Merge development for v0.8.0 release

Integrates Milestone 13 polish and closes #177, #178, #184, #176, #185, #179.

Generated with Devin

AGENTS.md

@@ -1,5 +1,34 @@
 # ICCery Agent Notes
 
+## Stage 5 Verification / Profcheck
+
+- `profcheck` output is parsed from both JSON summaries (preferred) and legacy plain-text report formats.
+- If no delta-E values can be detected, the report cards show 0.00 and a warning is appended to the process log.
+- The `.gam` file for the 3D viewer is parsed using `parseGamutFile`, which supports multiple `BEGIN_DATA` blocks (some Argyll files use a separate block per surface section), inline `#` comments, and out-of-bounds vertex warnings.
+- Manual parser tests live in `src/js/gamut_viewer.test.js`.
+
+## 3D Gamut Viewer
+
+- The viewer renders the measured/derived `.gam` volume and an optional sRGB reference wireframe in CIELAB.
+- Layer controls (profile, sRGB, axes) each have visibility toggles and opacity sliders.
+- Click **Reset View** or press **R** to return the camera to its default position.
+- Full JSDoc is provided on the public API in `src/js/gamut_viewer.js`.
+
+## Stage 4 colprof Options
+
+- `colprof` options are exposed in the Stage 4 UI with contextual tooltips:
+  - **FWA / OBA Compensation** (`-f`): choose D50, None, D65, or a custom `.sp` spectrum file.
+  - **Standard Illuminant** (`-i`) and **Observer** (`-o`): override default D50 / 1931 2° for CIE colourimetric calculations.
+  - **Viewing Conditions** (`-c` input, `-d` output): set CIE viewing-condition transforms for the profile table and output intent.
+- The backend `build_colprof_args` in `commands.rs` maps these UI values to `colprof` CLI flags. Unit tests cover all combinations.
+
+## Stage 3 Swatch Grid
+
+- Swatch patches render a 135° diagonal split: top-left is the intended/expected colour, bottom-right is the measured colour.
+- Argyll `chartread` emits `is_pad` for boundary/spacer patches. White reference patches (e.g. `-e` white steps) may also carry `is_pad`, but they have valid `expected.Lab` or non-zero `device` data. The guard skips only pads with no measurement *and* all-zero device values.
+- Row/patch order from `chartread` (rows A→Z, patches 1→N within each row) is rendered left-to-right / top-to-bottom to match the `printtarg` output.
+- Tooltip shows intended Lab (or device %), measured Lab, and ΔE₀₀ with a Good/Warning/Bad classification.
+
 ## UI Button Conventions
 
 The frontend uses a tiered button sizing system defined in `src/styles/main.css`. Prefer these utility classes over inline `style` attributes.
@@ -18,6 +47,12 @@ The frontend uses a tiered button sizing system defined in `src/styles/main.css`
 - All action rows use one of: `.stage-actions`, `.modal-actions`, `.chartread-actions`, `.print-actions-row`, `.btn-row`, `.btn-row-sm`, `.btn-row-end`, or `.input-row-sm`.
 - Avoid inline `style` on `<button>` elements or their immediate parent rows.
 
+## Settings & Preferences
+
+- Settings are persisted to `settings.json` in the app data directory and include the Stage 3 ΔE₀₀ traffic-light thresholds.
+- Valid threshold values must be non-negative and `delta_e_good_max < delta_e_warning_max`; both the frontend and backend enforce this.
+- Saving settings dispatches a `settings-saved` custom event so live components (e.g. the swatch grid) can re-classify on the fly.
+
 ## Build Commands
 
 - **Rust backend**: `cd src-tauri && CARGO_INCREMENTAL=0 cargo check` (the project lives on a network filesystem that doesn't support file locking, so `CARGO_INCREMENTAL=0` is required)

README.md

@@ -16,9 +16,9 @@
 - 🪄 **Linear 5-Stage Wizard Workflow**:
   1. **Stage 1 — Patch Generation (`targen`)**: Configure RGB (driver-managed) or CMYK (RIP-managed) patch sets with custom counts, profiling presets, and neutral/grey axis boosting.
   2. **Stage 2 — Target Creation & Raw Printing (`printtarg`)**: Format patch targets for spectrophotometers (i1Pro, i1Pro2, ColorMunki, SpyderPrint). View high-resolution downscaled TIFF previews and print directly using native OS raw unmanaged pathways (Windows GDI uncorrected / Linux CUPS `raw`).
-  3. **Stage 3 — Interactive Measurement (`chartread`) & Averaging (`average`)**: Instrument auto-detection (`instlist`), real-time calibration prompts, interactive strip reading state machine, live swatch grid with CIEDE2000 ($\Delta E_{00}$) quality indicators, and multi-pass sheet averaging for measurement noise reduction.
-  4. **Stage 4 — Profile Calculation (`colprof`)**: Generate high-precision cLUT mathematical ICC/ICM profiles with configurable algorithm quality, descriptions, and copyright tagging.
-  5. **Stage 5 — Verification & 3D Gamut (`profcheck` + `iccgamut`)**: Comprehensive mathematical validation report (Peak, Average, RMS $\Delta E$) paired with an interactive 3D CIELAB convex hull color volume viewer, touch controls, and bundled sRGB reference wireframe comparison.
+  3. **Stage 3 — Interactive Measurement (`chartread`) & Averaging (`average`)**: Instrument auto-detection (`instlist`), real-time calibration prompts, interactive strip reading state machine, live swatch grid with CIEDE2000 ($\Delta E_{00}$) quality indicators and user-configurable traffic-light thresholds, diagonally split intended-vs-measured colour swatches, white reference patch preservation, and multi-pass sheet averaging for measurement noise reduction.
+  4. **Stage 4 — Profile Calculation (`colprof`)**: Generate high-precision cLUT mathematical ICC/ICM profiles with configurable algorithm quality, OBA/FWA compensation, illuminant/observer selection, viewing-condition transforms, custom ambient spectrum support, descriptions, and copyright tagging.
+  5. **Stage 5 — Verification & 3D Gamut (`profcheck` + `iccgamut`)**: Comprehensive mathematical validation report (Peak, Average, RMS $\Delta E$) paired with an interactive 3D CIELAB convex hull color volume viewer, per-vertex true-colour rendering, layer opacity controls, camera reset, keyboard shortcut, touch controls, bundled sRGB reference wireframe comparison, and robust parsing of both JSON and legacy profcheck output formats.
 - 📋 **Profiling Presets**: One-click configuration presets (Standard RGB Photo, High-Gamut CMYK Proofing, Fast RGB Draft) with custom preset export/import and security validation.
 - 🐧 **glibc Compatibility**: Pre-built Linux packages compiled with Ubuntu 22.04 LTS compatibility for Debian/Ubuntu environments.
 - 🛡️ **Disk Artefact Gating**: Stepper navigation strictly verifies generated artefacts on disk (`.ti1`, `.ti2`, `.ti3`, `.icc`/`.icm`), preventing out-of-order execution while preserving backward navigation.

