Do not use transparent ink

[radarhere]

#9772 returns early in C when the ink is transparent in a draw operation.

We already have a mechanism in Python for checking if the ink is usable or not

Pillow/src/PIL/ImageDraw.py

Lines 245 to 246 in fef1035

	ink = self._getink(fill)[0]
	if ink is not None and width != 0:

So this PR expands on that, reporting transparent ink as None in Python.

[codspeed]

Merging this PR will improve performance by ×25

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 639 untouched benchmarks
⏩ 338 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	test_draw_lines_blend[1237x811-0]	1,185.8 µs	48.1 µs	×25

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing radarhere:getink (dae7204) with main (fef1035)}

Footnotes

1. 338 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