How to paint color on gray image !

DQUY05

Hi,
How to paint color on gray image ! I tried like this, but the end result is still Gray image
Can someone help me?
Thanks!

QImage img= QImage((const unsigned char*)(videoFrame.data),
                                         videoFrame.cols,videoFrame.rows,
                                         QImage::Format_Grayscale8);    // format Gray

                     QPainter painter;
                     QBrush brush=QBrush(QColor(Qt::red));  //   I need paint color on gray image (img)
                     painter.begin(&img);
                     painter.fillRect(0,0,100,100,brush);
                     painter.end();

                     ui->label_2->setPixmap(QPixmap::fromImage(img));

ollarch

@DQUY05 convert the image to RGB.

DQUY05

Dear Mr. @ollarch
Is this what you mean? I tried it, and it's red, but the original gray (img) image is lost

QImage img= QImage((const unsigned char*)(videoFrame.data),
                                         videoFrame.cols,videoFrame.rows,
                                         QImage::Format_Grayscale8);    // format Gray

                     QImage img2{img.size(), QImage::Format_RGB888};  //    convert to RGB

                     QPainter painter;
                     QBrush brush=QBrush(QColor(Qt::red));  //   I need paint color on gray image (img)
                     painter.begin(&img2);
                     painter.fillRect(0,0,100,100,brush);
                     painter.end();

                     ui->label_2->setPixmap(QPixmap::fromImage(img2));

Kent-Dorfman

start with an RGB colorspace image and rectfill it with the RGB values that would make it grey, then overlay any other colors you want, where you want.

DQUY05

Hi,
I converted to RGB and it worked
Thanks !