ROADMAP.md

@@ -101,12 +101,12 @@ ICCery is a native, cross-platform desktop application built with:
 
 ### Milestone 13 — UI/UX & Workflow Polish
 
-- [ ] **Global Button Standardization (#177)**: Enforce `.btn-sm`/`.btn-md`/`.btn-lg`/`.btn-icon-sq` tiers across all stages, remove inline button styles, and add CSS custom properties for button metrics.
-- [ ] **Swatch Grid White Patch & Orientation Polish (#178)**: Finalise `is_pad` guard documentation, diagonally split swatch tooltips, and validate `printtarg` row/column ordering.
-- [ ] **Configurable CIEDE2000 Thresholds (#184)**: User-configurable good/warning ΔE₀₀ upper bounds in Settings, persisted across sessions and applied to the Stage 3 swatch grid.
-- [ ] **Stage 4 OBA/FWA Tooltips & Tests (#176)**: Contextual help for OBA/FWA, illuminant, observer, and viewing-condition controls; additional `colprof` arg builder tests.
-- [ ] **3D Gamut Viewer Controls (#185)**: Camera reset, opacity sliders, keyboard shortcut, and full public-API JSDoc.
-- [ ] **Gamut / Profcheck Hardening (#179)**: Validate `.gam` vertex/face parsing, improved `profcheck` regex fallbacks for legacy text output, and user-visible parser warnings.
+- [x] **Global Button Standardization (#177)**: Enforce `.btn-sm`/`.btn-md`/`.btn-lg`/`.btn-icon-sq` tiers across all stages, remove inline button styles, and add CSS custom properties for button metrics.
+- [x] **Swatch Grid White Patch & Orientation Polish (#178)**: Finalise `is_pad` guard documentation, diagonally split swatch tooltips, and validate `printtarg` row/column ordering.
+- [x] **Configurable CIEDE2000 Thresholds (#184)**: User-configurable good/warning ΔE₀₀ upper bounds in Settings, persisted across sessions and applied to the Stage 3 swatch grid.
+- [x] **Stage 4 OBA/FWA Tooltips & Tests (#176)**: Contextual help for OBA/FWA, illuminant, observer, and viewing-condition controls; additional `colprof` arg builder tests.
+- [x] **3D Gamut Viewer Controls (#185)**: Camera reset, opacity sliders, keyboard shortcut, and full public-API JSDoc.
+- [x] **Gamut / Profcheck Hardening (#179)**: Validate `.gam` vertex/face parsing, improved `profcheck` regex fallbacks for legacy text output, and user-visible parser warnings.
 
 ### Milestone 12 — Future Workflow & Advanced Analytics (Deferred)
 - [ ] **Batch Verification & Drift Tracking (#95)**: Track printer drift over time by comparing periodic verification measurements against a baseline profile.

src-tauri/Cargo.lock

@@ -1423,7 +1423,7 @@ dependencies = [
 
 [[package]]
 name = "iccery"
-version = "0.7.4"
+version = "0.8.0"
 dependencies = [
  "base64 0.22.1",
  "image",

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "iccery"
-version = "0.7.4"
+version = "0.8.0"
 description = "Modern Printer Profiling UI frontend for ArgyllCMS"
 authors = ["Gordon"]
 edition = "2021"

src-tauri/src/commands.rs

@@ -1783,6 +1783,33 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_build_colprof_args_combined_fwa_illuminant_observer_viewing() {
+        let config = ColprofConfig {
+            algorithm: "x".to_string(),
+            quality: "u".to_string(),
+            intent: Some("a".to_string()),
+            copyright: Some("C".to_string()),
+            description: Some("D".to_string()),
+            basename: "profile".to_string(),
+            cwd: "".to_string(),
+            fwa: Some("D65".to_string()),
+            illuminant: Some("D65".to_string()),
+            observer: Some("2015_2".to_string()),
+            input_viewing_cond: Some("pc".to_string()),
+            output_viewing_cond: Some("md".to_string()),
+        };
+        let args = build_colprof_args(&config);
+        assert_eq!(
+            args,
+            vec![
+                "-v", "-a", "x", "-q", "u", "-t", "a",
+                "-f", "D65", "-i", "D65", "-o", "2015_2",
+                "-c", "pc", "-d", "md", "-D", "D", "-C", "C", "profile"
+            ]
+        );
+    }
+
     #[test]
     fn test_build_profcheck_args() {
         let config = ProfcheckConfig {

src-tauri/src/settings.rs

@@ -60,15 +60,48 @@ pub struct ProfilingPreset {
     pub no_randomize: Option<bool>,
 }
 
-#[derive(Debug, Deserialize, Serialize, Default, Clone)]
+fn default_delta_e_good_max() -> f64 { 2.0 }
+fn default_delta_e_warning_max() -> f64 { 5.0 }
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
 pub struct AppSettings {
     pub argyll_binary_dir: Option<String>,
     pub default_instrument: Option<String>,
     pub log_level: Option<String>,
+    #[serde(default = "default_delta_e_good_max")]
+    pub delta_e_good_max: f64,
+    #[serde(default = "default_delta_e_warning_max")]
+    pub delta_e_warning_max: f64,
     #[serde(default)]
     pub custom_presets: Vec<ProfilingPreset>,
 }
 
+impl Default for AppSettings {
+    fn default() -> Self {
+        Self {
+            argyll_binary_dir: None,
+            default_instrument: None,
+            log_level: None,
+            delta_e_good_max: default_delta_e_good_max(),
+            delta_e_warning_max: default_delta_e_warning_max(),
+            custom_presets: Vec::new(),
+        }
+    }
+}
+
+impl AppSettings {
+    /// Validate thresholds and other cross-field invariants.
+    pub fn validate(&self) -> Result<(), String> {
+        if self.delta_e_good_max < 0.0 || self.delta_e_warning_max < 0.0 {
+            return Err("ΔE thresholds cannot be negative.".to_string());
+        }
+        if self.delta_e_good_max >= self.delta_e_warning_max {
+            return Err("Good ΔE threshold must be strictly less than the warning threshold.".to_string());
+        }
+        Ok(())
+    }
+}
+
 pub fn get_default_presets() -> Vec<ProfilingPreset> {
     vec![
         ProfilingPreset {
@@ -239,6 +272,7 @@ pub fn load_settings(app: AppHandle) -> Result<AppSettings, String> {
 
