【OpenCV】四通道图像复制到三通道图像上

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https://blog.csdn.net/taily_duan/article/details/81214815

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while (true){
		cap >> frame;
		imshow("frame", frame);
		switch (frame.type())
		{
		case CV_8UC1:
			gray = frame;
			break;
		case CV_8UC2:
			cv::cvtColor(frame, gray, CV_BGR5652GRAY);
			break;
		case CV_8UC3:
			cv::cvtColor(frame, gray, CV_BGR2GRAY); //Almost
			break;
		case CV_8UC4:
			cv::cvtColor(frame, gray, CV_BGRA2GRAY);
			break;
		default:
			LOG_ERROR("unsupported video format!");
			return -1;
		}

		bool hasFace = faceTracker.updateFace(gray);

		//switch (frame.type())
		//{
		//case CV_8UC1:
		//	cv::cvtColor(frame, egeMat, CV_GRAY2BGRA);
		//	break;
		//case CV_8UC2:
		//	cv::cvtColor(frame, egeMat, CV_BGR5652BGRA);
		//	break;
		//case CV_8UC3:
		//	cv::cvtColor(frame, egeMat, CV_BGR2BGRA); //Almost
		//	break;
		//case CV_8UC4:
		//	frame.copyTo(egeMat);
		//	break;
		//default:
		//	LOG_ERROR("unsupported video format!");
		//	return -1;
		//}

		frame.copyTo(egeMat);

		if (hasFace)
		{
			const CGE::Vec2f& v = faceTracker.getEyeCenterPos();
			cout << "Eye : " << v[0] << ", " << v[1] << endl;
			CGE::Vec2f&& eyeDir = faceTracker.getRightDir();
			float eyeDis = eyeDir.length();
			float roll = -asinf(eyeDir[1] / eyeDis);
			if (eyeDir[0] < 0.0f)
			{
				roll = PI/2 - roll;
			}
			//else
			//{
			//	//roll += PI/2;
			//}
			roll *= 180;
			cout << "roll : " << roll << endl;

			float catScaling = eyeDis / catSprite.getWidth() * 4.0f;
			Mat cat = catSprite.render( v[0], v[1], 0.5f, 1.0f, roll, catScaling);
			mapToMat(cat, egeMat, v[0]-cat.cols/2, v[1]-cat.rows);
			float glassScaling = eyeDis / glassSprite.getWidth() * 2.5f;
			Mat glass = glassSprite.render(v[0], v[1], 0.5f, 0.5f, roll, glassScaling);
			mapToMat(glass, egeMat, v[0] - glass.cols / 2, v[1] - glass.rows / 2);
			cout << catScaling << ", " << glassScaling << endl;
			imshow("egeMat", egeMat);
		}
		else
		{
			faceTracker.resetFrame();
		}

		{
			static clock_t lastTime = clock();
			static int frameCount = 0;
			++frameCount;
			clock_t currentTime = clock();
			if (currentTime - lastTime > CLOCKS_PER_SEC)
			{
				LOG_INFO("相机帧率: %d\n", frameCount);
				frameCount = 0;
				lastTime = currentTime;
			}
		}
		if(cv::waitKey(1) == 27) 
			return 0;

 

 

四通道图片Copy到RGB图片上：

void mapToMat(const cv::Mat &srcAlpha, cv::Mat &dest, int x, int y)
{
	int nc = 3;
	int alpha = 0;

	for (int j = 0; j < srcAlpha.rows; j++)
	{
		for (int i = 0; i < srcAlpha.cols * 3; i += 3)
		{
			// 目的图片为三通道，所以是三通道的遍历、四通道的源图
			// i/3*4表示第i/3个像素的位置 
			// i/3*4 + 3表示本像素的alpha通道的值
			alpha = srcAlpha.ptr(j)[i / 3 * 4 + 3];
			//alpha = 255-alpha;
			if (alpha != 0) //4通道图像的alpha判断
			{
				for (int k = 0; k < 3; k++)
				{
					// if (src1.ptr(j)[i / nc*nc + k] != 0)
					if ((j + y < dest.rows) && (j + y >= 0) &&
						((i + x * 3) / 3 * 3 + k < dest.cols * 3) && ((i + x * 3) / 3 * 3 + k >= 0) &&
						(i / nc * 4 + k < srcAlpha.cols * 4) && (i / nc * 4 + k >= 0))
					{
						dest.ptr(j + y)[(i + x*nc) / nc*nc + k] = srcAlpha.ptr(j)[(i) / nc * 4 + k];
					}
				}
			}
		}
	}
}

