bool WicFile::Read(RasterImage &imgDst, unsigned int frameNo)
{
::IWICBitmapFrameDecode *frame(nullptr);
::IWICFormatConverter *format_converter(nullptr);
try
{
// Get a frame.
if (FAILED(decoder->GetFrame(frameNo, &frame)))
throw std::runtime_error("Failed to get a frame.");
// Create a format converter,
// and convert the source image frame to 32bit BGRA regardless of original format.
if (FAILED(this->factory->CreateFormatConverter(&format_converter)))
throw std::runtime_error("Failed to create a format converter.");
if (FAILED(format_converter->Initialize(frame, ::GUID_WICPixelFormat32bppPBGRA, ::WICBitmapDitherTypeNone,
nullptr, 0.0, ::WICBitmapPaletteTypeCustom)))
throw std::runtime_error("Failed to convert the source image frame.");
// Copy image data to the destination.
// Set the size with unsigned int instead of ::size_t because ::size_t (== unsigned long)
// can be wider than unsigned int.
unsigned int w, h;
if (FAILED(format_converter->GetSize(&w, &h)))
throw std::runtime_error("Failed to get the size of the source image frame.");
unsigned int sz = w * h * 4;
imgDst.Resize(1, 4, w, h);
if (FAILED(format_converter->CopyPixels(nullptr, w * 4, sz, imgDst.data.data())))
throw std::runtime_error("Failed to copy pixels from the source image frame.");
}
catch (const std::exception &ex)
{
SafeRelease(format_converter);
SafeRelease(frame);
throw ex; // Re-throw the exception.
}
SafeRelease(format_converter);
SafeRelease(frame);
return true; // redundant response to maintain the class protocol.
}
