标签: cgbitmapcontextcreate

好吧,我有一个难以追踪内存泄漏的世界.运行此脚本时,我没有看到任何内存泄漏,但我的objectalloc正在攀爬.Instruments指向CGBitmapContextCreateImage> create_bitmap_data_provider> malloc,这占我的objectalloc的60%.

使用NSTimer多次调用此代码.

 //GET IMAGE FROM RESOURCE DIR
  NSString * fileLocation = [[NSBundle mainBundle] pathForResource:imgMain ofType:@"jpg"];
  NSData * imageData = [NSData dataWithContentsOfFile:fileLocation];
  UIImage * blurMe = [UIImage imageWithData:imageData];

  NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    UIImage * scaledImage = [blurMe _imageScaledToSize:CGSizeMake(blurMe.size.width / dblBlurLevel, blurMe.size.width / dblBlurLevel) interpolationQuality:3.0];
    UIImage * labelImage = [scaledImage _imageScaledToSize:blurMe.size interpolationQuality:3.0];
    UIImage * imageCopy = [[UIImage alloc] initWithCGImage:labelImage.CGImage];

  [pool drain]; // deallocates scaledImage and labelImage

  imgView.image = imageCopy;
  [imageCopy release];

下面是模糊功能.我相信objectalloc问题位于此处.也许我只需要一双新鲜的眼睛.如果有人能想到这一点会很棒.对不起它有点长......我会试着缩短它.

    @implementation UIImage(Blur)
    - (UIImage *)blurredCopy:(int)pixelRadius …

我已经在这几个小时了,甚至不知道如何调试这个错误.也许有一位SO专家知道发生了什么.

- (void) prepareSubset {

CGSize size = [image size];

float scale = fminf(1.0f, fmaxf(SUBSET_SIZE / cropRect.size.width, SUBSET_SIZE / cropRect.size.height));
CGPoint offset = CGPointMake(-cropRect.origin.x, -cropRect.origin.y);

subsetWidth = cropRect.size.width * scale;
subsetHeight = cropRect.size.height * scale;

subsetBytesPerRow = ((subsetWidth + 0xf) >> 4) << 4;
subsetData = (unsigned char *)malloc(subsetBytesPerRow * subsetHeight);

CGColorSpaceRef grayColorSpace = CGColorSpaceCreateDeviceGray();

CGContextRef ctx = CGBitmapContextCreate(subsetData, subsetWidth, subsetHeight, 8, subsetBytesPerRow, grayColorSpace, kCGImageAlphaNone);
CGColorSpaceRelease(grayColorSpace);
CGContextSetInterpolationQuality(ctx, kCGInterpolationNone);
CGContextSetAllowsAntialiasing(ctx, false);

CGContextTranslateCTM(ctx, 0.0, subsetHeight);
CGContextScaleCTM(ctx, 1.0, -1.0);  

UIGraphicsPushContext(ctx);
CGRect rect = …

我不确定我是否理解如何释放位图上下文.

我正在做以下事情:

CGContextRef context = CGBitmapContextCreate(nil, size.width, size.height, 8, 0, CGColorSpaceCreateDeviceRGB(), kCGBitmapAlphaInfoMask);
.
. // (All straightforward code)
. 
CGContextRelease(context);

Xcode Analyze仍然在CGBitmapContextCreate行上给我一个"潜在的内存泄漏".

我究竟做错了什么？

我正在寻找一种方法来优化图像，将其颜色从 32 位转换为 16 位，而不仅仅是调整其大小。这就是我正在做的：

- (UIImage *)optimizeImage:(UIImage *)image
{
    float newWidth = image.size.width;
    float newHeight = image.size.height;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(NULL, newWidth, newHeight, 5, newWidth * 4,
                                                 colorSpace, kCGImageAlphaNone | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);

    CGInterpolationQuality quality = kCGInterpolationHigh;
    CGContextSetInterpolationQuality(context, quality);

    CGImageRef srcImage = CGImageRetain(image.CGImage);

    CGContextDrawImage(context, CGRectMake(0, 0, newWidth, newHeight),
                       srcImage);
    CGImageRelease(srcImage);
    CGImageRef dst = CGBitmapContextCreateImage(context);
    CGContextRelease(context);

    UIImage *result = [UIImage imageWithCGImage:dst];
    CGImageRelease(dst);

    UIGraphicsEndImageContext();

    return result;
}

这段代码的问题是，当我运行它时，我收到以下错误：

CGBitmapContextCreate：不支持的参数组合：5 个整数位/组件；16 位/像素；三分量色彩空间；kCGImageAlphaNone; 10392 字节/行。

所以我的问题是：支持的组合是什么CGBitmapContextCreate？这种情况下参数应该选择什么bitmapInfo？请建议。

我写了这段代码:

 bitmapData = calloc(1, bitmapByteCount );
 context = CGBitmapContextCreate (bitmapData,
                                 pixelsWide,
                                 pixelsHigh,
                                 8,
                                 bitmapBytesPerRow,
                                 colorSpace,
                                 kCGImageAlphaOnly);

当我这样做时,CGBitmapContext是复制我的bitmapData,所以在这些行后我应该写

free(bitmapData);