Displaying SVG on a QGraphicsView

DoubleFelix

I've been trying to load an SVG file into a QGraphicsView object. From the error messages I get, I assume I need to use a QGraphicsScene and add my SVG to that, and then give the scene to the view. I did some searching and found a QSvgRenderer class which I can successfully load my SVG file into, but I'm not sure how to provide this to the QGraphicsScene.

I tried this:

        svg_renderer = QSvgRenderer()
        svg_renderer.load("assets\\key_signatures\\c_sharp.svg")
        scene = QGraphicsScene()
        scene.addItem(svg_renderer)
        self.ui.c_major_display.setScene(scene)

But I get errors about QGraphicsScene needing a QGraphicsItem.
An old StackOverflow post I found says to use a QGraphicsWebView like this:

    item = QGraphicsWebView()
    item.load('file.svg')
    view = QGraphicsView()
    scene = QGraphicsScene()
    scene.addItem(item)
    view.setScene(scene)
    view.show()
    sys.exit(app.exec_())

But to my knowledge, this is deprecated (it not only crashes Qt Designer, but also doesn't show up in the import list).

I also found docs on a QGraphicsSvgItem which explicitly states its purpose is to load SVGs into a QGraphicsView, but I can't seem to import it in PySide6.
Any ideas?

DoubleFelix

Update: I figured it out. I found in the changelog for Qt 6 that much of QtSvg has been moved into QtSvgWidgets. From here, I was able to do this:

from PySide6.QtSvgWidgets import QGraphicsSvgItem
from PySide6.QtWidgets import QGraphicsScene

svg_item = QGraphicsSvgItem("assets\\key_signatures\\c.svg")
scene = QGraphicsScene()
scene.addItem(svg_item)
my_graphics_view.setScene(scene)

SGaist

Hi,

One note: use forward slashes for your paths. It's less error prone and Qt handles the conversion if needed.

DoubleFelix

@SGaist I just kind of threw it in there as a placeholder. Does Qt handle it completely, or should I still use os.path.join to be safe?

SGaist

Qt handles the conversion internally so you'll be fine. Currently you have a Windows specific path so not really portable.

If you want to stay in the Python land, you should use pathlib and convert the path to a string before passing it to Qt.