如何在 iOS 上将 cvMat 保存到 CoreData 中？

发布于 2024-11-03 18:30:06 字数 1374 浏览 0 评论 0原文

我在我的项目中使用 CoreData。我可以通过在我的项目中使用 UIImageToDataTransformer 类来保存 UIImage。另外，我正在使用 opencv 库，我需要保存一些 cvMat 结构（它们是结构，对吧？）。我读过一些关于可转换的文章，但仍然不知道如何将其保存在 coredata 中并取回。

我有一个名为“Human”的实体，它有一个名为 ProjVal 的属性，其类型是可转换的，它保存 cvMat 的数据。

我的下一步应该是什么？

下面是 UIImage 的转换器类，但如何转换 cvMat 的数据？感谢您的建议。

#import "UIImageToDataTransformer.h"
@implementation UIImageToDataTransformer

+ (BOOL)allowsReverseTransformation {
    return YES;
}

+ (Class)transformedValueClass {
    return [NSData class];
}

- (id)transformedValue:(id)value {
    return UIImagePNGRepresentation(value);
}

- (id)reverseTransformedValue:(id)value {
    return [[[UIImage alloc] initWithData:value] autorelease];
}
@end

编辑：使用其类型作为二进制数据类型而不是可转换类型是更好的方法吗？我为我的实体使用自动创建的类。

使用这段代码

CvMat *mat = cvCreateMat(3, 3, CV_32FC1);
for (int i=0; i<9; i++) {
    mat->data.fl[i] = 1.0f;
}


NSData *projValData = [[NSData alloc] initWithBytes:&mat length:sizeof(mat)];
human.projVal = projValData;

我在保存和读回时

CvMat *mat;
NSData *data =  [[humansArray objectAtIndex:0] projVal];
memcpy(&mat,[data bytes],[data length]);
if (mat) {
    NSLog(@"if mat works");
    for (int i=0; i<9; i++) {
        NSLog(@"%f",mat->data.fl[i]);
    }
}

：它不能很好地工作并且在 for 循环中崩溃。我的错误在哪里？

原文

I am using CoreData in my project. I can save UIImage by using UIImageToDataTransformer class in my project. Also I am using opencv library and I need to save some cvMat struct (they are structs, right?). I have read some posts about transformable but still cant figure out how to save it in coredata and fetch it back.

I have one entity called "Human" and it has a attribute called ProjVal and its type is transformable which holds data of cvMat.

What should my next step be?

Below its the transformer class for UIImage but how can I transform cvMat's data? Thank for your advices.

#import "UIImageToDataTransformer.h"
@implementation UIImageToDataTransformer

+ (BOOL)allowsReverseTransformation {
    return YES;
}

+ (Class)transformedValueClass {
    return [NSData class];
}

- (id)transformedValue:(id)value {
    return UIImagePNGRepresentation(value);
}

- (id)reverseTransformedValue:(id)value {
    return [[[UIImage alloc] initWithData:value] autorelease];
}
@end

Edit: Is it a better way to use its type as Binary Data type instead Transformable type? Im using auto-created classes for my entities.

I use this code while saving

CvMat *mat = cvCreateMat(3, 3, CV_32FC1);
for (int i=0; i<9; i++) {
    mat->data.fl[i] = 1.0f;
}


NSData *projValData = [[NSData alloc] initWithBytes:&mat length:sizeof(mat)];
human.projVal = projValData;

and while reading it back:

CvMat *mat;
NSData *data =  [[humansArray objectAtIndex:0] projVal];
memcpy(&mat,[data bytes],[data length]);
if (mat) {
    NSLog(@"if mat works");
    for (int i=0; i<9; i++) {
        NSLog(@"%f",mat->data.fl[i]);
    }
}

it doesnt work well and crashed in for loop. Where is my mistake?

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