1.简单描述
在现在比较流行的App中,gif动画其实已经成为了核心的功能点，不管是刷新加载时候放上App独有的gif图，还是各种动效使用。尤其是段视频，电商等较为娱乐与金钱结合的App。这里简单描述下实现方式。
gif动画是iOS开发中很常用的一个功能，有的是为了显示加载视频的过程，更多的是为了显示一个结果状态（动画更直观）。
那么如何执行gif动画，方法有很多。（这里只写一下方法三，前两种之前都用过）
方法一使用UIWebView来显示；
方法二使用UIImageView的帧动画显示；
方法三使用SDWebImage这个三方框架来显示。
2.简单使用
1、显示gif动画（三方框架SDWebImage的UIImage+GIF分类）
#import "UIImage+GIF.h"
#import "SDWebImageGIFCoder.h"
#import "NSImage+WebCache.h"
@implementation UIImage (GIF)
+ (UIImage *)sd_animatedGIFWithData:(NSData *)data {
if (!data) {
return nil;
}
return [[SDWebImageGIFCoder sharedCoder] decodedImageWithData:data];
}
- (BOOL)isGIF {
return (self.images != nil);
}
@end
//使用
NSData *gifData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"live_sign" ofType:@"gif"]];
UIImage *signSuccessGifImg = [UIImage sd_animatedGIFWithData:gifData];
self.imageView.image = signSuccessGifImg;
2、获取gif动画时长
//获取gif图片的总时长
- (NSTimeInterval)durationForGifData:(NSData *)data{
//将GIF图片转换成对应的图片源
CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
//获取其中图片源个数，即由多少帧图片组成
size_t frameCout = CGImageSourceGetCount(gifSource);
//定义数组存储拆分出来的图片
NSMutableArray* frames = [[NSMutableArray alloc] init];
NSTimeInterval totalDuration = 0;
for (size_t i=0; i<frameCout; i++) {
//从GIF图片中取出源图片
CGImageRef imageRef = CGImageSourceCreateImageAtIndex(gifSource, i, NULL);
//将图片源转换成UIimageView能使用的图片源
UIImage* imageName = [UIImage imageWithCGImage:imageRef];
//将图片加入数组中
[frames addObject:imageName];
NSTimeInterval duration = [self gifImageDeleyTime:gifSource index:i];
totalDuration += duration;
CGImageRelease(imageRef);
}
//获取循环次数
NSInteger loopCount;//循环次数
CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
if (properties) {
CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
if (gif) {
CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
if (loop) {
//如果loop == NULL，表示不循环播放，当loopCount == 0时，表示无限循环；
CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
};
}
}
CFRelease(gifSource);
return totalDuration;
}
//获取GIF图片每帧的时长
- (NSTimeInterval)gifImageDeleyTime:(CGImageSourceRef)imageSource index:(NSInteger)index {
NSTimeInterval duration = 0;
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, NULL);
if (imageProperties) {
CFDictionaryRef gifProperties;
BOOL result = CFDictionaryGetValueIfPresent(imageProperties, kCGImagePropertyGIFDictionary, (const void **)&gifProperties);
if (result) {
const void *durationValue;
if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFUnclampedDelayTime, &durationValue)) {
duration = [(__bridge NSNumber *)durationValue doubleValue];
if (duration < 0) {
if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFDelayTime, &durationValue)) {
duration = [(__bridge NSNumber *)durationValue doubleValue];
}
}
}
}
}
return duration;
}
3、获取gif动画执行次数
//获取gif图片的循环次数
-(NSInteger)repeatCountForGifData:(NSData *)data{
//将GIF图片转换成对应的图片源
CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
//获取循环次数
NSInteger loopCount = 0;//循环次数
CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
if (properties) {
CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
if (gif) {
CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
if (loop) {
//如果loop == NULL，表示不循环播放，当loopCount == 0时，表示无限循环；
CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
};
}
}
CFRelease(gifSource);
return loopCount;
}
三.创建分类
import "UIImageView+GIFProperty.h"
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface UIImageView (GIFProperty)
-(NSTimeInterval)durationForGifData:(NSData *)data;//获取gif动画总时长
-(NSInteger)repeatCountForGifData:(NSData *)data; //获取gif动画循环总次数 0:表示无限循环
@end
NS_ASSUME_NONNULL_END
#import "UIImageView+GIFProperty.h"
@implementation UIImageView (GIFProperty)
//获取gif图片的总时长
- (NSTimeInterval)durationForGifData:(NSData *)data{
//将GIF图片转换成对应的图片源
CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
//获取其中图片源个数，即由多少帧图片组成
size_t frameCout = CGImageSourceGetCount(gifSource);
//定义数组存储拆分出来的图片
NSMutableArray* frames = [[NSMutableArray alloc] init];
NSTimeInterval totalDuration = 0;
for (size_t i=0; i<frameCout; i++) {
//从GIF图片中取出源图片
CGImageRef imageRef = CGImageSourceCreateImageAtIndex(gifSource, i, NULL);
//将图片源转换成UIimageView能使用的图片源
UIImage* imageName = [UIImage imageWithCGImage:imageRef];
//将图片加入数组中
[frames addObject:imageName];
NSTimeInterval duration = [self gifImageDeleyTime:gifSource index:i];
totalDuration += duration;
CGImageRelease(imageRef);
}
//获取循环次数
NSInteger loopCount;//循环次数
CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
if (properties) {
CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
if (gif) {
CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
if (loop) {
//如果loop == NULL，表示不循环播放，当loopCount == 0时，表示无限循环；
CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
};
}
}
CFRelease(gifSource);
return totalDuration;
}
//获取gif图片的循环次数
-(NSInteger)repeatCountForGifData:(NSData *)data{
//将GIF图片转换成对应的图片源
CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
//获取循环次数
NSInteger loopCount = 0;//循环次数
CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
if (properties) {
CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
if (gif) {
CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
if (loop) {
//如果loop == NULL，表示不循环播放，当loopCount == 0时，表示无限循环；
CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
};
}
}
CFRelease(gifSource);
return loopCount;
}
//获取GIF图片每帧的时长
- (NSTimeInterval)gifImageDeleyTime:(CGImageSourceRef)imageSource index:(NSInteger)index {
NSTimeInterval duration = 0;
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, NULL);
if (imageProperties) {
CFDictionaryRef gifProperties;
BOOL result = CFDictionaryGetValueIfPresent(imageProperties, kCGImagePropertyGIFDictionary, (const void **)&gifProperties);
if (result) {
const void *durationValue;
if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFUnclampedDelayTime, &durationValue)) {
duration = [(__bridge NSNumber *)durationValue doubleValue];
if (duration < 0) {
if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFDelayTime, &durationValue)) {
duration = [(__bridge NSNumber *)durationValue doubleValue];
}
}
}
}
}
return duration;
}
@end
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