ios - QCAR::Image 到 UIImage - CoreGraphics 并保留崩溃

Question

我正在使用 Vuforia，尝试从相机实例获取像素并转换为 UIImage

- (UIImage *)createUIImage:(const QCAR::Image *)qcarImage
{
    int width = qcarImage->getWidth();
    int height = qcarImage->getHeight();
    int bitsPerComponent = 8;
    int bitsPerPixel = QCAR::getBitsPerPixel(QCAR::RGB888);
    int bytesPerRow = qcarImage->getBufferWidth() * bitsPerPixel / bitsPerComponent;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaNone;
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, qcarImage->getPixels(), QCAR::getBufferSize(width, height, QCAR::RGB888), NULL);

    CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
    CGImageRef imageRefRetain = CGImageRetain(imageRef);
    UIImage *image = [UIImage imageWithCGImage:imageRefRetain];

    CGDataProviderRelease(provider);
    CGColorSpaceRelease(colorSpaceRef);
    CGImageRelease(imageRef);

    return image;
}

获取图像后，我将其添加到一个可变数组中。

从可变数组中检索图像后，我在每种方法上都会崩溃即

UIImageView setImage: 

甚至打电话

NSData* comppressedData = UIImageJPEGRepresentation(image,1);

让我的应用程序不崩溃的唯一方法是添加以下内容

- (UIImage *)createUIImage:(const QCAR::Image *)qcarImage
{
    ...
    UIImage *image = [UIImage imageWithCGImage:imageRefRetain];

    CGDataProviderRelease(provider);
    CGColorSpaceRelease(colorSpaceRef);
    CGImageRelease(imageRef);

    NSData* comppressedData = UIImageJPEGRepresentation(image,1);
                    UIImage* jpegImage = [UIImage imageWithData:comppressedData];
    return jpegImage;
}

所以我认为这是与 CGImageRef 发布相关的问题。我真的需要了解发生了什么，以及为什么在存在该方法后图像引用无效。

Answer 1

问题是 qcarImage 超出范围并带走了原始图像数据。复制图像缓冲区并将其提供给 CGDataProviderRef

NSData * imageData = [NSData dataWithBytes:qcarImage->getPixels() 
                                    length:QCAR::getBufferSize(width, height, QCAR::RGB888)];
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, imageData.bytes, imageData.length, NULL);
CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
//This was leaking memory, commenting out
//CGImageRef imageRefRetain = CGImageRetain(imageRef);
UIImage *image = [UIImage imageWithCGImage:imageRef];