0.30.9

# v0.30.9 — Closer to OpenCV without OpenCV

Installs without OpenCV now draw and resize like OpenCV, and the COCO and CreateML loaders stop accepting reversed boxes.

- **`BoxAnnotator`** borders paint the same pixels with or without OpenCV installed.
- **`get_video_frames_generator`** reads browser-recorded WebM and variable frame rate MKV to the end.
- **`from_coco`**, `from_pascal_voc` and `from_createml` no longer build boxes with `x_min` past `x_max`.
- **`get_top_k`** rejects a negative `k` instead of dropping one classification.
- **`DetectionsSmoother`** forgets expired tracks on frames without `tracker_id`.

Drop-in upgrade. Without OpenCV, borders and resized regions shift toward OpenCV's output. Negative `k`, negative COCO/CreateML box sizes and an `epsilon` that is `NaN`, infinite or `1e30` and larger are now rejected; without OpenCV, so is rectangle `thickness` above 32767.

## ✨ Spotlights / highlights

### NumPy fallback matches OpenCV

Without `opencv-python`, thick rectangle borders were drawn entirely inside the rectangle. They now extend `(thickness + 1) // 2` pixels outside it, like OpenCV. The same release fixes `cv2.resize` with `fx`/`fy` sampling the wrong source pixels (it hit `PixelateAnnotator`) and `approxPolyDP` dropping vertices that sit beyond a segment endpoint. For polygons, the fallback now follows OpenCV 4.13 and later; older OpenCV keeps the infinite-line rule, so results differ by installed backend. (#2675, #2690, #2673)

```python
import numpy as np
import supervision as sv

scene = np.zeros((100, 100, 3), dtype=np.uint8)
detections = sv.Detections(xyxy=np.array([[20, 20, 80, 60]]), class_id=np.array([0]))
annotated = sv.BoxAnnotator(thickness=2).annotate(scene, detections)
# before (no OpenCV): 392 painted pixels, border drawn inside the box
# now:                596 painted pixels, same as with OpenCV
```

### Video reads to the end of the stream

With no `end`, `sv.get_video_frames_generator` stopped at OpenCV's frame count. A WebM without a duration reports a huge negative count, so browser recordings yielded no frames. It now reads until the stream ends, and `sv.process_video` without `max_frames` does the same. (#2672)

```python
for frame in sv.get_video_frames_generator("recording.webm"):
    ...
# before: no frames yielded
# now:    every frame
```

### No more reversed boxes from COCO, Pascal VOC and CreateML

This finishes the `from_yolo` fix from 0.30.8. COCO and CreateML name an extent, so a negative width or height is rejected. Pascal VOC names two corners, so a reversed pair is ordered. The three exporters order corners first, so a reversed `Detections` box is written as the same rectangle. (#2683)

### A negative `k` no longer hides a classification

`get_top_k(-1)` returned every classification except the lowest-confidence one. It now raises. (#2695)

```python
classifications.get_top_k(-1)
# before: all but the lowest-confidence classification
# now:    ValueError: k must be non-negative
```

### Empty and untracked frames behave

`InferenceSlicer` keeps its oriented-box sequential fallback and warning when the first batch is empty. `DetectionsSmoother` ages its history on frames without `tracker_id`, so expired boxes stop affecting a returning track. `KeyPoints.from_transformers` returns an empty `KeyPoints` instead of raising `IndexError` when pose post-processing finds nothing. (#2685, #2676, #2671)

## 🔄 Migration guide

No migration required for this release. COCO and CreateML annotation files with a negative box width or height now fail to load; correct or remove those boxes.

## 📝 Notable changes

### 🌱 Changed

- `sv.DetectionDataset.from_coco` and `from_createml` raise on a negative box width or height; `from_pascal_voc` orders a reversed corner pair. The three exporters order the corners of a reversed `Detections` box first and the COCO exporter writes the ordered origin; normal boxes are unchanged. (#2683)
- `sv.Classifications.get_top_k` raises `ValueError` for a negative `k`; `k=0` and `k` larger than the number of classifications are unchanged. (#2695)
- Without OpenCV, rectangle `thickness` must be an integer of at most 32767, as in OpenCV: a non-integer raises `TypeError`, a larger value `ValueError`. (#2675)

### 🔧 Fixed

- `sv.BoxAnnotator`, `sv.CropAnnotator`, `sv.PercentageBarAnnotator` and `sv.draw_rectangle` draw a border of `thickness` 2 or more identically with and without `opencv-python`. Filled rectangles and `thickness=1` borders are unchanged, except zero-height rectangles, which no longer draw 1 or 2 extra pixels. (#2675)
- The NumPy fallback for `cv2.resize` maps pixels with `fx`/`fy` when `dsize` is not given, as OpenCV does. `sv.PixelateAnnotator` could sample the wrong source pixels without OpenCV. (#2690)
- The NumPy fallback for `cv2.approxPolyDP`, used by `sv.approximate_polygon` and YOLO/COCO polygon export, measures distance to the finite segment as OpenCV 4.13+ does, and raises `ValueError` for a `NaN`, infinite or `1e30`-and-larger `epsilon`. (#2673)
- `sv.get_video_frames_generator` and `sv.process_video` read to the end of the stream when no `end` or `max_frames` is given. A positive frame count still rejects an `end` past it. (#2672)
- `sv.InferenceSlicer` probes past leading empty batches before choosing threaded or sequential execution, so batched callbacks producing oriented boxes keep the sequential fallback and warning. (#2685)
- `sv.DetectionsSmoother` ages cached track history on frames without `tracker_id`; short gaps still preserve smoothing. (#2676)
- `sv.KeyPoints.from_transformers` returns an empty `KeyPoints` when pose post-processing returns no instances for an image. (#2671)

## 🏆 Contributors

- **Atikul Islam Munna** (@atikulmunna, [LinkedIn](https://www.linkedin.com/in/aimunna/)) — centered thick rectangle borders in the NumPy fallback.
- **Mohammad Hijjawi** (@MohammadHijjawi97, [LinkedIn](https://www.linkedin.com/in/mohammadhijjawi)) — fixed video reading past an unreliable frame count.
- **A Aswanth Raj** (@aswanth-07, [LinkedIn](https://www.linkedin.com/in/a-aswanth-raj/)) — fixed `InferenceSlicer` empty-batch probing and `DetectionsSmoother` history aging.
- **Miral Amin** (@aminmiral) — made COCO, Pascal VOC and CreateML reject or order reversed boxes.
- **NIKHIL** (@Nikhi00718) — rejected negative `get_top_k` counts and handled empty Transformers pose results.
- **Raashish Aggarwal** (@raashish1601) — fixed `cv2.resize` pixel mapping with `fx` and `fy`.
- **kevin** (@kevin9327) — fixed `approxPolyDP` distance measurement in the NumPy fallback.

*Automated contributions: @dependabot, @pre-commit-ci*

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**Full changelog**: <https://github.com/roboflow/supervision/compare/0.30.8...0.30.9>