qimage

I do not understand what is the difference between QImage and QPixmap, they seem to offer the same functionality. When should I use a QImage and when should I use a QPixmap? karlphillip Easilly answered by reading the docs on QImage and QPixmap : The QPixmap class is an off-screen image representation that can be used as a paint device. The QImage class provides a hardware-independent image representation that allows direct access to the pixel data, and can be used as a paint device. Edit: Also, from @Dave's answer: You can't manipulate a QPixmap outside the GUI-thread, but QImage has no such

I have a QImage and I need to convert it to grayscale, then later paint over that with colors. I found an allGray() and isGrayScale() function to check if an image is already grayscale, but no toGrayScale() or similarly-named function. Right now I'm using this code, but it's does not have a very good performance: for (int ii = 0; ii < image.width(); ii++) { for (int jj = 0; jj < image.height(); jj++) { int gray = qGray(image.pixel(ii, jj)); image.setPixel(ii, jj, QColor(gray, gray, gray).rgb()); } } What would be the best way, performance-wise, to convert a QImage to grayscale? UmNyobe Rather

I have got a RGB image (224x224x3) and an overlay (224x224). Now I want to apply my overlay as red pixels on my RGB image, which I make therefore to grayscale. The overlay range from 0 to 255. Higher values should make a stronger red. I tried to use Stefan's tutorial, but I could not adapt it: tutorial . Here is my code: # RGB input, shape (224x224x3) img = self.inputImage # make to grayscale img = np.average(img, axis=2) rows, cols = img.shape[0], img.shape[1] color_mask = np.zeros((rows, cols, 3)) # convert to uint8 to plot in QImage::Format_RGB888 img = img.astype(np.uint8) overlay = self

I am new to Qt, and I am trying to create a simple GUI Application that displays an image once a button has been clicked on. I can read the image in a QImage object, but is there any simple way to call a Qt function that takes the QImage as an input, and displays it? Simple, but complete example showing how to display QImage might look like this: #include <QtGui/QApplication> #include <QLabel> int main(int argc, char *argv[]) { QApplication a(argc, argv); QImage myImage; myImage.load("test.png"); QLabel myLabel; myLabel.setPixmap(QPixmap::fromImage(myImage)); myLabel.show(); return a.exec(); }

I'm trying to show an opencv image with a QLabel. I got two different versions of the image, first one is the opencv BGR image, the second one is the RGB image using image[:,:,::-1], the BGR version works fine but the RGB version doesn't work. The following code works fine src = cv.imread('image.jpg') h,w,ch = src.shape bytesPerLine = ch * w qImg = QImage(src.data, w, h, bytesPerLine, QImage.Format_RGB888) qImg = qImg.rgbSwapped() self.ui.label.setPixmap(QPixmap.fromImage(qImg)) These code doesn't work : src = cv.imread('image.jpg') src = src[:,:,::-1] h,w,ch = src.shape bytesPerLine = ch * w

Suppose I am taking an image from the webcam using opencv. _, img = self.cap.read() # numpy.ndarray (480, 640, 3) Then I create a QImage qimg using img : qimg = QImage( data=img, width=img.shape[1], height=img.shape[0], bytesPerLine=img.strides[0], format=QImage.Format_Indexed8) But it gives an error saying that: TypeError: 'data' is an unknown keyword argument But said in this documentation, the constructor should have an argument named data . I am using anaconda environment to run this project. opencv version = 3.1.4 pyqt version = 5.9.2 numpy version = 1.15.0 What they are indicating is

I'm trying to use a JPEG image in a QImage object from a Python script, with PyQt4. The script itself works perfectly, the image loads and can be manipulated and rendered and all. However, when I try to "compile" this script with py2exe, everything works but the JPEG image. Replacing it with a PNG equivalent works, but since my program downloads images from the web, they won't always be in PNG format and I can't afford converting them all with another library. I've discovered that JPEG image support for QImage, along with other image formats, is provided by some DLLs in the \qt\plugins