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Autosizing Text in Jetpack Compose
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| import androidx.compose.material.LocalTextStyle | |
| import androidx.compose.material.Text | |
| import androidx.compose.runtime.* | |
| import androidx.compose.ui.Modifier | |
| import androidx.compose.ui.draw.drawWithContent | |
| import androidx.compose.ui.graphics.Color | |
| import androidx.compose.ui.text.AnnotatedString | |
| import androidx.compose.ui.text.TextStyle | |
| import androidx.compose.ui.text.font.FontFamily | |
| import androidx.compose.ui.text.font.FontStyle | |
| import androidx.compose.ui.text.font.FontWeight | |
| import androidx.compose.ui.text.style.TextAlign | |
| import androidx.compose.ui.text.style.TextDecoration | |
| import androidx.compose.ui.text.style.TextOverflow | |
| import androidx.compose.ui.unit.TextUnit | |
| sealed class AutoSizeConstraint(open val min: TextUnit = TextUnit.Unspecified) { | |
| data class Width(override val min: TextUnit = TextUnit.Unspecified): AutoSizeConstraint(min) | |
| data class Height(override val min: TextUnit = TextUnit.Unspecified): AutoSizeConstraint(min) | |
| } | |
| @Composable | |
| fun AutoSizeText( | |
| text: AnnotatedString, | |
| modifier: Modifier = Modifier, | |
| color: Color = Color.Unspecified, | |
| fontSize: TextUnit = TextUnit.Unspecified, | |
| fontStyle: FontStyle? = null, | |
| fontWeight: FontWeight? = null, | |
| fontFamily: FontFamily? = null, | |
| letterSpacing: TextUnit = TextUnit.Unspecified, | |
| textDecoration: TextDecoration? = null, | |
| textAlign: TextAlign? = null, | |
| lineHeight: TextUnit = TextUnit.Unspecified, | |
| overflow: TextOverflow = TextOverflow.Clip, | |
| softWrap: Boolean = true, | |
| maxLines: Int = Int.MAX_VALUE, | |
| style: TextStyle = LocalTextStyle.current, | |
| constraint: AutoSizeConstraint = AutoSizeConstraint.Width(), | |
| ) { | |
| var textStyle by remember { mutableStateOf(style) } | |
| var readyToDraw by remember { mutableStateOf(false) } | |
| Text( | |
| modifier = modifier.drawWithContent { | |
| if (readyToDraw) drawContent() | |
| }, | |
| text = text, | |
| color = color, | |
| fontSize = fontSize, | |
| fontStyle = fontStyle, | |
| fontWeight = fontWeight, | |
| fontFamily = fontFamily, | |
| letterSpacing = letterSpacing, | |
| textDecoration = textDecoration, | |
| textAlign = textAlign, | |
| lineHeight = lineHeight, | |
| overflow = overflow, | |
| softWrap = softWrap, | |
| maxLines = maxLines, | |
| style = style, | |
| onTextLayout = { result -> | |
| fun constrain() { | |
| val reducedSize = textStyle.fontSize * 0.9f | |
| if (constraint.min != TextUnit.Unspecified && reducedSize <= constraint.min) { | |
| textStyle = textStyle.copy(fontSize = constraint.min) | |
| readyToDraw = true | |
| } else { | |
| textStyle = textStyle.copy(fontSize = textStyle.fontSize * 0.9f) | |
| } | |
| } | |
| when (constraint) { | |
| is AutoSizeConstraint.Height -> { | |
| if (result.didOverflowHeight) { | |
| constrain() | |
| } else { | |
| readyToDraw = true | |
| } | |
| } | |
| is AutoSizeConstraint.Width -> { | |
| if (result.didOverflowWidth) { | |
| constrain() | |
| } else { | |
| readyToDraw = true | |
| } | |
| } | |
| } | |
| } | |
| ) | |
| } | |
| @Composable | |
| fun AutoSizeText( | |
| text: String, | |
| modifier: Modifier = Modifier, | |
| color: Color = Color.Unspecified, | |
| fontSize: TextUnit = TextUnit.Unspecified, | |
| fontStyle: FontStyle? = null, | |
| fontWeight: FontWeight? = null, | |
| fontFamily: FontFamily? = null, | |
| letterSpacing: TextUnit = TextUnit.Unspecified, | |
| textDecoration: TextDecoration? = null, | |
| textAlign: TextAlign? = null, | |
| lineHeight: TextUnit = TextUnit.Unspecified, | |
| overflow: TextOverflow = TextOverflow.Clip, | |
| softWrap: Boolean = true, | |
| maxLines: Int = Int.MAX_VALUE, | |
| style: TextStyle = LocalTextStyle.current, | |
| constraint: AutoSizeConstraint = AutoSizeConstraint.Width(), | |
| ) { | |
| AutoSizeText( | |
| modifier = modifier, | |
| text = AnnotatedString(text), | |
| color = color, | |
| fontSize = fontSize, | |
| fontStyle = fontStyle, | |
| fontWeight = fontWeight, | |
| fontFamily = fontFamily, | |
| letterSpacing = letterSpacing, | |
| textDecoration = textDecoration, | |
| textAlign = textAlign, | |
| lineHeight = lineHeight, | |
| overflow = overflow, | |
| softWrap = softWrap, | |
| maxLines = maxLines, | |
| style = style, | |
| constraint = constraint | |
| ) | |
| } |
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Here is an issue that I want to feed back: the text size won't be recomputed when text is changed.
And an possible solution to that is:
Yeah, it's to support a key to the
rememberfunction in this file.