How can i convert base64 to bitmap in compose multiplatform? whats the alternative of

android.graphics.BitmapFactory

?

That’s how I do it in my code:

import org.jetbrains.skia.Image

	val PNG_BASE64_HEADER = "data:image/png;base64,"

    @OptIn(ExperimentalEncodingApi::class)
    private fun resolveImage(imgBase64: String?): ByteArray? {
        try {
            return imgBase64?.let {
                if (it.startsWith(PNG_BASE64_HEADER)) {
                    Base64.Default.decode(it.replaceFirst(PNG_BASE64_HEADER,""))
                } else {
                    log.debug { "Unknown image format: '${imgBase64.take(20)}'" }
                    null
                }
            }
        } catch (e: Exception) {
            throw Exception("Could not resolve image from base 64 string.", e)
        }
    }
    
    fun imageBitmapFromBytes(encodedImageData: ByteArray): ImageBitmap {
        return Image.makeFromEncoded(encodedImageData).toComposeImageBitmap()
    }

Should also work on iOS but I haven’t tested it there.

thank you Michael, but i get an error on Image.makeFromEncoded...

Function invocation 'Image(...)' expected

No. This is the original code (copied directly from some other project) which I use for iOS.

override fun imageBitmapFromBytes(encodedImageData: ByteArray): ImageBitmap {
        return Image.makeFromEncoded(encodedImageData).toComposeImageBitmap()
    }

Check the import statement for Image

import org.jetbrains.skia.Image

This code is of course platform specific, so you can’t use it in common.

ahh i'm looking for any common main which could work on both android and ios. btw thanks

On Android you would just use this corresponding code variant.

override fun imageBitmapFromBytes(encodedImageData: ByteArray): ImageBitmap {
    return BitmapFactory.decodeByteArray(encodedImageData, 0, encodedImageData.size).asImageBitmap()
}

In my code these variants are part of a class which is declared via expect/actual. You can then call

imageBitmapFromBytes

in your common code.

It works, thank you. ❤️