How do I speed up Core Image rendering

To speed up Core Image rendering, you can leverage several techniques and optimizations discussed in the WWDC sessions. Here are some key points:

Use Metal for Rendering: If your app needs performance or control beyond what is provided by UIImage, you can display using Core Image and Metal. This is particularly useful when you want to interactively change the image. Setting up an MTK view for extended range content and applying filters to create an edited CI image can help in achieving better performance.
Optimize with Swift Concurrency: When processing multiple images, using concurrency can significantly improve performance. Instead of processing images one at a time in a loop, you can process batches of images simultaneously. This approach is discussed in the session on Vision framework enhancements, but the principles can be applied to Core Image as well.
Efficient Use of Filters: Apply appropriate filters to create edited CI images and use the apply gain map API to combine images efficiently. This can help in reducing the rendering time by optimizing the filter application process.
Use of Extended Range Contexts: When rendering HDR images, create an extended range CGContext with RGBA half-float pixels and an extended color space. This allows you to use the full dynamic range of the context, which can improve rendering performance.

For more detailed information, you can refer to the following sessions and chapters:

These sessions provide insights into optimizing image processing and rendering using Core Image and related technologies.