react-native/Libraries/Image/RCTImageEditingManager.m

125 lines
4.0 KiB
Objective-C

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
#import "RCTImageEditingManager.h"
#import <UIKit/UIKit.h>
#import "RCTConvert.h"
#import "RCTLog.h"
#import "RCTUtils.h"
#import "RCTImageStoreManager.h"
#import "RCTImageLoader.h"
@implementation RCTImageEditingManager
RCT_EXPORT_MODULE()
@synthesize bridge = _bridge;
/**
* Crops an image and adds the result to the image store.
*
* @param imageTag A URL, a string identifying an asset etc.
* @param cropData Dictionary with `offset`, `size` and `displaySize`.
* `offset` and `size` are relative to the full-resolution image size.
* `displaySize` is an optimization - if specified, the image will
* be scaled down to `displaySize` rather than `size`.
* All units are in px (not points).
*/
RCT_EXPORT_METHOD(cropImage:(NSString *)imageTag
cropData:(NSDictionary *)cropData
successCallback:(RCTResponseSenderBlock)successCallback
errorCallback:(RCTResponseErrorBlock)errorCallback)
{
CGRect rect = {
[RCTConvert CGPoint:cropData[@"offset"]],
[RCTConvert CGSize:cropData[@"size"]]
};
NSString *resizeMode = cropData[@"resizeMode"] ?: @"contain";
[_bridge.imageLoader loadImageWithTag:imageTag callback:^(NSError *error, UIImage *image) {
if (error) {
errorCallback(error);
return;
}
// Crop image
CGRect rectToDrawIn = {{-rect.origin.x, -rect.origin.y}, image.size};
UIGraphicsBeginImageContextWithOptions(rect.size, !RCTImageHasAlpha(image.CGImage), image.scale);
[image drawInRect:rectToDrawIn];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if (cropData[@"displaySize"]) {
CGSize targetSize = [RCTConvert CGSize:cropData[@"displaySize"]];
croppedImage = [self scaleImage:croppedImage targetSize:targetSize resizeMode:resizeMode];
}
[_bridge.imageStoreManager storeImage:croppedImage withBlock:^(NSString *croppedImageTag) {
if (!croppedImageTag) {
NSString *errorMessage = @"Error storing cropped image in RCTImageStoreManager";
RCTLogWarn(@"%@", errorMessage);
errorCallback(RCTErrorWithMessage(errorMessage));
return;
}
successCallback(@[croppedImageTag]);
}];
}];
}
- (UIImage *)scaleImage:(UIImage *)image targetSize:(CGSize)targetSize resizeMode:(NSString *)resizeMode
{
if (CGSizeEqualToSize(image.size, targetSize)) {
return image;
}
CGFloat imageRatio = image.size.width / image.size.height;
CGFloat targetRatio = targetSize.width / targetSize.height;
CGFloat newWidth = targetSize.width;
CGFloat newHeight = targetSize.height;
// contain vs cover
// http://blog.vjeux.com/2013/image/css-container-and-cover.html
if ([resizeMode isEqualToString:@"contain"]) {
if (imageRatio <= targetRatio) {
newWidth = targetSize.height * imageRatio;
newHeight = targetSize.height;
} else {
newWidth = targetSize.width;
newHeight = targetSize.width / imageRatio;
}
} else if ([resizeMode isEqualToString:@"cover"]) {
if (imageRatio <= targetRatio) {
newWidth = targetSize.width;
newHeight = targetSize.width / imageRatio;
} else {
newWidth = targetSize.height * imageRatio;
newHeight = targetSize.height;
}
} // else assume we're stretching the image
// prevent upscaling
newWidth = MIN(newWidth, image.size.width);
newHeight = MIN(newHeight, image.size.height);
// perform the scaling @1x because targetSize is in actual pixel width/height
UIGraphicsBeginImageContextWithOptions(targetSize, NO, 1.0f);
[image drawInRect:CGRectMake(0.f, 0.f, newWidth, newHeight)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return scaledImage;
}
@end