 #[tauri::command]
 pub fn save_settings(app: AppHandle, settings: AppSettings) -> Result<(), String> {
+    settings.validate()?;
     let path = app.path().app_data_dir().unwrap();
     fs::create_dir_all(&path).map_err(|e| e.to_string())?;
     let json = serde_json::to_string_pretty(&settings).unwrap();
@@ -380,6 +414,39 @@ mod tests {
         assert_eq!(preset, imported);
     }
 
+    #[test]
+    fn test_default_delta_e_thresholds() {
+        let settings = AppSettings::default();
+        assert_eq!(settings.delta_e_good_max, 2.0);
+        assert_eq!(settings.delta_e_warning_max, 5.0);
+        assert!(settings.delta_e_good_max < settings.delta_e_warning_max);
+        assert!(settings.validate().is_ok());
+    }
+
+    #[test]
+    fn test_delta_e_threshold_serialization_defaults() {
+        let json = "{}";
+        let settings: AppSettings = serde_json::from_str(json).unwrap();
+        assert_eq!(settings.delta_e_good_max, 2.0);
+        assert_eq!(settings.delta_e_warning_max, 5.0);
+    }
+
+    #[test]
+    fn test_delta_e_threshold_validation() {
+        let mut settings = AppSettings::default();
+        settings.delta_e_good_max = 5.0;
+        settings.delta_e_warning_max = 2.0;
+        assert!(settings.validate().is_err());
+
+        settings.delta_e_good_max = -1.0;
+        settings.delta_e_warning_max = 2.0;
+        assert!(settings.validate().is_err());
+
+        settings.delta_e_good_max = 1.0;
+        settings.delta_e_warning_max = 3.0;
+        assert!(settings.validate().is_ok());
+    }
+
     #[test]
     fn test_parse_log_level_filter() {
         assert_eq!(parse_log_level_filter(Some("error")), log::LevelFilter::Error);

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ICCery",
-  "version": "0.7.4",
+  "version": "0.8.0",
   "identifier": "com.gronod.iccery",
   "build": {
     "frontendDist": "../src"

src/index.html

@@ -648,7 +648,7 @@
               </select>
             </div>
             
-            <div class="form-group">
+            <div class="form-group has-tooltip">
               <label>OBA / FWA Compensation</label>
               <select id="colprofFwa">
                 <option value="D50" selected>Calculated M1 — D50 FWA Compensation (Recommended)</option>
@@ -656,14 +656,24 @@
                 <option value="D65">D65 FWA Compensation</option>
                 <option value="custom">Custom Ambient Spectrum (.sp)...</option>
               </select>
+              <div class="tooltip-text">
+                Select how colprof handles Optical Brightening Agent (OBA) / Fluorescent Whitening Agent (FWA) compensation.<br>
+                • <strong>D50</strong>: Simulates ISO 3664 M1 viewing (D50, UV-cut) — recommended for modern OBA papers.<br>
+                • <strong>None</strong>: Native M0; no FWA compensation. Can look yellow under D50 if the paper contains OBA.<br>
+                • <strong>D65</strong>: Simulates outdoor D65 daylight; useful for outdoor display / packaging proofing.<br>
+                • <strong>Custom (.sp)</strong>: Provide an Argyll spectrum file describing the viewing booth illuminant.
+              </div>
             </div>
 
-            <div class="form-group hidden" id="colprofCustomSpRow">
+            <div class="form-group hidden has-tooltip" id="colprofCustomSpRow">
               <label>Custom Spectrum File (.sp)</label>
               <div class="input-row-sm">
                 <input type="text" id="colprofCustomSpPath" placeholder="Select .sp file..." readonly>
                 <button class="secondary btn-sm" id="btnBrowseCustomSp">Browse</button>
               </div>
+              <div class="tooltip-text">
+                Path to an Argyll-format spectrum file (.sp) representing the ambient illuminant. This is passed to colprof via the -f option and overrides the built-in D50/D65 compensation.
+              </div>
             </div>
 
             <details class="advanced-section-details">
@@ -673,7 +683,7 @@
               </summary>
               <div class="advanced-content">
                 <div class="advanced-grid-2col">
-                  <div class="form-group">
+                  <div class="form-group has-tooltip">
                     <label>Standard Illuminant</label>
                     <select id="colprofIlluminant">
                       <option value="" selected>Default (D50)</option>
@@ -685,8 +695,11 @@
                       <option value="F8">F8</option>
                       <option value="F10">F10</option>
                     </select>
+                    <div class="tooltip-text">
+                      Illuminant used for the CIE colourimetric calculations in colprof (option -i). Leave at Default (D50) for normal print profiling.
+                    </div>
                   </div>
-                  <div class="form-group">
+                  <div class="form-group has-tooltip">
                     <label>Standard Observer</label>
                     <select id="colprofObserver">
                       <option value="" selected>Default (1931 2°)</option>
@@ -694,8 +707,11 @@
                       <option value="2015_2">2015 2°</option>
                       <option value="2015_10">2015 10°</option>
                     </select>
+                    <div class="tooltip-text">
+                      CIE standard observer used for the colourimetric calculations (option -o). The 1931 2° observer is the default for graphic-arts profiling.
+                    </div>
                   </div>
-                  <div class="form-group">
+                  <div class="form-group has-tooltip">
                     <label>Input Viewing Condition</label>
                     <select id="colprofInputViewCond">
                       <option value="none" selected>None</option>
@@ -704,8 +720,11 @@
                       <option value="pe">Print evaluation (CIE 116-1995)</option>
                       <option value="pm">Print evaluation (partial mid-tone adaptation)</option>
                     </select>
+                    <div class="tooltip-text">
+                      Viewing condition under which the print target was measured (option -c). This affects the adapted white point used in the profile lookup table.
+                    </div>
                   </div>
-                  <div class="form-group">
+                  <div class="form-group has-tooltip">
                     <label>Output Viewing Condition</label>
                     <select id="colprofOutputViewCond">
                       <option value="none" selected>None</option>
@@ -716,6 +735,9 @@
                       <option value="jd">Projector in dark environment</option>
                       <option value="tv">Television/Film Studio</option>
                     </select>
+                    <div class="tooltip-text">
+                      Viewing condition under which the profile is intended to be used (option -d). Useful for creating display / output-referred profiles.
+                    </div>
                   </div>
                 </div>
               </div>
@@ -805,6 +827,10 @@
                     <span class="gamut-toggle-slider"></span>
                   </label>
                 </div>
+                <div class="gamut-legend-item gamut-slider-item">
+                  <label for="rngProfileOpacity" class="gamut-slider-label">Opacity</label>
+                  <input type="range" id="rngProfileOpacity" min="0.1" max="1" step="0.05" value="0.88">
+                </div>
 
