PolygonShapeTransformScope

Artifact: androidx.compose.foundation:foundation

Cmn

sealed interface PolygonShapeTransformScope : Density

Transforms a PolygonShape's geometry inside PolygonShape.transform.

Exposes the layout resolution inputs (size, layoutDirection, and Density). Operations (rotate, translate, scale, transform, and scaleToFit) concatenate onto the transformation matrix in the exact order they are called (for example, scale followed by translate differs from translate followed by scale).

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CornerRounding
import androidx.compose.foundation.shape.PolygonShape
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.unit.dp

// A square polygon rotated 45 degrees around its center and scaled into the layout bounds in a
// single pass so the rotated diamond stays inscribed without clipping.
val diamond = remember {
    PolygonShape { polygon(numVertices = 4, rounding = CornerRounding.fraction(0.15f)) }
        .apply {
            transform {
                rotate(degrees = 45f)
                scaleToFit(contentScale = ContentScale.Fit)
            }
        }
}
Box(Modifier.size(96.dp).clip(diamond).background(Color(0xFFE91E63)))

import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CornerRounding
import androidx.compose.foundation.shape.PolygonShape
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

// Creates an unrotated badge shape and an independent rotated copy using copy() + transform {}.
val badge = remember {
    PolygonShape.star(
        numPoints = 8,
        innerRadiusRatio = 0.75f,
        outerRounding = CornerRounding.fraction(0.4f),
    )
}
val selectedBadge =
    remember(badge) { badge.copy().apply { transform { rotate(degrees = 22.5f) } } }
var selected by remember { mutableStateOf(false) }
val shape = if (selected) selectedBadge else badge
Box(
    Modifier.size(96.dp).clip(shape).background(Color(0xFF00695C)).clickable {
        selected = !selected
    }
)

Summary

Public functions
`Unit`	`rotate(degrees: Float, pivot: Offset)` Rotates the polygon clockwise by `degrees` around `pivot`.	Cmn
`Unit`	`scale(scaleX: Float, scaleY: Float, pivot: Offset)` Scales the polygon by `scaleX` horizontally and `scaleY` vertically around `pivot`.	Cmn
`Unit`	`scaleToFit(contentScale: ContentScale, alignment: Alignment)` Scales and aligns the polygon's bounding box into `size` in call order.	Cmn
`Unit`	`transform(matrix: Matrix)` Multiplies the current transformation by the affine `matrix` around the polygon's center.	Cmn
`Unit`	`translate(x: Float, y: Float)` Translates the polygon by (`x`, `y`) pixels.	Cmn

Public properties
`LayoutDirection`	`layoutDirection` Layout direction of the shape.	Cmn
`Size`	`size` Size of the shape's layout container in pixels.	Cmn

Inherited functions

From androidx.compose.ui.unit.Density

`open Int`	`Dp.roundToPx()` Convert `Dp` to `Int` by rounding	Cmn
`open Int`	`TextUnit.roundToPx()` Convert Sp to `Int` by rounding	Cmn
`open Dp`	`Int.toDp()` Convert an `Int` pixel value to `Dp`.	Cmn
`open Dp`	`Float.toDp()` Convert a `Float` pixel value to a Dp	Cmn
`open DpSize`	`Size.toDpSize()` Convert a `Size` to a `DpSize`.	Cmn
`open Float`	`Dp.toPx()` Convert `Dp` to pixels.	Cmn
`open Float`	`TextUnit.toPx()` Convert Sp to pixels.	Cmn
`open Rect`	`DpRect.toRect()` Convert a `DpRect` to a `Rect`.	Cmn
`open Size`	`DpSize.toSize()` Convert a `DpSize` to a `Size`.	Cmn
`open TextUnit`	`Int.toSp()` Convert an `Int` pixel value to Sp.	Cmn
`open TextUnit`	`Float.toSp()` Convert a `Float` pixel value to a Sp	Cmn

From androidx.compose.ui.unit.FontScaling

`Dp`	`TextUnit.toDp()` Convert Sp to `Dp`.	Cmn
`TextUnit`	`Dp.toSp()` Convert `Dp` to Sp.	Cmn

Inherited properties

From androidx.compose.ui.unit.Density

Float

density

The logical density of the display.

Cmn

From androidx.compose.ui.unit.FontScaling

Float

fontScale

Current user preference for the scaling factor for fonts.

