我已经努力了两天,以webp
显示动画的UIImageView
图像,但没有成功。
主要问题在于文件的解码步骤中出现此错误:VP8_STATUS_UNSUPPORTED_FEATURE
。
我试过了
https://github.com/seanooi/iOS-WebP
https://github.com/mattt/WebPImageSerialization
这些项目提供了用于使用UIImage
文件创建webp
的代码,并且可以在没有动画的图像上正常工作,但是在尝试对带有动画的图像进行解码时,它们均会失败,并出现与上述相同的错误。
我越狱了,检查了文件系统,我发现Facebook的Messenger应用程序具有.webp
格式的一些标签,并且在许可证中还提到了Google的“webp”库,因此,我确定这是有可能的。
最佳答案
使用this header顶部的代码段成功解码了动画.webp,其中也包含对所用数据结构的说明。
static NSDictionary* DecodeWebPURL(NSURL *url) {
NSMutableDictionary *info = [NSMutableDictionary dictionary];
NSMutableArray *images = [NSMutableArray array];
NSData *imgData = [NSData dataWithContentsOfURL:url];
WebPData data;
WebPDataInit(&data);
data.bytes = (const uint8_t *)[imgData bytes];
data.size = [imgData length];
WebPDemuxer* demux = WebPDemux(&data);
int width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
int height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
if (flags & ANIMATION_FLAG) {
WebPIterator iter;
if (WebPDemuxGetFrame(demux, 1, &iter)) {
WebPDecoderConfig config;
WebPInitDecoderConfig(&config);
config.input.height = height;
config.input.width = width;
config.input.has_alpha = iter.has_alpha;
config.input.has_animation = 1;
config.options.no_fancy_upsampling = 1;
config.options.bypass_filtering = 1;
config.options.use_threads = 1;
config.output.colorspace = MODE_RGBA;
[info setObject:[NSNumber numberWithInt:iter.duration] forKey:@"duration"];
do {
WebPData frame = iter.fragment;
VP8StatusCode status = WebPDecode(frame.bytes, frame.size, &config);
if (status != VP8_STATUS_OK) {
NSLog(@"Error decoding frame");
}
uint8_t *data = WebPDecodeRGBA(frame.bytes, frame.size, &width, &height);
CGDataProviderRef provider = CGDataProviderCreateWithData(&config, data, config.options.scaled_width * config.options.scaled_height * 4, NULL);
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaLast;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef imageRef = CGImageCreate(width, height, 8, 32, 4 * width, colorSpaceRef, bitmapInfo, provider, NULL, YES, renderingIntent);
[images addObject:[UIImage imageWithCGImage:imageRef]];
CGImageRelease(imageRef);
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
} while (WebPDemuxNextFrame(&iter));
WebPDemuxReleaseIterator(&iter);
}
}
WebPDemuxDelete(demux);
[info setObject:images forKey:@"frames"];
return info;
}
关于ios - 解码动画Webp iOS时出错,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/28231580/