1 /* <lambda>null2 * Copyright (C) 2024 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.compose.animation.scene.demo 18 19 import androidx.compose.material3.LocalContentColor 20 import androidx.compose.material3.LocalTextStyle 21 import androidx.compose.runtime.Composable 22 import androidx.compose.runtime.remember 23 import androidx.compose.ui.Modifier 24 import androidx.compose.ui.draw.drawBehind 25 import androidx.compose.ui.graphics.ColorProducer 26 import androidx.compose.ui.layout.Layout 27 import androidx.compose.ui.text.TextLayoutResult 28 import androidx.compose.ui.text.TextMeasurer 29 import androidx.compose.ui.text.TextStyle 30 import androidx.compose.ui.text.drawText 31 import androidx.compose.ui.text.style.TextOverflow 32 33 /** 34 * A text whose measures can be cached outside composition using [textMeasurer]. 35 * 36 * Important: DO NOT USE THIS IN PRODUCTION CODE. You should always use the Text() or BasicText() 37 * composables instead. This was introduced only to optimize the SceneTransitionLayout benchmarks 38 * and make their frame time metrics more stable. 39 */ 40 @Composable 41 fun CachedText( 42 text: String, 43 textMeasurer: TextMeasurer, 44 modifier: Modifier = Modifier, 45 style: TextStyle = LocalTextStyle.current, 46 overflow: TextOverflow = TextOverflow.Clip, 47 softWrap: Boolean = true, 48 maxLines: Int = Int.MAX_VALUE, 49 color: ColorProducer? = null, 50 ) { 51 val lastLayoutResult = remember { 52 object { 53 var value: TextLayoutResult? = null 54 } 55 } 56 57 val localColor = if (color != null) null else LocalContentColor.current 58 Layout( 59 modifier = 60 modifier.drawBehind { 61 val textLayoutResult = 62 lastLayoutResult.value ?: error("draw happened before layout") 63 val color = 64 color?.let { it() } 65 ?: localColor 66 ?: error("localColor should not be null when color is null") 67 drawText(textLayoutResult, color) 68 } 69 ) { _, constraints -> 70 val layoutResult = 71 textMeasurer.measure(text, style, overflow, softWrap, maxLines, constraints).also { 72 lastLayoutResult.value = it 73 } 74 layout(layoutResult.size.width, layoutResult.size.height) {} 75 } 76 } 77