Cocoa 创建不需要的分配/未能释放分配

我在释放分配时遇到问题。我的仪器中的分配工具指示bitmapData=malloc bitmapByteCount；是分配的来源，并且它没有被释放。我不熟悉cocoa和xcode。如何纠正此问题并防止下面的代码使用越来越多的内存？我感谢你的帮助。谢谢

#import "imagewell.h"

@implementation imagewell

- (id)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code here.



        NSString *path =@"/Users/ethansanford/Desktop/mutable string logic/mutable string logic/long-arrow-right.png" ;
        CGDataProviderRef provider = CGDataProviderCreateWithFilename(path.fileSystemRepresentation);
        imageRef2 =CGImageCreateWithPNGDataProvider(provider, NULL, false, kCGRenderingIntentDefault);
        CGDataProviderRelease(provider);


    }
    return self;
}


-(void)mouseDown:(NSEvent *)theEvent{

    NSPoint point = [theEvent locationInWindow];//where image was tapped
    [self convertPoint:point fromView:nil];
    clicks = clicks+ 1;
    colorpt=[self getPixelColorAtLocation:point];
    [self SetPixelColorAtLocation:point withColor:[NSColor redColor]];

    NSPoint pointz = NSPointFromCGPoint(CGPointMake(200, 100));




    [self setNeedsDisplay:YES];

}

- (void)drawRect:(NSRect)dirtyRect{

      CGContextRef myContext;
    myContext = [NSGraphicsContext.currentContext graphicsPort];

    imageRef = imageRef2;
   // NSLog(@"%@ %zu",@"height",CGImageGetHeight(imageRef));
        NSLog(@" %@ %f %f %f %f ", @"color1 argb", colorpt.alphaComponent*255, colorpt.redComponent*255, colorpt.greenComponent*255, colorpt.blueComponent*255);
    CGContextSetFillColorWithColor(myContext, colorpt.CGColor);
    CGRect rectangle = CGRectMake(0,0, 100, 100);
    CGContextFillRect(myContext,rectangle);
    CGContextDrawImage(myContext, dirtyRect, imageRef);


}


- (NSColor*) getPixelColorAtLocation:(NSPoint)point {
    NSColor* color1 = nil;



    // Create off screen bitmap context to draw the image into. Format ARGB is 4 bytes for each pixel: Alpa, Red, Green, Blue
    CGContextRef cgctx = [self createARGBBitmapContextFromImage:imageRef];
    if (cgctx == NULL) { return nil; /* error */ }

     w = CGImageGetWidth(imageRef);
    size_t h = CGImageGetHeight(imageRef);
    CGRect rect = {{0,0},{w,h}};

    // Draw the image to the bitmap context. Once we draw, the memory
    // allocated for the context for rendering will then contain the
    // raw image data in the specified color space.
    CGContextDrawImage(cgctx, rect, imageRef);

    // Now we can get a pointer to the image data associated with the bitmap
    // context.


    data = CGBitmapContextGetData (cgctx);
    bitmap_info_of_context = CGBitmapContextGetBitmapInfo(cgctx);
    bits_per_component_of_context = CGBitmapContextGetBitsPerPixel(cgctx);
    bytes_per_row_of_context = CGBitmapContextGetBytesPerRow(cgctx);
    width_of_context = CGImageGetWidth(imageRef);
    height_of_context = CGImageGetHeight(imageRef);



    if (data != NULL) {
        //pos_in_array locates the pixel in the data from x,y.
        //4 for 4 bytes of data per pixel, w is width of one row of data.
        int pos_in_array = 4*((w*round(point.y))+round(point.x));
        int alpha =  data[pos_in_array];
        int red = data[pos_in_array+1];
        int green = data[pos_in_array+2];
        int blue = data[pos_in_array+3];
        //NSLog(@"pos_in_array: %i colors: RGB A %i %i %i  %i",pos_in_array,red,green,blue,alpha);
        color1 = [NSColor colorWithCalibratedRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];
    }

    // When finished, release the context
    CGContextRelease(cgctx);
    // Free image data memory for the context



    return color1;
}



- (CGContextRef) createARGBBitmapContextFromImage:(CGImageRef) imageRef {


    CGContextRef    context = NULL;
    CGColorSpaceRef colorSpace;
    void *          bitmapData;
    int             bitmapByteCount;
    int             bitmapBytesPerRow;

    // Get image width, height. We'll use the entire image.
    size_t pixelsWide = CGImageGetWidth(imageRef);
    size_t pixelsHigh = CGImageGetHeight(imageRef);

    // Declare the number of bytes per row. Each pixel in the bitmap in this
    // example is represented by 4 bytes; 8 bits each of red, green, blue, and
    // alpha.
    bitmapBytesPerRow   = (pixelsWide * 4);
    bitmapByteCount     = (bitmapBytesPerRow * pixelsHigh);

    // Use the generic RGB color space.
    colorSpace = CGColorSpaceCreateDeviceRGB();

    if (colorSpace == NULL)
    {
        fprintf(stderr, "Error allocating color space\n");
        return NULL;
    }

    // Allocate memory for image data. This is the destination in memory
    // where any drawing to the bitmap context will be rendered.
        bitmapData = malloc( bitmapByteCount );



    if (bitmapData == NULL)
    {
        NSLog(@"%@", @"shit");
        CGColorSpaceRelease( colorSpace );
        return NULL;
    }

    // Create the bitmap context. We want pre-multiplied ARGB, 8-bits
    // per component. Regardless of what the source image format is
    // (CMYK, Grayscale, and so on) it will be converted over to the format
    // specified here by CGBitmapContextCreate.
    context = CGBitmapContextCreate (bitmapData,
                                     pixelsWide,
                                     pixelsHigh,
                                     8,      // bits per component
                                     bitmapBytesPerRow,
                                     colorSpace,
                                     (CGBitmapInfo)kCGImageAlphaPremultipliedFirst);
    if (context == NULL)
    {

        fprintf (stderr, "Context not created!");
    }

    // Make sure and release colorspace before returning
    CGColorSpaceRelease( colorSpace );

    return context;
    CGContextRelease(context);






}

-(void)SetPixelColorAtLocation:(CGPoint)location withColor:(NSColor*)replacement{

    if (data != NULL) {
        //pos_in_array locates the pixel in the data from x,y.
        //4 for 4 bytes of data per pixel, w is width of one row of data.
        int pos_in_array = 4*((w*round(location.y))+round(location.x));
        data[pos_in_array]= 255;
        data[pos_in_array+1] = 0;
        data[pos_in_array+2] = 255;
        data[pos_in_array+3] = 0;
        //NSLog(@"it happened");


        CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
        CGContextRef context=  CGBitmapContextCreate(data, width_of_context, height_of_context, 8, bytes_per_row_of_context, colorspace, (CGBitmapInfo)kCGImageAlphaPremultipliedFirst);

        imageRef2 = CGBitmapContextCreateImage(context);

        CGColorSpaceRelease(colorspace);
        CGContextRelease(context);
    }

}



@end

如果您使用malloc内存，您通常负责后者调用free来释放它。但是，从CGBitmapContextCreate的文档中可以看出：

在iOS 4.0及更高版本和OS X v10.6及更高版本中，如果希望Quartz为位图分配内存，则可以传递NULL。这将使您从管理自己的内存中解放出来，从而减少内存泄漏问题

因此，在这种情况下，您应该能够删除malloc并传递NULL

---

HTH

我未能释放CGImage对象。 释放它可以防止泄漏。 我现在避免了可以在多种方法中使用的全局变量