I am attempting to understand the following code and how you would convert it to Swift. Specifically, I understand this adds an instance method you can call on an instance of CIImage. My question is, how you can do the same thing in a Swift class?
This code is taken from AAPLAssetViewController.m in Apple's example app using the Photos framework.
@implementation CIImage (Convenience)
- (NSData *)aapl_jpegRepresentationWithCompressionQuality:(CGFloat)compressionQuality {
static CIContext *ciContext = nil;
if (!ciContext) {
EAGLContext *eaglContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
ciContext = [CIContext contextWithEAGLContext:eaglContext];
}
CGImageRef outputImageRef = [ciContext createCGImage:self fromRect:[self extent]];
UIImage *uiImage = [[UIImage alloc] initWithCGImage:outputImageRef scale:1.0 orientation:UIImageOrientationUp];
if (outputImageRef) {
CGImageRelease(outputImageRef);
}
NSData *jpegRepresentation = UIImageJPEGRepresentation(uiImage, compressionQuality);
return jpegRepresentation;
}
@end
Call it like so:
NSData *jpegData = [myCIImage aapl_jpegRepresentationWithCompressionQuality:0.9f];
From The Swift Programming Language - Extensions:
Extensions add new functionality to an existing class, structure, or enumeration type. (...) Extensions are similar to categories in Objective-C.