Render no-wrap syntax directly

[KRRT7]

Summary

Optimizes Syntax(word_wrap=False, line_numbers=False) for non-transparent themes by rendering, cropping, and padding split Text lines directly instead of routing the highlighted text through Console.render_lines(...).

This stacks on #4179 and targets the remaining simple syntax rendering path that still used the generic render_lines pipeline.

Performance framing

Observed:
The simple no-wrap, no-line-number syntax path still used Console.render_lines(...) to crop and pad highlighted text.

Target:
Split the highlighted Text once, render each line directly, and use Segment.adjust_line_length(...) with the line base style for padding.

Hypothesis:
Avoiding the generic render_lines path should reduce overhead for large syntax blocks while preserving crop, padding, blank-line, trailing-newline, and theme-background behavior.

Target workload

User-visible operation: Console.print(Syntax(...)) for large Python syntax output without line wrapping or line numbers.

Workload:

code = snippets.PYTHON_SNIPPET * 120
syntax = Syntax(code=code, lexer="python", word_wrap=False, line_numbers=False)
console = Console(file=StringIO(), color_system="truecolor", legacy_windows=False, width=80)
console.print(syntax)

Environment:

• Darwin arm64
• Python 3.14.6
• Pygments 2.20.0
• pytest 9.0.3

Performance

Before, on #4179 tip before this change:

median: 0.474942s over 15 runs

After:

median: 0.427367s over 15 runs

This is about a 10.0% speedup for the target workload.

Correctness

python3 -m pytest tests/test_syntax.py tests/test_console.py
126 passed

uvx black --check rich/syntax.py benchmarks/benchmarks.py tests/test_syntax.py
3 files would be left unchanged

I also checked output preservation for cropped lines, blank middle lines, and trailing newlines, and smoke-tested the new ASV benchmark method:

SyntaxLargeNoWrapSuite.setup()
SyntaxLargeNoWrapSuite.time_text_wide_terminal_no_wrapping()

Tradeoffs

No new cache or retained state. This duplicates the small part of Console.render_lines(...) needed for this hot path: rendering split text lines, applying the configured background style, fixed-width adjustment, and newline emission.

Stack

Order	PR	Branch	Merge after
1	#4177	optimize-syntax-word-wrap	main
2	#4178	perf/syntax-line-numbers-word-wrap	#4177
3	#4179	perf/syntax-direct-word-wrap	#4178
4	#4181	perf/syntax-direct-no-wrap	#4179

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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4181   +/-   ##
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  Coverage        ?   97.81%           
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  Files           ?       96           
  Lines           ?     8391           
  Branches        ?        0           
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  Hits            ?     8208           
  Misses          ?      183           
  Partials        ?        0           

Flag	Coverage Δ
unittests	97.81% <100.00%> (?)

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