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Improve Threshold node, move Gamma into Exposure node

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This commit is contained in:
Keavon Chambers
2023-02-08 17:48:08 -08:00
parent 8e3480e952
commit 875f2a5cd1
6 changed files with 128 additions and 54 deletions
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node-graph/gcore/src/raster/adjustments.rs
+29 -31
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@@ -7,22 +7,16 @@ use core::fmt::Debug;
pub struct GrayscaleNode;
#[node_macro::node_fn(GrayscaleNode)]
fn grayscale_color_node(input: Color) -> Color {
let avg = (input.r() + input.g() + input.b()) / 3.0;
map_rgb(input, |_| avg)
}
fn grayscale_color_node(color: Color) -> Color {
// TODO: Remove conversion to linear when the whole node graph uses linear color
let color = color.to_linear_srgb();
#[derive(Debug)]
pub struct GammaNode<Gamma> {
gamma: Gamma,
}
let luminance = color.luminance();
// https://www.dfstudios.co.uk/articles/programming/image-programming-algorithms/image-processing-algorithms-part-6-gamma-correction/
#[node_macro::node_fn(GammaNode)]
fn gamma_color_node(color: Color, gamma: f64) -> Color {
let inverse_gamma = 1. / gamma;
let per_channel = |channel: f32| channel.powf(inverse_gamma as f32);
map_rgb(color, per_channel)
// TODO: Remove conversion to linear when the whole node graph uses linear color
let luminance = Color::linear_to_srgb(luminance);
color.map_rgb(|_| luminance)
}
#[cfg(not(target_arch = "spirv"))]
@@ -56,7 +50,7 @@ pub struct InvertRGBNode;
#[node_macro::node_fn(InvertRGBNode)]
fn invert_image(color: Color) -> Color {
map_rgb(color, |c| 1. - c)
color.map_rgb(|c| 1. - c)
}
#[derive(Debug, Clone, Copy)]
@@ -66,8 +60,12 @@ pub struct ThresholdNode<Threshold> {
#[node_macro::node_fn(ThresholdNode)]
fn threshold_node(color: Color, threshold: f64) -> Color {
let avg = (color.r() + color.g() + color.b()) / 3.0;
if avg >= threshold as f32 {
let threshold = Color::srgb_to_linear(threshold as f32);
// TODO: Remove conversion to linear when the whole node graph uses linear color
let color = color.to_linear_srgb();
if color.luminance() >= threshold {
Color::WHITE
} else {
Color::BLACK
@@ -100,7 +98,7 @@ fn adjust_image_brightness_and_contrast(color: Color, brightness: f64, contrast:
let (brightness, contrast) = (brightness as f32, contrast as f32);
let factor = (259. * (contrast + 255.)) / (255. * (259. - contrast));
let channel = |channel: f32| ((factor * (channel * 255. + brightness - 128.) + 128.) / 255.).clamp(0., 1.);
map_rgb(color, channel)
color.map_rgb(channel)
}
#[derive(Debug, Clone, Copy)]
@@ -126,25 +124,25 @@ fn posterize(color: Color, posterize_value: f64) -> Color {
let number_of_areas = posterize_value.recip();
let size_of_areas = (posterize_value - 1.).recip();
let channel = |channel: f32| (channel / number_of_areas).floor() * size_of_areas;
map_rgb(color, channel)
color.map_rgb(channel)
}
#[derive(Debug, Clone, Copy)]
pub struct ExposureNode<E> {
exposure: E,
pub struct ExposureNode<Exposure, Offset, GammaCorrection> {
exposure: Exposure,
offset: Offset,
gamma_correction: GammaCorrection,
}
// Based on https://stackoverflow.com/questions/12166117/what-is-the-math-behind-exposure-adjustment-on-photoshop
#[node_macro::node_fn(ExposureNode)]
fn exposure(color: Color, exposure: f64) -> Color {
fn exposure(color: Color, exposure: f64, offset: f64, gamma_correction: f64) -> Color {
let multiplier = 2_f32.powf(exposure as f32);
let channel = |channel: f32| channel * multiplier;
map_rgb(color, channel)
}
pub fn map_rgba<F: Fn(f32) -> f32>(color: Color, f: F) -> Color {
Color::from_rgbaf32_unchecked(f(color.r()), f(color.g()), f(color.b()), f(color.a()))
}
pub fn map_rgb<F: Fn(f32) -> f32>(color: Color, f: F) -> Color {
Color::from_rgbaf32_unchecked(f(color.r()), f(color.g()), f(color.b()), color.a())
color
// TODO: Fix incorrect behavior of offset
.map_rgb(|channel: f32| channel + offset as f32)
// TODO: Fix incorrect behavior of exposure
.map_rgb(|channel: f32| channel * multiplier)
// TODO: While gamma correction is correct on its own, determine and implement the correct order of these three operations
.gamma(gamma_correction as f32)
}