Xcode [noob] 释放对象，因为内存和 CPU 负载

Posted 2023-03-15

【中文标题】Xcode [noob] 释放对象，因为内存和 CPU 负载

【英文标题】：Xcode [noob] Release of objects, because of memory and CPU load

【发布时间】：2015-01-10 09:46:35

【问题描述】：

作为一名 c# unity 和 php 程序员，我完全是 Objective-c 的菜鸟。我设法将一个项目与cordoba-phonegap-objective C一起复制粘贴，以制作一个项目，其基本概念是一个类似于应用程序的镜像（具有各种额外的，仍需编程）..镜像工作，但在xcode中cpu和内存的负载不断增加，最后崩溃..当我搜索时，我认为我犯了一个错误，没有释放对象，但这是一个幸运的猜测..我希望你能帮助我......

#import "CanvasCamera.h"
@implementation CanvasCamera
- (void)startCapture:(CDVInvokedUrlCommand*)command

self.session = [[AVCaptureSession alloc] init];
self.session.sessionPreset = AVCaptureSessionPreset352x288;
self.device = [self frontCamera];
self.input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

self.output = [[AVCaptureVideoDataOutput alloc] init];
self.output.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];

dispatch_queue_t queue;
queue = dispatch_queue_create("canvas_camera_queue", NULL);
[self.output setSampleBufferDelegate:(id)self queue:queue];
[self.session addInput:self.input];
[self.session addOutput:self.output];
[self.session startRunning];


- (AVCaptureDevice *)frontCamera 
 NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice *device in devices) 
    if ([device position] == AVCaptureDevicePositionFront) 
        return device;
    

return nil;



- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection

CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer,0);
uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef newContext = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);

CGImageRef newImage = CGBitmapContextCreateImage(newContext);
CGContextRelease(newContext);
CGColorSpaceRelease(colorSpace);
UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 orientation:UIImageOrientationUp];
NSData *imageData = UIImageJPEGRepresentation(image, 1.0);
NSString *encodedString = [imageData base64Encoding];

NSString *javascript = @"CanvasCamera.capture('data:image/jpeg;base64,";
javascript = [javascript stringByAppendingString:encodedString];
javascript = [javascript stringByAppendingString:@"');"];
[self.webView performSelectorOnMainThread:@selector(stringByEvaluatingJavaScriptFromString:) withObject:javascript waitUntilDone:YES];

CGImageRelease(newImage);
CVPixelBufferUnlockBaseAddress(imageBuffer,0);

@end

【参考方案1】：

查看您对 NSAutoreleasepool 的使用，查看 Objective C 的自动引用计数和this documentation from Apple。

【讨论】：

我不明白整个 NSAutoreleasepool 的概念...我尝试了几件事 ..但它对我来说仍然是 abracadabra...你能帮我解释一下我的代码吗？跨度>