如何从 Jetpack Compose 中的 Painter 获取 ImageBitmap？

Question

我应该使用以图像位图作为参数的

Image()

可组合项。

如何在 Compose 中将

Painter

转换为

ImageBitmap

？

Answer 1

这是 Compose Multiplatform fork 中此文件中的

asBitmap()

函数的解决方案：

fun Painter.toImageBitmap(
    size: Size,
    density: Density,
    layoutDirection: LayoutDirection,
): ImageBitmap {
    val bitmap = ImageBitmap(size.width.toInt(), size.height.toInt())
    val canvas = Canvas(bitmap)
    CanvasDrawScope().draw(density, layoutDirection, canvas, size) {
        draw(size)
    }
    return bitmap
}

用途：

val myPainter = ...
val size = myPainter.intrinsicSize // OR, for example, Size(300f, 100f)
val density = LocalDensity.current // OR, for example, Density(1f, 1f)
val direction = LocalLayoutDirection.current // OR, for example, LayoutDirection.Ltr
val myImageBitmap = myPainter.toImageBitmap(size, density, direction)