Hi there,

I am using QT4 and opencv in windows for my master's project.

I managed to find some code for converting an IplImage from opencv to a pixmap for use in a QT GUI which has been working. I am now using it on the fly to display video (so far surprisingly working well in real-time). However, with exactly the same code it is showing up in the window somehow mirrored vertically across the midpoint of the pixmap.

The only thiing different is as I am streaming video from a frame grabber, the IplImage is created in a seperate thread from the main program using CvCapture and connected to the QT label using a signal/slot.

Any help would be much appreciated, thanks

Code below:
Qt Code: 
  1. void Video::IplImageToQPixmap(IplImage *iplImage, QPixmap *qp)
  2. {
  3. 	uchar *qImageBuffer = NULL;
  4. 	int width = iplImage->width;
  5. 	int widthStep = iplImage->widthStep;
  6. 	int height = iplImage->height;
  7. 		//OpenCV image is stored with 3 byte color pixels (3 channels).
  8. 		qImageBuffer = (uchar *) malloc(width * height * 4 * sizeof(uchar));
  9. 		uchar *QImagePtr = qImageBuffer;
  10. 		const uchar *iplImagePtr = (const uchar *) iplImage->imageData;
  11. 		for (int y = 0; y < height; y++)
  12. 		{
  13. 			for (int x = 0; x < width; x++)
  14. 			{
  15. 				QImagePtr[0] = iplImagePtr[0];
  16. 				QImagePtr[1] = iplImagePtr[1];
  17. 				QImagePtr[2] = iplImagePtr[2];
  18. 				QImagePtr[3] = 255;
  19. 				QImagePtr += 4;
  20. 				iplImagePtr += 3;
  21. 			}
  22. 			iplImagePtr += widthStep - 3 * width;
  23. 		}
  24. 		delete QImagePtr;
  25.  
  26.  
  27. 	*qp = QPixmap::fromImage(QImage(qImageBuffer, width, height, QImage::Format_ARGB32));
  28. 	delete qImageBuffer;
  29. }
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