Adds OGImageView

OGImage/OGImageCache.m

@@ -41,7 +41,7 @@ + (OGImageCache *)shared {
 + (NSString *)MD5:(NSString *)string {
     const char *d = [string UTF8String];
     unsigned char r[CC_MD5_DIGEST_LENGTH];
-    CC_MD5(d, strlen(d), r);
+    CC_MD5(d, (CC_LONG)strlen(d), r);
     NSMutableString *hexString = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH];
     for (int ii = 0; ii < CC_MD5_DIGEST_LENGTH; ++ii) {
         [hexString appendFormat:@"%02x", r[ii]];
@@ -104,8 +104,13 @@ - (void)imageForKey:(NSString *)key block:(OGImageCacheCompletionBlock)block {
 }
 
 - (void)setImage:(__OGImage *)image forKey:(NSString *)key {
+    // assert for developers, and guard against production crashes
     NSParameterAssert(nil != image);
     NSParameterAssert(nil != key);
+    if (nil == image || nil == key) {
+        return;
+    }
+
     [_memoryCache setObject:image forKey:key];
     dispatch_async(_cacheFileTasksQueue, ^{
         NSURL *fileURL = [OGImageCache fileURLForKey:key];

OGImage/OGImageProcessing.m

@@ -88,15 +88,21 @@ OSStatus UIImageToVImageBuffer(UIImage *image, vImage_Buffer *buffer, CGImageAlp
                                              buffer->width,
                                              buffer->height, 8,
                                              buffer->rowBytes, colorSpace, alphaInfo);
-    if (UIImageOrientationRight == image.imageOrientation) {
-        CGContextRotateCTM(ctx, -M_PI/2.f);
-        CGContextTranslateCTM(ctx, -(CGFloat)height, 0.f);
-    } else if (UIImageOrientationLeft == image.imageOrientation) {
-        CGContextRotateCTM(ctx, M_PI/2.f);
-        CGContextTranslateCTM(ctx, 0.f, -(CGFloat)width);
+    if (NULL == ctx) {
+        free(buffer->data);
+        buffer->data = NULL;
+        err = OGImageProcessingError;
+    } else {
+        if (UIImageOrientationRight == image.imageOrientation) {
+            CGContextRotateCTM(ctx, -M_PI/2.f);
+            CGContextTranslateCTM(ctx, -(CGFloat)height, 0.f);
+        } else if (UIImageOrientationLeft == image.imageOrientation) {
+            CGContextRotateCTM(ctx, M_PI/2.f);
+            CGContextTranslateCTM(ctx, 0.f, -(CGFloat)width);
+        }
+        CGContextDrawImage(ctx, CGRectMake(0.f, 0.f, CGImageGetWidth(cgImage), CGImageGetHeight(cgImage)), cgImage);
+        CGContextRelease(ctx);
     }
-    CGContextDrawImage(ctx, CGRectMake(0.f, 0.f, CGImageGetWidth(cgImage), CGImageGetHeight(cgImage)), cgImage);
-    CGContextRelease(ctx);
     CGColorSpaceRelease(colorSpace);
     return err;
 }
@@ -184,6 +190,9 @@ - (void)scaleImage:(__OGImage *)image toSize:(CGSize)size cornerRadius:(CGFloat)
             if (kCGImageAlphaNone == alphaInfo) {
                 // kCGImageAlphaNone w/8-bit channels not supported
                 alphaInfo = kCGImageAlphaNoneSkipLast;
+            } else if (kCGImageAlphaFirst == alphaInfo || kCGImageAlphaLast == alphaInfo) {
+                // non-premultiplied contexts are not supported
+                alphaInfo = kCGImageAlphaPremultipliedFirst;
             }
             if (0.f < cornerRadius) {
                 alphaInfo = kCGImageAlphaPremultipliedFirst;

OGImage/OGImageRequest.m

@@ -75,7 +75,7 @@ - (void)prepareImageAndNotify {
         }
     } else {
         // if we get here, we have an http status code other than 200
-        tmpError = [NSError errorWithDomain:NSCocoaErrorDomain code:OGImageLoadingError userInfo:@{NSLocalizedDescriptionKey : [NSString stringWithFormat:@"OGImage: Received http status code: %d", _httpResponse.statusCode]}];
+        tmpError = [NSError errorWithDomain:NSCocoaErrorDomain code:OGImageLoadingError userInfo:@{NSLocalizedDescriptionKey : [NSString stringWithFormat:@"OGImage: Received http status code: %ld", (long)_httpResponse.statusCode]}];
     }
     NSAssert((nil == tmpImage && nil != tmpError) || (nil != tmpImage && nil == tmpError), @"One of tmpImage or tmpError should be non-nil");
     dispatch_async(dispatch_get_main_queue(), ^{

