PAINTROID-687 Improve Zoom Window performance

[khalid-nasralla]

PAINTROID-687

Improved the performance of the Zoom Window feature by:

• Removing redundant operations in the code (which are not needed anymore after the fixes in Paintroid-680 and Paintroid-686)
• Changing some of the calculations for the zoom window bitmap making them more efficient.
• Changing the way the zoom window bitmap is getting cropped out from the whole bitmap (by drawing a circle around the coordinates where the user is currently drawing with the desired radius and then cropping it out).

This seemed to make it much faster now, especially on the emulator in Android Studio it was a significant improvement. In my opinion the improvement can also be felt when drawing on a physical device. At least it feels a little bit smoother now on the physical device.

• Include the name of the Jira ticket in the PR’s title
• Include a summary of the changes plus the relevant context
• Choose the proper base branch (develop)
• Confirm that the changes follow the project’s coding guidelines
• Verify that the changes generate no compiler or linter warnings
• Perform a self-review of the changes
• Verify to commit no other files than the intentionally changed ones
• Include reasonable and readable tests verifying the added or changed behavior
• Confirm that new and existing unit tests pass locally
• Check that the commits’ message style matches the project’s guideline
• Stick to the project’s gitflow workflow
• Verify that your changes do not have any conflicts with the base branch
• After the PR, verify that all CI checks have passed
• Post a message in the #paintroid Slack channel and ask for a code reviewer

[Lenkomotive]

👍🏼