Draw text on a bitmap

DrawText.kt

@OptIn(ExperimentalAnimationApi::class)
@Composable
private fun DrawText(it: PaddingValues) {
    Column(Modifier.padding(it)) {
        var text by remember { mutableStateOf("Vel eum voluptatem nulla. Ut enim unde sit autem laboriosam consequatur ut. Quo eius veniam occaecati minima. Porro architecto et omnis. Et dolor qui non. Tempora et consequuntur ea quia iste qui ducimus cum.\n") }
        OutlinedTextField(value = text, onValueChange = { text = it.trim() })

        val baseFontSizePx = with(LocalDensity.current) { 24.sp.toPx() }
        val context = LocalContext.current
        var bitmap by remember { mutableStateOf<ImageBitmap?>(null) }
        LaunchedEffect(key1 = text) {
            bitmap = null
            launch {
                val baseDrawable = ResourcesCompat.getDrawable(context.resources, R.drawable.myImage, context.theme)
                    as? BitmapDrawable ?: error("Damnit")
                val bitmapWithText = baseDrawable.bitmap.drawTextOnTop(text, baseFontSizePx, context.resources)
                bitmap = bitmapWithText.asImageBitmap()
            }
        }

        Spacer(modifier = Modifier.weight(1f))

        AnimatedContent(targetState = bitmap, label = "My thing") { imageBitmap ->
            if (imageBitmap == null) {
                Box(
                    modifier = Modifier
                        .fillMaxWidth()
                        .height(100.dp), contentAlignment = Alignment.Center
                ) {
                    CircularProgressIndicator()
                }
            } else {
                Image(painter = BitmapPainter(imageBitmap), contentDescription = text)
            }
        }
    }
}

private fun Bitmap.drawTextOnTop(text: String, textSize: Float, resources: Resources): Bitmap =
    drawTextOnBitmap(this, text, textSize, Color.White, resources.getFont(R.font.pacifico))
        ?: this

private fun drawTextOnBitmap(bitmap: Bitmap, text: String, textSize: Float, textColor: Color, typeface: android.graphics.Typeface): Bitmap? {
    if (textSize <= 0f) {
        Timber.tag("DrawText").e("Text is too big to fit")
        return null
    }

    val paint = TextPaint().apply {
        this.textSize = textSize
        this.color = textColor.toArgb()
        this.typeface = typeface
        this.style = Paint.Style.FILL
    }

    val availableWidth = bitmap.width * .9f // 10% (5% + 5%) padding
    val layout = StaticLayout.Builder.obtain(text, 0, text.length, paint, availableWidth.toInt())
        .setAlignment(Layout.Alignment.ALIGN_CENTER)
        .build()

    // Get the size of the static layout.
    val layoutWidth = layout.width
    val layoutHeight = layout.height

    // Make sure that the static layout fits in the bitmap.
    val availableHeight = bitmap.height * .9f // 10% (5% + 5%) padding
    if (layoutWidth > availableWidth || layoutHeight > availableHeight) {
        // The static layout is too wide. Reduce the text size.
        return drawTextOnBitmap(bitmap, text, textSize - 1f, textColor, typeface)
    }

    // Draw the static layout on the bitmap.
    val newBitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true)
    val canvas = Canvas(newBitmap)
    canvas.withSave {
        // Apply padding by translating to 5% of width and height before drawing
        translate(bitmap.width * .05f, bitmap.height * .05f)
        layout.draw(canvas)
    }

    return newBitmap
}