IOS 获取网络图像尺寸 更改 图像色彩值 什么一套方法灰色
直接在代码 头文件
// 图片处理 0 半灰色 1 灰度 2 深棕色 3 反色 +(UIImage*)imageWithImage:(UIImage*)image grayLevelType:(UIImageGrayLevelType)type; //色值 变暗多少 0.0 - 1.0 +(UIImage*)imageWithImage:(UIImage*)image darkValue:(float)darkValue; /** 获取网络图片的Size, 先通过文件头来获取图片大小 假设失败 会下载完整的图片Data 来计算大小 所以最好别放在主线程 假设你有使用SDWebImage就会先看下 SDWebImage有缓存过改图片没有 支持文件头大小的格式 png、gif、jpg http://www.cocoachina.com/bbs/read.php?tid=165823 */ +(CGSize)downloadImageSizeWithURL:(id)imageURL;
代码实现:
//讨厌警告 -(id)diskImageDataBySearchingAllPathsForKey:(id)key{return nil;} +(CGSize)downloadImageSizeWithURL:(id)imageURL { NSURL* URL = nil; if([imageURL isKindOfClass:[NSURL class]]){ URL = imageURL; } if([imageURL isKindOfClass:[NSString class]]){ URL = [NSURL URLWithString:imageURL]; } if(URL == nil) return CGSizeZero; NSString* absoluteString = URL.absoluteString; #ifdef dispatch_main_sync_safe if([[SDImageCache sharedImageCache] diskImageExistsWithKey:absoluteString]) { UIImage* image = [[SDImageCache sharedImageCache] imageFromMemoryCacheForKey:absoluteString]; if(!image) { NSData* data = [[SDImageCache sharedImageCache] performSelector:@selector(diskImageDataBySearchingAllPathsForKey:) withObject:URL.absoluteString]; image = [UIImage imageWithData:data]; } if(image) { return image.size; } } #endif NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:URL]; NSString* pathExtendsion = [URL.pathExtension lowercaseString]; CGSize size = CGSizeZero; if([pathExtendsion isEqualToString:@"png"]){ size = [self downloadPNGImageSizeWithRequest:request]; } else if([pathExtendsion isEqual:@"gif"]) { size = [self downloadGIFImageSizeWithRequest:request]; } else{ size = [self downloadJPGImageSizeWithRequest:request]; } if(CGSizeEqualToSize(CGSizeZero, size)) { NSData* data = [NSURLConnection sendSynchronousRequest:[NSURLRequest requestWithURL:URL] returningResponse:nil error:nil]; UIImage* image = [UIImage imageWithData:data]; if(image) { #ifdef dispatch_main_sync_safe [[SDImageCache sharedImageCache] storeImage:image recalculateFromImage:YES imageData:data forKey:URL.absoluteString toDisk:YES]; #endif size = image.size; } } return size; } +(CGSize)downloadPNGImageSizeWithRequest:(NSMutableURLRequest*)request { [request setValue:@"bytes=16-23" forHTTPHeaderField:@"Range"]; NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; if(data.length == 8) { int w1 = 0, w2 = 0, w3 = 0, w4 = 0; [data getBytes:&w1 range:NSMakeRange(0, 1)]; [data getBytes:&w2 range:NSMakeRange(1, 1)]; [data getBytes:&w3 range:NSMakeRange(2, 1)]; [data getBytes:&w4 range:NSMakeRange(3, 1)]; int w = (w1 << 24) + (w2 << 16) + (w3 << 8) + w4; int h1 = 0, h2 = 0, h3 = 0, h4 = 0; [data getBytes:&h1 range:NSMakeRange(4, 1)]; [data getBytes:&h2 range:NSMakeRange(5, 1)]; [data getBytes:&h3 range:NSMakeRange(6, 1)]; [data getBytes:&h4 range:NSMakeRange(7, 1)]; int h = (h1 << 24) + (h2 << 16) + (h3 << 8) + h4; return CGSizeMake(w, h); } return CGSizeZero; } +(CGSize)downloadGIFImageSizeWithRequest:(NSMutableURLRequest*)request { [request setValue:@"bytes=6-9" forHTTPHeaderField:@"Range"]; NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; if(data.length == 4) { short w1 = 0, w2 = 0; [data getBytes:&w1 range:NSMakeRange(0, 1)]; [data getBytes:&w2 range:NSMakeRange(1, 1)]; short w = w1 + (w2 << 8); short h1 = 0, h2 = 0; [data getBytes:&h1 range:NSMakeRange(2, 1)]; [data getBytes:&h2 range:NSMakeRange(3, 1)]; short h = h1 + (h2 << 8); return CGSizeMake(w, h); } return CGSizeZero; } +(CGSize)downloadJPGImageSizeWithRequest:(NSMutableURLRequest*)request { [request setValue:@"bytes=0-209" forHTTPHeaderField:@"Range"]; NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; if ([data length] <= 0x58) { return CGSizeZero; } if ([data length] < 210) {// 肯定仅仅有一个DQT字段 short w1 = 0, w2 = 0; [data getBytes:&w1 range:NSMakeRange(0x60, 0x1)]; [data getBytes:&w2 range:NSMakeRange(0x61, 0x1)]; short w = (w1 << 8) + w2; short h1 = 0, h2 = 0; [data getBytes:&h1 range:NSMakeRange(0x5e, 0x1)]; [data getBytes:&h2 range:NSMakeRange(0x5f, 0x1)]; short h = (h1 << 8) + h2; return CGSizeMake(w, h); } else { short word = 0x0; [data getBytes:&word range:NSMakeRange(0x15, 0x1)]; if (word == 0xdb) { [data getBytes:&word range:NSMakeRange(0x5a, 0x1)]; if (word == 0xdb) {// 两个DQT字段 short w1 = 0, w2 = 0; [data getBytes:&w1 range:NSMakeRange(0xa5, 0x1)]; [data getBytes:&w2 range:NSMakeRange(0xa6, 0x1)]; short w = (w1 << 8) + w2; short h1 = 0, h2 = 0; [data getBytes:&h1 range:NSMakeRange(0xa3, 0x1)]; [data getBytes:&h2 range:NSMakeRange(0xa4, 0x1)]; short h = (h1 << 8) + h2; return CGSizeMake(w, h); } else {// 一个DQT字段 short w1 = 0, w2 = 0; [data getBytes:&w1 range:NSMakeRange(0x60, 0x1)]; [data getBytes:&w2 range:NSMakeRange(0x61, 0x1)]; short w = (w1 << 8) + w2; short h1 = 0, h2 = 0; [data getBytes:&h1 range:NSMakeRange(0x5e, 0x1)]; [data getBytes:&h2 range:NSMakeRange(0x5f, 0x1)]; short h = (h1 << 8) + h2; return CGSizeMake(w, h); } } else { return CGSizeZero; } } }
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