From f32760550bd99f3af1a104cc86b6718e8654c35f Mon Sep 17 00:00:00 2001
From: Joshua Tsuji <tsuji@google.com>
Date: Fri, 6 Nov 2020 18:03:44 -0500
Subject: [PATCH] Adds the LightRevealScrim, and the 'lift' reveal effect.

This effect will be used for all AOD/Lockscreen transitions - a subsequent CL is adding additional effects (like power button/AOD tap) and also using this effect for Unlocked -> AOD/Locked.

Test: manual
Bug: 169693662
Change-Id: I4546b96a29cabd14fc317478f33d8ee4db040eeb
---
 .../res/layout/super_notification_shade.xml   |   6 +
 .../systemui/statusbar/LightRevealScrim.kt    | 207 ++++++++++++++++++
 .../systemui/statusbar/phone/StatusBar.java   |  18 ++
 3 files changed, 231 insertions(+)
 create mode 100644 packages/SystemUI/src/com/android/systemui/statusbar/LightRevealScrim.kt

diff --git a/packages/SystemUI/res/layout/super_notification_shade.xml b/packages/SystemUI/res/layout/super_notification_shade.xml
index d322e0905ef66..0ba546eff6896 100644
--- a/packages/SystemUI/res/layout/super_notification_shade.xml
+++ b/packages/SystemUI/res/layout/super_notification_shade.xml
@@ -43,6 +43,12 @@
                    android:visibility="invisible" />
     </com.android.systemui.statusbar.BackDropView>
 
