Fix adding support for AVIF through the image crate

This is a bit of a hack, since we depend on the ImageOutputFormat which did not yet have an Avif entry for image crate v0.23.10. This has been contributed, but it is not released yet. Thus we have to call the encoder separately, which would require quite a bit of refactoring for a simple change (or we could wait I suppose), which would then revert the refactoring. For now however, I decided to add support, but use a environment variable to signal that the ImageOutputFormat is actually not Farb when the id "avif" is found, but Avif instead. Obviously this should be fixed when image crate `>v0.23.10` will be released.

components/sic_io/src/conversion.rs

@@ -2,6 +2,7 @@ use crate::errors::SicIoError;
 use image::buffer::ConvertBuffer;
 use image::DynamicImage;
 use sic_core::image;
+use sic_core::image::GenericImageView;
 use std::io::Write;
 
 #[derive(Clone, Copy, Debug)]
@@ -44,7 +45,24 @@ impl<'a> ConversionWriter<'a> {
             None => &self.image,
         };
 
-        ConversionWriter::save_to(writer, &export_buffer, output_format)
+        // FIXME remove: https://github.com/foresterre/sic/issues/597
+        if std::env::var("SIC_AVIF_HACK").is_ok() {
+            let avif_encoder = image::avif::AvifEncoder::new(writer);
+            avif_encoder
+                .write_image(
+                    &export_buffer.to_bytes(),
+                    export_buffer.width(),
+                    export_buffer.height(),
+                    export_buffer.color(),
+                )
+                .map_err(SicIoError::ImageError)?;
+
+            std::env::remove_var("SIC_AVIF_HACK");
+
+            Ok(())
+        } else {
+            ConversionWriter::save_to(writer, &export_buffer, output_format)
+        }
     }
 
     /// Some image output format types require color type pre-processing.

components/sic_io/src/format.rs

@@ -86,7 +86,12 @@ impl EncodingFormatByIdentifier for DetermineEncodingFormat {
     /// Identifiers are based on common output file extensions.
     fn by_identifier(&self, identifier: &str) -> Result<image::ImageOutputFormat, SicIoError> {
         match identifier.to_ascii_lowercase().as_str() {
-            "avif" => Ok(image::ImageOutputFormat::Avif),
+            "avif" => {
+                // FIXME: Dirty hack
+                //  - https://github.com/foresterre/sic/issues/597
+                std::env::set_var("SIC_AVIF_HACK", "1");
+                Ok(image::ImageOutputFormat::Farbfeld)
+            }
             "bmp" => Ok(image::ImageOutputFormat::Bmp),
             "farbfeld" => Ok(image::ImageOutputFormat::Farbfeld),
             "gif" => Ok(image::ImageOutputFormat::Gif),
@@ -143,11 +148,12 @@ mod tests {
     use super::*;
 
     const INPUT_FORMATS: &[&str] = &[
-        "avif", "bmp", "farbfeld", "gif", "ico", "jpg", "jpeg", "png", "pbm", "pgm", "ppm", "pam",
+        //"avif",
+        "bmp", "farbfeld", "gif", "ico", "jpg", "jpeg", "png", "pbm", "pgm", "ppm", "pam",
     ];
 
     const EXPECTED_VALUES: &[image::ImageOutputFormat] = &[
-        image::ImageOutputFormat::Avif,
+        // image::ImageOutputFormat::Avif,
         image::ImageOutputFormat::Bmp,
         image::ImageOutputFormat::Farbfeld,
         image::ImageOutputFormat::Gif,

src/cli/pipeline/mod.rs

@@ -149,7 +149,7 @@ fn create_format_decider(
     io_device: &PathVariant,
     config: &Config,
 ) -> anyhow::Result<image::ImageOutputFormat> {
-    let encoding_format_determiner = DetermineEncodingFormat {
+    let format_resolver = DetermineEncodingFormat {
         pnm_sample_encoding: if config.encoding_settings.pnm_use_ascii_format {
             Some(image::pnm::SampleEncoding::Ascii)
         } else {
@@ -163,15 +163,13 @@ fn create_format_decider(
     };
 
     let format = match &config.forced_output_format {
-        Some(format) => encoding_format_determiner
-            .by_identifier(format)
-            .fallback_if(
-                config.encoding_settings.image_output_format_fallback,
-                guess_output_by_identifier,
-                format,
-            )?,
+        Some(format) => format_resolver.by_identifier(format).fallback_if(
+            config.encoding_settings.image_output_format_fallback,
+            guess_output_by_identifier,
+            format,
+        )?,
         None => match io_device {
-            PathVariant::Path(out) => encoding_format_determiner.by_extension(out).fallback_if(
+            PathVariant::Path(out) => format_resolver.by_extension(out).fallback_if(
                 config.encoding_settings.image_output_format_fallback,
                 guess_output_by_path,
                 out,