[automerge] Restrict maximum size of FontInterpolator font caches 2p: 39dbe90004

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22757815

Bug: 275486055
Change-Id: I1cf0bfffd88cf766f5b6ece99fa3b502c6c7705b
Merged-In: Id6e2b127f44f5e553ff7ac4ba640fd4f6f4698b0

packages/SystemUI/animation/src/com/android/systemui/animation/FontInterpolator.kt

@@ -18,8 +18,10 @@ package com.android.systemui.animation
 
 import android.graphics.fonts.Font
 import android.graphics.fonts.FontVariationAxis
+import android.util.LruCache
 import android.util.MathUtils
 import android.util.MathUtils.abs
+import androidx.annotation.VisibleForTesting
 import java.lang.Float.max
 import java.lang.Float.min
 
@@ -34,6 +36,10 @@ private const val FONT_ITALIC_MIN = 0f
 private const val FONT_ITALIC_ANIMATION_STEP = 0.1f
 private const val FONT_ITALIC_DEFAULT_VALUE = 0f
 
+// Benchmarked via Perfetto, difference between 10 and 50 entries is about 0.3ms in
+// frame draw time on a Pixel 6.
+@VisibleForTesting const val FONT_CACHE_MAX_ENTRIES = 10
+
 /** Provide interpolation of two fonts by adjusting font variation settings. */
 class FontInterpolator {
 
@@ -81,8 +87,8 @@ class FontInterpolator {
     // Font interpolator has two level caches: one for input and one for font with different
     // variation settings. No synchronization is needed since FontInterpolator is not designed to be
     // thread-safe and can be used only on UI thread.
-    private val interpCache = hashMapOf<InterpKey, Font>()
+    private val interpCache = LruCache<InterpKey, Font>(FONT_CACHE_MAX_ENTRIES)
-    private val verFontCache = hashMapOf<VarFontKey, Font>()
+    private val verFontCache = LruCache<VarFontKey, Font>(FONT_CACHE_MAX_ENTRIES)
 
     // Mutable keys for recycling.
     private val tmpInterpKey = InterpKey(null, null, 0f)
@@ -152,7 +158,7 @@ class FontInterpolator {
         tmpVarFontKey.set(start, newAxes)
         val axesCachedFont = verFontCache[tmpVarFontKey]
         if (axesCachedFont != null) {
-            interpCache[InterpKey(start, end, progress)] = axesCachedFont
+            interpCache.put(InterpKey(start, end, progress), axesCachedFont)
             return axesCachedFont
         }
 
@@ -160,8 +166,8 @@ class FontInterpolator {
         // Font.Builder#build won't throw IOException since creating fonts from existing fonts will
         // not do any IO work.
         val newFont = Font.Builder(start).setFontVariationSettings(newAxes.toTypedArray()).build()
-        interpCache[InterpKey(start, end, progress)] = newFont
+        interpCache.put(InterpKey(start, end, progress), newFont)
-        verFontCache[VarFontKey(start, newAxes)] = newFont
+        verFontCache.put(VarFontKey(start, newAxes), newFont)
         return newFont
     }
 

packages/SystemUI/animation/src/com/android/systemui/animation/TextAnimator.kt

@@ -24,8 +24,10 @@ import android.graphics.Canvas
 import android.graphics.Typeface
 import android.graphics.fonts.Font
 import android.text.Layout
+import android.util.LruCache
 
 private const val DEFAULT_ANIMATION_DURATION: Long = 300
+private const val TYPEFACE_CACHE_MAX_ENTRIES = 5
 
 typealias GlyphCallback = (TextAnimator.PositionedGlyph, Float) -> Unit
 /**
@@ -114,7 +116,7 @@ class TextAnimator(layout: Layout, private val invalidateCallback: () -> Unit) {
 
     private val fontVariationUtils = FontVariationUtils()
 
-    private val typefaceCache = HashMap<String, Typeface?>()
+    private val typefaceCache = LruCache<String, Typeface>(TYPEFACE_CACHE_MAX_ENTRIES)
 
     fun updateLayout(layout: Layout) {
         textInterpolator.layout = layout
@@ -218,12 +220,12 @@ class TextAnimator(layout: Layout, private val invalidateCallback: () -> Unit) {
         }
 
         if (!fvar.isNullOrBlank()) {
-            textInterpolator.targetPaint.typeface =
+            textInterpolator.targetPaint.typeface = typefaceCache.get(fvar) ?: run {
-                typefaceCache.getOrElse(fvar) {
+                textInterpolator.targetPaint.fontVariationSettings = fvar
-                    textInterpolator.targetPaint.fontVariationSettings = fvar
+                textInterpolator.targetPaint.typeface?.also {
                     typefaceCache.put(fvar, textInterpolator.targetPaint.typeface)
-                    textInterpolator.targetPaint.typeface
                 }
+            }
         }
 
         if (color != null) {

packages/SystemUI/tests/src/com/android/systemui/animation/FontInterpolatorTest.kt

@@ -106,4 +106,29 @@ class FontInterpolatorTest : SysuiTestCase() {
         val reversedFont = interp.lerp(endFont, startFont, 0.5f)
         assertThat(resultFont).isSameInstanceAs(reversedFont)
     }
+
+    @Test
+    fun testCacheMaxSize() {
+        val interp = FontInterpolator()
+
+        val startFont = Font.Builder(sFont)
+                .setFontVariationSettings("'wght' 100")
+                .build()
+        val endFont = Font.Builder(sFont)
+                .setFontVariationSettings("'wght' 1")
+                .build()
+        val resultFont = interp.lerp(startFont, endFont, 0.5f)
+        for (i in 0..FONT_CACHE_MAX_ENTRIES + 1) {
+            val f1 = Font.Builder(sFont)
+                    .setFontVariationSettings("'wght' ${i * 100}")
+                    .build()
+            val f2 = Font.Builder(sFont)
+                    .setFontVariationSettings("'wght' $i")
+                    .build()
+            interp.lerp(f1, f2, 0.5f)
+        }
+
+        val cachedFont = interp.lerp(startFont, endFont, 0.5f)
+        assertThat(resultFont).isNotSameInstanceAs(cachedFont)
+    }
 }