The scale attribute on Label seems to be being applied twice.
lesamouraipourpre opened this issue · 5 comments
When setting the scale of text created with Label, the scale appears to be applied twice causing the scale to be squared.
In the test script below the word 'Scale' is printed to screen in scale=1, 2 and 3
text_scale_test.py.txt
The output txt follows, note the scale in the absolute_transform:
text_test_output.txt
Below is a photograph of the resulting image on my Pimoroni 128x128 OLED:
I think this bug is specifically inside of Blinka_Displayio instead of this library. If you run the same code on a PyPortal (or other microcontroller) the scale won't get doubled up. There is an issue here that is for what I think the root cause is: adafruit/Adafruit_Blinka_Displayio#45
After a few hours of trying to figure out the design of Label, it seems to be because of the sub-Group within the label, the init method refers to
# self Group will contain a single local_group which contains a Group (self.local_group)
# which contains a TileGrid
# The self scale should always be 1
super().__init__(max_size=1, scale=1, **kwargs)
# local_group will set the scale
self.local_group = displayio.Group(max_size=max_glyphs + 1, scale=scale)
However, both the local scale and the local_group scale value are adjusted when scale is updated after a transformation
def scale(self, new_scale):
current_anchored_position = self.anchored_position
self._scale = new_scale
self.local_group.scale = new_scale
self.anchored_position = current_anchored_position
The attached diff is one possible fix, that keeps the local scale at 1 and uses the scale from the local_group
diff.txt
This produces the attached image:
@lesamouraipourpre
Good find on this bug. I agree with your solution. Can you submit a pull request to fix?
Nice! I tested this out successfully with Blinka_Displayio and it does resolve the extra scaling. Thank you for digging into this and finding a solution @lesamouraipourpre.
I am still kind of curious about what the difference between core displayio and blinka_displayio that might cause the current code to behave differently.
But definitely happy to have a solution for it here in this library as well. If you can make a PR for this it would be awesome. No worries if not though I can work making on with this change in the next few days.