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我试图捕获显示内容并从显示器的色彩空间转换为sRGB。我正在尝试使用vImage和低级别的ColorSync变换API来完成此操作，但输出的像素块的奇怪倍增。我的ColorSyncTransformRef似乎是正确的，因为ColorSyncTransformConvert（）工作，但加速框架版本使用vImage不。有没有人看过这个，知道如何解决它？谢谢！ColorSync和vImage产生错误的输出
这里是输出的样子，你可以看到奇怪的加倍：
这里是我使用的代码：
CGImageRef screenshot = CGDisplayCreateImage(CGMainDisplayID());
CFDataRef rawData = CGDataProviderCopyData(CGImageGetDataProvider(screenshot));
uint8_t *basePtr = (uint8_t *)CFDataGetBytePtr(rawData);
const void *keys[] = {kColorSyncProfile, kColorSyncRenderingIntent, kColorSyncTransformTag};
ColorSyncProfileRef srcProfile = ColorSyncProfileCreateWithDisplayID(CGMainDisplayID());
ColorSyncProfileRef destProfile = ColorSyncProfileCreateWithName(kColorSyncSRGBProfile);
const void *srcVals[] = {srcProfile, kColorSyncRenderingIntentPerceptual, kColorSyncTransformDeviceToPCS};
const void *dstVals[] = {destProfile, kColorSyncRenderingIntentPerceptual, kColorSyncTransformPCSToDevice};
CFDictionaryRef srcDict = CFDictionaryCreate (
NULL,
(const void **)keys,
(const void **)srcVals,
3,
&kCFTypeDictionaryKeyCallBacks,
&kCFTypeDictionaryValueCallBacks);
CFDictionaryRef dstDict = CFDictionaryCreate (
NULL,
(const void **)keys,
(const void **)dstVals,
3,
&kCFTypeDictionaryKeyCallBacks,
&kCFTypeDictionaryValueCallBacks);
const void* arrayVals[] = {srcDict, dstDict, NULL};
CFArrayRef profileSequence = CFArrayCreate(NULL, (const void **)arrayVals, 2, &kCFTypeArrayCallBacks);
CFTypeRef codeFragment = NULL;
/* transform to be used for converting color */
ColorSyncTransformRef transform = ColorSyncTransformCreate(profileSequence, NULL);
/* get the code fragment specifying the full conversion */
codeFragment = ColorSyncTransformCopyProperty(transform, kColorSyncTransformFullConversionData, NULL);
if (transform) CFRelease (transform);
if (codeFragment) CFShow(codeFragment);
vImage_Error err;
vImage_CGImageFormat inFormat = {
.bitsPerComponent = 8,
.bitsPerPixel = 32,
.colorSpace = CGColorSpaceCreateWithPlatformColorSpace(srcProfile),
.bitmapInfo = kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little,
}; // .version, .renderingIntent and .decode all initialized to 0 per C rules
vImage_CGImageFormat outFormat = {
.bitsPerComponent = 8,
.bitsPerPixel = 32,
.colorSpace = CGColorSpaceCreateWithPlatformColorSpace(destProfile),
.bitmapInfo = kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little,
}; // .version, .renderingIntent and .decode all initialized to 0 per C rules
/* create a converter to do the image format conversion. */
vImageConverterRef converter = vImageConverter_CreateWithColorSyncCodeFragment(codeFragment, &inFormat, &outFormat, NULL, kvImagePrintDiagnosticsToConsole, &err);
NSAssert(err == kvImageNoError, @"Unable to setup the colorsync transform!");
/* Check to see if the converter will work in place. */
vImage_Error outOfPlace = vImageConverter_MustOperateOutOfPlace(converter, NULL, NULL, kvImageNoFlags);
NSAssert(!outOfPlace, @"We expect the image convert to work in place");
if (srcDict) CFRelease (srcDict);
if (dstDict) CFRelease (dstDict);
if (profileSequence) CFRelease (profileSequence);
// ColorSync converter time!
size_t width = CGImageGetWidth(screenshot);
size_t height = CGImageGetHeight(screenshot);
vImage_Buffer buf;
err = vImageBuffer_Init(&buf, height, width, 32, kvImageNoFlags);
NSAssert(err == kvImageNoError, @"Failed to init buffer");
memcpy(buf.data, basePtr, width * height * 4);
vImage_Buffer vimg_src = { buf.data, height, width, width * 4 };
vImage_Buffer vimg_dest = { buf.data, height, width, width * 4 };
vImage_Error colorSyncErr = vImageConvert_AnyToAny(converter, &vimg_src, &vimg_dest, NULL, kvImageNoFlags);
NSAssert(colorSyncErr == kvImageNoError, @"ColorSync conversion failed");
NSData *pngData = AOPngDataForBuffer(buf.data, (int)width, (int)height);
[pngData writeToFile:@"/tmp/out.png" atomically:YES];
self.imageView.image = [[NSImage alloc] initWithData:pngData];
free(buf.data);
CFRelease(rawData);