当应用过滤器时释放CGDataProviderWithCopyOfData

Question

我有一种应用色调效果过滤器并创建CGBitmapContext的方法。每次用户点击过滤器的按钮时，都会增加内存，并且内存不会被ARC释放。它每次增加600KB。我已经做了一些研究，发现仪器分配，核心图形增加600KB上CGDataProviderWithCopyOfData。我怎样才能释放这个CGRaster数据？

这里是方法：

-(UIImage *)modifyImageTintColor:(UIImage *)source imageRawData:(Byte *)rawData degree:(int)degree{ 

double PI = 3.14159; 
double HALF_CIRCLE_DEGREE = 180; 
double RANGE = 256; 

int RY, GY, BY, RYY, GYY, BYY, R, G, B, Y; 
double angle = (PI * (double)degree)/HALF_CIRCLE_DEGREE; 

int S = (int)(RANGE * sin(angle)); 
int C = (int)(RANGE * cos(angle)); 

CGFloat r, g, b; 
//apply sepia effect 

int byteIndex = 0; 
for(int i = 0; i < _imageWidth * _imageHeight; ++i){ 

    r = rawData[byteIndex]; 
    g = rawData[byteIndex + 1]; 
    b = rawData[byteIndex + 2]; 

    RY = (70 * r - 59 * g - 11 * b)/100; 
    GY = (-30 * r + 41 * g - 11 * b)/100; 
    BY = (-30 * r - 59 * g + 89 * b)/100; 
    Y = (30 * r + 59 * g + 11 * b)/100; 
    RYY = (S * BY + C * RY)/256; 
    BYY = (C * BY - S * RY)/256; 
    GYY = (-51 * RYY - 19 * BYY)/100; 
    R = Y + RYY; 
    R = (R < 0) ? 0 : ((R > 255) ? 255 : R); 
    G = Y + GYY; 
    G = (G < 0) ? 0 : ((G > 255) ? 255 : G); 
    B = Y + BYY; 
    B = (B < 0) ? 0 : ((B > 255) ? 255 : B); 

    rawData[byteIndex] = R; 
    rawData[byteIndex + 1] = G; 
    rawData[byteIndex + 2] = B; 

    byteIndex += 4; 


} 

NSUInteger bytesPerPixel = 4; 
NSUInteger bytesPerRow = bytesPerPixel * _imageWidth; 
NSUInteger bitsPerComponent = 8; 
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
CGImageRef imageRef; 

CGContextRef ctx; 
ctx = CGBitmapContextCreate(rawData, 
          _imageWidth, 
          _imageHeight, 
          bitsPerComponent, 
          bytesPerRow, 
          colorSpace, 
          kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big); 

imageRef = CGBitmapContextCreateImage(ctx); 
UIImage *result = [UIImage imageWithCGImage:imageRef]; 
CGContextRelease(ctx); 
CGColorSpaceRelease(colorSpace); 
CFRelease(ctx); 

return result; 

}

Answer 1

你需要调用CFRelease上imageRef这样的：

imageRef = CGBitmapContextCreateImage(ctx); 
UIImage *result = [UIImage imageWithCGImage:imageRef]; 
CFRelease (imageRef); 
CGContextRelease(ctx); 
CGColorSpaceRelease(colorSpace); 
CFRelease(ctx); 

此外，它可以看起来更整洁（和可读性更强）以总是使用CFRelease代替这样的定制版本：

imageRef = CGBitmapContextCreateImage(ctx); 
UIImage *result = [UIImage imageWithCGImage:imageRef]; 
CFRelease (imageRef); 
CGRelease(ctx); 
CGRelease(colorSpace); 
CFRelease(ctx);