展示本地gif圖片
SDWebImage比較占內(nèi)存,FLAnimatedImage不怎么占用內(nèi)存
1.使用SDWebImage
- 導(dǎo)入頭文件
#import "UIImage+GIF.h" - 設(shè)置gif圖
self.imageView.image = [UIImage sd_animatedGIFNamed:@"test"];
也可以通過(guò)NSData導(dǎo)入
+ (UIImage *)sd_animatedGIFWithData:(NSData *)data
2.使用FLAnimatedImage
- 導(dǎo)入頭文件
#import "FLAnimatedImage.h" - 設(shè)置gif圖
NSString *path = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"gif"];
NSData *data = [NSData dataWithContentsOfFile:path];
FLAnimatedImage *image = [FLAnimatedImage animatedImageWithGIFData:data];
self.imageView.animatedImage = image;
3.SDWebImage實(shí)現(xiàn)原理
使用UIImage + GIF分類
1.將gif圖的每一幀導(dǎo)出為一個(gè)UIImage,并且算出每一幀的播放時(shí)間,將導(dǎo)出的image放入images數(shù)組中
2.使用+ animatedImageWithImages: duration: 方法創(chuàng)建image,參數(shù)為第一步的images數(shù)組和播放總時(shí)長(zhǎng)
3.設(shè)置UIImageView的image時(shí)用sd_animatedGIFNamed:方法即可展示gif
方法1: 通過(guò)NSData獲取gif的UIImage
方法名:+ (UIImage )sd_animatedGIFWithData:(NSData *)data;
- 獲取gif數(shù)據(jù),及其幀數(shù)
- 獲取每幀的像素位圖,求出每幀的播放時(shí)間
- 按照屏幕分辨率生成UIImage并放入數(shù)組
- 通過(guò)+ animatedImageWithImages: duration:生成UIImage
+ (UIImage *)sd_animatedGIFWithData:(NSData *)data {
if (!data) {
return nil;
}
//通過(guò)CFData讀取gif文件的數(shù)據(jù)
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
//獲取gif文件的幀數(shù)
size_t count = CGImageSourceGetCount(source);
UIImage *animatedImage;
if (count <= 1) {
animatedImage = [[UIImage alloc] initWithData:data];
}
else {//大于一張圖片時(shí)
NSMutableArray *images = [NSMutableArray array];
//設(shè)置gif播放的時(shí)間
NSTimeInterval duration = 0.0f;
for (size_t i = 0; i < count; i++) {
//獲取gif指定幀的像素位圖
CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);
if (!image) {
continue;
}
//獲取每張圖的播放時(shí)間
duration += [self sd_frameDurationAtIndex:i source:source];
[images addObject:[UIImage imageWithCGImage:image scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp]];
CGImageRelease(image);
}
if (!duration) {//如果播放時(shí)間為空
duration = (1.0f / 10.0f) * count;
}
animatedImage = [UIImage animatedImageWithImages:images duration:duration];
}
CFRelease(source);
return animatedImage;
}
方法2:獲取指定幀的image的播放時(shí)間
方法名:+ (float)sd_frameDurationAtIndex:(NSUInteger)index source:(CGImageSourceRef)source
- 獲取指定幀圖片的屬性字典
- 獲取圖片的gif屬性字典
- 獲取每一幀的播放時(shí)間(如果小于0.1,設(shè)置為0.1)
+ (float)sd_frameDurationAtIndex:(NSUInteger)index source:(CGImageSourceRef)source {
float frameDuration = 0.1f;
//獲取這一幀圖片的屬性字典
CFDictionaryRef cfFrameProperties = CGImageSourceCopyPropertiesAtIndex(source, index, nil);
NSDictionary *frameProperties = (__bridge NSDictionary *)cfFrameProperties;
//獲取gif屬性字典
NSDictionary *gifProperties = frameProperties[(NSString *)kCGImagePropertyGIFDictionary];
//獲取這一幀持續(xù)的時(shí)間
NSNumber *delayTimeUnclampedProp = gifProperties[(NSString *)kCGImagePropertyGIFUnclampedDelayTime];