                 <div class="gamut-legend-item">
                   <span class="gamut-swatch gamut-swatch-srgb"></span>
@@ -814,6 +840,10 @@
                     <span class="gamut-toggle-slider"></span>
                   </label>
                 </div>
+                <div class="gamut-legend-item gamut-slider-item">
+                  <label for="rngSrgbOpacity" class="gamut-slider-label">Opacity</label>
+                  <input type="range" id="rngSrgbOpacity" min="0.1" max="1" step="0.05" value="0.55">
+                </div>
 
                 <div class="gamut-legend-item">
                   <span class="gamut-swatch gamut-swatch-axes"></span>
@@ -823,6 +853,15 @@
                     <span class="gamut-toggle-slider"></span>
                   </label>
                 </div>
+                <div class="gamut-legend-item gamut-slider-item">
+                  <label for="rngAxisOpacity" class="gamut-slider-label">Opacity</label>
+                  <input type="range" id="rngAxisOpacity" min="0.1" max="1" step="0.05" value="0.8">
+                </div>
+
+                <div class="gamut-controls-actions">
+                  <button type="button" id="btnGamutResetCamera" class="btn-sm" title="Reset camera to default view (R)">⟲ Reset View</button>
+                  <span class="gamut-keyboard-hint">Press R to reset</span>
+                </div>
               </div>
             </div>
           </div>
@@ -848,6 +887,23 @@
           <label for="default_instrument">Default Instrument Override</label>
           <input type="text" id="default_instrument" placeholder="e.g. i1">
         </div>
+        <div class="form-group" style="margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border-color, #333);">
+          <label style="font-weight: 600;">Stage 3 ΔE₀₀ Traffic-Light Thresholds</label>
+          <div class="input-row" style="margin-top: 8px; align-items: flex-start;">
+            <div>
+              <label for="deltaEGoodMax" class="sub-label">Good / Warning boundary</label>
+              <input type="number" id="deltaEGoodMax" min="0" step="0.1" value="2.0">
+              <small class="help-hint" style="display:block; font-size:0.75rem; color:var(--text-muted, #888); margin-top:3px;">ΔE below this value is shown as green (Good).</small>
+            </div>
+            <div>
+              <label for="deltaEWarningMax" class="sub-label">Warning / Bad boundary</label>
+              <input type="number" id="deltaEWarningMax" min="0" step="0.1" value="5.0">
+              <small class="help-hint" style="display:block; font-size:0.75rem; color:var(--text-muted, #888); margin-top:3px;">ΔE above this value is shown as red (Bad).</small>
+            </div>
+          </div>
+          <small id="deltaEThresholdError" class="help-hint" style="display:none; color: var(--error-color, #ff5f5f); margin-top: 6px;">Good threshold must be less than warning threshold.</small>
+        </div>
+
         <div class="form-group" style="margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border-color, #333);">
           <label style="font-weight: 600;">Diagnostics &amp; Logging</label>
           <div class="input-row" style="margin-top: 8px;">

src/js/gamut_viewer.js

@@ -204,30 +204,80 @@ function _line(from, to, material) {
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
-// Parse .gam file text → { vertices: [[L,a,b],...], faces: [[v0,v1,v2],...] }
+/**
+ * Parse an Argyll `.gam` text file into vertex and face arrays.
+ *
+ * Argyll `.gam` files contain a header followed by one or more `BEGIN_DATA`
+ * ... `END_DATA` blocks. The first data block is a vertex list
+ * (index L a b); subsequent blocks contain triangle face indices (v0 v1 v2).
+ * Blank lines and hash `#` comments outside data blocks are ignored.
+ *
+ * @param {string} text - Raw contents of the .gam file.
+ * @returns {{ vertices: number[][], faces: number[][], warnings: string[] }}
+ */
 // ─────────────────────────────────────────────────────────────────────────────
 export function parseGamutFile(text) {
     const lines = text.split('\n');
     const vertices = [];
     const faces    = [];
+    const warnings = [];
     let dataStarted = false;
-    let dataBlock   = 0;   // 1 = vertices section, 2 = faces section
+    let dataBlock   = 0;   // 1 = vertices section, 2+ = faces sections
 
-    for (const line of lines) {
-        const trimmed = line.trim();
-        if (trimmed === 'BEGIN_DATA') { dataBlock++;  dataStarted = true;  continue; }
-        if (trimmed === 'END_DATA')   {               dataStarted = false; continue; }
+    for (let lineIdx = 0; lineIdx < lines.length; lineIdx++) {
+        const raw = lines[lineIdx];
+        const trimmed = raw.replace(/#.*$/, '').trim();  // strip inline comments
+        if (trimmed === '') continue;
+
+        if (trimmed.toUpperCase() === 'BEGIN_DATA') {
+            dataBlock++;
+            dataStarted = true;
+            continue;
+        }
+        if (trimmed.toUpperCase() === 'END_DATA') {
+            dataStarted = false;
+            continue;
+        }
         if (!dataStarted) continue;
 
         const parts = trimmed.split(/\s+/).map(Number);
-        if (dataBlock === 1 && parts.length >= 4) {
-            vertices.push([parts[1], parts[2], parts[3]]);   // [L, a, b]
-        } else if (dataBlock === 2 && parts.length >= 3) {
-            faces.push([parts[0], parts[1], parts[2]]);
+        const allNumeric = parts.every(n => !Number.isNaN(n));
+        if (!allNumeric) {
+            warnings.push(`Skipping non-numeric data at line ${lineIdx + 1}`);
+            continue;
+        }
+
+        if (dataBlock === 1) {
+            if (parts.length >= 4) {
+                // Vertex format: index L a b (index is usually ignored)
+                const [_, L, a, b] = parts;
+                if (L < 0 || L > 100 || Math.abs(a) > 128 || Math.abs(b) > 128) {
+                    warnings.push(`Vertex at line ${lineIdx + 1} is outside plausible CIELAB bounds: L=${L}, a=${a}, b=${b}`);
+                }
+                vertices.push([L, a, b]);
+            } else {
+                warnings.push(`Vertex data at line ${lineIdx + 1} has only ${parts.length} values`);
+            }
+        } else {
+            // Face data can appear in multiple blocks (some .gam files use a
+            // separate DATA block per surface type or per convex-hull section).
+            if (parts.length >= 3) {
+                faces.push([parts[0], parts[1], parts[2]]);
+            } else {
+                warnings.push(`Face data at line ${lineIdx + 1} has only ${parts.length} values`);
+            }
         }
     }
 
-    return { vertices, faces };
+    if (vertices.length > 0 && faces.length === 0) {
+        warnings.push(`Parsed ${vertices.length} vertices but no faces; will compute convex hull on the fly.`);
+    }
+
+    if (dataBlock === 0) {
+        warnings.push('No BEGIN_DATA blocks found; file may be empty or not a valid Argyll .gam file.');
+    }
+
+    return { vertices, faces, warnings };
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
@@ -304,7 +354,10 @@ function _renderSrgbReference(text, previousGroup) {
         });
     }
 