+    <com.android.systemui.statusbar.LightRevealScrim
+        android:id="@+id/light_reveal_scrim"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:visibility="gone" />
+
     <com.android.systemui.statusbar.ScrimView
         android:id="@+id/scrim_behind"
         android:layout_width="match_parent"
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/LightRevealScrim.kt b/packages/SystemUI/src/com/android/systemui/statusbar/LightRevealScrim.kt
new file mode 100644
index 0000000000000..86377fb014ae8
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/LightRevealScrim.kt
@@ -0,0 +1,207 @@
+package com.android.systemui.statusbar
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Matrix
+import android.graphics.Paint
+import android.graphics.PointF
+import android.graphics.PorterDuff
+import android.graphics.PorterDuffColorFilter
+import android.graphics.PorterDuffXfermode
+import android.graphics.RadialGradient
+import android.graphics.Shader
+import android.os.SystemProperties
+import android.util.AttributeSet
+import android.view.View
+import com.android.systemui.Interpolators
+
+val enableLightReveal =
+        SystemProperties.getBoolean("persist.sysui.show_new_screen_on_transitions", false)
+
+/**
+ * Provides methods to modify the various properties of a [LightRevealScrim] to reveal between 0% to
+ * 100% of the view(s) underneath the scrim.
+ */
+interface LightRevealEffect {
+    fun setRevealAmountOnScrim(amount: Float, scrim: LightRevealScrim)
+
+    companion object {
+
+        /**
+         * Returns the percent that the given value is past the threshold value. For example, 0.9 is
+         * 50% of the way past 0.8.
+         */
+        fun getPercentPastThreshold(value: Float, threshold: Float): Float {
+            return (value - threshold).coerceAtLeast(0f) * (1f / (1f - threshold))
+        }
+    }
+}
+
+/**
+ * Light reveal effect that shows light entering the phone from the bottom of the screen. The light
+ * enters from the bottom-middle as a narrow oval, and moves upward, eventually widening to fill the
+ * screen.
+ */
+object LiftReveal : LightRevealEffect {
+
+    /** Widen the oval of light after 35%, so it will eventually fill the screen. */
+    private const val WIDEN_OVAL_THRESHOLD = 0.35f
+
+    /** After 85%, fade out the black color at the end of the gradient. */
+    private const val FADE_END_COLOR_OUT_THRESHOLD = 0.85f
+
+    /** The initial width of the light oval, in percent of scrim width. */
+    private const val OVAL_INITIAL_WIDTH_PERCENT = 0.5f
+
+    /** The initial top value of the light oval, in percent of scrim height. */
+    private const val OVAL_INITIAL_TOP_PERCENT = 1.05f
+
+    /** The initial bottom value of the light oval, in percent of scrim height. */
+    private const val OVAL_INITIAL_BOTTOM_PERCENT = 1.2f
+
+    /** Interpolator to use for the reveal amount. */
+    private val INTERPOLATOR = Interpolators.FAST_OUT_SLOW_IN_REVERSE
+
+    override fun setRevealAmountOnScrim(amount: Float, scrim: LightRevealScrim) {
+        val interpolatedAmount = INTERPOLATOR.getInterpolation(amount)
+        val ovalWidthIncreaseAmount =
+                LightRevealEffect.getPercentPastThreshold(interpolatedAmount, WIDEN_OVAL_THRESHOLD)
+
+        val initialWidthMultiplier = (1f - OVAL_INITIAL_WIDTH_PERCENT) / 2f
+
+        with(scrim) {
+            revealGradientEndColorAlpha = 1f - LightRevealEffect.getPercentPastThreshold(
+                    amount, FADE_END_COLOR_OUT_THRESHOLD)
+            setRevealGradientBounds(
+                    scrim.width * initialWidthMultiplier +
+                            -scrim.width * ovalWidthIncreaseAmount,
+                    scrim.height * OVAL_INITIAL_TOP_PERCENT -
+                            scrim.height * interpolatedAmount,
+                    scrim.width * (1f - initialWidthMultiplier) +
+                            scrim.width * ovalWidthIncreaseAmount,
+                    scrim.height * OVAL_INITIAL_BOTTOM_PERCENT +
+                            scrim.height * interpolatedAmount)
+        }
+    }
+}
+
+/**
+ * Scrim view that partially reveals the content underneath it using a [RadialGradient] with a
+ * transparent center. The center position, size, and stops of the gradient can be manipulated to
+ * reveal views below the scrim as if they are being 'lit up'.
+ */
+class LightRevealScrim(context: Context?, attrs: AttributeSet?) : View(context, attrs) {
+
+    /**
+     * How much of the underlying views are revealed, in percent. 0 means they will be completely
+     * obscured and 1 means they'll be fully visible.
+     */
+    var revealAmount: Float = 0f
+        set(value) {
+            if (field != value) {
+                field = value
+
+                revealEffect.setRevealAmountOnScrim(value, this)
+                invalidate()
+            }
+        }
+
+    /**
+     * The [LightRevealEffect] used to manipulate the radial gradient whenever [revealAmount]
+     * changes.
+     */
+    var revealEffect: LightRevealEffect = LiftReveal
+        set(value) {
+            if (field != value) {
+                field = value
+
+                revealEffect.setRevealAmountOnScrim(revealAmount, this)
+                invalidate()
+            }
+        }
+
+    var revealGradientCenter = PointF()
+    var revealGradientWidth: Float = 0f
+    var revealGradientHeight: Float = 0f
+
+    var revealGradientEndColor: Int = Color.BLACK
+        set(value) {
+            if (field != value) {
+                field = value
+                setPaintColorFilter()
+            }
+        }
+
+    var revealGradientEndColorAlpha = 0f
+        set(value) {
