加载gif图过渡效果

加载gif图片，过渡效果：

调用：

- (id)initWithGifView:(UIView *)view

{

self = [super initWithView:view];

if (self) {

self.color = [UIColor clearColor];

NSString  *filePath = [[NSBundle bundleWithPath:[[NSBundle mainBundle] bundlePath]] pathForResource:@"loading2.gif" ofType:nil];

NSData  *imageData = [NSData dataWithContentsOfFile:filePath];

UIImageView *loadingImgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 110, 90)];

loadingImgView.contentMode = UIViewContentModeCenter;

loadingImgView.image = [UIImage sd_animatedGIFWithData:imageData];

self.customView = loadingImgView;

self.mode = MBProgressHUDModeCustomView;

[view addSubview:self];

[self show:YES];

}

return self;

}

封装：

+ (UIImage *)sd_animatedGIFWithData:(NSData *)data {

if (!data) {

return nil;

}

CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);

size_t count = CGImageSourceGetCount(source);

UIImage *animatedImage;

if (count <= 1) {

animatedImage = [[UIImage alloc] initWithData:data];

}

else {

NSMutableArray *images = [NSMutableArray array];

NSTimeInterval duration = 0.0f;

for (size_t i = 0; i < count; i++) {

CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);

duration += [self sd_frameDurationAtIndex:i source:source];

[images addObject:[UIImage imageWithCGImage:image scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp]];

CGImageRelease(image);

}

if (!duration) {

duration = (1.0f / 10.0f) * count;

}

animatedImage = [UIImage animatedImageWithImages:images duration:duration];

}

CFRelease(source);

return animatedImage;

}

+ (float)sd_frameDurationAtIndex:(NSUInteger)index source:(CGImageSourceRef)source {

float frameDuration = 0.1f;

CFDictionaryRef cfFrameProperties = CGImageSourceCopyPropertiesAtIndex(source, index, nil);

NSDictionary *frameProperties = (__bridge NSDictionary *)cfFrameProperties;

NSDictionary *gifProperties = frameProperties[(NSString *)kCGImagePropertyGIFDictionary];

NSNumber *delayTimeUnclampedProp = gifProperties[(NSString *)kCGImagePropertyGIFUnclampedDelayTime];

if (delayTimeUnclampedProp) {

frameDuration = [delayTimeUnclampedProp floatValue];

}

else {

NSNumber *delayTimeProp = gifProperties[(NSString *)kCGImagePropertyGIFDelayTime];

if (delayTimeProp) {

frameDuration = [delayTimeProp floatValue];

}

}

// Many annoying ads specify a 0 duration to make an image flash as quickly as possible.

// We follow Firefox's behavior and use a duration of 100 ms for any frames that specify

// a duration of <= 10 ms. See <rdar://problem/7689300> and <http://webkit.org/b/36082>

// for more information.

if (frameDuration < 0.011f) {

frameDuration = 0.100f;

}

CFRelease(cfFrameProperties);

return frameDuration;

}

+ (UIImage *)sd_animatedGIFNamed:(NSString *)name {

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];

}

}

- (UIImage *)sd_animatedImageByScalingAndCroppingToSize:(CGSize)size {

if (CGSizeEqualToSize(self.size, size) || CGSizeEqualToSize(size, CGSizeZero)) {

return self;

}

CGSize scaledSize = size;

CGPoint thumbnailPoint = CGPointZero;

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;

if (widthFactor > heightFactor) {

thumbnailPoint.y = (size.height - scaledSize.height) * 0.5;

}

else if (widthFactor < heightFactor) {

thumbnailPoint.x = (size.width - scaledSize.width) * 0.5;

}

NSMutableArray *scaledImages = [NSMutableArray array];

UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);

for (UIImage *image in self.images) {

[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];

}

我调用的类是继承MBProgressHUD的。大家看的时候自己在研究下。