use new OnDiskBitmap API

examples/gizmo_eink_simpletest.py

@@ -15,24 +15,17 @@
 display_group = displayio.Group()
 
 # Display a ruler graphic from the root directory of the CIRCUITPY drive
-with open("/display-ruler.bmp", "rb") as file:
-    picture = displayio.OnDiskBitmap(file)
-    # Create a Tilegrid with the bitmap and put in the displayio group
-    # CircuitPython 6 & 7 compatible
-    sprite = displayio.TileGrid(
-        picture,
-        pixel_shader=getattr(picture, "pixel_shader", displayio.ColorConverter()),
-    )
-    # CircuitPython 7 compatible only
-    # sprite = displayio.TileGrid(picture, pixel_shader=bitmap.pixel_shader)
-    display_group.append(sprite)
-
-    # Place the display group on the screen
-    display.root_group = display_group
-
-    # Refresh the display to have it actually show the image
-    # NOTE: Do not refresh eInk displays sooner than 180 seconds
-    display.refresh()
-    print("refreshed")
-
-    time.sleep(180)
+picture = displayio.OnDiskBitmap("/display-ruler.bmp")
+# Create a Tilegrid with the bitmap and put in the displayio group
+sprite = displayio.TileGrid(picture, pixel_shader=picture.pixel_shader)
+display_group.append(sprite)
+
+# Place the display group on the screen
+display.root_group = display_group
+
+# Refresh the display to have it actually show the image
+# NOTE: Do not refresh eInk displays sooner than 180 seconds
+display.refresh()
+print("refreshed")
+
+time.sleep(180)