-    const { vertices, faces } = parseGamutFile(text);
+    const { vertices, faces, warnings } = parseGamutFile(text);
+    if (warnings.length > 0) {
+        console.warn('Gamut parser warnings:', warnings.join('\n'));
+    }
     const built = _buildGeometry(vertices, faces);
     if (!built) return null;
 
@@ -348,7 +401,10 @@ function _renderProfileGamut(text, previousMesh) {
         if (previousMesh.material) previousMesh.material.dispose();
     }
 
-    const { vertices, faces } = parseGamutFile(text);
+    const { vertices, faces, warnings } = parseGamutFile(text);
+    if (warnings.length > 0) {
+        console.warn('Gamut parser warnings:', warnings.join('\n'));
+    }
     const built = _buildGeometry(vertices, faces);
     if (!built) return null;
 
@@ -383,7 +439,77 @@ function _renderProfileGamut(text, previousMesh) {
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
-// Public: load bundled sRGB reference gamut
+// Camera & view controls
+// ─────────────────────────────────────────────────────────────────────────────
+/**
+ * Reset the camera to its default home position and orientation.
+ * Also resets orbit controls target to the centre of the CIELAB volume.
+ */
+export function resetCamera() {
+    if (!camera || !controls) return;
+    camera.position.set(180, 120, 180);
+    camera.lookAt(0, 50, 0);
+    controls.target.set(0, 50, 0);
+    controls.update();
+}
+
+/**
+ * Set the opacity of the rendered profile gamut surface (0–1).
+ * @param {number} opacity
+ */
+export function setProfileOpacity(opacity) {
+    if (currentProfileMesh && currentProfileMesh.material) {
+        currentProfileMesh.material.opacity = Math.max(0, Math.min(1, opacity));
+        currentProfileMesh.material.transparent = opacity < 1;
+        currentProfileMesh.material.needsUpdate = true;
+    }
+}
+
+/**
+ * Set the opacity of the sRGB reference wireframe and fill (0–1).
+ * @param {number} opacity
+ */
+export function setSrgbReferenceOpacity(opacity) {
+    if (sRgbGroup) {
+        sRgbGroup.traverse((child) => {
+            if (child.material) {
+                child.material.opacity = child.material.opacity >= 0.5
+                    ? Math.max(0.05, Math.min(1, opacity))
+                    : Math.max(0.02, Math.min(0.2, opacity * 0.2));
+            }
+        });
+    }
+}
+
+/**
+ * Set the opacity of the CIELAB axis scaffold (0–1).
+ * @param {number} opacity
+ */
+export function setAxisOpacity(opacity) {
+    if (axisScaffoldGroup) {
+        axisScaffoldGroup.traverse((child) => {
+            if (child.material) {
+                child.material.opacity = Math.max(0, Math.min(1, opacity));
+            }
+        });
+    }
+}
+
+/**
+ * Handle keyboard shortcuts for the gamut viewer.
+ * @param {KeyboardEvent} e
+ */
+function _onKeyDown(e) {
+    if (e.key === 'r' || e.key === 'R') {
+        resetCamera();
+    }
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+/**
+ * Load and render the bundled sRGB reference gamut.
+ * @returns {Promise<void>}
+ */
 // ─────────────────────────────────────────────────────────────────────────────
 export async function loadSrgbReferenceGamut() {
     try {
@@ -398,7 +524,11 @@ export async function loadSrgbReferenceGamut() {
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
-// Public: load and render a profile gamut from a .gam file path
+/**
+ * Load and render a profile gamut from a `.gam` file path.
+ * @param {string} gamFilePath - Absolute path to the gamut file.
+ * @returns {Promise<THREE.Mesh|null>}
+ */
 // ─────────────────────────────────────────────────────────────────────────────
 export async function loadGamutMesh(gamFilePath) {
     try {
@@ -428,7 +558,7 @@ export function toggleAxes(visible) {
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
-// Wire legend toggle checkboxes to the toggle functions
+// Wire legend toggle checkboxes, opacity sliders, and reset button
 // ─────────────────────────────────────────────────────────────────────────────
 function _wireToggles() {
     const bindings = [
@@ -440,4 +570,32 @@ function _wireToggles() {
         const el = document.getElementById(id);
         if (el) el.addEventListener('change', (e) => fn(e.target.checked));
     }
+
+    const resetBtn = document.getElementById('btnGamutResetCamera');
+    if (resetBtn) resetBtn.addEventListener('click', resetCamera);
+
+    const profileOpacity = document.getElementById('rngProfileOpacity');
+    if (profileOpacity) {
+        profileOpacity.addEventListener('input', (e) => setProfileOpacity(parseFloat(e.target.value)));
+    }
+
+    const srgbOpacity = document.getElementById('rngSrgbOpacity');
+    if (srgbOpacity) {
+        srgbOpacity.addEventListener('input', (e) => setSrgbReferenceOpacity(parseFloat(e.target.value)));
+    }
+
+    const axisOpacity = document.getElementById('rngAxisOpacity');
+    if (axisOpacity) {
+        axisOpacity.addEventListener('input', (e) => setAxisOpacity(parseFloat(e.target.value)));
+    }
+
+    // Only listen for 'R' reset when the viewer tab is active.
+    const stage5 = document.getElementById('stage-5');
+    if (stage5) {
+        stage5.addEventListener('keydown', (e) => {
+            if ((e.key === 'r' || e.key === 'R') && !stage5.classList.contains('hidden')) {
+                resetCamera();
+            }
+        });
+    }
 }

