Revise observable styling

Distinguish constraints from observables using dark background rather
than marker. Customize focus highlighting. Drop the input type selector
that used to make styling apply to the Lorentz product field but not the
constraint activation check box.

app-proto/main.css

@@ -3,7 +3,8 @@
   --text-bright: white;
   --text-invalid: #f58fc2; /* bright pink */
   --border: #555; /* light gray */
-  --border-focus: #aaa; /* bright gray */
+  --border-focus-dark: #aaa; /* bright gray */
+  --border-focus-light: white;
   --border-invalid: #70495c; /* dusky pink */
   --selection-highlight: #444; /* medium gray */
   --page-background: #222; /* dark gray */
@@ -77,12 +78,12 @@ summary.selected {
   background-color: var(--selection-highlight);
 }
 
-summary > div, .constraint {
+summary > div, .observable {
   padding-top: 4px;
   padding-bottom: 4px;
 }
 
-.element, .constraint {
+.element, .observable {
   display: flex;
   flex-grow: 1;
   padding-left: 8px;
@@ -107,7 +108,7 @@ details[open]:has(li) .element-switch::after {
   flex-grow: 1;
 }
 
-.constraint-label {
+.observable-label {
   flex-grow: 1;
 }
 
@@ -123,26 +124,32 @@ details[open]:has(li) .element-switch::after {
   width: 56px;
 }
 
-.constraint {
+.observable {
   font-style: italic;
 }
 
-.constraint.invalid {
+.observable.invalid-constraint {
   color: var(--text-invalid);
 }
 
-.constraint > input[type=checkbox] {
-  margin: 0px 8px 0px 0px;
-}
-
-.constraint > input[type=text] {
+.observable > input {
   color: inherit;
   background-color: inherit;
   border: 1px solid var(--border);
   border-radius: 2px;
 }
 
-.constraint.invalid > input[type=text] {
+.observable > input::placeholder {
+  color: inherit;
+  opacity: 54%;
+  font-style: italic;
+}
+
+.observable.valid-constraint > input {
+  background-color: var(--display-background);
+}
+
+.observable.invalid-constraint > input {
   border-color: var(--border-invalid);
 }
 
@@ -154,7 +161,7 @@ details[open]:has(li) .element-switch::after {
   font-style: normal;
 }
 
-.invalid > .status::after, details:has(.invalid):not([open]) .status::after {
+.invalid-constraint > .status::after, details:has(.invalid-constraint):not([open]) .status::after {
   content: '⚠';
   color: var(--text-invalid);
 }
@@ -171,5 +178,11 @@ canvas {
 }
 
 canvas:focus {
-  border-color: var(--border-focus);
+  border-color: var(--border-focus-dark);
+  outline: none;
+}
+
+input:focus {
+  border-color: var(--border-focus-light);
+  outline: none;
 }

app-proto/src/add_remove.rs

@@ -1,7 +1,17 @@
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue};
 
-use crate::{engine, AppState, assembly::{Assembly, Constraint, Element}};
+use crate::{
+    engine,
+    AppState,
+    assembly::{
+        Assembly,
+        Observable,
+        ObservableRole,
+        Element
+    },
+    engine::Q
+};
 
 /* DEBUG */
 // load an example assembly for testing. this code will be removed once we've
@@ -190,41 +200,49 @@ pub fn AddRemove() -> View {
                             (subject_vec[0].clone(), subject_vec[1].clone())
                         }
                     );
-                    let lorentz_prod = create_signal(0.0);
-                    let lorentz_prod_valid = create_signal(false);
-                    let active = create_signal(true);
-                    state.assembly.insert_constraint(Constraint {
+                    let measured = state.assembly.elements.map(
+                        move |elts| {
+                            let reps = (
+                                elts[subjects.0].representation.get_clone(),
+                                elts[subjects.1].representation.get_clone()
+                            );
+                            reps.0.dot(&(&*Q * reps.1))
+                        }
+                    );
+                    let desired = create_signal(0.0);
+                    let role = create_signal(ObservableRole::Measurement);
+                    state.assembly.insert_observable(Observable {
                         subjects: subjects,
-                        lorentz_prod: lorentz_prod,
-                        lorentz_prod_text: create_signal(String::new()),
-                        lorentz_prod_valid: lorentz_prod_valid,
-                        active: active,
+                        measured: measured,
+                        desired: desired,
+                        desired_text: create_signal(String::new()),
+                        role: role,
                     });
                     state.selection.update(|sel| sel.clear());
                     
