如何将CBitmap转换为cv::Mat？

Question

如何将CBitmap转换为cv::Mat？也许有一些白痴或者别的什么..。比如..。

CBitmap bitmap;
bitmap.CreateBitmap(128, 128, 1, 24, someData);
cv::Mat outBitmap(128,128,someData,1,24);

但是那个代码是不正确的。

谢谢!

Answer 1

还有另一种方法，您可以将CBitmap转换为HBitmap，然后将HBitmap转换为GdiPlus::Bitmap，然后将其转换为cv::Mat。您可以这样做，但请注意，此解决方案仅适用于RGB24像素格式：

步骤1: CBitmap to HBITMAP

HBITMAP hBmp = (HBITMAP)yourCBitmap.GetSafeHandle();

步骤2: HBITMAP to Gdiplus::Bitmap (从this问题复制)

#include <GdiPlus.h>
#include <memory>

Gdiplus::Status HBitmapToBitmap( HBITMAP source, Gdiplus::PixelFormat pixel_format, Gdiplus::Bitmap** result_out )
{
  BITMAP source_info = { 0 };
  if( !::GetObject( source, sizeof( source_info ), &source_info ) )
    return Gdiplus::GenericError;

  Gdiplus::Status s;

  std::auto_ptr< Gdiplus::Bitmap > target( new Gdiplus::Bitmap( source_info.bmWidth, source_info.bmHeight, pixel_format ) );
  if( !target.get() )
    return Gdiplus::OutOfMemory;
  if( ( s = target->GetLastStatus() ) != Gdiplus::Ok )
    return s;

  Gdiplus::BitmapData target_info;
  Gdiplus::Rect rect( 0, 0, source_info.bmWidth, source_info.bmHeight );

  s = target->LockBits( &rect, Gdiplus::ImageLockModeWrite, pixel_format, &target_info );
  if( s != Gdiplus::Ok )
    return s;

  if( target_info.Stride != source_info.bmWidthBytes )
    return Gdiplus::InvalidParameter; // pixel_format is wrong!

  CopyMemory( target_info.Scan0, source_info.bmBits, source_info.bmWidthBytes * source_info.bmHeight );

  s = target->UnlockBits( &target_info );
  if( s != Gdiplus::Ok )
    return s;

  *result_out = target.release();

  return Gdiplus::Ok;
}

调用此函数并将您的HBITMAP传递给它。

步骤3: Gdiplus::Bitmap to cv::Mat

cv::Mat GdiPlusBitmapToCvMat(Gdiplus::Bitmap* bmp)
{
    auto format = bmp->GetPixelFormat();
    if (format != PixelFormat24bppRGB)
        return cv::Mat();

    int width = bmp->GetWidth();
    int height = bmp->GetHeight();
    Gdiplus::Rect rcLock(0, 0, width, height);
    Gdiplus::BitmapData bmpData;

    if (!bmp->LockBits(&rcLock, Gdiplus::ImageLockModeRead, format, &bmpData) == Gdiplus::Ok)
        return cv::Mat();

    cv::Mat mat = cv::Mat(height, width, CV_8UC3, static_cast<unsigned char*>(bmpData.Scan0), bmpData.Stride).clone();

    bmp->UnlockBits(&bmpData);
    return mat;
}

将您在最后一步创建的Gdiplus::Bitmap传递到此函数，您将得到您的cv:Mat。正如我之前说过的，这个函数只适用于RGB24像素格式。