 

Mat sprite;
		int w = m_sprites[m_index].cols;
		int h = m_sprites[m_index].rows;
		
		length = sqrt(w*w+h*h);
		cv::Mat tempImg(length, length, m_sprites[m_index].type());
		tempImg = 0;
		imshow("tempImg", tempImg);

		int ROI_x = length / 2 - w * centerX;//ROI矩形左上角的x坐标
		if (ROI_x < 0) ROI_x = 0;
		int ROI_y = length / 2 - h * centerY;//ROI矩形左上角的y坐标
		if (ROI_y < 0) ROI_y = 0;
		cv::Rect ROIRect(ROI_x, ROI_y, w, h);//ROI矩形

		cv::Mat tempImgROI2(tempImg, ROIRect);//tempImg的中间部分
		m_sprites[m_index].copyTo(tempImgROI2);//将原图复制到tempImg的中心
		imshow("tempImg", tempImg);

		Point2f center;
		center.x = tempImg.cols / 2;
		center.y = tempImg.rows / 2;
		Mat M1 = getRotationMatrix2D(center, rot, scaling);
		warpAffine(tempImgROI2, sprite, M1, Size(length, length), 0, 0);//仿射变换
		imshow("sprite", sprite);

		//Mat dst(480, 640, m_sprites[m_index].type());
		//cv::Rect rect(x - length / 2, y - length / 2, tempImg.cols, tempImg.rows);
		//if (rect.x < 0) rect.x = 0;
		//if (rect.y < 0) rect.y = 0;
		//if (rect.x + rect.width > dst.cols) rect.width = dst.cols - rect.x;
		//if (rect.y + rect.height > dst.rows) rect.height = dst.rows - rect.y;
		//cv::Mat temp(dst, rect);
		//sprite.copyTo(temp);
		//imshow("dst", dst);

		//waitKey(10);
		++m_index;
		m_index %= m_sprites.size();
		return sprite;

 

 

void mapToMat(const cv::Mat &srcAlpha, cv::Mat &dest, int x, int y)
{
	int nc = 3;
	int alpha = 0;

	for (int i = 0; i < srcAlpha.rows; i++)
	{
		for (int j = 0; j < srcAlpha.cols; j++)
		{
			// 目的图片为三通道，所以是三通道的遍历、四通道的源图
			// i/3*4表示第i/3个像素的位置 
			// i/3*4 + 3表示本像素的alpha通道的值
			//alpha = srcAlpha.ptr(j)[i / 3 * 4 + 3];
			alpha = srcAlpha.at(i, j)[3];
			//alpha = 255-alpha;
			if (alpha != 0) //4通道图像的alpha判断
			{
				if ((i + y) < dest.rows && (i + y) >= 0 && (j + x) < dest.cols && (j + x) >= 0) {

					dest.at(i + y, j + x)[0] = srcAlpha.at(i, j)[0] * float(srcAlpha.at(i, j)[3]) / 255 + dest.at(i + y, j + x)[0] * float(255 - srcAlpha.at(i, j)[3]) / 255;
					dest.at(i + y, j + x)[1] = srcAlpha.at(i, j)[1] * float(srcAlpha.at(i, j)[3]) / 255 + dest.at(i + y, j + x)[1] * float(255 - srcAlpha.at(i, j)[3]) / 255;
					dest.at(i + y, j + x)[2] = srcAlpha.at(i, j)[2] * float(srcAlpha.at(i, j)[3]) / 255 + dest.at(i + y, j + x)[2] * float(255 - srcAlpha.at(i, j)[3]) / 255;
				}
			}
		}
	}
}

仿射旋转时参数

 

Mat rot1;
	rot1.create(Size(m.rows, m.rows), CV_8UC4);
	Point2f center1;
	center1.x = m.cols / 2;
	center1.y = m.rows / 2;
	Mat M1 = getRotationMatrix2D(center1, 30, 1.0);
	warpAffine(m, rot1, M1, Size(m.cols, m.rows), CV_INTER_LINEAR + CV_WARP_FILL_OUTLIERS, 0);//仿射变换  
	imshow("rot1", rot1);