Ios 将UIImage转换为二进制，接收EXC\u BAD\u访问

我正在使用source from向用户展示一个视图，用户可以在其中签名。然后我将签名的图像发送到Heroku上运行的服务器。这在模拟器中运行良好。当我在实际设备（iPad）上测试时，应用程序会在以下行崩溃：

UIImagePNGRepresentation（signature）

处理签名提交的控制器方法： （signatureView是从前面提到的github repo下载的NISignatureView的一个实例）

NISignatureView的getSignatureImage方法：

- (UIImage *)getSignatureImage {
if (!self.drawnSignature)
    return nil;

CGFloat width = self.frame.size.width;
CGFloat height = self.frame.size.height;
NSInteger myDataLength = width * height * 4;

// allocate array and read pixels into it.
GLubyte *buffer = (GLubyte *) malloc(myDataLength);
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

// gl renders "upside down" so swap top to bottom into new array.
// there's gotta be a better way, but this works.
GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);
for (int y = 0; y < height; y++) {
    for (int x = 0; x < width * 4; x++) {
        buffer2[(((int) height - 1) - y) * (int) width * 4 + x] = buffer[y * 4 * (int) width + x];
    }
}

// make data provider with data.
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer2, myDataLength, NULL);

// prep the ingredients
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

// make the cgimage
CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);

// then make the uiimage from that
UIImage *myImage = [[UIImage alloc] initWithCGImage:imageRef];

// release memory
CGImageRelease(imageRef);
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
free(buffer);
free(buffer2);

return myImage;

-（UIImage*）getSignatureImage{
如果（！自身图纸签名）
返回零；
CGFloat width=self.frame.size.width；
CGFloat高度=self.frame.size.height；
NSInteger myDataLength=宽度*高度*4；
//分配数组并将像素读入其中。
GLubyte*buffer=（GLubyte*）malloc（myDataLength）；
glReadPixels（0，0，宽度，高度，GL_RGBA，GL_无符号字节，缓冲区）；
//gl呈现“倒置”，以便从上到下交换到新阵列中。
//肯定有更好的办法，但这是可行的。
GLubyte*buffer2=（GLubyte*）malloc（myDataLength）；
对于（int y=0；y

}

从控制器调用的帮助程序：

- (void)sendSignature:(UIImage *)signature total:(NSNumber *)total orderId:(NSNumber *)orderId authToken:(NSString *)authToken successBlock:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, id JSON))successBlock failureBlock:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON))failureBlock view:(UIView *)view {
    NSData *imageData = UIImagePNGRepresentation(signature);
    MBProgressHUD *submit = [MBProgressHUD showHUDAddedTo:view animated:YES];
    submit.labelText = @"Saving";
    [submit show:NO];
    NSString *url = [NSString stringWithFormat:@"%@?%@=%@", [NSString stringWithFormat:kDBCAPTURESIG([orderId intValue])], kAuthToken, authToken];
    AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:url]];
    [client setParameterEncoding:AFJSONParameterEncoding];
    NSDictionary *parameters = @{@"total" : total};
    NSMutableURLRequest *request = [client multipartFormRequestWithMethod:@"POST" path:@"" parameters:parameters constructingBodyWithBlock:^(id <AFMultipartFormData> formData) {
        [formData appendPartWithFileData:imageData name:@"signature" fileName:@"signature" mimeType:@"image/png"];
    }];
    AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
                                                                                        success:^(NSURLRequest *req, NSHTTPURLResponse *response, id json) {
                                                                                            [submit hide:NO];
                                                                                            if (successBlock) successBlock(req, response, json);
                                                                                        } failure:^(NSURLRequest *req, NSHTTPURLResponse *response, NSError *error, id json) {
                [submit hide:NO];
                if (failureBlock) failureBlock(req, response, error, json);
                NSInteger statusCode = [[[error userInfo] objectForKey:AFNetworkingOperationFailingURLResponseErrorKey] statusCode];
                NSString *alertMessage = [NSString stringWithFormat:@"There was an error processing this request. Status Code: %d", statusCode];
                [[[UIAlertView alloc] initWithTitle:@"Error!" message:alertMessage delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
            }];
    [operation start];
}

