%20%3D%20Exposure,-%27vibA%27%20%3D%20Vibrance
// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#:~:text=Flag%20(%20%3D%20128%20)-,Exposure,-Key%20is%20%27expA
//
// Algorithm based on:
// https://geraldbakker.nl/psnumbers/exposure.html
#[node_macro::node(category("Raster: Adjustment"), properties("exposure_properties"))]
async fn exposure<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut input: T,
	exposure: f64,
	offset: f64,
	#[default(1.)]
	#[range((0.01, 10.))]
	#[hard_min(0.0001)]
	gamma_correction: f64,
) -> T {
	input.adjust(|color| {
		let adjusted = color
		// Exposure
		.map_rgb(|c: f32| c * 2_f32.powf(exposure as f32))
		// Offset
		.map_rgb(|c: f32| c + offset as f32)
		// Gamma correction
		.gamma(gamma_correction as f32);

		adjusted.map_rgb(|c: f32| c.clamp(0., 1.))
	});
	input
}

const WINDOW_SIZE: usize = 1024;

#[node_macro::node(category(""))]
fn generate_curves<C: Channel + crate::raster::Linear>(_: impl Ctx, curve: Curve, #[implementations(f32, f64)] _target_format: C) -> ValueMapperNode<C> {
	use bezier_rs::{Bezier, TValue};

	let [mut pos, mut param]: [[f32; 2]; 2] = [[0.; 2], curve.first_handle];
	let mut lut = vec![C::from_f64(0.); WINDOW_SIZE];
	let end = CurveManipulatorGroup {
		anchor: [1.; 2],
		handles: [curve.last_handle, [0.; 2]],
	};
	for sample in curve.manipulator_groups.iter().chain(core::iter::once(&end)) {
		let [x0, y0, x1, y1, x2, y2, x3, y3] = [pos[0], pos[1], param[0], param[1], sample.handles[0][0], sample.handles[0][1], sample.anchor[0], sample.anchor[1]].map(f64::from);

		let bezier = Bezier::from_cubic_coordinates(x0, y0, x1, y1, x2, y2, x3, y3);

		let [left, right] = [pos[0], sample.anchor[0]].map(|c| c.clamp(0., 1.));
		let lut_index_left: usize = (left * (lut.len() - 1) as f32).floor() as _;
		let lut_index_right: usize = (right * (lut.len() - 1) as f32).ceil() as _;
		for index in lut_index_left..=lut_index_right {
			let x = index as f64 / (lut.len() - 1) as f64;
			let y = if x <= x0 {
				y0
			} else if x >= x3 {
				y3
			} else {
				bezier.find_tvalues_for_x(x)
					.next()
					.map(|t| bezier.evaluate(TValue::Parametric(t.clamp(0., 1.))).y)
					// Fall back to a very bad approximation if Bezier-rs fails
					.unwrap_or_else(|| (x - x0) / (x3 - x0) * (y3 - y0) + y0)
			};
			lut[index] = C::from_f64(y);
		}

		pos = sample.anchor;
		param = sample.handles[1];
	}
	ValueMapperNode::new(lut)
}

#[node_macro::node(category("Raster: Adjustment"))]
fn color_overlay<T: Adjust<Color>>(
	_: impl Ctx,
	#[implementations(
		Color,
		RasterDataTable<CPU>,
		GradientStops,
	)]
	mut image: T,
	#[default(Color::BLACK)] color: Color,
	blend_mode: BlendMode,
	#[default(100.)] opacity: Percentage,
) -> T {
	let opacity = (opacity as f32 / 100.).clamp(0., 1.);

	image.adjust(|pixel| {
		let image = pixel.map_rgb(|channel| channel * (1. - opacity));

		// The apply blend mode function divides rgb by the alpha channel for the background. This undoes that.
		let associated_pixel = Color::from_rgbaf32_unchecked(pixel.r() * pixel.a(), pixel.g() * pixel.a(), pixel.b() * pixel.a(), pixel.a());
		let overlay = apply_blend_mode(color, associated_pixel, blend_mode).map_rgb(|channel| channel * opacity);

		Color::from_rgbaf32_unchecked(image.r() + overlay.r(), image.g() + overlay.g(), image.b() + overlay.b(), pixel.a())
	});
	image
}

// pub use index_node::IndexNode;

// mod index_node {
// 	use crate::raster::{Color, Image};
// 	use crate::Ctx;

// 	#[node_macro::node(category(""))]
// 	pub fn index<T: Default + Clone>(
// 		_: impl Ctx,
// 		#[implementations(Vec<Image<Color>>, Vec<Color>)]
// 		#[widget(ParsedWidgetOverride::Hidden)]
// 		input: Vec<T>,
// 		index: u32,
// 	) -> T {
// 		if (index as usize) < input.len() {
// 			input[index as usize].clone()
// 		} else {
// 			warn!("The number of segments is {} but the requested segment is {}!", input.len(), index);
// 			Default::default()
// 		}
// 	}
// }

#[cfg(test)]
mod test {
	use crate::raster::adjustments::BlendMode;
	use crate::raster::image::Image;
	use crate::raster_types::{Raster, RasterDataTable};
	use crate::{Color, Node};
	use std::pin::Pin;

	#[derive(Clone)]
	pub struct FutureWrapperNode<T: Clone>(T);

	impl<'i, T: 'i + Clone + Send> Node<'i, ()> for FutureWrapperNode<T> {
		type Output = Pin<Box<dyn core::future::Future<Output = T> + 'i + Send>>;
		fn eval(&'i self, _input: ()) -> Self::Output {
			let value = self.0.clone();
			Box::pin(async move { value })
		}
	}

	#[tokio::test]
	async fn color_overlay_multiply() {
		let image_color = Color::from_rgbaf32_unchecked(0.7, 0.6, 0.5, 0.4);
		let image = Image::new(1, 1, image_color);

		// Color { red: 0., green: 1., blue: 0., alpha: 1. }
		let overlay_color = Color::GREEN;

		// 100% of the output should come from the multiplied value
		let opacity = 100_f64;

		let result = super::color_overlay((), RasterDataTable::new(Raster::new_cpu(image.clone())), overlay_color, BlendMode::Multiply, opacity);
		let result = result.instance_ref_iter().next().unwrap().instance;

		// The output should just be the original green and alpha channels (as we multiply them by 1 and other channels by 0)
		assert_eq!(result.data[0], Color::from_rgbaf32_unchecked(0., image_color.g(), 0., image_color.a()));
	}
}