541a4feae1
- Introduce `shiftRadius` to allow positional tolerances by searching a local neighborhood, absorbing sub-pixel shifts and MSAA quirks. - Introduce `blurRadius` to apply local area averaging, ignoring high-frequency noise like hardware dithering. - Enhance `ImageDiffResult` to include an `averageError` array and a 10-bin `errorHistogram` for actionable failure debugging. - Update Android JNI bindings (`ImageDiff.java` and `ImageDiff.cpp`) to propagate the new error distribution statistics to Java callers. - Update C++ unit tests to cover the new heuristic options. - Document the new parameters and JSON result format in README.md. - Add synthetic image generation tests in `tools/diffimg/tests/` to validate the CLI tool's handling of spatial shifts and dithering.
51 lines
2.1 KiB
Markdown
51 lines
2.1 KiB
Markdown
# DiffImg Python Tests
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This directory contains a suite of synthetic image tests to validate the `diffimg` tool's robustness configurations (`shiftRadius` and `blurRadius`).
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## Files
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- `gen_images.py`: A Python script that generates synthetic `PPM` images.
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- `ref.ppm`: A reference image of a white circle.
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- `cand_shift.ppm`: The same circle shifted by 1 pixel horizontally.
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- `cand_blur.ppm`: The reference circle with high-frequency dithering noise added.
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- `config_strict.json`: An exact-match configuration (`maxAbsDiff = 0.01`).
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- `config_shift.json`: A configuration with a 1-pixel shift tolerance (`shiftRadius = 1`).
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- `config_blur.json`: A configuration with a local area average check (`blurRadius = 1`).
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## How to Run
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Because `diffimg` depends on `libs/imageio`, which may use varying decoders based on OS capabilities, it is recommended to test with `PNG` files.
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**Prerequisites:**
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- Python 3
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- `sips` (macOS native) or `ImageMagick` (for Linux/Windows) to convert PPM to PNG.
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- A compiled `diffimg` binary.
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**Steps (macOS Example):**
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1. Navigate to this directory:
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```bash
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cd tools/diffimg/tests/
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```
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2. Generate the PPM images:
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```bash
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python3 gen_images.py
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```
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3. Convert the generated PPM images to PNG (diffimg natively handles PNG cross-platform without needing LibTIFF or specific backends):
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```bash
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sips -s format png ref.ppm --out ref.png
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sips -s format png cand_shift.ppm --out cand_shift.png
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sips -s format png cand_blur.ppm --out cand_blur.png
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```
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4. Run the validation checks using the compiled binary (assuming it's built in `out/cmake-release` at the project root):
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```bash
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# Test spatial shift (should FAIL with strict, PASS with shift)
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../../../out/cmake-release/tools/diffimg/diffimg -c config_strict.json ref.png cand_shift.png
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../../../out/cmake-release/tools/diffimg/diffimg -c config_shift.json ref.png cand_shift.png
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# Test high-frequency noise (should FAIL with strict, PASS with blur)
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../../../out/cmake-release/tools/diffimg/diffimg -c config_strict.json ref.png cand_blur.png
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../../../out/cmake-release/tools/diffimg/diffimg -c config_blur.json ref.png cand_blur.png
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``` |