I have unsigned 16 bit image data that I displayed by subclassing QQuickPaintedItem in Qt 5.12.3. I used QImage with Format_RGB32 and scaled the data from [0, 16383] to [0, 255] and set that as the color value for all three R,G,B. Now, I am using Qt 5.15.2 which has a QImage FORMAT_GrayScale16 that I'd like to use but for some reason the image is displayed incorrectly. The code I used to convert my unsigned 16 bit image data to QImage for both formats is shown below. The QQuickPaintedItem is a basic subclassing with drawImage(window(), my_qimage);
that I pass the QImage as returned from the code below. Why is the new format not displaying correctly?
Format_RGB32 method
QImage image(image_dim, QImage::Format_RGB32);
unsigned int pixel = 0;
for (uint16_t row = 0; row < nrow; row ) {
uint *scanLine = reinterpret_cast<uint *>(image.scanLine(row));
for (uint16_t col = 0; col < ncols; col ) {
uint16_t value = xray_image.data()[pixel ]; // Get each pixel
unsigned short color_value = uint16_t((float(value) / 16383) * 255.0f); // scale [0, 255]
*scanLine = qRgb(int(color_value), int(color_value), int(color_value));
}
}
return image;
Format_Grayscale16 method
QImage image(image_dim, QImage::Format_Grayscale16);
unsigned int pixel = 0;
for (uint16_t row = 0; row < nrow; row ) {
// **EDIT WRONG:** uint *scanLine = reinterpret_cast<uint *>(image.scanLine(row));
uint16_t *scanLine = reinterpret_cast<uint16_t *>(image.scanLine(row));
for (uint16_t col = 0; col < ncols; col ) {
*scanLine = xray_image.data()[pixel ]; // Get each pixel
}
}
return image;
CodePudding user response:
This worked for me (below is just fragments):
class Widget : public QWidget
{
private:
QImage m_image;
QImage m_newImage;
QGraphicsScene *m_scene;
QPixmap m_pixmap;
};
...
m_image.load("your/file/path/here");
m_newImage = m_image.convertToFormat(QImage::Format_Grayscale8);
m_pixmap.convertFromImage(m_newImage);
m_scene = new QGraphicsScene(this);
m_scene->addPixmap(m_pixmap);
m_scene->setSceneRect(m_pixmap.rect());
ui->graphicsView->setScene(m_scene);
Based on your OP, you probably want to render it differently. graphicsView is just a QGraphicsView defined in design mode.