【QT】【OpenCV】【C++】QImage和Mat转换代码

在涉及到QT和OpenCV的联合开发过程中，经常需要使用到在QT界面中显示图像的操作，但由于官方库并不存在互转函数，需要我们根据图片类型自行转换格式。转换函数如下：

CvMat转QImage函数

QPixmap CvMat2QImage(cv::Mat& img)

QPixmap CvMat2QImage(cv::Mat& img)
{
	if (img.depth() != CV_8U){
		cv::Mat tmpImg;
		if (img.depth() == CV_8S){
			img.convertTo(tmpImg, CV_8UC(img.channels()), 1, 128);
		}
		else if (img.channels() == 1){
			double maxVal, minVal;
			cv::minMaxLoc(img, &minVal, &maxVal);
			double t = 255 / (maxVal - minVal);
			img.convertTo(tmpImg, CV_8UC(img.channels()), t, -minVal * t);
		}
		else{
			assert(false);
		}
		if (tmpImg.empty() == false){
			img = tmpImg;
		}
	}
	QImage qimg;
	cv::Mat cvtImg;
	int nType = img.type();
	int nStep = img.step;
	switch (img.type())
	{
	case CV_8UC1:
		qimg = QImage(img.data, img.cols, img.rows, img.step, QImage::Format_Grayscale8);
		break;
	case CV_8UC3:
		cv::cvtColor(img, cvtImg, cv::COLOR_BGR2RGB);
		qimg = QImage(cvtImg.data, cvtImg.cols, cvtImg.rows, cvtImg.step, QImage::Format_RGB888);
		break;
	case CV_8UC4:
		cvtImg = img;
		qimg = QImage(cvtImg.data, cvtImg.cols, cvtImg.rows, cvtImg.step, QImage::Format_RGB32);
		break;
	default:
		qimg = QImage(img.data, img.cols, img.rows, img.step, QImage::Format_Grayscale8);
		break;
	}
	return QPixmap::fromImage(std::move(qimg));
}

CvMat转QImage函数

cv::Mat QImage2cvMat(QImage image)

cv::Mat QImage2cvMat(QImage image)
{
	cv::Mat mat;
	switch (image.format())
	{
	case QImage::Format_ARGB32:
	case QImage::Format_RGB32:
	case QImage::Format_ARGB32_Premultiplied:
		mat = cv::Mat(image.height(), image.width(), CV_8UC4, (void*)image.constBits(), image.bytesPerLine());
		break;
	case QImage::Format_RGB888:
		mat = cv::Mat(image.height(), image.width(), CV_8UC3, (void*)image.constBits(), image.bytesPerLine());
		cv::cvtColor(mat, mat, cv::COLOR_BGR2RGB);
		break;
	case QImage::Format_Indexed8:
	case QImage::Format_Grayscale8:
		mat = cv::Mat(image.height(), image.width(), CV_8UC1, (void*)image.constBits(), image.bytesPerLine());
		break;
	default:
		break;
	}
	return mat;
}