color-management-v1: implement target color volume

src/cmm/cmm_description.rs

@@ -1,13 +1,13 @@
 use {
     crate::{
         cmm::{
-            cmm_luminance::{Luminance, white_balance},
+            cmm_luminance::{Luminance, TargetLuminance, white_balance},
             cmm_manager::Shared,
             cmm_primaries::{NamedPrimaries, Primaries},
             cmm_transfer_function::TransferFunction,
             cmm_transform::{ColorMatrix, Local, Xyz, bradford_adjustment},
         },
-        utils::free_list::FreeList,
+        utils::{free_list::FreeList, ordered_float::F64},
     },
     std::rc::Rc,
 };
@@ -38,6 +38,10 @@ pub struct LinearColorDescription {
     pub xyz_from_local: ColorMatrix<Xyz, Local>,
     pub local_from_xyz: ColorMatrix<Local, Xyz>,
     pub luminance: Luminance,
+    pub target_primaries: Primaries,
+    pub target_luminance: TargetLuminance,
+    pub max_cll: Option<F64>,
+    pub max_fall: Option<F64>,
     pub(super) shared: Rc<Shared>,
 }
 
@@ -45,7 +49,6 @@ pub struct LinearColorDescription {
 pub struct ColorDescription {
     pub id: ColorDescriptionId,
     pub linear: Rc<LinearColorDescription>,
-    #[expect(dead_code)]
     pub named_primaries: Option<NamedPrimaries>,
     pub transfer_function: TransferFunction,
     pub(super) shared: Rc<Shared>,
@@ -62,6 +65,26 @@ impl LinearColorDescription {
         }
         mat * self.xyz_from_local
     }
+
+    pub fn embeds_into(&self, target: &Self) -> bool {
+        if self.id == target.id {
+            return true;
+        }
+        if self.primaries != target.primaries {
+            return false;
+        }
+        if self.luminance != target.luminance {
+            return false;
+        }
+        true
+    }
+}
+
+impl ColorDescription {
+    pub fn embeds_into(&self, target: &Self) -> bool {
+        self.transfer_function == target.transfer_function
+            && self.linear.embeds_into(&target.linear)
+    }
 }
 
 impl Drop for LinearColorDescription {

src/cmm/cmm_luminance.rs

@@ -10,6 +10,12 @@ pub struct Luminance {
     pub white: F64,
 }
 
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct TargetLuminance {
+    pub min: F64,
+    pub max: F64,
+}
+
 impl Luminance {
     pub const SRGB: Self = Self {
         min: F64(0.2),
@@ -46,6 +52,15 @@ impl Luminance {
     };
 }
 
+impl Luminance {
+    pub fn to_target(&self) -> TargetLuminance {
+        TargetLuminance {
+            min: self.min,
+            max: self.max,
+        }
+    }
+}
+
 impl Default for Luminance {
     fn default() -> Self {
         Self::SRGB

src/cmm/cmm_manager.rs

@@ -5,11 +5,11 @@ use {
                 ColorDescription, ColorDescriptionIds, LinearColorDescription,
                 LinearColorDescriptionId, LinearColorDescriptionIds,
             },
-            cmm_luminance::Luminance,
+            cmm_luminance::{Luminance, TargetLuminance},
             cmm_primaries::{NamedPrimaries, Primaries},
             cmm_transfer_function::TransferFunction,
         },
-        utils::{copyhashmap::CopyHashMap, numcell::NumCell},
+        utils::{copyhashmap::CopyHashMap, numcell::NumCell, ordered_float::F64},
     },
     std::rc::{Rc, Weak},
 };
@@ -35,6 +35,10 @@ pub(super) struct Shared {
 struct LinearDescriptionKey {
     primaries: Primaries,
     luminance: Luminance,
+    target_primaries: Primaries,
+    target_luminance: TargetLuminance,
+    max_cll: Option<F64>,
+    max_fall: Option<F64>,
 }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
@@ -60,6 +64,10 @@ impl ColorManager {
             Primaries::SRGB,
             Luminance::SRGB,
             TransferFunction::Srgb,
+            Primaries::SRGB,
+            Luminance::SRGB.to_target(),
+            None,
+            None,
         );
         let srgb_linear = get_description(
             &shared,
@@ -70,6 +78,10 @@ impl ColorManager {
             Primaries::SRGB,
             Luminance::SRGB,
             TransferFunction::Linear,
+            Primaries::SRGB,
+            Luminance::SRGB.to_target(),
+            None,
+            None,
         );
         let windows_scrgb = get_description(
             &shared,
@@ -80,6 +92,10 @@ impl ColorManager {
             Primaries::SRGB,
             Luminance::WINDOWS_SCRGB,
             TransferFunction::Linear,
+            Primaries::BT2020,
+            Luminance::ST2084_PQ.to_target(),
+            None,
+            None,
         );
         Rc::new(Self {
             linear_ids,
@@ -110,6 +126,10 @@ impl ColorManager {
         primaries: Primaries,
         luminance: Luminance,
         transfer_function: TransferFunction,
+        target_primaries: Primaries,
+        target_luminance: TargetLuminance,
+        max_cll: Option<F64>,
+        max_fall: Option<F64>,
     ) -> Rc<ColorDescription> {
         get_description(
             &self.shared,
@@ -120,6 +140,10 @@ impl ColorManager {
             primaries,
             luminance,
             transfer_function,
+            target_primaries,
+            target_luminance,
+            max_cll,
+            max_fall,
         )
     }
 }
@@ -133,6 +157,10 @@ fn get_description(
     primaries: Primaries,
     luminance: Luminance,
     transfer_function: TransferFunction,
+    target_primaries: Primaries,
+    target_luminance: TargetLuminance,
+    max_cll: Option<F64>,
+    max_fall: Option<F64>,
 ) -> Rc<ColorDescription> {
     macro_rules! gc {
         ($d:ident, $i:expr) => {
@@ -147,6 +175,10 @@ fn get_description(
     let key = LinearDescriptionKey {
         primaries,
         luminance,
+        target_primaries,
+        target_luminance,
+        max_cll,
+        max_fall,
     };
     if let Some(d) = linear_descriptions.get(&key) {
         if let Some(d) = d.upgrade() {
@@ -180,6 +212,10 @@ fn get_description(
         xyz_from_local,
         local_from_xyz,
         luminance,
+        target_primaries,
+        target_luminance,
+        max_cll,
+        max_fall,
         shared: shared.clone(),
     });
     linear_descriptions.set(key, Rc::downgrade(&d));

src/cmm/cmm_tests.rs

@@ -141,7 +141,18 @@ mod transforms {
 
     fn check(p1: Primaries, p2: Primaries, expected: [[f64; 4]; 3]) {
         let manager = ColorManager::new();
-        let d = |p| manager.get_description(None, p, Luminance::SRGB, TransferFunction::Linear);
+        let d = |p| {
+            manager.get_description(
+                None,
+                p,
+                Luminance::SRGB,
+                TransferFunction::Linear,
+                p,
+                Luminance::SRGB.to_target(),
+                None,
+                None,
+            )
+        };
         let d1 = d(p1);
         let d2 = d(p2);
         let m = d1.linear.color_transform(&d2.linear);