Cmn

Public functions

rotate

Cmn

Added in 1.13.0-beta01

fun rotate(degrees: Float, pivot: Offset = Offset.Unspecified): Unit

Rotates the polygon clockwise by degrees around pivot.

Parameters
`degrees: Float`	clockwise rotation in degrees
`pivot: Offset = Offset.Unspecified`	rotation center in pixels, or `Offset.Unspecified` for the polygon's center

scale

Cmn

Added in 1.13.0-beta01

fun scale(scaleX: Float, scaleY: Float = scaleX, pivot: Offset = Offset.Unspecified): Unit

Scales the polygon by scaleX horizontally and scaleY vertically around pivot.

Parameters
`scaleX: Float`	horizontal scale factor
`scaleY: Float = scaleX`	vertical scale factor, defaults to `scaleX` for uniform scaling
`pivot: Offset = Offset.Unspecified`	scale center in pixels, or `Offset.Unspecified` for the polygon's center

scaleToFit

Cmn

Added in 1.13.0-beta01

fun scaleToFit(
    contentScale: ContentScale = ContentScale.Fit,
    alignment: Alignment = Alignment.Center
): Unit

Scales and aligns the polygon's bounding box into size in call order.

Call before rotate, scale, or translate to fit the unrotated polygon first, then transform it around its fitted center.
Call after rotate or transform to fit the transformed bounding box into size.
ContentScale.Fit (default) scales uniformly to fit within bounds, preserving aspect ratio
ContentScale.FillBounds stretches each axis independently to fill the bounds
ContentScale.Crop fills the bounds, preserving aspect ratio and clipping overflow
ContentScale.None applies no scaling

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CornerRounding
import androidx.compose.foundation.shape.PolygonShape
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.unit.dp

// Inside a wide container the star keeps its aspect ratio and is centered; passing
// ContentScale.FillBounds instead would stretch it to fill the container.
val star = remember {
    PolygonShape.star(
            numPoints = 5,
            innerRadiusRatio = 0.5f,
            outerRounding = CornerRounding.fraction(0.3f),
        )
        .apply { transform { scaleToFit(contentScale = ContentScale.Fit) } }
}
Box(Modifier.size(width = 160.dp, height = 64.dp).clip(star).background(Color(0xFF9C27B0)))

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CornerRounding
import androidx.compose.foundation.shape.PolygonShape
import androidx.compose.foundation.shape.PolygonShapeGeometry
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

// A kite authored in the unit square [0..1] with per-vertex rounding as fractions of the
// bounds, scaled and centered into the container via transform { scaleToFit() }.
val kite = remember {
    val geometry =
        PolygonShapeGeometry(
            vertices =
                listOf(Offset(0.5f, 0f), Offset(1f, 0.4f), Offset(0.5f, 1f), Offset(0f, 0.4f)),
            perVertexRounding =
                listOf(
                    CornerRounding.fraction(0.1f),
                    CornerRounding.fraction(0.15f),
                    CornerRounding.fraction(0.05f),
                    CornerRounding.fraction(0.15f),
                ),
        )
    PolygonShape { geometry }.apply { transform { scaleToFit() } }
}

Box(Modifier.size(width = 120.dp, height = 84.dp).clip(kite).background(Color(0xFF673AB7)))

Parameters
`contentScale: ContentScale = ContentScale.Fit`	policy for scaling the polygon's bounding box into the layout bounds
`alignment: Alignment = Alignment.Center`	placement of the scaled polygon within the layout bounds

transform

Cmn

Added in 1.13.0-beta01

fun transform(matrix: Matrix): Unit

Multiplies the current transformation by the affine matrix around the polygon's center.

Linear components (rotation, scale, skew) pivot around the polygon's center, while translation components offset the polygon directly.

Parameters
`matrix: Matrix`	affine transformation matrix to multiply

Throws
`IllegalArgumentException`	if `matrix` contains perspective components

translate

Cmn

Added in 1.13.0-beta01

fun translate(x: Float = 0.0f, y: Float = 0.0f): Unit

Translates the polygon by (x, y) pixels.

Parameters
`x: Float = 0.0f`	horizontal offset in pixels
`y: Float = 0.0f`	vertical offset in pixels

Public properties

layoutDirection

Cmn

Added in 1.13.0-beta01

val layoutDirection: LayoutDirection

Layout direction of the shape.

size

Cmn

val size: Size

Size of the shape's layout container in pixels.