Add iOS implementation

RNImageResizer/ImageResizerModule.m

@@ -0,0 +1,83 @@
+//
+//  ImageResize.m
+//  ChoozItApp
+//
+//  Created by Florian Rival on 19/11/15.
+//
+
+#import <AssetsLibrary/AssetsLibrary.h>
+#import "RCTBridgeModule.h"
+#include "ImageHelpers.h"
+
+@interface ImageResizerModule : NSObject <RCTBridgeModule>
+@end
+
+@implementation ImageResizerModule
+
+RCT_EXPORT_MODULE();
+
+void saveImage(NSString * fullPath, UIImage * image, float quality)
+{
+  NSData* data = UIImageJPEGRepresentation(image, quality / 100.0);
+  NSFileManager* fileManager = [NSFileManager defaultManager];
+  [fileManager createFileAtPath:fullPath contents:data attributes:nil];
+}
+
+NSString * generateCacheFilePath(NSString * ext)
+{
+  NSArray* paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
+  NSString* cacheDirectory = [paths firstObject];
+  NSString* name = [[NSUUID UUID] UUIDString];
+  NSString* fullName = [NSString stringWithFormat:@"%@.%@", name, ext];
+  NSString* fullPath = [cacheDirectory stringByAppendingPathComponent:fullName];
+
+  return fullPath;
+}
+
+RCT_EXPORT_METHOD(createResizedImage:(NSString *)path width:(float)width height:(float)height quality:(float)quality callback:(RCTResponseSenderBlock)callback)
+{
+  CGSize newSize = CGSizeMake(width, height);
+  NSString* fullPath = generateCacheFilePath(@".jpg");
+
+  NSURL* url = [NSURL URLWithString:path];
+  if ([[url scheme] isEqualToString:@"assets-library"]) {
+    ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
+
+    // Ask for the "Asset" for the URL. An asset is a representation of an image in the Photo application.
+    [library assetForURL:url resultBlock:^(ALAsset *asset) {
+        // Here, we have the asset, let's retrieve the image from it
+        CGImageRef imgRef = [[asset defaultRepresentation] fullResolutionImage];
+        UIImage * image = [UIImage imageWithCGImage:imgRef];
+
+        //Do the resizing
+        UIImage * scaledImage = [image scaleToSize:newSize];
+        if (scaledImage == nil) {
+          callback(@[@"Can't resize the image.", @""]);
+          return;
+        }
+
+        saveImage(fullPath, scaledImage, quality);
+        callback(@[[NSNull null], fullPath]);
+      } failureBlock:^(NSError *error) {
+        callback(@[@"Can't retrieve the file from assets library.", @""]);
+      }];
+  } else {
+    //Get the image from its path
+    UIImage* image = [[UIImage alloc] initWithContentsOfFile:path];
+    if (image == nil) {
+      callback(@[@"Can't retrieve the file from the path.", @""]);
+      return;
+    }
+
+    //Do the resizing
+    UIImage * scaledImage = [image scaleToSize:newSize];
+    if (scaledImage == nil) {
+      callback(@[@"Can't resize the image.", @""]);
+      return;
+    }
+
+    saveImage(fullPath, scaledImage, quality);
+    callback(@[[NSNull null], fullPath]);
+  }
+}
+@end