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Example of creating an animated GIF on iOS, with no 3rd-party code required. This should also be easy to port to OS X.
#import <UIKit/UIKit.h>
#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>
static UIImage *frameImage(CGSize size, CGFloat radians) {
UIGraphicsBeginImageContextWithOptions(size, YES, 1); {
[[UIColor whiteColor] setFill];
UIRectFill(CGRectInfinite);
CGContextRef gc = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(gc, size.width / 2, size.height / 2);
CGContextRotateCTM(gc, radians);
CGContextTranslateCTM(gc, size.width / 4, 0);
[[UIColor redColor] setFill];
CGFloat w = size.width / 10;
CGContextFillEllipseInRect(gc, CGRectMake(-w / 2, -w / 2, w, w));
}
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
static void makeAnimatedGif(void) {
static NSUInteger kFrameCount = 16;
NSDictionary *fileProperties = @{
(__bridge id)kCGImagePropertyGIFDictionary: @{
(__bridge id)kCGImagePropertyGIFLoopCount: @0, // 0 means loop forever
}
};
NSDictionary *frameProperties = @{
(__bridge id)kCGImagePropertyGIFDictionary: @{
(__bridge id)kCGImagePropertyGIFDelayTime: @0.02f, // a float (not double!) in seconds, rounded to centiseconds in the GIF data
}
};
NSURL *documentsDirectoryURL = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:nil];
NSURL *fileURL = [documentsDirectoryURL URLByAppendingPathComponent:@"animated.gif"];
CGImageDestinationRef destination = CGImageDestinationCreateWithURL((__bridge CFURLRef)fileURL, kUTTypeGIF, kFrameCount, NULL);
CGImageDestinationSetProperties(destination, (__bridge CFDictionaryRef)fileProperties);
for (NSUInteger i = 0; i < kFrameCount; i++) {
@autoreleasepool {
UIImage *image = frameImage(CGSizeMake(300, 300), M_PI * 2 * i / kFrameCount);
CGImageDestinationAddImage(destination, image.CGImage, (__bridge CFDictionaryRef)frameProperties);
}
}
if (!CGImageDestinationFinalize(destination)) {
NSLog(@"failed to finalize image destination");
}
CFRelease(destination);
NSLog(@"url=%@", fileURL);
}
@perlmunger

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perlmunger Feb 21, 2013

Have you seen this code generate the following error when CGImageDestinationFinalize is called?

: The function `CGContextClear' is obsolete and will be removed in an upcoming update. Unfortunately, this application, or a library it uses, is using this obsolete function, and is thereby contributing to an overall degradation of system performance.

Have you seen this code generate the following error when CGImageDestinationFinalize is called?

: The function `CGContextClear' is obsolete and will be removed in an upcoming update. Unfortunately, this application, or a library it uses, is using this obsolete function, and is thereby contributing to an overall degradation of system performance.

@NikhilManapure

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NikhilManapure Sep 7, 2017

Wish, this was in Swift. I am trying to convert, once I am done I will post it.

Wish, this was in Swift. I am trying to convert, once I am done I will post it.

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@NikhilManapure

NikhilManapure Sep 7, 2017

I implemented it in Swift 3, it's here.

I implemented it in Swift 3, it's here.

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