Fixes for mosaic output pixels not covered by inputs #579

Job	Run time
tests / Load tox environments	9s
tests / py39-test-oldestdeps (macos-latest)	12m 52s
tests / py310-test (macos-latest)	14m 8s
tests / py311-test (macos-latest)	16m 10s
tests / py312-test (macos-latest)	16m 39s
tests / py39-test-oldestdeps (ubuntu-latest)	9m 1s
tests / py310-test (ubuntu-latest)	9m 57s
tests / py311-test (ubuntu-latest)	9m 53s
tests / py312-test (ubuntu-latest)	12m 0s
tests / py312-test-devdeps (ubuntu-latest)	12m 13s
tests / py39-test-oldestdeps (windows-latest)	11m 25s
tests / py310-test (windows-latest)	13m 14s
tests / py311-test (windows-latest)	13m 17s
tests / py312-test (windows-latest)	14m 0s
publish / Load build targets	7s
publish / Build source distribution	6m 27s
publish / Build cp*-manylinux_x86_64 wheels	24m 8s
publish / Build cp*-manylinux_aarch64 wheels	14m 33s
publish / Build cp*-macosx_x86_64 wheels	35m 1s
publish / Build cp*-macosx_arm64 wheels	3m 45s
publish / Build cp*-win_amd64 wheels	29m 24s
publish / Upload	0s
	4h 38m 23s

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