Comments on Codes:
The highest priority comment is that the `redraw_pixels` method in the `Canvas` class is missing the implementation. This method is called when the zoom level is changed and it should redraw all the pixels on the canvas according to the new zoom level. Currently, the method is empty and needs to be implemented to ensure that the pixels are correctly redrawn when zooming in or out.
To fix this, you can add the following implementation to the `redraw_pixels` method in the `Canvas` class: