TextMeasurerHelper.kt
/*
* Copyright 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.ui.text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.platform.LocalFontFamilyResolver
import androidx.compose.ui.platform.LocalLayoutDirection
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.unit.Density
import androidx.compose.ui.unit.LayoutDirection
/**
* This value should reflect the default cache size for TextMeasurer.
*/
private val DefaultCacheSize: Int = 8
/**
* Creates and remembers a [TextMeasurer] that reads default values for optional parameters from
* CompositionLocals. Returned TextMeasurer also carries an internal [TextLayoutCache] at a given
* capacity. Provide 0 as capacity to opt-out from internal caching behavior.
*
* All given parameters can be overridden during a [TextMeasurer.measure] call except the maximum
* size of the TextLayoutCache. Instead the cache can be disabled at will during measure by passing
* in skipCache as true.
*
* @param fontFamilyResolver default [FontFamily.Resolver] to be used to load the font given
* in [SpanStyle]s.
* @param density default density.
* @param layoutDirection default layout direction.
* @param cacheSize Capacity of internal cache inside TextMeasurer.
*/
@ExperimentalTextApi
@Composable
fun rememberTextMeasurer(
fontFamilyResolver: FontFamily.Resolver = LocalFontFamilyResolver.current,
density: Density = LocalDensity.current,
layoutDirection: LayoutDirection = LocalLayoutDirection.current,
cacheSize: Int = DefaultCacheSize
): TextMeasurer {
return remember(fontFamilyResolver, density, layoutDirection, cacheSize) {
TextMeasurer(fontFamilyResolver, density, layoutDirection, cacheSize)
}
}