src/js/gamut_viewer.test.js

@@ -0,0 +1,80 @@
+// Manual / browser-console tests for gamut_viewer.js and profcheck.js parsing.
+// Run in a browser/devtools console after the app has loaded:
+//   import('./gamut_viewer.test.js').then(m => m.runAll())
+
+import { parseGamutFile } from './gamut_viewer.js';
+
+export function runAll() {
+  console.group('gamut/profcheck parser tests');
+  testParseGamutBasic();
+  testParseGamutDualTable();
+  testParseGamutWithComments();
+  console.groupEnd();
+}
+
+function assertEqual(actual, expected, message) {
+  const ok = JSON.stringify(actual) === JSON.stringify(expected);
+  if (ok) {
+    console.log('PASS:', message);
+  } else {
+    console.error('FAIL:', message, 'expected', expected, 'got', actual);
+  }
+  return ok;
+}
+
+function testParseGamutBasic() {
+  const text = `GAMUT file
+BEGIN_DATA
+0 50 0 0
+1 100 0 0
+2 0 -128 0
+3 0 0 128
+END_DATA
+BEGIN_DATA
+0 1 2
+1 2 3
+END_DATA`;
+  const { vertices, faces, warnings } = parseGamutFile(text);
+  assertEqual(vertices.length, 4, 'basic gamut vertex count');
+  assertEqual(faces.length, 2, 'basic gamut face count');
+  assertEqual(warnings.length, 0, 'basic gamut no warnings');
+}
+
+function testParseGamutDualTable() {
+  const text = `GAMUT file
+BEGIN_DATA
+0 50 0 0
+1 100 0 0
+2 0 -128 0
+3 0 0 128
+END_DATA
+BEGIN_DATA
+0 1 2
+END_DATA
+BEGIN_DATA
+1 2 3
+END_DATA`;
+  const { vertices, faces, warnings } = parseGamutFile(text);
+  assertEqual(vertices.length, 4, 'dual-table gamut vertex count');
+  assertEqual(faces.length, 2, 'dual-table gamut face count');
+  assertEqual(warnings.length, 0, 'dual-table gamut no warnings');
+}
+
+function testParseGamutWithComments() {
+  const text = `GAMUT file
+# this is a comment
+BEGIN_DATA
+0 50 0 0
+1 100 0 0
+# inline comment
+2 0 -128 0
+3 0 0 128
+END_DATA
+BEGIN_DATA
+0 1 2
+1 2 3
+END_DATA`;
+  const { vertices, faces, warnings } = parseGamutFile(text);
+  assertEqual(vertices.length, 4, 'commented gamut vertex count');
+  assertEqual(faces.length, 2, 'commented gamut face count');
+}

src/js/profcheck.js

@@ -98,7 +98,14 @@ export function initProfcheck() {
 
             // Ensure gamut mesh is loaded into 3D viewer
             const gamFilePath = cwd ? `${cwd}${sep}${basename}.gam` : `${basename}.gam`;
-            loadGamutMesh(gamFilePath, 0x3b82f6);
+            try {
+              const result = await loadGamutMesh(gamFilePath);
+              if (!result) {
+                logPre.textContent += `\n[WARN] Could not render 3D gamut mesh from ${gamFilePath}.\n`;
+              }
+            } catch (gamErr) {
+              logPre.textContent += `\n[WARN] 3D gamut render failed: ${gamErr}\n`;
+            }
           } else {
             logPre.textContent += `\n[ERROR] profcheck exited with code ${event.payload.code}.\n`;
           }
@@ -113,33 +120,89 @@ export function initProfcheck() {
     }
   });
 
+  /**
+   * Parse profcheck output for Average, Peak, and RMS delta-E values.
+   * Supports both Argyll's JSON-style summary and plain-text legacy output.
+   * @param {string} stdout - Full profcheck stdout.
+   */
   function parseAndRenderReport(stdout) {
     reportCard.classList.remove("hidden");
 
     let avgDe = 0.0;
     let maxDe = 0.0;
     let rmsDe = 0.0;
+    let parserWarnings = [];
 
-    // Check if JSON output is present
-    const jsonMatch = stdout.match(/\{[\s\S]*"avg_de"[\s\S]*\}/);
-    if (jsonMatch) {
+    // Argyll's JSON output can appear either as a compact object on a single
+    // line or embedded inside larger text. Try to find and parse the LAST valid
+    // JSON object in the output, which is most likely the summary.
+    const jsonObjects = [];
+    const re = /\{[\s\S]*?\}/g;
+    let m;
+    while ((m = re.exec(stdout)) !== null) {
       try {
-        const json = JSON.parse(jsonMatch[0]);
-        avgDe = json.avg_de || 0;
-        maxDe = json.max_de || json.peak_de || 0;
-        rmsDe = json.rms_de || 0;
+        const parsed = JSON.parse(m[0]);
+        if (typeof parsed === 'object' && parsed !== null && ('avg_de' in parsed || 'peak_de' in parsed || 'rms_de' in parsed)) {
+          jsonObjects.push(parsed);
+        }
       } catch (e) {
-        console.error("JSON parse error:", e);
+        // Not a valid JSON object, ignore.
       }
+    }
+
+    if (jsonObjects.length > 0) {
+      const json = jsonObjects[jsonObjects.length - 1];
+      avgDe = typeof json.avg_de === 'number' ? json.avg_de : 0;
+      maxDe = typeof json.max_de === 'number' ? json.max_de : (typeof json.peak_de === 'number' ? json.peak_de : 0);
+      rmsDe = typeof json.rms_de === 'number' ? json.rms_de : 0;
     } else {
-      // Regex fallbacks for standard profcheck output
-      const avgMatch = stdout.match(/avg\.\s*(?:dE\s*)?=\s*([\d\.]+)/i) || stdout.match(/average\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i);
-      const maxMatch = stdout.match(/max\.\s*(?:dE\s*)?=\s*([\d\.]+)/i) || stdout.match(/peak\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i);
-      const rmsMatch = stdout.match(/RMS\s*(?:dE\s*)?=\s*([\d\.]+)/i) || stdout.match(/rms\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i);
+      // Regex fallbacks for standard profcheck text output
+      const avgPatterns = [
+        /avg(?:\.?|erage)\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i,
+        /average\s+(?:dE\s*)?([\d\.]+)/i,
+        /mean\s+(?:dE\s*)?([\d\.]+)/i,
+        /dE\s+average[^\d]*([\d\.]+)/i,
+      ];
+      const maxPatterns = [
+        /max(?:\.?|imum)\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i,
+        /peak\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i,
+        /worst\s*(?:dE\s*)?([\d\.]+)/i,
+        /dE\s+max[^\d]*([\d\.]+)/i,
+      ];
+      const rmsPatterns = [
+        /RMS\s*(?:dE\s*)?[:=]\s*([\d\.]+)/i,
+        /rms\s*(?:dE\s*)?([\d\.]+)/i,
+        /root\s+mean\s+sq(?:uare)?\s*(?:dE\s*)?([\d\.]+)/i,
+      ];
+
+      const find = (patterns) => {
+        for (const p of patterns) {
+          const match = stdout.match(p);
+          if (match) return match;
+        }
+        return null;
+      };
+
+      const avgMatch = find(avgPatterns);
+      const maxMatch = find(maxPatterns);
+      const rmsMatch = find(rmsPatterns);
 
       if (avgMatch) avgDe = parseFloat(avgMatch[1]);
+      else parserWarnings.push('Could not detect Average ΔE in profcheck output.');
+
       if (maxMatch) maxDe = parseFloat(maxMatch[1]);
+      else parserWarnings.push('Could not detect Peak ΔE in profcheck output.');
+
       if (rmsMatch) rmsDe = parseFloat(rmsMatch[1]);
+      else parserWarnings.push('Could not detect RMS ΔE in profcheck output.');
+
+      if (!avgMatch && !maxMatch && !rmsMatch) {
+        parserWarnings.push('No delta-E values were found in profcheck output.');
+      }
+    }
+
+    if (parserWarnings.length > 0) {
+      logPre.textContent += `\n[WARN] ${parserWarnings.join(' ')}\n`;
     }
 
     avgDeEl.textContent = avgDe.toFixed(2);

src/js/settings.js

@@ -1,6 +1,13 @@
 const { invoke } = window.__TAURI__.core;
 import { logger } from './logger.js';
 
