GifEncoder

ViewController.m

//
//  ViewController.m
//  GifEncoderTest
//
//  Created by willard on 2017/10/18.
//  Copyright © 2017年 willard. All rights reserved.
//

#import "ViewController.h"
#import <Photos/Photos.h>


#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSMutableArray *images = [NSMutableArray arrayWithCapacity:3];
    NSMutableArray *timeIntervals = [NSMutableArray arrayWithCapacity:3];
    
    for (NSUInteger i = 0 ; i < 3; i++) {
        NSString *imageFileName = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"number_%ld", i+1] ofType:@"png"];
        
        UIImage *image = [UIImage imageWithContentsOfFile:imageFileName];
        
        [images addObject:image];
        [timeIntervals addObject:@1];
    }
    
    [self makeAnimatedGif:images.copy timeIntervals:timeIntervals.copy fileName:@"fff.gif"];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)makeAnimatedGif:(NSArray <UIImage *>*)images
          timeIntervals:(NSArray <NSNumber *>*)timeIntervals
               fileName:(NSString *)fileName {
    
    NSUInteger kFrameCount = images.count;
    
    NSDictionary *fileProperties = @{
                                     (__bridge id)kCGImagePropertyGIFDictionary: @{
                                             (__bridge id)kCGImagePropertyGIFLoopCount: @0, // 0 means loop forever
                                             }
                                     };
    NSURL *path = [self getFullPathWithName:fileName];
    CGImageDestinationRef destination = CGImageDestinationCreateWithURL((__bridge CFURLRef)path, kUTTypeGIF, kFrameCount, NULL);
    CGImageDestinationSetProperties(destination, (__bridge CFDictionaryRef)fileProperties);
    
    for (NSUInteger i = 0; i < kFrameCount; i++) {
        NSDictionary *frameProperties = @{
                                          (__bridge id)kCGImagePropertyGIFDictionary: @{
                                                  (__bridge id)kCGImagePropertyGIFDelayTime: timeIntervals[i], // a float (not double!) in seconds, rounded to centiseconds in the GIF data
                                                  }
                                          };
        @autoreleasepool {
            UIImage *image =[images objectAtIndex:i];  //Here is the change
            NSData *imgData = UIImagePNGRepresentation(image); //1 it represents the quality of the image.
            CGImageDestinationAddImage(destination, image.CGImage, (__bridge CFDictionaryRef)frameProperties);
        }
    }
    
    if (!CGImageDestinationFinalize(destination)) {
        NSLog(@"failed to finalize image destination");
    }
    CFRelease(destination);
    
}

- (NSURL *)getFullPathWithName:(NSString *)fileName {
    NSURL *documentsDirectoryURL = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:nil];
    NSURL *fileURL = [documentsDirectoryURL URLByAppendingPathComponent:fileName];
    NSLog(@"%@",documentsDirectoryURL.path);
    return fileURL;
}

@end