add minimal qt example

kushalkolar · kushalkolar · commit 1ba03d7935b4 · 2023-10-26T14:36:02.000-04:00
diff --git a/examples/qt/minimal.py b/examples/qt/minimal.py
@@ -0,0 +1,35 @@
+"""
+Minimal PyQt example that displays an image. Press "r" key to autoscale
+"""
+from PyQt6 import QtWidgets
+import fastplotlib as fpl
+import imageio.v3 as iio
+
+# Qt app MUST be instantiated before creating any fpl objects, or any other Qt objects
+app = QtWidgets.QApplication([])
+
+img = iio.imread("imageio:astronaut.png")
+
+# force qt canvas, wgpu will sometimes pick glfw by default even if Qt is present
+plot = fpl.Plot(canvas="qt")
+
+plot.add_image(img)
+plot.camera.local.scale *= -1
+
+# must call plot.show() to start rendering loop
+plot.show()
+
+# set QWidget initial size from image width and height
+plot.canvas.resize(*img.shape[:2])
+
+
+def autoscale(ev):
+    if ev.key == "r":
+        plot.auto_scale()
+
+
+# useful if you pan/zoom away from the image
+plot.renderer.add_event_handler(autoscale, "key_down")
+
+# execute Qt app
+app.exec()
