Image viewer in undecorated window?

Question

Are there any solutions for viewing sensor_msgs::Image messages in an undecorated window (no menu or border) with ros dynamically controlled width, height, x and y screen position?

I think I can implement this in Qt, or barring that X or maybe GDK (I want some optimal mix of ease-of-implementation and performance, and portability at least across linux distributions), but if it already exists, or something close to it I can adapt exists, I'd rather use that.

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Originally posted by lucasw on ROS Answers with karma: 8729 on 2014-12-17

Post score: 0

Answer 1

Qt in python turned out to be a lot easier than I was expecting.

The full code is https://github.com/lucasw/vimjay/blob/master/scripts/display.py, and the important lines are

class UndecoratedWindow(QtGui.QLabel): 
...
    self.setWindowFlags(Qt.FramelessWindowHint)

And in response to a new x,y and width and height:

    self.resize(roi.width, roi.height)
    self.move(roi.x_offset, roi.y_offset)

and converting the image for use in Qt:

def imageCallback(self, msg):
    np_arr = np.fromstring(msg.data, np.uint8)
    sz = (msg.height, msg.width, msg.step / msg.width)
    image = np.reshape(np_arr, sz)

    ... do some stuff with image to keep aspect raio ...

     self.qimage = QImage.rgbSwapped(QImage(image.tostring(), 
            self.wd, self.ht, 
            QImage.Format_RGB888))

Do this in qt thread to update the display, not the callback thread:

    self.setPixmap(QtGui.QPixmap.fromImage(self.qimage))

(I think my code might lack some thread safetyness regarding self.qimage)

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Originally posted by lucasw with karma: 8729 on 2014-12-19

This answer was ACCEPTED on the original site

Post score: 0