1 /* <lambda>null2 * Copyright (C) 2020 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.systemui.animation 18 19 import android.graphics.fonts.Font 20 import android.graphics.fonts.FontVariationAxis 21 import android.util.Log 22 import android.util.LruCache 23 import android.util.MathUtils 24 import androidx.annotation.VisibleForTesting 25 import kotlin.math.roundToInt 26 27 /** Caches for font interpolation */ 28 interface FontCache { 29 val animationFrameCount: Int 30 31 fun get(key: InterpKey): Font? 32 33 fun get(key: VarFontKey): Font? 34 35 fun put(key: InterpKey, font: Font) 36 37 fun put(key: VarFontKey, font: Font) 38 } 39 40 /** Cache key for the interpolated font. */ 41 data class InterpKey(val start: Font?, val end: Font?, val frame: Int) 42 43 /** Cache key for the font that has variable font. */ 44 data class VarFontKey(val sourceId: Int, val index: Int, val sortedAxes: List<FontVariationAxis>) { 45 constructor( 46 font: Font, 47 axes: List<FontVariationAxis>, <lambda>null48 ) : this(font.sourceIdentifier, font.ttcIndex, axes.sortedBy { it.tag }) 49 } 50 51 class FontCacheImpl(override val animationFrameCount: Int = DEFAULT_FONT_CACHE_MAX_ENTRIES / 2) : 52 FontCache { 53 // Font interpolator has two level caches: one for input and one for font with different 54 // variation settings. No synchronization is needed since FontInterpolator is not designed to be 55 // thread-safe and can be used only on UI thread. 56 val cacheMaxEntries = animationFrameCount * 2 57 private val interpCache = LruCache<InterpKey, Font>(cacheMaxEntries) 58 private val verFontCache = LruCache<VarFontKey, Font>(cacheMaxEntries) 59 getnull60 override fun get(key: InterpKey): Font? = interpCache[key] 61 62 override fun get(key: VarFontKey): Font? = verFontCache[key] 63 64 override fun put(key: InterpKey, font: Font) { 65 interpCache.put(key, font) 66 } 67 putnull68 override fun put(key: VarFontKey, font: Font) { 69 verFontCache.put(key, font) 70 } 71 72 companion object { 73 // Benchmarked via Perfetto, difference between 10 and 50 entries is about 0.3ms in frame 74 // draw time on a Pixel 6. 75 @VisibleForTesting const val DEFAULT_FONT_CACHE_MAX_ENTRIES = 10 76 } 77 } 78 79 /** Provide interpolation of two fonts by adjusting font variation settings. */ 80 class FontInterpolator(val fontCache: FontCache = FontCacheImpl()) { 81 /** Linear interpolate the font variation settings. */ lerpnull82 fun lerp(start: Font, end: Font, progress: Float, linearProgress: Float): Font { 83 if (progress <= 0f) return start 84 if (progress >= 1f) return end 85 86 val startAxes = start.axes ?: EMPTY_AXES 87 val endAxes = end.axes ?: EMPTY_AXES 88 89 if (startAxes.isEmpty() && endAxes.isEmpty()) { 90 return start 91 } 92 93 // Check we already know the result. This is commonly happens since we draws the different 94 // text chunks with the same font. 95 val iKey = 96 InterpKey(start, end, (linearProgress * fontCache.animationFrameCount).roundToInt()) 97 fontCache.get(iKey)?.let { 98 if (DEBUG) { 99 Log.d(LOG_TAG, "[$progress, $linearProgress] Interp. cache hit for $iKey") 100 } 101 return it 102 } 103 104 // General axes interpolation takes O(N log N), this is came from sorting the axes. Usually 105 // this doesn't take much time since the variation axes is usually up to 5. If we need to 106 // support more number of axes, we may want to preprocess the font and store the sorted axes 107 // and also pre-fill the missing axes value with default value from 'fvar' table. 108 val newAxes = 109 lerp(startAxes, endAxes) { tag, startValue, endValue -> 110 MathUtils.lerp(startValue, endValue, progress) 111 } 112 113 // Check if we already make font for this axes. This is typically happens if the animation 114 // happens backward and is being linearly interpolated. 115 val vKey = VarFontKey(start, newAxes) 116 fontCache.get(vKey)?.let { 117 fontCache.put(iKey, it) 118 if (DEBUG) { 119 Log.d(LOG_TAG, "[$progress, $linearProgress] Axis cache hit for $vKey") 120 } 121 return it 122 } 123 124 // This is the first time to make the font for the axes. Build and store it to the cache. 125 // Font.Builder#build won't throw IOException since creating fonts from existing fonts will 126 // not do any IO work. 127 val newFont = Font.Builder(start).setFontVariationSettings(newAxes.toTypedArray()).build() 128 fontCache.put(iKey, newFont) 129 fontCache.put(vKey, newFont) 130 131 // Cache misses are likely to create memory leaks, so this is logged at error level. 132 Log.e(LOG_TAG, "[$progress, $linearProgress] Cache MISS for $iKey / $vKey") 133 return newFont 134 } 135 lerpnull136 private fun lerp( 137 start: Array<FontVariationAxis>, 138 end: Array<FontVariationAxis>, 139 filter: (tag: String, left: Float, right: Float) -> Float, 140 ): List<FontVariationAxis> { 141 // Safe to modify result of Font#getAxes since it returns cloned object. 142 start.sortBy { axis -> axis.tag } 143 end.sortBy { axis -> axis.tag } 144 145 val result = mutableListOf<FontVariationAxis>() 146 var i = 0 147 var j = 0 148 while (i < start.size || j < end.size) { 149 val tagA = if (i < start.size) start[i].tag else null 150 val tagB = if (j < end.size) end[j].tag else null 151 152 val comp = 153 when { 154 tagA == null -> 1 155 tagB == null -> -1 156 else -> tagA.compareTo(tagB) 157 } 158 159 val tag = 160 when { 161 comp == 0 -> tagA!! 162 comp < 0 -> tagA!! 163 else -> tagB!! 164 } 165 166 val axisDefinition = GSFAxes.getAxis(tag) 167 require(comp == 0 || axisDefinition != null) { 168 "Unable to interpolate due to unknown default axes value: $tag" 169 } 170 171 val axisValue = 172 when { 173 comp == 0 -> filter(tag, start[i++].styleValue, end[j++].styleValue) 174 comp < 0 -> filter(tag, start[i++].styleValue, axisDefinition!!.defaultValue) 175 else -> filter(tag, axisDefinition!!.defaultValue, end[j++].styleValue) 176 } 177 178 // Round axis value to valid intermediate steps. This improves the cache hit rate. 179 val step = axisDefinition?.animationStep ?: DEFAULT_ANIMATION_STEP 180 result.add(FontVariationAxis(tag, (axisValue / step).roundToInt() * step)) 181 } 182 return result 183 } 184 185 companion object { 186 private const val LOG_TAG = "FontInterpolator" 187 private val DEBUG = Log.isLoggable(LOG_TAG, Log.DEBUG) 188 private val EMPTY_AXES = arrayOf<FontVariationAxis>() 189 private const val DEFAULT_ANIMATION_STEP = 1f 190 191 // Returns true if given two font instance can be interpolated. canInterpolatenull192 fun canInterpolate(start: Font, end: Font) = 193 start.ttcIndex == end.ttcIndex && start.sourceIdentifier == end.sourceIdentifier 194 } 195 } 196