Tilling Image Background with ShaderBrush and ImageShader

img_star_background.png

starBackground.kt

package com.dladukedev.tiledimage

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.drawBehind
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.ImageShader
import androidx.compose.ui.graphics.LinearGradientShader
import androidx.compose.ui.graphics.ShaderBrush
import androidx.compose.ui.graphics.TileMode
import androidx.compose.ui.res.imageResource
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp


@Composable
fun Modifier.starBackground(): Modifier {
    val image = ImageBitmap.imageResource(R.drawable.img_star_background)
    val starBrush = remember(image) { ShaderBrush(ImageShader(image, TileMode.Repeated, TileMode.Repeated)) }

    return this.background(brush = starBrush)
}

@Composable
fun Modifier.starBackground(color: Color): Modifier {
    val image = ImageBitmap.imageResource(R.drawable.img_star_background)
    val starBrush = remember(image) { ShaderBrush(ImageShader(image, TileMode.Repeated, TileMode.Repeated)) }

    return this.drawBehind {
        drawRect(starBrush, colorFilter = ColorFilter.tint(color))
    }
}

@Preview
@Composable
fun PreviewStarBackground() {
    Box(modifier = Modifier.size(400.dp).starBackground())
}

@Preview
@Composable
fun PreviewStarBackgroundBlue() {
    Box(modifier = Modifier.size(400.dp).starBackground(Color.Blue))
}

@Preview
@Composable
fun PreviewStarBackgroundComplex() {
    Box(modifier = Modifier.size(400.dp)
        .background(Color.White)
        .starBackground(Color.Blue)
        .background(Brush.verticalGradient(
            Pair(.15f, Color.White),
            Pair(.5f, Color.White.copy(alpha = 0.6f)),
            Pair(.85f, Color.White.copy(alpha = 0.4f)),
            Pair(1f, Color.Transparent))
        )
    )
}