                     /* DEBUG */
-                    // print updated constraint list
-                    console::log_1(&JsValue::from("Constraints:"));
-                    state.assembly.constraints.with(|csts| {
-                        for (_, cst) in csts.into_iter() {
+                    // print updated observable list
+                    console::log_1(&JsValue::from("Observables:"));
+                    state.assembly.observables.with(|obsls| {
+                        for (_, obs) in obsls.into_iter() {
                             console::log_5(
                                 &JsValue::from(" "),
-                                &JsValue::from(cst.subjects.0),
-                                &JsValue::from(cst.subjects.1),
+                                &JsValue::from(obs.subjects.0),
+                                &JsValue::from(obs.subjects.1),
                                 &JsValue::from(":"),
-                                &JsValue::from(cst.lorentz_prod.get_untracked())
+                                &JsValue::from(obs.desired.get_untracked())
                             );
                         }
                     });
                     
-                    // update the realization when the constraint becomes active
-                    // and valid, or is edited while active and valid
+                    // update the realization when the observable becomes
+                    // constrained, or is edited while constrained
                     create_effect(move || {
                         console::log_1(&JsValue::from(
-                            format!("Constraint ({}, {}) updated", subjects.0, subjects.1)
+                            format!("Updated constraint with subjects ({}, {})", subjects.0, subjects.1)
                         ));
-                        lorentz_prod.track();
-                        if active.get() && lorentz_prod_valid.get() {
+                        desired.track();
+                        if role.with(|rl| rl.is_valid_constraint()) {
                             state.assembly.realize();
                         }
                     });

app-proto/src/assembly.rs

@@ -7,9 +7,9 @@ use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
 use crate::engine::{realize_gram, local_unif_to_std, ConfigSubspace, PartialMatrix};
 
-// the types of the keys we use to access an assembly's elements and constraints
+// the types of the keys we use to access an assembly's elements and observables
 pub type ElementKey = usize;
-pub type ConstraintKey = usize;
+pub type ObservableKey = usize;
 
 pub type ElementColor = [f32; 3];
 
@@ -26,7 +26,7 @@ pub struct Element {
     pub label: String,
     pub color: ElementColor,
     pub representation: Signal<DVector<f64>>,
-    pub constraints: Signal<BTreeSet<ConstraintKey>>,
+    pub observables: Signal<BTreeSet<ObservableKey>>,
 
     // a serial number, assigned by `Element::new`, that uniquely identifies
     // each element
@@ -61,7 +61,7 @@ impl Element {
             label: label,
             color: color,
             representation: create_signal(representation),
-            constraints: create_signal(BTreeSet::default()),
+            observables: create_signal(BTreeSet::default()),
             serial: serial,
             column_index: None
         }
@@ -111,13 +111,33 @@ impl Element {
     }
 }
 
+pub enum ObservableRole {
+    Measurement,
+    Constraint(bool)
+}
+
+impl ObservableRole {
+    pub fn is_valid_constraint(&self) -> bool {
+        match self {
+            ObservableRole::Measurement => false,
+            ObservableRole::Constraint(valid) => *valid
+        }
+    }
+}
+
 #[derive(Clone)]
-pub struct Constraint {
+pub struct Observable {
     pub subjects: (ElementKey, ElementKey),
-    pub lorentz_prod: Signal<f64>,
-    pub lorentz_prod_text: Signal<String>,
-    pub lorentz_prod_valid: Signal<bool>,
-    pub active: Signal<bool>
+    pub measured: ReadSignal<f64>,
+    pub desired: Signal<f64>,
+    pub desired_text: Signal<String>,
+    pub role: Signal<ObservableRole>
+}
+
+impl Observable {
+    fn role_is_valid_constraint_untracked(&self) -> bool {
+        self.role.with_untracked(|role| role.is_valid_constraint())
+    }
 }
 
