Keep original orientation while converting

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libcaesium"
-version = "0.16.1"
+version = "0.16.2"
 authors = ["Matteo Paonessa <matteo.paonessa@gmail.com>"]
 edition = "2021"
 categories = ["multimedia::images"]
@@ -42,10 +42,10 @@ bytes = "1.6"
 lodepng = { version = "3.10", optional = true }
 imagequant = { version = "4.3", optional = true, default-features = false }
 tiff = { version = "0.9" }
+kamadak-exif = "0.5"
 
 [dev-dependencies]
 dssim = { version = "3.3", default-features = false, features = ["no-macos-vimage"] }
-kamadak-exif = "0.5"
 
 [[bin]]
 name = "main"

src/convert.rs

@@ -5,16 +5,18 @@ use image::{ColorType, DynamicImage, ImageFormat};
 use image::io::Reader as ImageReader;
 use img_parts::{DynImage, ImageEXIF, ImageICC};
 
-use crate::error::CaesiumError;
 use crate::{compress_in_memory, CSParameters, SupportedFileTypes};
+use crate::error::CaesiumError;
 use crate::utils::get_filetype_from_memory;
 
 pub fn convert_in_memory(in_file: Vec<u8>, format: SupportedFileTypes, parameters: &CSParameters) -> Result<Vec<u8>, CaesiumError> {
+    let mut iccp = None;
+    let mut exif = None;
+
     let output_format = map_image_format(format)?;
+    let original_file_type = get_filetype_from_memory(&in_file);
 
-    let file_type = get_filetype_from_memory(&in_file);
-
-    if file_type == format {
+    if original_file_type == format {
         return Err(CaesiumError {
             message: "Cannot convert to the same format".into(),
             code: 10407,
@@ -32,6 +34,29 @@ pub fn convert_in_memory(in_file: Vec<u8>, format: SupportedFileTypes, parameter
             code: 10403,
         })?;
 
+    if parameters.keep_metadata {
+        if original_file_type == SupportedFileTypes::Jpeg {
+            let orientation = get_jpeg_orientation(in_file.as_slice());
+            original_image = match orientation {
+                2 => original_image.fliph(),
+                3 => original_image.rotate180(),
+                4 => original_image.flipv(),
+                5 => original_image.rotate90().fliph(),
+                6 => original_image.rotate90(),
+                7 => original_image.fliph().rotate90(),
+                8 => original_image.rotate270(),
+                _ => original_image
+            }
+        }
+
+        (iccp, exif) = DynImage::from_bytes(Bytes::from(in_file))
+            .map_err(|e| CaesiumError {
+                message: e.to_string(),
+                code: 10401,
+            })?
+            .map_or((None, None), |dimg| (dimg.icc_profile(), dimg.exif()));
+    }
+
     if format == SupportedFileTypes::Jpeg {
         original_image = match original_image.color() {
             ColorType::Rgba8 => DynamicImage::from(original_image.to_rgb8()),
@@ -55,13 +80,6 @@ pub fn convert_in_memory(in_file: Vec<u8>, format: SupportedFileTypes, parameter
         })?;
 
     if parameters.keep_metadata {
-        let (iccp, exif) = DynImage::from_bytes(Bytes::from(in_file))
-            .map_err(|e| CaesiumError {
-                message: e.to_string(),
-                code: 10401,
-            })?
-            .map_or((None, None), |dimg| (dimg.icc_profile(), dimg.exif()));
-
         let dyn_image = DynImage::from_bytes(Bytes::from(compressed_converted_image.clone()))
             .map_err(|e| CaesiumError {
                 message: e.to_string(),
@@ -110,3 +128,20 @@ fn map_image_format(format: SupportedFileTypes) -> Result<ImageFormat, CaesiumEr
 
     Ok(image_format)
 }
+
+fn get_jpeg_orientation(data: &[u8]) -> u32 {
+    let reader = exif::Reader::new();
+    let mut cursor = Cursor::new(data);
+
+    let exif_data = match reader.read_from_container(&mut cursor) {
+        Ok(v) => v,
+        Err(_) => return 1
+    };
+
+    let exif_field = match exif_data.get_field(exif::Tag::Orientation, exif::In::PRIMARY) {
+        Some(value) => value,
+        None => return 1,
+    };
+
+    exif_field.value.get_uint(0).unwrap_or(1)
+}