non-visible-tiles-optimization for multi-tile-composition

[ptahmose]

Description

• Optimization of the tile-composition: before loading relevant subblocks, the tiles are checked whether they are visible (or whether they are completely overdrawn).
• This optimization is implemented for the ISingleChannelTileAccessor and ISingleChannelScalingTileAccessor. Although this optimization is expected to give exact same results (as before/without optimization enabled) and there should be no reason for not enabling it, it can be enabled/disabled with the corresponding options-structure. It is disabled by default currently.
• Fixed bug in CBitmapOperations::Fill_Gray8.

Fixes #75

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

• extensive unittests for the optimization are provided with the PR

Checklist:

• [x] I followed the Contributing Guidelines.
• [x] I did a self-review.
• [x] I commented my code, particularly in hard-to-understand areas.
• [x] I updated the documentation.
• [x] I updated the version of libCZI following Versioning of libCZI depending on the type of change
  • Bug fix -> PATCH
  • New feature -> MINOR
  • Breaking change -> MAJOR
• [x] I have added tests that prove my fix is effective or that my feature works.
• [x] New and existing unit tests pass locally with my changes.

[codecov[bot]]

Codecov Report

Attention: 39 lines in your changes are missing coverage. Please review.

Comparison is base (c0ff6f9) 64.46% compared to head (d9221e4) 65.11%.

Files	Patch %	Lines
Src/libCZI/SingleChannelScalingTileAccessor.cpp	55.81%	19 Missing :warning:
...c/libCZI/SingleChannelPyramidLevelTileAccessor.cpp	42.85%	12 Missing :warning:
Src/libCZI/utilities.cpp	90.66%	7 Missing :warning:
Src/libCZI/SingleChannelTileCompositor.cpp	66.66%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #78 +/- ## ========================================== + Coverage 64.46% 65.11% +0.65% ========================================== Files 81 81 Lines 10311 10470 +159 ========================================== + Hits 6647 6818 +171 + Misses 3664 3652 -12 ``` | [Flag](https://app.codecov.io/gh/ZEISS/libczi/pull/78/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ZEISS) | Coverage Δ | | |---|---|---| | [windows-latest](https://app.codecov.io/gh/ZEISS/libczi/pull/78/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ZEISS) | `65.11% <81.06%> (+0.65%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ZEISS#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[ptahmose]

I put the PR in draft state again, I want to rework it a bit.