OGImage/OGImageView.h

@@ -0,0 +1,32 @@
+//
+//  OGImageView.h
+//  OGImageDemo
+//
+//  Created by Art Gillespie on 8/23/13.
+//  Copyright (c) 2013 Origami Labs. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+@interface OGImageView : UIImageView
+
+/**
+ * Set image view's image with the image at `url`. `OGImageView` supports the following
+ * protocols:
+ *
+ * * `http` 
+ * * `file`
+ * * `assets-library`
+ *
+ * The image will be scaled and fit according to the view's `bounds` and `contentMode`,
+ * respectively.
+ */
+- (void)setImageURL:(NSURL *)url placeholder:(UIImage *)image;
+
+/**
+ * If there's a problem loading the image, this property will be set. KVO-observable.
+ * @see `OGImage.error`
+ */
+@property (nonatomic, strong, readonly) NSError *imageError;
+
+@end

OGImage/OGImageView.m

@@ -0,0 +1,52 @@
+//
+//  OGImageView.m
+//  OGImageDemo
+//
+//  Created by Art Gillespie on 8/23/13.
+//  Copyright (c) 2013 Origami Labs. All rights reserved.
+//
+
+#import "OGImageView.h"
+#import "OGScaledImage.h"
+
+static NSString *KVOContext = @"OGImageView observation";
+
+@implementation OGImageView {
+    OGScaledImage *_scaledImage;
+}
+
+- (void)setImageURL:(NSURL *)url placeholder:(UIImage *)placeholder {
+    self.image = placeholder;
+    [_scaledImage removeObserver:self context:&KVOContext];
+    OGImageProcessingScaleMethod scaleMethod = OGImageProcessingScale_AspectFill;
+    if (UIViewContentModeScaleAspectFit == self.contentMode) {
+        scaleMethod = OGImageProcessingScale_AspectFit;
+    }
+    _scaledImage = [[OGScaledImage alloc] initWithURL:url size:self.bounds.size cornerRadius:0.f method:scaleMethod key:nil placeholderImage:nil];
+    [_scaledImage addObserver:self context:&KVOContext];
+    if (nil != _scaledImage.scaledImage) {
+        self.image = _scaledImage.scaledImage;
+    }
+}
+
+#pragma mark KVO
+
+- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
+    if (((void *)&KVOContext) == context) {
+        if ([@"scaledImage" isEqualToString:keyPath]) {
+            self.image = _scaledImage.scaledImage;
+        } else if ([@"error" isEqualToString:keyPath]) {
+            [self willChangeValueForKey:@"imageError"];
+            _imageError = _scaledImage.error;
+            [self didChangeValueForKey:@"imageError"];
+        }
+    } else {
+        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
+    }
+}
+
+- (void)dealloc {
+    [_scaledImage removeObserver:self context:&KVOContext];
+}
+
+@end

OGImage/OGScaledImage.m

@@ -8,8 +8,8 @@
 #import "OGScaledImage.h"
 #import "OGImageCache.h"
 
-NSString *OGKeyWithSize(NSString *origKey, CGSize size, CGFloat cornerRadius) {
-    return [NSString stringWithFormat:@"%@-%f-%f-%f", origKey, size.width, size.height, cornerRadius];
+NSString *OGKeyWithSize(NSString *origKey, CGSize size, CGFloat cornerRadius, OGImageProcessingScaleMethod method) {
+    return [NSString stringWithFormat:@"%@-%f-%f-%f-%ld", origKey, size.width, size.height, cornerRadius, (long)method];
 }
 
 @implementation OGScaledImage {
@@ -45,7 +45,7 @@ - (id)initWithURL:(NSURL *)url size:(CGSize)size cornerRadius:(CGFloat)cornerRad
         self.scaledImage = placeholderImage;
         _scaledSize = size;
         _cornerRadius = cornerRadius;
-        _scaledKey = OGKeyWithSize(self.key, _scaledSize, _cornerRadius);
+        _scaledKey = OGKeyWithSize(self.key, _scaledSize, _cornerRadius, method);
         [self loadImageFromURL];
     }
     return self;