if (delayTimeUnclampedProp) {
frameDuration = [delayTimeUnclampedProp floatValue];
}
else {
NSNumber *delayTimeProp = gifProperties[(NSString *)kCGImagePropertyGIFDelayTime];
if (delayTimeProp) {
frameDuration = [delayTimeProp floatValue];
}
}
//如果幀數(shù)小于0.1,則指定為0.1
if (frameDuration < 0.011f) {
frameDuration = 0.100f;
}
CFRelease(cfFrameProperties);
return frameDuration;
}
方法3:通過(guò)圖片的Name獲取UIImage
方法名:+ (UIImage *)sd_animatedGIFNamed:(NSString *)name;
- 根據(jù)屏幕分辨率給圖片自動(dòng)加后綴(@2x)
- 從mainBundle中獲取Data數(shù)據(jù)
- 調(diào)用方法 + sd_animatedGIFWithData:
+ (UIImage *)sd_animatedGIFNamed:(NSString *)name {
//判斷屏幕分辨率
CGFloat scale = [UIScreen mainScreen].scale;
if (scale > 1.0f) {
NSString *retinaPath = [[NSBundle mainBundle] pathForResource:[name stringByAppendingString:@"@2x"] ofType:@"gif"];
NSData *data = [NSData dataWithContentsOfFile:retinaPath];
if (data) {
return [UIImage sd_animatedGIFWithData:data];
}
NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"gif"];
data = [NSData dataWithContentsOfFile:path];
if (data) {
return [UIImage sd_animatedGIFWithData:data];
}
return [UIImage imageNamed:name];
}
else {
NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"gif"];
NSData *data = [NSData dataWithContentsOfFile:path];
if (data) {
return [UIImage sd_animatedGIFWithData:data];
}
return [UIImage imageNamed:name];
}
}
方法4:對(duì)gif按比例進(jìn)行縮放
方法名:- (UIImage *)sd_animatedImageByScalingAndCroppingToSize:(CGSize)size;
- 獲取較大的縮放比例值,寬高等比縮放
- 調(diào)整位置,使縮放后的圖居中
- 遍歷self.images, 將圖片縮放后導(dǎo)出放入數(shù)組
- 通過(guò)animatedImageWithImages:duration:返回image
- (UIImage *)sd_animatedImageByScalingAndCroppingToSize:(CGSize)size {
if (CGSizeEqualToSize(self.size, size) || CGSizeEqualToSize(size, CGSizeZero)) {
return self;
}
CGSize scaledSize = size;
CGPoint thumbnailPoint = CGPointZero;
//獲取較大的縮放比例值,寬高等比縮放
CGFloat widthFactor = size.width / self.size.width;
CGFloat heightFactor = size.height / self.size.height;
CGFloat scaleFactor = (widthFactor > heightFactor) ? widthFactor : heightFactor;
scaledSize.width = self.size.width * scaleFactor;
scaledSize.height = self.size.height * scaleFactor;
//調(diào)整位置,使縮放后的圖居中
if (widthFactor > heightFactor) {
thumbnailPoint.y = (size.height - scaledSize.height) * 0.5;
}
else if (widthFactor < heightFactor) {
thumbnailPoint.x = (size.width - scaledSize.width) * 0.5;
}
//遍歷self.images, 將圖片縮放后導(dǎo)出放入數(shù)組
NSMutableArray *scaledImages = [NSMutableArray array];
for (UIImage *image in self.images) {
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
[image drawInRect:CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledSize.width, scaledSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
[scaledImages addObject:newImage];
UIGraphicsEndImageContext();
}
return [UIImage animatedImageWithImages:scaledImages duration:self.duration];
}
