Feature: Native -> PNG (#13)

* Rename Image to PNGImage

* Update PNG Image methods + cmd line

* fmt

* Add NativeImage and conversions

* Add writing PNG and parsing TLUT

* Fix bugs and add tests

* Add CI png exports

* fmt

* Passing tests

* Remove debugging output

* Add ia4 from rgb8 png conversion

* Add more tests and fixes

* Add CI4 test + fixes

* Update some comments

* Small fixes

* Fix fmt

Cargo.toml

@@ -10,3 +10,4 @@ png = "0.17.9"
 clap = { version = "4.1.12", features = ["derive"] }
 anyhow = "1.0.72"
 byteorder = "1.4.3"
+num_enum = "0.6.1"

src/color.rs

@@ -32,6 +32,17 @@ impl Color {
         Color { r, g, b, a: 0xFF }
     }
 
+    /// Creates a new color from a 32-bit RGBA pixel.
+    #[inline]
+    pub fn from_u32(pixel: u32) -> Color {
+        let r = ((pixel >> 24) & 0xFF) as u8;
+        let g = ((pixel >> 16) & 0xFF) as u8;
+        let b = ((pixel >> 8) & 0xFF) as u8;
+        let a = (pixel & 0xFF) as u8;
+
+        Color { r, g, b, a }
+    }
+
     /// Converts a 16-bit RGBA pixel to a 32-bit RGBA color.
     #[inline]
     pub fn from_u16(pixel: u16) -> Color {
@@ -62,15 +73,15 @@ impl Color {
     /// Converts a 32-bit RGBA color to a 16-bit RGBA pixel and
     /// returns the two 8-bit components.
     #[inline]
-    pub fn rgba16(self) -> (u8, u8) {
+    pub fn rgba16(self) -> [u8; 2] {
         let pixel = self.to_u16();
-        ((pixel >> 8) as u8, (pixel & 0xFF) as u8)
+        [(pixel >> 8) as u8, (pixel & 0xFF) as u8]
     }
 
     /// Converts the rgb components to a single intensity value.
     /// This is used for grayscale images.
     #[inline]
     pub fn rgb_to_intensity(&self) -> u8 {
-        (self.r as f32 * 0.2126 + self.g as f32 * 0.7152 + 0.0722 * self.b as f32) as u8
+        (self.r as f32 * 0.2126 + self.g as f32 * 0.7152 + 0.0722 * self.b as f32).round() as u8
     }
 }

src/image/mod.rs

@@ -1 +1,2 @@
+pub mod native_image;
 pub mod png_image;