If the image looks like pseudo-random noise, your pixel format is wrong.
The SaveBitmapToFile method is only used for testing, In a real-life scenario I'm actually passing the captured pixels through libavcodec to convert and save the frames to an FLV format, but the end result is the same, the image gets scrambled.ĭoes anyone have any idea why the code doesn't work for 1366x768 (or other non-standard 4:3 or 16:9 resolutions for that matter)?įirst you should try to render the CGImageRef to screen right after capture to make sure that the data is valid. Ssize_t bytesWritten = write(fileDescriptor, bufferFileHeader.get()->getData(), sizeBITMAPFILEHEADER) īytesWritten = write(fileDescriptor, bufferInfoHeader.get()->getData(), sizeBITMAPINFOHEADER) īytesWritten = write(fileDescriptor, pBitmapBits, bmpInfoHeader.biSizeImage)
returning if error encountered when opening fileīufferInfoHeader.write(&bmpInfoHeader.biSize, 4) īufferInfoHeader.write(&bmpInfoHeader.biWidth, 4) īufferInfoHeader.write(&bmpInfoHeader.biHeight, 4) īufferInfoHeader.write(&bmpInfoHeader.biPlanes, 2) īufferInfoHeader.write(&bmpInfoHeader.biBitCount, 2) īufferInfoHeader.write(&bmpInfoHeader.biCompression, 4) īufferInfoHeader.write(&bmpInfoHeader.biSizeImage, 4) īufferInfoHeader.write(&bmpInfoHeader.biXPelsPerMeter, 4) īufferInfoHeader.write(&bmpInfoHeader.biYPelsPerMeter, 4) īufferInfoHeader.write(&bmpInfoHeader.biClrUsed, 4) īufferInfoHeader.write(&bmpInfoHeader.biClrImportant, 4) īufferFileHeader.write(&bfh.bfReserved1, 2) īufferFileHeader.write(&bfh.bfReserved2, 2) īufferFileHeader.write(&bfh.bfOffBits, 4) Int fileDescriptor = open(lpszFileName, O_CREAT | O_WRONLY) This is the SaveBitmapFile method that is used for saving the pixels: void BitmapUtility::SaveBitmapToFile(u8* pBitmapBits, long lWidth, long lHeight, unsigned short wBitsPerPixel, char* lpszFileName)īmpInfoHeader.biSize = sizeBITMAPINFOHEADER īmpInfoHeader.biBitCount = wBitsPerPixel īmpInfoHeader.biSizeImage = lWidth* lHeight * (wBitsPerPixel / 8) īfh.bfOffBits = sizeBITMAPINFOHEADER + sizeBITMAPFILEHEADER īfh.bfSize = bfh.bfOffBits + bmpInfoHeader.biSizeImage The code works well for resolutions such as 1024x768, 1280x1024, 1280x960, 1280x768 etc., but it completely scrambles the image for 1366x768. Uint8_t* pixels = (uint8_t*)CFDataGetBytePtr(dataRef) īitmapUtility::SaveBitmapToFile(pixels, width, height, 32, "/Users/Main/test32.bmp")
I've implemented the following code in a C++ project on Mac OS X, for capturing the desktop screen: int ScreenCaptureRoutines::CaptureImage(int width, int height)ĬGImageRef img = CGWindowListCreateImage(captureRect, kCGWindowListOptionOnScreenOnly, kCGNullWindowID, kCGWindowImageDefault) įprintf(stderr, "CGWindowListCreateImage failed\n!") ĬGDataProviderRef provider = CGImageGetDataProvider(img) ĬFDataRef dataRef = CGDataProviderCopyData(provider)
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