Creating Graphics on Android Tiles

I am creating an Android Tile that is meant to display custom and dynamically created graphics, i.e. a chart.

However, due to several limitations I have yet to find a way to do so. Tiles seem to work fundamentally different than Activities do and the Tiles' API only allows for several, predefined UI elements to be created. The only usable one for me seems to be the Image LayoutElement.

The Image can be created by either passing a resource or a ByteArray. Former is not possible when dealing with dynamically created graphs.

Thus, my only hope (I think) is to create an Image in the form of a ByteArray myself. How can I do this? Is there any Java framework to draw graphics directly?

I have considered the following:

Using the provided UI elements: wouldn't work since the placement is way to imprecise and the exact position of an element cannot be controlled. Also, these elements are not meant for drawing.
Using AWT: doesn't work on Android. Thus, almost any drawing and/or charting library is out of the game.
JavaFX: would probably work but there seems to be now way to draw directly on ByteArrays/BufferedImages as the application needs to be rendered first. Rendering JavaFX doesn't seem possible for Tiles.
Using Android's Canvas: again, an Activity is needed.

Solution

Turns out I was wrong: you can very well use the Canvas within a Tile. Converting it to a resource is, however, a little tricky, so here's some code:

final Bitmap bitmap = Bitmap.createBitmap(chart.getWidth(), chart.getHeight(),
        Bitmap.Config.RGB_565);
final Canvas canvas = new Canvas(bitmap);
// Sets the background color
final Color background = Color.valueOf(chart.getBackgroundColor());
canvas.drawRGB(
        Math.round(background.red() * 255),
        Math.round(background.green() * 255),
        Math.round(background.blue() * 255)
);

// YOUR DRAWING OPERATIONS: e.g. canvas.drawRect

final ByteBuffer byteBuffer = ByteBuffer.allocate(bitmap.getByteCount());
bitmap.copyPixelsToBuffer(byteBuffer);
final byte[] bytes = byteBuffer.array();

return new ResourceBuilders.ImageResource.Builder()
        .setInlineResource(
                new ResourceBuilders.InlineImageResource.Builder()
                        .setData(bytes)
                        .setWidthPx(chart.getWidth())
                        .setHeightPx(chart.getHeight())
                        .setFormat(ResourceBuilders.IMAGE_FORMAT_RGB_565)
                        .build()
        )
        .build();