Image handling improvements

[psuzn]

• CompositionLocal based image loader
• Resizing the image container(Placeholder) to better fit the different image sizes.

Before	After

We can use a different image loader to load the images. Here is a snippet using Kamel to load the images

object KamelImageLoader : ImageTransformer {
    @Composable
    override fun transform(link: String): Painter? {
        return when (val resource = asyncPainterResource(link)) {
            is Resource.Failure -> null
            is Resource.Loading -> null
            is Resource.Success -> resource.value
        }
    }
}

val scrollState = rememberScrollState()

 Markdown(
      markdown,
      imageTransformer = KamelImageLoader,
      modifier = Modifier
          .fillMaxSize()
          .verticalScroll(scrollState)
  )

[psuzn]

On a side note, while testing this I've created a sample project with multiplatform support(Android, JVM and IOS). We can also merge that here if it adds any value.

https://github.com/psuzn/multiplatform-markdown-renderer/compare/sp/image-handler...psuzn:multiplatform-markdown-renderer:sp/sample-multiplatform-project?expand=1

[mikepenz]

The PR looks great! Haven't had time to go into full depth yet, but overall this looks really promising.

Thank you so much for opening the PR!

Added a few comments and questions

[mikepenz]

No local ImageTransformer

[psuzn]

We can provide the ImageTransformerImpl here and remove the imageTransformer parameter from Markdown() composable but doing that if the user wants to use a different imagetransformer they have to use provide the imageTransformer using composition local provider in their code. There is noting wrong with it but I think providing imageTransformer as a parameter is more intuitive.

[mikepenz]

Oh I believe you missunderstood me. I only meant the error message. It states: ImageLinkTransformer instead of ImageTransformer

(the comment was basically repeating the error message but in fixed form :D)

[psuzn]

sorry my bad, I had named it ImageLinkTransformer initially.

[mikepenz]

I believe it would probably better to make this a normal class instead of an object. As we won't need it to exist if somebody provides their own implementation.

[mikepenz]

Thank you!

[mikepenz]

Using TextSize for an image? Would it maybe make more sense to have this exposed as normal IntSize instead? 🤔

[psuzn]

I made this sp size class because the Placeholder needs sp dimensions and doing conversion here is better. I might be able to remove it. Let's see.

[mikepenz]

Once again thank you so much for this PR!