+function getInputValueAsFloat(id, fallback) {
+  const el = document.getElementById(id);
+  if (!el) return fallback;
+  const v = parseFloat(el.value);
+  return Number.isNaN(v) ? fallback : v;
+}
+
 export async function initSettings() {
     const dialog = document.getElementById('settingsDialog');
     const openBtn = document.getElementById('openSettingsBtn');
@@ -11,6 +18,9 @@ export async function initSettings() {
     const btnCopyLogPath = document.getElementById('btnCopyLogPath');
     const btnCopyLogExcerpt = document.getElementById('btnCopyLogExcerpt');
     const logPathDisplay = document.getElementById('logPathDisplay');
+    const deltaEGoodMax = document.getElementById('deltaEGoodMax');
+    const deltaEWarningMax = document.getElementById('deltaEWarningMax');
+    const deltaEThresholdError = document.getElementById('deltaEThresholdError');
 
     if (!dialog || !openBtn) return;
 
@@ -24,6 +34,24 @@ export async function initSettings() {
         }
     }
 
+    function validateDeltaEThresholds() {
+        if (!deltaEGoodMax || !deltaEWarningMax) return true;
+        const good = parseFloat(deltaEGoodMax.value);
+        const warn = parseFloat(deltaEWarningMax.value);
+        const valid = !Number.isNaN(good) && !Number.isNaN(warn) && good < warn && good >= 0 && warn >= 0;
+        if (deltaEThresholdError) {
+            deltaEThresholdError.style.display = valid ? 'none' : 'block';
+        }
+        return valid;
+    }
+
+    if (deltaEGoodMax) {
+        deltaEGoodMax.addEventListener('input', validateDeltaEThresholds);
+    }
+    if (deltaEWarningMax) {
+        deltaEWarningMax.addEventListener('input', validateDeltaEThresholds);
+    }
+
     openBtn.addEventListener('click', async () => {
         try {
             const settings = await invoke('load_settings');
@@ -32,6 +60,13 @@ export async function initSettings() {
             if (logLevelSelect && settings.log_level) {
                 logLevelSelect.value = settings.log_level;
             }
+            if (deltaEGoodMax) {
+                deltaEGoodMax.value = Number(settings.delta_e_good_max ?? 2.0).toFixed(1);
+            }
+            if (deltaEWarningMax) {
+                deltaEWarningMax.value = Number(settings.delta_e_warning_max ?? 5.0).toFixed(1);
+            }
+            validateDeltaEThresholds();
             await refreshLogPath();
             dialog.showModal();
         } catch (e) {
@@ -99,18 +134,26 @@ export async function initSettings() {
     if (saveBtn) {
         saveBtn.addEventListener('click', async () => {
             try {
+                if (!validateDeltaEThresholds()) {
+                    throw new Error('Invalid ΔE thresholds');
+                }
                 const currentSettings = await invoke('load_settings').catch(() => ({}));
                 const settings = {
                     ...currentSettings,
                     argyll_binary_dir: document.getElementById('argyll_binary_dir').value.trim() || null,
                     default_instrument: document.getElementById('default_instrument').value.trim() || null,
                     log_level: logLevelSelect ? logLevelSelect.value : (currentSettings.log_level || 'info'),
+                    delta_e_good_max: getInputValueAsFloat('deltaEGoodMax', 2.0),
+                    delta_e_warning_max: getInputValueAsFloat('deltaEWarningMax', 5.0),
                 };
                 await invoke('save_settings', { settings });
                 logger.info(`Settings saved. Log level set to: ${settings.log_level}`, 'Settings');
+                // Notify other UI modules (e.g. swatch grid) that settings changed.
+                window.dispatchEvent(new CustomEvent('settings-saved', { detail: settings }));
                 dialog.close();
             } catch (e) {
                 logger.error(`Failed to save settings: ${e}`, 'Settings');
+                alert(`Failed to save settings: ${e}`);
             }
         });
     }

src/js/swatch_grid.js

@@ -1,10 +1,76 @@
 import { computeDeltaE00 } from './delta_e.js';
 import { labToCss, deviceRgbToCss, deviceCmykToCss } from './color_convert.js';
 
-const { listen } = window.__TAURI__.event;
+const { listen, emit } = window.__TAURI__.event;
+const { invoke } = window.__TAURI__.core;
 
 let unlistenJsonRow = null;
 
+// Cached ΔE thresholds; refreshed from settings on load and when settings change.
+let deltaEThresholds = { goodMax: 2.0, warnMax: 5.0 };
+
+/**
+ * Load the ΔE traffic-light thresholds from persisted app settings.
+ * Falls back to 2.0 / 5.0 if settings are missing or malformed.
+ */
+async function refreshDeltaEThresholds() {
+  try {
+    const s = await invoke('load_settings');
+    deltaEThresholds = {
+      goodMax: s.delta_e_good_max ?? 2.0,
+      warnMax: s.delta_e_warning_max ?? 5.0,
+    };
+    // Enforce the invariant at runtime in case a user hand-edited settings.json.
+    if (deltaEThresholds.goodMax > deltaEThresholds.warnMax) {
+      console.warn('ΔE thresholds invalid (good > warning); resetting to defaults.');
+      deltaEThresholds = { goodMax: 2.0, warnMax: 5.0 };
+    }
+  } catch (err) {
+    console.warn('Could not load ΔE thresholds, using defaults:', err);
+    deltaEThresholds = { goodMax: 2.0, warnMax: 5.0 };
+  }
+}
+
+/**
+ * Classify a CIEDE2000 value using the current thresholds.
+ * @param {number} deltaE
+ * @returns {{ label: string, cssClass: string }}
+ */
+function classifyDeltaE(deltaE) {
+  if (deltaE < deltaEThresholds.goodMax) {
+    return { label: "Good", cssClass: "de-good" };
+  } else if (deltaE < deltaEThresholds.warnMax) {
+    return { label: "Warning", cssClass: "de-warning" };
+  } else {
+    return { label: "Bad", cssClass: "de-bad" };
+  }
+}
+
+/**
+ * Re-classify all already-rendered swatches using the current thresholds.
+ * Call this after the user changes thresholds in Settings.
+ */
+function reclassifySwatches() {
+  document.querySelectorAll('.swatch-patch[data-delta-e]').forEach((patchEl) => {
+    const deltaE = parseFloat(patchEl.dataset.deltaE);
+    if (Number.isNaN(deltaE)) return;
+
+    patchEl.classList.remove('de-good', 'de-warning', 'de-bad');
+    const { cssClass, label } = classifyDeltaE(deltaE);
+    patchEl.classList.add(cssClass);
+
+    // Update the classification word in the title without re-parsing everything.
+    if (patchEl.title) {
+      patchEl.title = patchEl.title.replace(/\s*\([^)]*\)$/, '') + ` (${label})`;
+    }
+  });
+}
+
+// Listen for the custom event emitted by settings.js after a successful save.
+window.addEventListener('settings-saved', () => {
+  refreshDeltaEThresholds().then(reclassifySwatches);
+});
+
 /**
  * Start listening for row events from a chartread process.
  * @param {string} processId - The process ID (e.g. "chartread_my_profile")
@@ -16,6 +82,9 @@ export async function startSwatchListener(processId, onRowComplete) {
   const progressText = document.getElementById("readProgressText");
   const statsPanel = document.getElementById("readStats");
 
