feat(eco): warm the Energy page as driving hardens

The page background between the cards blends gradually towards ev_warn
as the harsh-acceleration share rises (none up to 6 %, full at 24 %),
eased per frame and gated on the eco advice switch. Cards keep their own
surface, so no figure loses contrast.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: malys

CHANGELOG.md

@@ -6,6 +6,11 @@ All notable changes follow [Keep a Changelog](https://keepachangelog.com/en/1.1.
 
 ### Added
 
+- **Energy page warms when driving is not smooth.** With eco advice on, the page background
+  between the cards blends gradually towards the warning colour as the harsh-acceleration share
+  rises: none up to 6 %, full at 24 % (the advice mark is 12 %). Eased over a few seconds,
+  never flashed; the cards keep their own surface, so no figure loses contrast, and the gauge's
+  word still carries the meaning.
 - **"Validation results complete" notice (unstable, CP-055).** Once every validation question
   has recorded at least one answer, a notification asks the driver to export the diagnostic to
   USB; tapping it opens Diagnostics. Posted once per process, only with the car read as stopped.

app/src/main/java/com/evsuite/chargepilot/EcoCoach.kt

@@ -171,6 +171,18 @@ class EcoCoach(context: Context) {
         private const val PREF_ADVICE = "advice_enabled"
         private const val PREF_VOICE = "voice_enabled"
 
+        /**
+         * How far the Energy page leans towards the warning colour: nothing up to half the
+         * advice mark, all the way at twice it. A ramp rather than a switch, so the page warms
+         * as the driving hardens instead of flipping on one sample; null (not a minute of
+         * movement yet) is no tint, never a guess.
+         */
+        fun harshTint(share: Double?): Float {
+            val mark = EcoDrivingMonitor.MIN_HARSH_SHARE_PERCENT
+            share ?: return 0f
+            return ((share - mark / 2) / (mark * 1.5)).coerceIn(0.0, 1.0).toFloat()
+        }
+
         fun adviceEnabled(context: Context): Boolean =
             prefs(context).getBoolean(PREF_ADVICE, EcoCoachDefaults.ADVICE_ENABLED)
 

app/src/main/java/com/evsuite/chargepilot/MainActivity.kt

@@ -17,6 +17,7 @@ import android.widget.TextView
 import android.widget.Toast
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.core.content.ContextCompat
+import androidx.core.graphics.ColorUtils
 import com.evsuite.chargepilot.databinding.ActivityMainBinding
 import com.evsuite.chargepilot.update.UpdateHook
 import com.evsuite.hardware.AppLogger
@@ -67,6 +68,8 @@ class MainActivity : PrimaryNavigationActivity() {
     /** The recorder owns the sampler; this screen is one of its readers. */
     private var recorder: TripRecordingService? = null
     private var loadedHistoryRevision = -1
+    /** The page tint as drawn, 0..1, eased towards [EcoCoach.harshTint] each frame. */
+    private var ecoTint = 0f
     /** Exact normalized service frame; the parked-only actions re-read it rather than the UI. */
     @Volatile private var latestSnapshot: EnergySnapshot? = null
 
@@ -265,6 +268,24 @@ class MainActivity : PrimaryNavigationActivity() {
         val gauge = line == null && EcoCoach.adviceEnabled(this)
         binding.ecoGauge.visibility = if (gauge) View.VISIBLE else View.GONE
         if (gauge) renderEcoGauge(eco.harshShare())
+        renderEcoTint(if (EcoCoach.adviceEnabled(this)) eco.harshShare() else null)
+    }
+
+    /**
+     * The page itself warms towards the warning colour as the driving hardens, so a glance
+     * catches it without reading the gauge. Only the background between the cards is tinted:
+     * every figure stays on its own surface and keeps its contrast. Eased per frame, never
+     * flashed, and the gauge's word stays the carrier of the meaning.
+     */
+    private fun renderEcoTint(share: Double?) {
+        ecoTint += (EcoCoach.harshTint(share) - ecoTint) * ECO_TINT_EASE
+        binding.root.setBackgroundColor(
+            ColorUtils.blendARGB(
+                ContextCompat.getColor(this, R.color.ev_background),
+                ContextCompat.getColor(this, R.color.ev_warn),
+                ecoTint * ECO_TINT_MAX,
+            ),
+        )
     }
 
     /** CP-084. Empty and grey before a minute of movement; amber once past the advice mark. */
@@ -518,5 +539,9 @@ class MainActivity : PrimaryNavigationActivity() {
         const val ARRIVAL_REFRESH_MS = 5_000L
         /** The full gauge: two and a half times the advice mark, so the mark sits left of centre. */
         const val ECO_GAUGE_FULL_PERCENT = 30.0
+        /** Share of the way to the target tint covered each frame: a few seconds to settle. */
+        const val ECO_TINT_EASE = 0.25f
+        /** The strongest blend of the warning colour into the page background. */
+        const val ECO_TINT_MAX = 0.6f
     }
 }

app/src/test/java/com/evsuite/chargepilot/EcoTintTest.kt

@@ -0,0 +1,22 @@
+package com.evsuite.chargepilot
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class EcoTintTest {
+
+    @Test
+    fun `no tint before a minute of movement or for a smooth drive`() {
+        assertEquals(0f, EcoCoach.harshTint(null))
+        assertEquals(0f, EcoCoach.harshTint(0.0))
+        assertEquals(0f, EcoCoach.harshTint(6.0))
+    }
+
+    @Test
+    fun `the tint grows with the harsh share and stops at full`() {
+        assertEquals(1f / 3, EcoCoach.harshTint(12.0), 1e-6f)
+        assertEquals(2f / 3, EcoCoach.harshTint(18.0), 1e-6f)
+        assertEquals(1f, EcoCoach.harshTint(24.0))
+        assertEquals(1f, EcoCoach.harshTint(80.0))
+    }
+}