Detect and correct non-optimal image orientation

cargo test passes

CHANGELOG.md

@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [0.4.0] - 2016-03-29
+### Changed
+- Add functions for detecting and correcting image orientation.
+
 ## [0.3.3] - 2016-03-17
 ### Changed
 - Allow libc version 0.2 or higher

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "magick_rust"
-version = "0.3.3"
+version = "0.4.0"
 authors = ["Nathan Fiedler <nathanfiedler@fastmail.fm>"]
 description = "Selection of Rust bindings for the ImageMagick library."
 homepage = "https://github.com/nlfiedler/magick-rust"

src/lib.rs

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 Nathan Fiedler
+ * Copyright 2015-2016 Nathan Fiedler
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -157,6 +157,24 @@ impl MagickWand {
         }
     }
 
+    /// Detect if the loaded image is not in top-left orientation, and
+    /// hence should be "auto" oriented so it is suitable for viewing.
+    pub fn requires_orientation(&self) -> bool {
+        unsafe {
+            bindings::MagickGetImageOrientation(self.wand) != bindings::TopLeftOrientation
+        }
+    }
+
+    /// Automatically adjusts the loaded image so that its orientation is
+    /// suitable for viewing (i.e. top-left orientation).
+    ///
+    /// Returns `true` if successful or `false` if an error occurred.
+    pub fn auto_orient(&self) -> bool {
+        unsafe {
+            bindings::MagickAutoOrientImage(self.wand) == bindings::MagickTrue
+        }
+    }
+
     /// Write the current image to the provided path.
     pub fn write_image(&self, path: &str) -> Result<(), &'static str> {
         let c_name = CString::new(path).unwrap();
@@ -181,7 +199,6 @@ impl MagickWand {
             bindings::MagickResetIterator(self.wand);
             bindings::MagickGetImageBlob(self.wand, &mut length)
         };
-        // would have used Vec::from_raw_buf() but it is unstable
         let mut bytes = Vec::with_capacity(length as usize);
         unsafe {
             bytes.set_len(length as usize);

tests/lib.rs

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 Nathan Fiedler
+ * Copyright 2015-2016 Nathan Fiedler
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -133,3 +133,25 @@ fn test_get_image_property() {
     assert!(missing_value.is_err());
     assert_eq!("missing property", missing_value.unwrap_err());
 }
+
+#[test]
+fn test_requires_orientation() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+    assert!(wand.read_image("tests/data/IMG_5745.JPG").is_ok());
+    assert_eq!(false, wand.requires_orientation());
+}
+
+#[test]
+fn test_auto_orient() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+    assert!(wand.read_image("tests/data/IMG_5745_rotl.JPG").is_ok());
+    assert_eq!(true, wand.requires_orientation());
+    assert!(wand.auto_orient());
+    assert_eq!(false, wand.requires_orientation());
+}