+            if (field != value) {
+                field = value
+                setPaintColorFilter()
+            }
+        }
+
+    /**
+     * Paint used to draw a transparent-to-white radial gradient. This will be scaled and translated
+     * via local matrix in [onDraw] so we never need to construct a new shader.
+     */
+    private val gradientPaint = Paint().apply {
+        shader = RadialGradient(
+                0f, 0f, 1f,
+                intArrayOf(Color.TRANSPARENT, Color.WHITE), floatArrayOf(0f, 1f),
+                Shader.TileMode.CLAMP)
+
+        // SRC_OVER ensures that we draw the semitransparent pixels over other views in the same
+        // window, rather than outright replacing them.
+        xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)
+    }
+
+    /**
+     * Matrix applied to [gradientPaint]'s RadialGradient shader to move the gradient to
+     * [revealGradientCenter] and set its size to [revealGradientWidth]/[revealGradientHeight],
+     * without needing to construct a new shader each time those properties change.
+     */
+    private val shaderGradientMatrix = Matrix()
+
+    /**
+     * Sets bounds for the transparent oval gradient that reveals the views below the scrim. This is
+     * simply a helper method that sets [revealGradientCenter], [revealGradientWidth], and
+     * [revealGradientHeight] for you.
+     *
+     * This method does not call [invalidate] - you should do so once you're done changing
+     * properties.
+     */
+    public fun setRevealGradientBounds(left: Float, top: Float, right: Float, bottom: Float) {
+        revealGradientWidth = right - left
+        revealGradientHeight = bottom - top
+
+        revealGradientCenter.x = left + (revealGradientWidth / 2f)
+        revealGradientCenter.y = top + (revealGradientHeight / 2f)
+    }
+
+    override fun onDraw(canvas: Canvas?) {
+        if (canvas == null || revealGradientWidth <= 0 || revealGradientHeight <= 0) {
+            return
+        }
+
+        with(shaderGradientMatrix) {
+            setScale(revealGradientWidth, revealGradientHeight, 0f, 0f)
+            postTranslate(revealGradientCenter.x, revealGradientCenter.y)
+
+            gradientPaint.shader.setLocalMatrix(this)
+        }
+
+        // Draw the gradient over the screen, then multiply the end color by it.
+        canvas.drawRect(0f, 0f, width.toFloat(), height.toFloat(), gradientPaint)
+    }
+
+    private fun setPaintColorFilter() {
+        gradientPaint.colorFilter = PorterDuffColorFilter(
+                Color.argb(
+                        (revealGradientEndColorAlpha * 255).toInt(),
+                        Color.red(revealGradientEndColor),
+                        Color.green(revealGradientEndColor),
+                        Color.blue(revealGradientEndColor)),
+                PorterDuff.Mode.MULTIPLY)
+    }
+}
\ No newline at end of file
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
index 5c7f54b4a9a93..3b530971d5211 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
@@ -35,6 +35,7 @@ import static com.android.systemui.keyguard.WakefulnessLifecycle.WAKEFULNESS_ASL
 import static com.android.systemui.keyguard.WakefulnessLifecycle.WAKEFULNESS_AWAKE;
 import static com.android.systemui.keyguard.WakefulnessLifecycle.WAKEFULNESS_WAKING;
 import static com.android.systemui.shared.system.WindowManagerWrapper.NAV_BAR_POS_INVALID;
+import static com.android.systemui.statusbar.LightRevealScrimKt.getEnableLightReveal;
 import static com.android.systemui.statusbar.NotificationLockscreenUserManager.PERMISSION_SELF;
 import static com.android.systemui.statusbar.phone.BarTransitions.MODE_LIGHTS_OUT;
 import static com.android.systemui.statusbar.phone.BarTransitions.MODE_LIGHTS_OUT_TRANSPARENT;
@@ -181,6 +182,8 @@ import com.android.systemui.statusbar.CrossFadeHelper;
 import com.android.systemui.statusbar.GestureRecorder;
 import com.android.systemui.statusbar.KeyboardShortcuts;
 import com.android.systemui.statusbar.KeyguardIndicationController;
+import com.android.systemui.statusbar.LiftReveal;
+import com.android.systemui.statusbar.LightRevealScrim;
 import com.android.systemui.statusbar.NotificationLockscreenUserManager;
 import com.android.systemui.statusbar.NotificationMediaManager;
 import com.android.systemui.statusbar.NotificationPresenter;
@@ -367,6 +370,7 @@ public class StatusBar extends SystemUI implements DemoMode,
     DozeServiceHost mDozeServiceHost;
     private boolean mWakeUpComingFromTouch;
     private PointF mWakeUpTouchLocation;
+    private LightRevealScrim mLightRevealScrim;
 
     private final Object mQueueLock = new Object();
 
@@ -1155,6 +1159,13 @@ public class StatusBar extends SystemUI implements DemoMode,
         });
         mScrimController.attachViews(scrimBehind, scrimInFront, scrimForBubble);
 
+        mLightRevealScrim = mNotificationShadeWindowView.findViewById(R.id.light_reveal_scrim);
+
+        if (getEnableLightReveal()) {
+            mLightRevealScrim.setVisibility(View.VISIBLE);
+            mLightRevealScrim.setRevealEffect(LiftReveal.INSTANCE);
+        }
+
         mNotificationPanelViewController.initDependencies(
                 this,
                 mNotificationShelfController);
@@ -3618,6 +3629,13 @@ public class StatusBar extends SystemUI implements DemoMode,
         Trace.endSection();
     }
 
+    @Override
+    public void onDozeAmountChanged(float linear, float eased) {
+        if (getEnableLightReveal()) {
+            mLightRevealScrim.setRevealAmount(1f - linear);
+        }
+    }
+
     @Override
     public void onDozingChanged(boolean isDozing) {
         Trace.beginSection("StatusBar#updateDozing");