Use row copies for contiguous image crops

[bghira]

Summary

• add a contiguous-array fast path that copies each crop row directly into the returned ndarray allocation
• preserve the generic ndarray path for strided and otherwise non-contiguous inputs
• route native batch center crops through the same optimized implementation
• reject overflowing crop coordinates and output sizes

Root cause

The default crop APIs materialized an ndarray slice with to_owned(). For RGB crops this performed generic element traversal instead of bulk row copies, even though consumer inputs are normally C-contiguous NumPy arrays.

Performance

Median local latency on Apple M3 Max for a 2048x1536 crop from a 4032x3024 RGB image:

• default API before: 1.380 ms
• default API after: 0.154 ms
• specialized TSR zero-copy API: 0.221 ms
• NumPy slice plus .copy(): 0.179 ms

Validation

• added a regression test for the non-contiguous fallback
• cargo test --features opencv,simd (61 passed)
• Python test suite (68 passed)
• repository pre-commit hooks, including competitive performance benchmarks

[Copilot]

Pull request overview

This pull request improves the performance of crop_image_array by adding a fast path for C-contiguous ndarray inputs, performing row-wise bulk copies into the output allocation while preserving a correct fallback for non-contiguous views. It also consolidates batch center-cropping to reuse the same optimized implementation and adds overflow-safe bounds/size validation.

Changes:

• Add a contiguous-array fast path in crop_image_array that uses crop_raw_buffer to copy rows directly into a preallocated output buffer.
• Preserve behavior for non-contiguous/strided inputs by keeping the existing slice(...).to_owned() fallback.
• Route batch_center_crop_arrays through crop_image_array and add a regression test covering the non-contiguous fallback.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/cropping.rs	Adds contiguous fast path with overflow-safe bounds checks; reuses the same implementation for batch center crops.
src/tests.rs	Adds coverage for cropping from a non-contiguous (strided) ndarray view to ensure the fallback path remains correct.

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