TextAutoSize

Artifact: androidx.compose.foundation:foundation

Added in 1.8.0

Cmn
```
interface TextAutoSize
```

Interface used by Text composables to override text size to automatically grow or shrink text to fill the layout bounds.

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.text.BasicText
import androidx.compose.foundation.text.TextAutoSize
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp

Box(modifier = Modifier.size(200.dp)) {
    // The text will find the biggest available font size that fits in the box.
    BasicText(text = "Hello World", autoSize = TextAutoSize.StepBased())
}

Summary

Public companion functions
`TextAutoSize`	`StepBased(minFontSize: TextUnit, maxFontSize: TextUnit, stepSize: TextUnit)` Automatically size the text with the biggest font size that fits the available space.	Cmn

Public functions
`operator Boolean`	`equals(other: Any?)` This type is used in performance-sensitive paths and requires providing equality guarantees.	Cmn
`TextUnit`	`TextAutoSizeLayoutScope.getFontSize( constraints: Constraints, text: AnnotatedString )` Calculates font size and provides access to `TextAutoSizeLayoutScope`, which offers `TextAutoSizeLayoutScope.performLayout` to lay out the text and use the measured size.	Cmn
`Int`	`hashCode()` This type is used in performance-sensitive paths and requires providing identity guarantees.	Cmn

Public companion functions

StepBased

Cmn

Added in 1.10.0-rc01

fun StepBased(
    minFontSize: TextUnit = TextAutoSizeDefaults.MinFontSize,
    maxFontSize: TextUnit = TextAutoSizeDefaults.MaxFontSize,
    stepSize: TextUnit = 0.25.sp
): TextAutoSize

Automatically size the text with the biggest font size that fits the available space.

When text auto size is performed with TextOverflow.Ellipsis, TextOverflow.StartEllipsis or TextOverflow.MiddleEllipsis (e.g. by specifying textOverflow on BasicText), this implementation will consider the text to be fitting the available space if it is not ellipsized.

Parameters
`minFontSize: TextUnit = TextAutoSizeDefaults.MinFontSize`	The smallest potential font size of the text. Default = 12.sp. This must be smaller than `maxFontSize`; an `IllegalArgumentException` will be thrown otherwise.
`maxFontSize: TextUnit = TextAutoSizeDefaults.MaxFontSize`	The largest potential font size of the text. Default = 112.sp. This must be larger than `minFontSize`; an `IllegalArgumentException` will be thrown otherwise.
`stepSize: TextUnit = 0.25.sp`	The smallest difference between potential font sizes. Specifically, every font size, when subtracted by `minFontSize`, is divisible by `stepSize`. Default = 0.25.sp. This must not be less than `0.0001f.sp`; an `IllegalArgumentException` will be thrown otherwise. If `stepSize` is greater than the difference between `minFontSize` and `maxFontSize`, `minFontSize` will be used for the layout.

Returns
`TextAutoSize`	AutoSize instance with the step-based configuration. Using this in a compatible composable will cause its text to be sized as above.

Public functions

equals

Cmn

Added in 1.8.0

operator fun equals(other: Any?): Boolean

This type is used in performance-sensitive paths and requires providing equality guarantees. Using a data class is sufficient. Singletons may implement this function with referential equality (this === other). Instances with no properties may implement this function by checking the type of the other object.

Returns
`Boolean`	true if both AutoSize instances are identical.

getFontSize

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.10.0-rc01

fun TextAutoSizeLayoutScope.getFontSize(
    constraints: Constraints,
    text: AnnotatedString
): TextUnit

Calculates font size and provides access to TextAutoSizeLayoutScope, which offers TextAutoSizeLayoutScope.performLayout to lay out the text and use the measured size.

import androidx.compose.foundation.layout.size
import androidx.compose.foundation.text.BasicText
import androidx.compose.foundation.text.TextAutoSize
import androidx.compose.foundation.text.modifiers.TextAutoSizeLayoutScope
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.text.AnnotatedString
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.TextUnit
import androidx.compose.ui.unit.sp

data class PresetsTextAutoSize(private val presets: Array<TextUnit>) : TextAutoSize {
    override fun TextAutoSizeLayoutScope.getFontSize(
        constraints: Constraints,
        text: AnnotatedString,
    ): TextUnit {
        var lastTextSize: TextUnit = TextUnit.Unspecified
        for (presetSize in presets) {
            val layoutResult = performLayout(constraints, text, presetSize)
            if (
                layoutResult.size.width <= constraints.maxWidth &&
                    layoutResult.size.height <= constraints.maxHeight
            ) {
                lastTextSize = presetSize
            } else {
                break
            }
        }
        return lastTextSize
    }
}

@Composable
fun App() {
    val autoSize = remember { PresetsTextAutoSize(arrayOf(10.sp, 14.sp, 21.sp)) }
    BasicText(text = "Hello World", autoSize = autoSize)
}

Returns
`TextUnit`	The derived optimal font size

See also
`performLayout`

hashCode

Cmn

Added in 1.8.0

fun hashCode(): Int

This type is used in performance-sensitive paths and requires providing identity guarantees.

Returns
`Int`	a unique hashcode for this AutoSize instance.