TextLayoutState.kt
/*
* Copyright 2023 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.foundation.text2.input.internal
import androidx.compose.foundation.text.InternalFoundationTextApi
import androidx.compose.foundation.text.TextDelegate
import androidx.compose.foundation.text.TextLayoutResultProxy
import androidx.compose.foundation.text.updateTextDelegate
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import androidx.compose.runtime.snapshots.Snapshot
import androidx.compose.ui.layout.MeasureScope
import androidx.compose.ui.text.AnnotatedString
import androidx.compose.ui.text.TextLayoutResult
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.Density
@OptIn(InternalFoundationTextApi::class)
internal class TextLayoutState(initialTextDelegate: TextDelegate) {
/**
* Set of parameters and an internal cache to compute text layout.
*/
var textDelegate: TextDelegate = initialTextDelegate
private set
/**
* Text Layout State.
*/
var layoutResult: TextLayoutResult? by mutableStateOf(null)
private set
/**
* A helper class to find positions on text layout relative to wrapping decoration box.
*/
var proxy: TextLayoutResultProxy? = null
fun MeasureScope.layout(
text: AnnotatedString,
textStyle: TextStyle,
softWrap: Boolean,
density: Density,
fontFamilyResolver: FontFamily.Resolver,
constraints: Constraints,
onTextLayout: Density.(TextLayoutResult) -> Unit
): TextLayoutResult {
val prevResult = Snapshot.withoutReadObservation { layoutResult }
val newTextDelegate = updateTextDelegate(
current = textDelegate,
text = text,
style = textStyle,
softWrap = softWrap,
density = density,
fontFamilyResolver = fontFamilyResolver,
placeholders = emptyList(),
)
return newTextDelegate.layout(
layoutDirection = layoutDirection,
constraints = constraints,
prevResult = prevResult
).also {
textDelegate = newTextDelegate
if (prevResult != it) {
onTextLayout(it)
}
layoutResult = it
proxy = TextLayoutResultProxy(it).apply {
decorationBoxCoordinates = proxy?.decorationBoxCoordinates
innerTextFieldCoordinates = proxy?.innerTextFieldCoordinates
}
}
}
}