32 lines
1.1 KiB
Python
32 lines
1.1 KiB
Python
"""Pure bucket math for KLEIN_BUCKET_SIZES.md. Stdlib only."""
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import math
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def pick_bucket(iw, ih, resolution=1280, divisible=64):
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"""Choose the on-grid bucket (W,H), area <= resolution^2, nearest to the
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image aspect (log distance; tie-break larger area)."""
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budget = resolution * resolution
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target = iw / ih
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best = None
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w = divisible
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w_max = budget // divisible
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while w <= w_max:
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h = (budget // w // divisible) * divisible # largest on-grid h within budget
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if h >= divisible:
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err = abs(math.log(w / h) - math.log(target))
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cand = (err, -(w * h), w, h) # min err, then max area
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if best is None or cand < best:
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best = cand
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w += divisible
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return best[2], best[3]
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def cover_crop_params(iw, ih, W, H):
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"""Cover-scale + centered crop to land (iw,ih) exactly on (W,H)."""
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scale = max(W / iw, H / ih)
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new_w = max(W, round(iw * scale))
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new_h = max(H, round(ih * scale))
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left = (new_w - W) // 2
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top = (new_h - H) // 2
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return new_w, new_h, left, top, scale
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