-（void）sendSignature:（UIImage*）签名总数：（NSNumber*）orderId:（NSNumber*）orderId authToken:（NSString*）authToken successBlock:（void（^）（NSURLRequest*请求，nshtpurlresponse*响应，id JSON））successBlock failureBlock:（void（^）（NSURLRequest*请求，nshtpurlresponse*响应，NSError*错误，id JSON））failureBlock视图：（UIView*）视图{
NSData*imageData=UIIMAGEPNGRE表示（签名）；
MBProgressHUD*submit=[MBProgressHUD showhuddedto:view animated:YES]；
submit.labelText=@“正在保存”；
[提交节目：否]；
NSString*url=[NSString stringWithFormat:@“%@？%@=%@”，[NSString stringWithFormat:kDBCAPTURESIG（[orderId intValue]），kAuthToken，authToken]；
AFHTTPClient*client=[[AFHTTPClient alloc]initWithBaseURL:[NSURL URLWithString:url]]；
[客户端设置参数编码：afjson参数编码]；
NSDictionary*参数=@{@“总计”：总计}；
NSMutableURLRequest*request=[客户端multipartFormRequestWithMethod:@“POST”路径：@”“参数：参数constructingBodyWithBlock:^（id

更新
应用程序并不是每次都崩溃。崩溃发生在同一行，但只是偶尔发生。我已经更新了描述，以包括NISignatureView的getSignatureImage方法。一些对象在该方法结束时被释放。我想知道这是否与错误的访问错误有关。我很惭愧地说，我还不了解发布并保留。
更新2
我在NISignatureView的NISignatureView属性的
getSignatureImage
中释放或释放对象。将释放/释放逻辑移动到一个单独的方法。在我将图像发送到服务器后调用此方法。这似乎可行。没有遇到崩溃。但我不知道我所做的是正确的方法来解决此问题。签名视图是否需要释放这些对象？在卸载视图时它们不会自动释放吗

- (void)sendSignature:(UIImage *)signature total:(NSNumber *)total orderId:(NSNumber *)orderId authToken:(NSString *)authToken successBlock:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, id JSON))successBlock failureBlock:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON))failureBlock view:(UIView *)view {
    NSData *imageData = UIImagePNGRepresentation(signature);
    MBProgressHUD *submit = [MBProgressHUD showHUDAddedTo:view animated:YES];
    submit.labelText = @"Saving";
    [submit show:NO];
    NSString *url = [NSString stringWithFormat:@"%@?%@=%@", [NSString stringWithFormat:kDBCAPTURESIG([orderId intValue])], kAuthToken, authToken];
    AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:url]];
    [client setParameterEncoding:AFJSONParameterEncoding];
    NSDictionary *parameters = @{@"total" : total};
    NSMutableURLRequest *request = [client multipartFormRequestWithMethod:@"POST" path:@"" parameters:parameters constructingBodyWithBlock:^(id <AFMultipartFormData> formData) {
        [formData appendPartWithFileData:imageData name:@"signature" fileName:@"signature" mimeType:@"image/png"];
    }];
    AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
                                                                                        success:^(NSURLRequest *req, NSHTTPURLResponse *response, id json) {
                                                                                            [submit hide:NO];
                                                                                            if (successBlock) successBlock(req, response, json);
                                                                                        } failure:^(NSURLRequest *req, NSHTTPURLResponse *response, NSError *error, id json) {
                [submit hide:NO];
                if (failureBlock) failureBlock(req, response, error, json);
                NSInteger statusCode = [[[error userInfo] objectForKey:AFNetworkingOperationFailingURLResponseErrorKey] statusCode];
                NSString *alertMessage = [NSString stringWithFormat:@"There was an error processing this request. Status Code: %d", statusCode];
                [[[UIAlertView alloc] initWithTitle:@"Error!" message:alertMessage delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
            }];
    [operation start];
}