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fix: resample key images with a real filter instead of nearest-neighbour #62

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fix: resample key images with a real filter instead of nearest-neighbour #62

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8b10397
fix: resample key images with a real filter instead of nearest-neighbour
constrictor Aug 5, 2026
5dcdd93
docs: drop an unjustified size claim from the resample comment
constrictor Aug 5, 2026
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14 changes: 13 additions & 1 deletion src/images.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,19 @@ pub fn convert_image_with_format(image_format: ImageFormat, image: DynamicImage)
ImageRotation::Rot270 => image.rotate270(),
};

let image = image.resize_exact(ws as u32, hs as u32, FilterType::Nearest);
// Nearest-neighbour discards the antialiasing of whatever the caller drew. At the
// Stream Deck +'s 6:5 ratio (144 -> 120) it drops every sixth row and column and
// point-samples soft edges into stair-steps.
//
// Cost scales with the source area, which is up to the caller, so skip the resample
// altogether when the image already matches the format. That is both the common case
// and the escape hatch: a caller that scales to the target size itself pays nothing
// here, rather than paying for a resample to get its own pixels back.
let image = if image.dimensions() == (ws as u32, hs as u32) {
image
} else {
image.resize_exact(ws as u32, hs as u32, FilterType::Lanczos3)
};

// Applying mirroring
let image = match image_format.mirror {
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