cmm: store render intent

src/cmm/cmm_description.rs

@@ -5,6 +5,7 @@ use {
             cmm_luminance::{Luminance, TargetLuminance, white_balance},
             cmm_manager::Shared,
             cmm_primaries::{NamedPrimaries, Primaries},
+            cmm_render_intent::RenderIntent,
             cmm_transform::{ColorMatrix, Local, Xyz, bradford_adjustment},
         },
         utils::ordered_float::F64,
@@ -39,12 +40,17 @@ pub struct ColorDescription {
 }
 
 impl LinearColorDescription {
-    pub fn color_transform(&self, target: &Self) -> ColorMatrix {
+    pub fn color_transform(&self, target: &Self, intent: RenderIntent) -> ColorMatrix {
         let mut mat = target.local_from_xyz;
         if self.luminance != target.luminance {
-            mat *= white_balance(&self.luminance, &target.luminance, target.primaries.wp);
+            mat *= white_balance(
+                &self.luminance,
+                &target.luminance,
+                target.primaries.wp,
+                intent,
+            );
         }
-        if self.primaries.wp != target.primaries.wp {
+        if self.primaries.wp != target.primaries.wp && intent.bradford_adjustment() {
             mat *= bradford_adjustment(self.primaries.wp, target.primaries.wp);
         }
         mat * self.xyz_from_local

src/cmm/cmm_luminance.rs

@@ -1,5 +1,8 @@
 use crate::{
-    cmm::cmm_transform::{ColorMatrix, Xyz},
+    cmm::{
+        cmm_render_intent::RenderIntent,
+        cmm_transform::{ColorMatrix, Xyz},
+    },
     utils::ordered_float::F64,
 };
 
@@ -68,12 +71,19 @@ impl Default for Luminance {
 }
 
 #[expect(non_snake_case)]
-pub fn white_balance(from: &Luminance, to: &Luminance, w_to: (F64, F64)) -> ColorMatrix<Xyz, Xyz> {
+pub fn white_balance(
+    from: &Luminance,
+    to: &Luminance,
+    w_to: (F64, F64),
+    intent: RenderIntent,
+) -> ColorMatrix<Xyz, Xyz> {
     let a = ((from.max - from.min) / (to.max - to.min) * (to.white - to.min)
         / (from.white - from.min))
         .0;
-    // let d = ((from.min - to.min) / (to.max - to.min)).0.max(0.0);
-    let d = 0.0;
+    let d = match intent.black_point_compensation() {
+        true => 0.0,
+        false => ((from.min - to.min) / (to.max - to.min)).0,
+    };
     let s = a - d;
     let (F64(x_to), F64(y_to)) = w_to;
     let X_to = x_to / y_to;

src/cmm/cmm_render_intent.rs

@@ -0,0 +1,29 @@
+use crate::{ifs::color_management::RENDER_INTENT_PERCEPTUAL, object::Version};
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Default)]
+pub enum RenderIntent {
+    #[default]
+    Perceptual,
+}
+
+impl RenderIntent {
+    pub fn from_wayland(intent: u32, _version: Version) -> Option<Self> {
+        let res = match intent {
+            RENDER_INTENT_PERCEPTUAL => Self::Perceptual,
+            _ => return None,
+        };
+        Some(res)
+    }
+
+    pub fn black_point_compensation(self) -> bool {
+        match self {
+            RenderIntent::Perceptual => true,
+        }
+    }
+
+    pub fn bradford_adjustment(self) -> bool {
+        match self {
+            RenderIntent::Perceptual => true,
+        }
+    }
+}

src/cmm/cmm_tests.rs

@@ -136,7 +136,7 @@ mod matrices {
 mod transforms {
     use crate::cmm::{
         cmm_eotf::Eotf, cmm_luminance::Luminance, cmm_manager::ColorManager,
-        cmm_primaries::Primaries,
+        cmm_primaries::Primaries, cmm_render_intent::RenderIntent,
     };
 
     fn check(p1: Primaries, p2: Primaries, expected: [[f64; 4]; 3]) {
@@ -155,7 +155,9 @@ mod transforms {
         };
         let d1 = d(p1);
         let d2 = d(p2);
-        let m = d1.linear.color_transform(&d2.linear);
+        let m = d1
+            .linear
+            .color_transform(&d2.linear, RenderIntent::Perceptual);
         println!("{:#?}", m);
         assert!((m.0[0][0].0 - expected[0][0]).abs() < 0.001);
         assert!((m.0[0][1].0 - expected[0][1]).abs() < 0.001);