OGImage/__OGImage.h

@@ -18,16 +18,17 @@
  *
  * When you create an __OGImage with a fileURL or NSData instance, it uses the
  * Image I/O framework under the hood to find out about the file's format, metadata
- * and alpha. Additionally, if the file ends with the extension `.@2x`, __OGImage
- * will set UIImage's `scale` property correctly.
+ * and alpha. Additionally, if the file ends with an extension like `.@2x`,
+ * __OGImage will set UIImage's `scale` property correctly.
  *
  * When you save an __OGImage using `writeToURL`, it will automatically choose
  * the best format based on the current alpha properties and original file format.
- * Additionally, if the superclass' property `scale` is `2.f`, `writeToURL` will
- * automatically append the `.@2x` suffix. (Ultimately, this `.@2x` stuff is
- * an implementation detail: If you're not worried about cache internals, you
- * don't need to worry about this. Just use keys normally and `__OGImage` and
- * friends will figure everything out for you.
+ * Additionally, if the superclass' property `scale` is > 1, `writeToURL` will
+ * automatically append a resolution suffix like `.@2x`.
+ * 
+ * (Ultimately, this `.@2x` stuff is an implementation detail: If you're not
+ * worried about cache internals, you don't need to worry about this. Just use
+ * keys normally and `__OGImage` and friends will figure everything out for you.
  */
 
 @interface __OGImage : UIImage

OGImage/__OGImage.m

@@ -35,17 +35,39 @@ UIImageOrientation OGEXIFOrientationToUIImageOrientation(NSInteger exif) {
     }
 }
 
+NSString *OGResolutionSuffixForScale(CGFloat scale) {
+  return [NSString stringWithFormat:@"@%.0fx", scale];
+}
+
 @implementation __OGImage
 
 - (id)initWithDataAtURL:(NSURL *)url {
     CGFloat scale = 1.f;
     if (NO == [[NSFileManager defaultManager] fileExistsAtPath:[url path]]) {
-        url = [url URLByAppendingPathExtension:@"@2x"];
-        if (NO == [[NSFileManager defaultManager] fileExistsAtPath:[url path]]) {
-            // no such file
+        // handling of scaled images is still limited, but at a practical level, the odds of seeing scale factors > 10 seem pretty long
+        // try to optimize by starting with screen rez of device
+        // possible that directory enumeration might be faster? but generally, hard to prove the negative proposition that there's no file
+        scale = [[UIScreen mainScreen] scale];
+        NSURL *scaledURL = [url URLByAppendingPathExtension:OGResolutionSuffixForScale(scale)];
+        if (YES == [[NSFileManager defaultManager] fileExistsAtPath:[scaledURL path]]) {
+            url = scaledURL;
+        }
+        else {
+            // no file at the device resolution; try others
+            // ??? or should we refuse to load images at mis-matched rez?
+            for (scale = 2.f; scale < 11.f; ++scale) {
+                if( scale != [[UIScreen mainScreen] scale] ) {
+                    scaledURL = [url URLByAppendingPathExtension:OGResolutionSuffixForScale(scale)];
+                    if (YES == [[NSFileManager defaultManager] fileExistsAtPath:[scaledURL path]]) {
+                        url = scaledURL;
+                        break;
+                    }
+                }
+            }
+        }
+        if( url != scaledURL ) {
             return nil;
         }
-        scale = 2.f;
     }
     NSData *data = [NSData dataWithContentsOfURL:url];
     return [self initWithData:data scale:scale];
@@ -89,8 +111,7 @@ - (id)initWithData:(NSData *)data scale:(CGFloat)scale {
             // do we have an OGImageDictionary?
             _originalFileType = (__bridge NSString *)CGImageSourceGetType(imageSource);
             _originalFileAlphaInfo = CGImageGetAlphaInfo(cgImage);
-            NSDictionary *propDict = CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL));
-            _originalFileOrientation = [propDict[(__bridge NSString *)kCGImagePropertyOrientation] integerValue];
+            _originalFileOrientation = [_originalFileProperties[(__bridge NSString *)kCGImagePropertyOrientation] integerValue];
             self = [super initWithCGImage:cgImage scale:scale orientation:OGEXIFOrientationToUIImageOrientation(_originalFileOrientation)];
             CGImageRelease(cgImage);
         }
@@ -115,8 +136,8 @@ - (BOOL)writeToURL:(NSURL *)fileURL error:(NSError **)error {
             imgType = @"public.jpeg";
         }
     }
-    if (2.f == self.scale) {
-        fileURL = [fileURL URLByAppendingPathExtension:@"@2x"];
+    if (1.f < self.scale) {
+        fileURL = [fileURL URLByAppendingPathExtension:OGResolutionSuffixForScale(self.scale)];
     }
     CGImageDestinationRef imageDestination = CGImageDestinationCreateWithURL((__bridge CFURLRef)fileURL, (__bridge CFStringRef)imgType, 1, NULL);
     if (NULL == imageDestination) {