+  // Load thresholds at listener start
+  await refreshDeltaEThresholds();
+
   // Clear previous state
   grid.innerHTML = "";
   let totalPatches = 0;
@@ -51,6 +120,8 @@ export async function startSwatchListener(processId, onRowComplete) {
     if (progressText) progressText.textContent = `Strip ${data.row_id} — ${data.row_index + 1} / ${data.total_rows}`;
 
     // Create row container
+    // Row and patch order from chartread (A->Z, 1->N) is rendered
+    // left-to-right / top-to-bottom to match the printtarg output.
     const rowEl = document.createElement("div");
     rowEl.className = "swatch-row";
 
@@ -63,6 +134,10 @@ export async function startSwatchListener(processId, onRowComplete) {
     rowPatches.className = "swatch-row-patches";
 
     for (const patch of data.patches) {
+      // Argyll marks spacer/boundary patches with is_pad. Some printtarg
+      // layouts also flag white reference patches (-e white steps) as pads,
+      // but those carry valid expected or measured device data. Only skip
+      // pads that have no measurement and no non-zero device coordinates.
       if (patch.is_pad && !patch.measured && (!patch.device || patch.device.every(v => v === 0))) continue;
 
       const patchEl = document.createElement("div");
@@ -84,20 +159,21 @@ export async function startSwatchListener(processId, onRowComplete) {
 
       const swatch = document.createElement("div");
       swatch.className = "swatch-color";
-      
+
       if (measuredCss) {
         swatch.style.background = `linear-gradient(135deg, ${intendedCss} 50%, ${measuredCss} 50%)`;
       } else {
         swatch.style.backgroundColor = intendedCss;
       }
-      
+
       patchEl.appendChild(swatch);
 
+      // Build a structured tooltip for the patch
       let titleStr = `${patch.loc} (ID: ${patch.id})`;
       if (patch.expected && patch.expected.Lab) {
         titleStr += `\nIntended Lab: ${patch.expected.Lab.map(v => v.toFixed(1)).join(', ')}`;
       } else if (patch.device) {
-        titleStr += `\nDevice: ${patch.device.map(v => v.toFixed(1)).join(', ')}`;
+        titleStr += `\nIntended Device: ${patch.device.map(v => v.toFixed(1)).join(', ')}`;
       }
 
       if (patch.measured && patch.measured.Lab) {
@@ -107,22 +183,19 @@ export async function startSwatchListener(processId, onRowComplete) {
       // Compute and display ΔE₀₀ if both expected and measured Lab are present
       if (patch.expected && patch.expected.Lab && patch.measured && patch.measured.Lab) {
         const deltaE = computeDeltaE00(patch.expected.Lab, patch.measured.Lab);
+        const { label, cssClass } = classifyDeltaE(deltaE);
+
+        // Persist the raw ΔE on the element so re-classification works after
+        // the user changes thresholds in Settings.
+        patchEl.dataset.deltaE = deltaE.toFixed(4);
 
         const deLabel = document.createElement("div");
         deLabel.className = "swatch-de";
         deLabel.textContent = deltaE.toFixed(1);
-        
-        titleStr += `\nΔE₀₀: ${deltaE.toFixed(2)}`;
 
-        // Traffic light classification
-        if (deltaE < 2) {
-          patchEl.classList.add("de-good");       // Green
-        } else if (deltaE < 5) {
-          patchEl.classList.add("de-warning");     // Amber
-        } else {
-          patchEl.classList.add("de-bad");          // Red
-        }
+        titleStr += `\nΔE₀₀: ${deltaE.toFixed(2)} (${label})`;
 
+        patchEl.classList.add(cssClass);
         patchEl.appendChild(deLabel);
 
         // Accumulate stats

src/js/swatch_grid.test.js

@@ -0,0 +1,16 @@
+// Manual smoke tests for swatch_grid.js
+// Run in a browser/devtools console after the app has loaded:
+//   import('./swatch_grid.test.js').then(m => m.runAll())
+
+export function runAll() {
+  console.group('swatch_grid smoke tests');
+  testClassifyDeltaE();
+  console.groupEnd();
+}
+
+function testClassifyDeltaE() {
+  // classifyDeltaE is currently internal to swatch_grid.js, but we can
+  // validate the visual classification by exercising the colour thresholds.
+  // This is a placeholder for a future unit-test harness.
+  console.log('testClassifyDeltaE: no direct export; validated by manual inspection');
+}

src/styles/main.css

@@ -1530,6 +1530,43 @@ button.danger:hover {
   margin-bottom: 0;
 }
 
+.gamut-legend-item.gamut-slider-item {
+  margin: -2px 0 8px 27px;
+  gap: 6px;
+}
+
+.gamut-slider-label {
+  font-size: 0.7rem;
+  opacity: 0.65;
+  min-width: 46px;
+}
+
+.gamut-slider-item input[type="range"] {
+  flex: 1;
+  margin: 0;
+  height: 4px;
+  accent-color: var(--accent-color, #3b82f6);
+}
+
+.gamut-controls-actions {
+  margin-top: 10px;
+  padding-top: 10px;
+  border-top: 1px solid rgba(255, 255, 255, 0.09);
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.gamut-controls-actions button {
+  width: 100%;
+}
+
+.gamut-keyboard-hint {
+  font-size: 0.68rem;
+  opacity: 0.5;
+  text-align: center;
+}
+
 .gamut-legend-label {
   flex: 1;
   white-space: nowrap;