本方法基本思路是把图片编码成某种格式图片的Buffer，然后QT或者OpenCV框架用该Buffer来构造出图片。
cv::Mat转成QImage和QPixmap
QImage MatToQImage(const Mat& cvImage) {
vector<uchar> imgBuf;
imencode(".bmp", cvImage, imgBuf);
QByteArray baImg((char*)imgBuf.data(), static_cast<int>(imgBuf.size()));
QImage image;
image.loadFromData(baImg, "BMP");
return image;
}
QPixmap MatToPixmap(const Mat& cvImage)
{
return QPixmap::fromImage(matToImage(cvImage));
}</int></uchar>
QImage和QPixmap转换cv::Mat
Mat QImageToMat(const QImage image) {
QByteArray ba;
QBuffer buffer(&ba);
buffer.open(QIODevice::WriteOnly);
image.save(&buffer, "BMP");
vector<uchar> imgBuf;
return imencode(std::vector<uchar>(ba.begin(), ba.end()), IMREAD_COLOR);
}
Mat PixmapToMat(const QPixmap& image) {
return imageToMat(image.toImage());
}</uchar></uchar>
我把图转换成BMP格式而没有转换成JPG、PNG格式，主要考虑的是性能因素。编码成JPG和PNG格式，编码器需要更多的CPU计算才可以完成，但是消耗少量的内存；与之相反，转换成BMP消耗更多的内存，而节省大量的CPU计算。请根据你自己的约束选择正确的策略。
cv::Mat转成QImage
QImage MatToQImage(const cv::Mat& mat)
{
if (mat.type() == CV_8UC1)
{
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;
}
// 8-bits unsigned, NO. OF CHANNELS = 3
else if (mat.type() == CV_8UC3)
{
// Copy input Mat
const uchar* pSrc = (const uchar*)mat.data;
// Create QImage with same dimensions as input Mat
QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_RGB888);
return image.rgbSwapped();
}
else if (mat.type() == CV_8UC4)
{
// Copy input Mat
const uchar* pSrc = (const uchar*)mat.data;
// Create QImage with same dimensions as input Mat
QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_ARGB32);
return image.copy();
}
else
{
//MessageInfo("ERROR: Mat could not be converted to QImage.", 1);
//emit sig_RunInfo("ERROR: Mat could not be converted to QImage.", 1);
//if (!globalPara.IsInlineRun) Runstateinfo("ERROR: Mat could not be converted to QImage.", 1);
return QImage();
}
}
QImage转成cv::Mat
cv::Mat QImageToMat(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_BGR2RGB);
break;
case QImage::Format_Indexed8:
mat = cv::Mat(image.height(), image.width(), CV_8UC1, (void*)image.constBits(), image.bytesPerLine());
break;
}
return mat;
}
Original: https://blog.csdn.net/lizaijinsheng/article/details/122193711
Author: TryRestart
Title: Opencv的mat转换成qimage或者qpixmap
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