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我们使用QT和opencv的过程中经常会碰到这样的问题：Mat怎么转化位QImage？Mat怎么转化为QPixmap？今天我来告诉大家一个比较好的解决方案（以下代码参考了别人的，增加了一些修改）
#include #include #include #include "opencv2/imgproc/imgproc.hpp"#include "opencv2/imgproc/types_c.h"namespace CVS { // 将Mat转化位QImageinline QImage cvMatToQImage( const cv::Mat &inMat ){ switch ( inMat.type() ) { // 8-bit, 4 channel case CV_8UC4: { QImage image( inMat.data, inMat.cols, inMat.rows, static_cast (inMat.step), QImage::Format_ARGB32 ); return image; } // 8-bit, 3 channel case CV_8UC3: { QImage image( inMat.data, inMat.cols, inMat.rows, static_cast (inMat.step), QImage::Format_RGB888 ); return image.rgbSwapped(); } // 8-bit, 1 channel case CV_8UC1: { #if QT_VERSION >= QT_VERSION_CHECK(5, 5, 0) QImage image( inMat.data, inMat.cols, inMat.rows, static_cast (inMat.step), QImage::Format_Grayscale8 );//Format_Alpha8 and Format_Grayscale8 were added in Qt 5.5#else//这里还有一种写法，最后给出 static QVector sColorTable; // only create our color table the first time if ( sColorTable.isEmpty() ) { sColorTable.resize( 256 ); for ( int i = 0; i < 256; ++i ) { sColorTable[i] = qRgb( i, i, i ); } } QImage image( inMat.data, inMat.cols, inMat.rows, static_cast (inMat.step), QImage::Format_Indexed8 ); image.setColorTable( sColorTable );#endif return image; } default: qWarning() << "CVS::cvMatToQImage() - cv::Mat image type not handled in switch:" << inMat.type(); break; } return QImage();}//将Mat转化为QPixmapinline QPixmap cvMatToQPixmap( const cv::Mat &inMat ){ return QPixmap::fromImage( cvMatToQImage( inMat ) );}//将QImage转化为Matinline cv::Mat QImageToCvMat( const QImage &inImage, bool inCloneImageData = true ){ switch ( inImage.format() ) { // 8-bit, 4 channel case QImage::Format_ARGB32: case QImage::Format_ARGB32_Premultiplied: { cv::Mat mat( inImage.height(), inImage.width(), CV_8UC4, const_cast (inImage.bits()), static_cast (inImage.bytesPerLine()) ); return (inCloneImageData ? mat.clone() : mat); } // 8-bit, 3 channel case QImage::Format_RGB32: case QImage::Format_RGB888: { if ( !inCloneImageData ) { qWarning() << "CVS::QImageToCvMat() - Conversion requires cloning because we use a temporary QImage"; } QImage swapped = inImage; if ( inImage.format() == QImage::Format_RGB32 ) { swapped = swapped.convertToFormat( QImage::Format_RGB888 ); } swapped = swapped.rgbSwapped(); return cv::Mat( swapped.height(), swapped.width(), CV_8UC3, const_cast (swapped.bits()), static_cast (swapped.bytesPerLine()) ).clone(); } // 8-bit, 1 channel case QImage::Format_Indexed8: { cv::Mat mat( inImage.height(), inImage.width(), CV_8UC1, const_cast (inImage.bits()), static_cast (inImage.bytesPerLine()) ); return (inCloneImageData ? mat.clone() : mat); } default: qWarning() << "CVS::QImageToCvMat() - QImage format not handled in switch:" << inImage.format(); break; } return cv::Mat();}//将QPixmap转化为Matinline cv::Mat QPixmapToCvMat( const QPixmap &inPixmap, bool inCloneImageData = true ){ return QImageToCvMat( inPixmap.toImage(), inCloneImageData );}}
//CV_8UC1另一种写法，不过我觉得上面的一种写法更优雅^_^QImage image(mat.cols, mat.rows, QImage::Format_Indexed8); // Set the color table (used to translate colour indexes to qRgb values) image.setColorCount(256); for(int i = 0; i < 256; i++) { image.setColor(i, qRgb(i, i, i)); } // Copy input Mat uchar *pSrc = mat.data; for(int row = 0; row < mat.rows; row ++) { uchar *pDest = image.scanLine(row); memcpy(pDest, pSrc, mat.cols); pSrc += mat.step; } return image; 新建一个头文件，将代码（CV_8UC1你自己挑一个吧）添加进去。
如何调用函数？在你要调函数的.cpp文件中添加using namespace CVS;即可。我推荐你这样去做CVS::函数。
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