CGImageSourceUpdateData

CGImageSource is a class in Apple's Core Graphics framework that provides a way to read and decode image data from various sources. It supports a wide range of image formats, including JPEG, PNG, GIF, TIFF, and more. The class is designed to be efficient and can handle large images without consuming excessive memory.

To use CGImageSource, you first create an instance of the class by calling the CGImageSourceCreateWithURL or CGImageSourceCreateWithData function, passing in the URL or data of the image you want to read. You can then use various functions to query the properties of the image, such as its size, color space, and metadata.

One of the key features of CGImageSource is its ability to read images incrementally. This means that you can start reading an image before it has been fully downloaded or decoded, which can be useful for displaying images in a web browser or other applications where performance is critical.

CGImageSource also supports the creation of thumbnail images, which can be useful for displaying a preview of an image in a gallery or other application. You can create a thumbnail by calling the CGImageSourceCreateThumbnailAtIndex function, passing in the index of the image you want to create a thumbnail for and the desired size of the thumbnail.

Overall, CGImageSource is a powerful and flexible class for reading and decoding image data in macOS and iOS applications. Its support for a wide range of image formats, incremental reading, and thumbnail creation make it a valuable tool for developers working with images.