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Fix grayscale_reduction option

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Andrew 2023-05-23 16:38:07 +12:00 committed by Josh Holmer
parent 12761bbfb1
commit 86fccf082a
3 changed files with 9 additions and 5 deletions
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2
benches/reductions.rs
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@ -257,7 +257,7 @@ fn reductions_palette_8_to_grayscale_8(b: &mut Bencher) {
)); ));
let png = PngData::new(&input, &Options::default()).unwrap(); let png = PngData::new(&input, &Options::default()).unwrap();
b.iter(|| color::indexed_to_channels(&png.raw)); b.iter(|| color::indexed_to_channels(&png.raw, true));
} }
#[bench] #[bench]

8
src/reduction/color.rs
View file

@ -132,7 +132,7 @@ pub fn reduced_rgb_to_grayscale(png: &PngImage) -> Option<PngImage> {
/// Attempt to convert indexed to a different color type, returning the resulting image if successful /// Attempt to convert indexed to a different color type, returning the resulting image if successful
#[must_use] #[must_use]
pub fn indexed_to_channels(png: &PngImage) -> Option<PngImage> { pub fn indexed_to_channels(png: &PngImage, allow_grayscale: bool) -> Option<PngImage> {
if png.ihdr.bit_depth != BitDepth::Eight { if png.ihdr.bit_depth != BitDepth::Eight {
return None; return None;
} }
@ -142,7 +142,11 @@ pub fn indexed_to_channels(png: &PngImage) -> Option<PngImage> {
}; };
// Determine which channels are required // Determine which channels are required
let is_gray = palette.iter().all(|c| c.r == c.g && c.g == c.b); let is_gray = if allow_grayscale {
palette.iter().all(|c| c.r == c.g && c.g == c.b)
} else {
false
};
let has_alpha = palette.iter().any(|c| c.a != 255); let has_alpha = palette.iter().any(|c| c.a != 255);
let color_type = match (is_gray, has_alpha) { let color_type = match (is_gray, has_alpha) {
(false, true) => ColorType::RGBA, (false, true) => ColorType::RGBA,

4
src/reduction/mod.rs
View file

@ -50,7 +50,7 @@ pub(crate) fn perform_reductions(
// Attempt to reduce RGB to grayscale // Attempt to reduce RGB to grayscale
// This is just removal of bytes and does not need to be evaluated // This is just removal of bytes and does not need to be evaluated
if opts.color_type_reduction && !deadline.passed() { if opts.color_type_reduction && opts.grayscale_reduction && !deadline.passed() {
if let Some(reduced) = reduced_rgb_to_grayscale(&png) { if let Some(reduced) = reduced_rgb_to_grayscale(&png) {
png = Arc::new(reduced); png = Arc::new(reduced);
reduction_occurred = true; reduction_occurred = true;
@ -98,7 +98,7 @@ pub(crate) fn perform_reductions(
// Attempt to convert from indexed to channels // Attempt to convert from indexed to channels
// This may give a better result due to dropping the PLTE chunk // This may give a better result due to dropping the PLTE chunk
if opts.color_type_reduction && !deadline.passed() { if opts.color_type_reduction && !deadline.passed() {
if let Some(reduced) = indexed_to_channels(&png) { if let Some(reduced) = indexed_to_channels(&png, opts.grayscale_reduction) {
// This result should not be passed on to subsequent reductions // This result should not be passed on to subsequent reductions
eval.try_image(Arc::new(reduced)); eval.try_image(Arc::new(reduced));
evaluation_added = true; evaluation_added = true;