Fix to #82 + added chroma subsampling option #81

Author: Lymphatus

Cargo.lock

@@ -22,7 +22,7 @@ rayon = "1.10"
 human_bytes = { version = "0.4", default-features = false }
 kamadak-exif = "0.6"
 imagesize = "0.13"
-libcaesium = "0.17.2"
+libcaesium = "0.17.3"
 clap = { version = "4.5", features = ["derive"] }
 
 [dev-dependencies]

Cargo.toml

@@ -1,6 +1,6 @@
 use crate::options::{OutputFormat, OverwritePolicy};
 use crate::scan_files::get_file_mime_type;
-use caesium::parameters::CSParameters;
+use caesium::parameters::{CSParameters, ChromaSubsampling};
 use caesium::{compress_in_memory, compress_to_size_in_memory, convert_in_memory, SupportedFileTypes};
 use indicatif::ProgressBar;
 use rayon::iter::ParallelIterator;
@@ -28,7 +28,6 @@ pub struct CompressionResult {
     pub message: String,
 }
 
-#[derive(Debug)]
 pub struct CompressionOptions {
     pub quality: Option<u32>,
     pub max_size: Option<usize>,
@@ -48,6 +47,7 @@ pub struct CompressionOptions {
     pub format: OutputFormat,
     pub keep_dates: bool,
     pub keep_structure: bool,
+    pub jpeg_chroma_subsampling: ChromaSubsampling,
 }
 
 pub fn start_compression(
@@ -251,6 +251,8 @@ fn build_compression_parameters(
 
     parameters.keep_metadata = options.exif;
 
+    parameters.jpeg.chroma_subsampling = options.jpeg_chroma_subsampling;
+
     parameters.png.optimization_level = options.png_opt_level;
     parameters.png.force_zopfli = options.zopfli;
 
@@ -774,6 +776,7 @@ mod tests {
             keep_dates: false,
             exif: true,
             png_opt_level: 0,
+            jpeg_chroma_subsampling: ChromaSubsampling::Auto,
             zopfli: false,
             base_path: PathBuf::new(),
         }

src/compressor.rs

@@ -1,6 +1,7 @@
 use crate::compressor::{start_compression, CompressionOptions, CompressionResult, CompressionStatus};
-use crate::options::CommandLineArgs;
+use crate::options::{CommandLineArgs, JpegChromaSubsampling};
 use crate::scan_files::scan_files;
+use caesium::parameters::ChromaSubsampling;
 use clap::Parser;
 use human_bytes::human_bytes;
 use indicatif::{ProgressBar, ProgressDrawTarget, ProgressStyle};
@@ -137,11 +138,22 @@ fn build_compression_options(args: &CommandLineArgs, base_path: &Path) -> Compre
         keep_dates: args.keep_dates,
         exif: args.exif,
         png_opt_level: args.png_opt_level,
+        jpeg_chroma_subsampling: parse_jpeg_chroma_subsampling(args.jpeg_chroma_subsampling),
         zopfli: args.zopfli,
         base_path: PathBuf::from(base_path),
     }
 }
 
+fn parse_jpeg_chroma_subsampling(arg: JpegChromaSubsampling) -> ChromaSubsampling {
+    match arg {
+        JpegChromaSubsampling::ChromaSubsampling444 => ChromaSubsampling::CS444,
+        JpegChromaSubsampling::ChromaSubsampling422 => ChromaSubsampling::CS422,
+        JpegChromaSubsampling::ChromaSubsampling420 => ChromaSubsampling::CS420,
+        JpegChromaSubsampling::ChromaSubsampling411 => ChromaSubsampling::CS411,
+        _ => ChromaSubsampling::Auto,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/main.rs

@@ -19,6 +19,20 @@ pub enum OutputFormat {
     Tiff,
     Original,
 }
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum, Debug)]
+pub enum JpegChromaSubsampling {
+    #[value(name = "4:4:4")]
+    ChromaSubsampling444,
+    #[value(name = "4:2:2")]
+    ChromaSubsampling422,
+    #[value(name = "4:2:0")]
+    ChromaSubsampling420,
+    #[value(name = "4:1:1")]
+    ChromaSubsampling411,
+    #[value(name = "auto")]
+    Auto,
+}
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
 pub struct CommandLineArgs {
@@ -39,6 +53,10 @@ pub struct CommandLineArgs {
     #[arg(long, default_value = "3")]
     pub png_opt_level: u8,
 
+    /// select level for PNG optimization, between [0-6]
+    #[arg(long, value_enum, default_value = "auto")]
+    pub jpeg_chroma_subsampling: JpegChromaSubsampling,
+
     /// use zopfli when optimizing PNG files (it may take a very long time to complete)
     #[arg(long)]
     pub zopfli: bool,