fork/Graphite
1
0
Fork 0
mirror of https://github.com/GraphiteEditor/Graphite.git synced 2026-09-15 14:18:04 +08:00
Code Issues Packages Projects Releases Wiki Activity

Make 'Gradient Map' use gamma-space luma and move it into adjustments.rs (#4524)

Browse Source 
Move Gradient Map into adjustments.rs and position it by the classic 0.3/0.59/0.11 luma
This commit is contained in:
Keavon Chambers
2026-09-12 18:24:38 -07:00
committed by GitHub
parent 21cceeb7ba
commit 89b797f4c1
4 changed files with 40 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
node-graph/nodes/raster/src/adjustments.rs
View File

@@ -613,6 +613,45 @@ fn threshold<T: Adjust<Color>>(
image
}
// 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)
//
// TODO: Full PSD interop needs a compatibility variant of `GradientInterpolation` with its own midpoint semantics, position warp,
// TODO: and smoothing (a `gradient_smoothness` attribute), plus noise gradients, which we don't yet support.
// TODO: Its axes differ from ours: its midpoint is always a knee in the position warp and its smoothness blends the curve over
// TODO: that fixed warp, while each variant here picks warp and curve together, so neither end of the blend is Linear or Smooth.
// TODO: Per channel in the gradient space (measured on gamma RGB):
// TODO: - Position t maps to a parameter p by a piecewise-linear knee through (stop position, index) and (midpoint, index - 0.5).
// TODO: - Linear lerps the interval's stop colors by the fraction of p. Smooth is a cubic Hermite over the stop index with tangent
// TODO: `(c[i + 1] - c[i - 1]) / 2`, the end stops repeated past the ends, so two stops give `0.5 p + 1.5 p^2 - p^3`.
// TODO: - The ramp is `(1 - s) * linear + s * smooth` for smoothness s, clamped per interval to its two stop colors.
#[cfg(feature = "std")]
#[node_macro::node(category("Raster: Adjustment"))]
async fn gradient_map<T: Adjust<Color> + Send>(
_: impl Ctx,
#[implementations(Raster<CPU>, Color, Gradient)] image: Item<T>,
#[default(Color::BLACK, Color::WHITE)] gradient: Item<Gradient>,
reverse: Item<bool>,
) -> Item<T> {
let mut image = image;
let settings = vector_types::GradientSettings::from(&gradient);
let evaluator = gradient.into_element().evaluator(settings);
let reverse = reverse.into_element();
image.element_mut().adjust(|color| {
// The classic 0.3/0.59/0.11 luma of the gamma-encoded channels picks the position along the gradient
let [r, g, b, alpha] = color.to_gamma_srgb_channels();
let intensity = 0.3 * r + 0.59 * g + 0.11 * b;
let intensity = if reverse { 1. - intensity } else { intensity };
// The source alpha is kept and the gradient's own alpha stops are ignored
evaluator.evaluate(intensity as f64).with_alpha(alpha)
});
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)

36
node-graph/nodes/raster/src/gradient_map.rs
View File

@@ -1,36 +0,0 @@
//! Not immediately shader compatible due to needing [`Gradient`] as a param, which needs [`Vec`]
use crate::adjust::Adjust;
use core_types::list::Item;
use core_types::{Color, Ctx};
use raster_types::{CPU, Raster};
use vector_types::Gradient;
// 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> + Send>(
_: impl Ctx,
#[implementations(
Raster<CPU>,
Color,
Gradient,
)]
image: Item<T>,
#[default(Color::BLACK, Color::WHITE)] gradient: Item<Gradient>,
reverse: Item<bool>,
) -> Item<T> {
let mut image = image;
let settings = vector_types::GradientSettings::from(&gradient);
let evaluator = gradient.into_element().evaluator(settings);
let reverse = reverse.into_element();
image.element_mut().adjust(|color| {
let intensity = color.luminance_rec_709();
let intensity = if reverse { 1. - intensity } else { intensity };
evaluator.evaluate(intensity as f64)
});
image
}

2
node-graph/nodes/raster/src/lib.rs
View File

@@ -15,8 +15,6 @@ pub mod dehaze;
#[cfg(feature = "std")]
pub mod filter;
#[cfg(feature = "std")]
pub mod gradient_map;
#[cfg(feature = "std")]
pub mod image_color_palette;
#[cfg(feature = "std")]
pub mod std_nodes;