 // the velocity is expressed in uniform coordinates
@@ -131,9 +151,9 @@ type AssemblyMotion<'a> = Vec<ElementMotion<'a>>;
 // a complete, view-independent description of an assembly
 #[derive(Clone)]
 pub struct Assembly {
-    // elements and constraints
+    // elements and observables
     pub elements: Signal<Slab<Element>>,
-    pub constraints: Signal<Slab<Constraint>>,
+    pub observables: Signal<Slab<Observable>>,
     
     // solution variety tangent space. the basis vectors are stored in
     // configuration matrix format, ordered according to the elements' column
@@ -155,13 +175,13 @@ impl Assembly {
     pub fn new() -> Assembly {
         Assembly {
             elements: create_signal(Slab::new()),
-            constraints: create_signal(Slab::new()),
+            observables: create_signal(Slab::new()),
             tangent: create_signal(ConfigSubspace::zero(0)),
             elements_by_id: create_signal(FxHashMap::default())
         }
     }
     
-    // --- inserting elements and constraints ---
+    // --- inserting elements and observables ---
     
     // insert an element into the assembly without checking whether we already
     // have an element with the same identifier. any element that does have the
@@ -204,14 +224,14 @@ impl Assembly {
         );
     }
     
-    pub fn insert_constraint(&self, constraint: Constraint) {
-        let subjects = constraint.subjects;
-        let key = self.constraints.update(|csts| csts.insert(constraint));
-        let subject_constraints = self.elements.with(
-            |elts| (elts[subjects.0].constraints, elts[subjects.1].constraints)
+    pub fn insert_observable(&self, observable: Observable) {
+        let subjects = observable.subjects;
+        let key = self.observables.update(|obsls| obsls.insert(observable));
+        let subject_observables = self.elements.with(
+            |elts| (elts[subjects.0].observables, elts[subjects.1].observables)
         );
-        subject_constraints.0.update(|csts| csts.insert(key));
-        subject_constraints.1.update(|csts| csts.insert(key));
+        subject_observables.0.update(|obsls| obsls.insert(key));
+        subject_observables.1.update(|obsls| obsls.insert(key));
     }
     
     // --- realization ---
@@ -228,13 +248,13 @@ impl Assembly {
         let (gram, guess) = self.elements.with_untracked(|elts| {
             // set up the off-diagonal part of the Gram matrix
             let mut gram_to_be = PartialMatrix::new();
-            self.constraints.with_untracked(|csts| {
-                for (_, cst) in csts {
-                    if cst.active.get_untracked() && cst.lorentz_prod_valid.get_untracked() {
-                        let subjects = cst.subjects;
+            self.observables.with_untracked(|obsls| {
+                for (_, obs) in obsls {
+                    if obs.role_is_valid_constraint_untracked() {
+                        let subjects = obs.subjects;
                         let row = elts[subjects.0].column_index.unwrap();
                         let col = elts[subjects.1].column_index.unwrap();
-                        gram_to_be.push_sym(row, col, cst.lorentz_prod.get_untracked());
+                        gram_to_be.push_sym(row, col, obs.desired.get_untracked());
                     }
                 }
             });

app-proto/src/outline.rs

@@ -8,49 +8,67 @@ use web_sys::{
     wasm_bindgen::JsCast
 };
 
-use crate::{AppState, assembly, assembly::{Constraint, ConstraintKey, ElementKey}};
+use crate::{
+    AppState,
+    assembly,
+    assembly::{
+        Observable,
+        ObservableKey,
+        ObservableRole::*,
+        ElementKey
+    }
+};
 
