Add WebP format support (fix SDWebImage#410)

How awesome is that?! =)

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "Vendors/libwebp"]
+	path = Vendors/libwebp
+	url = http://git.chromium.org/webm/libwebp.git

Examples/SDWebImage Demo/MasterViewController.m

@@ -31,6 +31,8 @@ - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
                                                                                action:@selector(flushCache)];
         _objects = [NSArray arrayWithObjects:
                     @"http://assets.sbnation.com/assets/2512203/dogflops.gif",
+                    @"http://www.ioncannon.net/wp-content/uploads/2011/06/test2.webp",
+                    @"http://www.ioncannon.net/wp-content/uploads/2011/06/test9.webp",
                     @"http://static2.dmcdn.net/static/video/656/177/44771656:jpeg_preview_small.jpg?20120509154705",
                     @"http://static2.dmcdn.net/static/video/629/228/44822926:jpeg_preview_small.jpg?20120509181018",
                     @"http://static2.dmcdn.net/static/video/116/367/44763611:jpeg_preview_small.jpg?20120509101749",

README.md

@@ -9,6 +9,7 @@ It provides:
 - An asynchronous image downloader
 - An asynchronous memory + disk image caching with automatic cache expiration handling
 - Animated GIF support
+- WebP format support
 - A background image decompression
 - A guarantee that the same URL won't be downloaded several times
 - A guarantee that bogus URLs won't be retried again and again

SDWebImage/SDWebImageDownloader.m

@@ -70,7 +70,7 @@ - (id)init
         _downloadQueue = NSOperationQueue.new;
         _downloadQueue.maxConcurrentOperationCount = 2;
         _URLCallbacks = NSMutableDictionary.new;
-        _HTTPHeaders = [NSMutableDictionary dictionaryWithObject:@"image/*" forKey:@"Accept"];
+        _HTTPHeaders = [NSMutableDictionary dictionaryWithObject:@"image/webp,image/*;q=0.8" forKey:@"Accept"];
         _barrierQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloaderBarrierQueue", DISPATCH_QUEUE_CONCURRENT);
     }
     return self;

SDWebImage/UIImage+MultiFormat.m

@@ -8,6 +8,7 @@
 
 #import "UIImage+MultiFormat.h"
 #import "UIImage+GIF.h"
+#import "UIImage+WebP.h"
 
 @implementation UIImage (MultiFormat)
 
@@ -24,6 +25,11 @@ + (UIImage *)sd_imageWithData:(NSData *)data
         image = [[UIImage alloc] initWithData:data];
     }
 
+    if (!image) // TODO: detect webp signature
+    {
+        image = [UIImage sd_imageWithWebPData:data];
+    }
+
     return image;
 }
 

SDWebImage/UIImage+WebP.h

@@ -0,0 +1,15 @@
+//
+//  UIImage+WebP.h
+//  SDWebImage
+//
+//  Created by Olivier Poitrey on 07/06/13.
+//  Copyright (c) 2013 Dailymotion. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+@interface UIImage (WebP)
+
++ (UIImage *)sd_imageWithWebPData:(NSData *)data;
+
+@end

SDWebImage/UIImage+WebP.m

@@ -0,0 +1,62 @@
+//
+//  UIImage+WebP.m
+//  SDWebImage
+//
+//  Created by Olivier Poitrey on 07/06/13.
+//  Copyright (c) 2013 Dailymotion. All rights reserved.
+//
+
+#import "UIImage+WebP.h"
+#import "webp/decode.h"
+
+// Callback for CGDataProviderRelease
+static void FreeImageData(void *info, const void *data, size_t size)
+{
+    free((void *)data);
+}
+
+@implementation UIImage (WebP)
+
++ (UIImage *)sd_imageWithWebPData:(NSData *)data
+{
+    WebPDecoderConfig config;
+    if (!WebPInitDecoderConfig(&config))
+    {
+        return nil;
+    }
+
+    config.output.colorspace = MODE_rgbA;
+    config.options.use_threads = 1;
+
+    // Decode the WebP image data into a RGBA value array.
+    if (WebPDecode(data.bytes, data.length, &config) != VP8_STATUS_OK)
+    {
+        return nil;
+    }
+
+    int width = config.input.width;
+    int height = config.input.height;
+    if (config.options.use_scaling)
+    {
+        width = config.options.scaled_width;
+        height = config.options.scaled_height;
+    }
+
+    // Construct a UIImage from the decoded RGBA value array.
+    CGDataProviderRef provider =
+    CGDataProviderCreateWithData(NULL, config.output.u.RGBA.rgba, config.output.u.RGBA.size, FreeImageData);
+    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
+    CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast;
+    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
+    CGImageRef imageRef = CGImageCreate(width, height, 8, 32, 4 * width, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
+
+    CGColorSpaceRelease(colorSpaceRef);
+    CGDataProviderRelease(provider);
+
+    UIImage *image = [[UIImage alloc] initWithCGImage:imageRef];
+    CGImageRelease(imageRef);
+
+    return image;
+}
+
+@end