I am needing to render some custom PNGs in a Windows 8 app.
Basically I need to create a custom live tile by putting some drawings made in my app on top of an image
Currently the only option is to use DirectX (or SharpDX) to create your image. You'll probably have to recreate the drawing using the low-level DirectX APIs. WritableBitmapEx might also be helpful if your drawings are simple.
WinRT XAML Toolkit has some extension methods for WriteableBitmap that you could use too. You could probably use WriteableBitmapLoadExtensions for loading and WriteableBitmapSaveExtensions for saving. It has a fairly limited blitting capability though since that is exposed by WriteableBitmapEx already and simple to write anyway. WriteableBitmapBlitBlockExtensions is only a method to blit a full width block of pixels from bitmaps of same width.
Edit* RenderTargetBitmap
is now available in Windows 8.1. It doesn't support some elements though (I think it doesn't render camera previews, media elements and perhaps WebViews
).