-// an editable view of the Lorentz product representing a constraint
+// an editable view of the Lorentz product representing an observable
 #[component(inline_props)]
-fn LorentzProductInput(constraint: Constraint) -> View {
+fn ObservableInput(observable: Observable) -> View {
     view! {
         input(
             r#type="text",
-            bind:value=constraint.lorentz_prod_text,
+            placeholder=observable.measured.with(|result| result.to_string()),
+            bind:value=observable.desired_text,
             on:change=move |event: Event| {
                 let target: HtmlInputElement = event.target().unwrap().unchecked_into();
+                let value = target.value();
+                if value.is_empty() {
+                    observable.role.set(Measurement);
+                } else {
                     match target.value().parse::<f64>() {
-                    Ok(lorentz_prod) => batch(|| {
-                        constraint.lorentz_prod.set(lorentz_prod);
-                        constraint.lorentz_prod_valid.set(true);
+                        Ok(desired) => batch(|| {
+                            observable.desired.set(desired);
+                            observable.role.set(Constraint(true));
                         }),
-                    Err(_) => constraint.lorentz_prod_valid.set(false)
+                        Err(_) => observable.role.set(Constraint(false))
                     };
                 }
+            }
         )
     }
 }
 
-// a list item that shows a constraint in an outline view of an element
+// a list item that shows an observable in an outline view of an element
 #[component(inline_props)]
-fn ConstraintOutlineItem(constraint_key: ConstraintKey, element_key: ElementKey) -> View {
+fn ObservableOutlineItem(observable_key: ObservableKey, element_key: ElementKey) -> View {
     let state = use_context::<AppState>();
     let assembly = &state.assembly;
-    let constraint = assembly.constraints.with(|csts| csts[constraint_key].clone());
-    let other_subject = if constraint.subjects.0 == element_key {
-        constraint.subjects.1
+    let observable = assembly.observables.with(|obsls| obsls[observable_key].clone());
+    let other_subject = if observable.subjects.0 == element_key {
+        observable.subjects.1
     } else {
-        constraint.subjects.0
+        observable.subjects.0
     };
     let other_subject_label = assembly.elements.with(|elts| elts[other_subject].label.clone());
-    let class = constraint.lorentz_prod_valid.map(
-        |&lorentz_prod_valid| if lorentz_prod_valid { "constraint" } else { "constraint invalid" }
+    let class = observable.role.map(
+        |role| match role {
+            Measurement => "observable",
+            Constraint(true) => "observable valid-constraint",
+            Constraint(false) => "observable invalid-constraint"
+        }
     );
     view! {
         li(class=class.get()) {
-            input(r#type="checkbox", bind:checked=constraint.active)
-            div(class="constraint-label") { (other_subject_label) }
-            LorentzProductInput(constraint=constraint)
+            div(class="observable-label") { (other_subject_label) }
+            ObservableInput(observable=observable)
             div(class="status")
         }
     }
@@ -74,9 +92,9 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
             ).collect::<Vec<_>>()
         )
     };
-    let constrained = element.constraints.map(|csts| csts.len() > 0);
-    let constraint_list = element.constraints.map(
-        |csts| csts.clone().into_iter().collect()
+    let observed = element.observables.map(|obsls| obsls.len() > 0);
+    let observable_list = element.observables.map(
+        |obsls| obsls.clone().into_iter().collect()
     );
     let details_node = create_node_ref();
     view! {
@@ -91,7 +109,7 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
                                     state.select(key, event.shift_key());
                                     event.prevent_default();
                                 },
-                                "ArrowRight" if constrained.get() => {
+                                "ArrowRight" if observed.get() => {
                                     let _ = details_node
                                         .get()
                                         .unchecked_into::<web_sys::Element>()
@@ -138,16 +156,16 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
                         div(class="status")
                     }
                 }
-                ul(class="constraints") {
+                ul(class="observables") {
                     Keyed(
-                        list=constraint_list,
-                        view=move |cst_key| view! {
-                            ConstraintOutlineItem(
-                                constraint_key=cst_key,
+                        list=observable_list,
+                        view=move |obs_key| view! {
+                            ObservableOutlineItem(
+                                observable_key=obs_key,
                                 element_key=key
                             )
                         },
-                        key=|cst_key| cst_key.clone()
+                        key=|obs_key| obs_key.clone()
                     )
                 }
             }
@@ -156,8 +174,8 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
 }
 
 // a component that lists the elements of the current assembly, showing the
-// constraints on each element as a collapsible sub-list. its implementation
-// is based on Kate Morley's HTML + CSS tree views:
+// observables associated with each element as a collapsible sub-list. its
+// implementation is based on Kate Morley's HTML + CSS tree views:
 //
 //   https://iamkate.com/code/tree-views/
 //