The iOS reading widget downsampled covers to a fractional target size.
UIGraphicsImageRenderer allocates a whole-pixel buffer while draw(in:)
fills only the exact fractional rect, so for portrait covers whose scaled
width rounds up the rightmost pixel column was left partially covered and
semi-transparent. Encoded to JPEG that column flattened into a visible
bright hairline along the right edge (intermittent, portrait covers only).
Round both target dimensions to whole pixels so the draw rect matches the
pixel buffer and every edge pixel is fully covered. Android is unaffected
because it scales to a fixed 240x360 and center-crops.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Huang Xin
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