1 files changed, 82 insertions, 0 deletions
diff --git a/src/gif.rs b/src/gif.rs
new file mode 100644
index 0000000..c3ef56b
--- /dev/null
+++ b/src/gif.rs
@@ -0,0 +1,82 @@
+use crate::block::{ColorTable, Image, ScreenDescriptor, Version};
+
+pub struct Gif {
+	pub header: Version,
+	pub screen_descriptor: ScreenDescriptor,
+	pub global_color_table: Option<ColorTable>,
+	pub images: Vec<Image>
+	// Trailer at the end of this struct is 0x3B //
+}
+
+impl Gif {
+	pub fn to_vec(&self) -> Vec<u8> {
+		let mut out = vec![];
+
+		out.extend_from_slice((&self.header).into());
+		
+		let mut boxed: Box<[u8]> = (&self.screen_descriptor).into();
+		out.extend_from_slice(&*boxed);
+
+		// While we output the color table, grab it's length to use when
+		// outputting the image, or 0 if we don't have a GCT
+		let mcs = if let Some(gct) = &self.global_color_table {
+			boxed = gct.into();
+			out.extend_from_slice(&*boxed);
+
+			gct.packed_len()
+		} else {
+			0
+		};
+
+		for image in self.images.iter() {
+			boxed = image.as_boxed_slice(mcs);
+			out.extend_from_slice(&*boxed);
+		}
+
+		// Write Trailer
+		out.push(0x3B);
+
+		out
+	}
+}
+
+#[cfg(test)]
+pub mod gif {
+	use crate::Color;
+	use crate::writer::{GifBuilder, ImageBuilder};
+	use super::*;
+
+	#[test]
+	fn to_vec() {
+		let gct = vec![
+			Color::new(1, 2, 3), Color::new(253, 254, 255)
+		];
+		let colortable = vec![
+			Color::new(0, 0, 0), Color::new(128, 0, 255)
+		];
+		let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
+
+		let expected_out = vec![
+			0x47, 0x49, 0x46, 0x38, 0x37, 0x61, // Version - GIF87a
+			0x04, 0x00, 0x04, 0x00, 0b1000_0000, 0x00, 0x00, // Logical Screen Descriptor
+			1, 2, 3, 253, 254, 255, // Global Color Table
+			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b1000_0000, // Image Descriptor 1
+			0, 0, 0, 128, 0, 255, // Color Table
+			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 1
+			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b0000_0000, // Image Descriptor 2
+			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 2
+			0x3B // Trailer
+		];
+
+		let actual_out = GifBuilder::new(Version::Gif87a, 4, 4)
+			.global_color_table(gct.into())
+			.image(ImageBuilder::new(4, 4)
+				.color_table(colortable.into())
+				.indicies(indicies.clone())
+			).image(ImageBuilder::new(4, 4)
+				.indicies(indicies)
+			).build().to_vec();
+
+		assert_eq!(actual_out, expected_out);
+	}
+}
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