In the past I have used QGraphicsTextItem with a monospace font for displaying grids of characters. That should yield good performance, depending on the size of your image.
On Fri, Dec 15, 2017 at 7:33 AM, Kuba Raczkowski <[email protected]> wrote: > Ok, well, managed to do it based on https://stackoverflow.com/ > questions/4763992/finding-out-what-portion-of-a- > qgraphicsitem-is-visible-in-a-qgraphicsview# > > FYI, this gives a visible rectangle inside an imageitem, in its > coordinates: > > view = self.getViewBox().getViewWidget() > portRect = view.viewport().rect() > sceneRect = view.mapToScene(portRect).boundingRect() > itemRect = self.mapRectFromScene(sceneRect) > isec = itemRect.intersected(self.boundingRect()) > > > Kuba > > On Friday, December 15, 2017 at 4:10:09 PM UTC+1, Kuba Raczkowski wrote: >> >> Hi, >> >> I'm trying to annotate the ImageItem's pixels by a textual value on top >> of every pixel. >> Got it working by extending the paint() and adding necessary drawText() >> calls, however, the performance is (obviously?) terrible. >> >> This is only meant to be useful when zooming in deeply - that I can >> treshold by figuring out pixelSize() of ImageItem. >> >> However, all labels seem to be painted even if only a few pixels are >> visible in the view. >> Any idea how to figure out the pixels (or a rectangle) that are actually >> visible in the view? I'm getting lost in all the coordinate mappings :/ >> >> >> Best regards, >> Kuba >> > -- > You received this message because you are subscribed to the Google Groups > "pyqtgraph" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/pyqtgraph/8a620fae-e972-4761-89da-25bf2490d095%40googlegroups.com > <https://groups.google.com/d/msgid/pyqtgraph/8a620fae-e972-4761-89da-25bf2490d095%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "pyqtgraph" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/pyqtgraph/CACZXET9QCrUQEnNWE_c5nksYBug2OQ_vcdKUnr8t%3D7aVQsr7SA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
