From c54872f011c135bbbc963f4a2b6b1d8ee4fa92bc Mon Sep 17 00:00:00 2001
From: Genny <gen@nyble.dev>
Date: Fri, 6 Nov 2020 23:33:01 -0600
Subject: Add gif components

---
 src/components/logicalscreendescriptor.rs | 40 +++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 src/components/logicalscreendescriptor.rs

(limited to 'src/components/logicalscreendescriptor.rs')

diff --git a/src/components/logicalscreendescriptor.rs b/src/components/logicalscreendescriptor.rs
new file mode 100644
index 0000000..b20c9d5
--- /dev/null
+++ b/src/components/logicalscreendescriptor.rs
@@ -0,0 +1,40 @@
+pub struct LogicalScreenDescriptor {
+	pub width: u16,
+	pub height: u16,
+	pub packed: u8,
+	pub background_color_index: u8,
+	pub pixel_aspect_ratio: u8
+}
+
+impl LogicalScreenDescriptor {
+	pub fn color_table_present(&mut self, is_present: bool) {
+		if is_present {
+			self.packed |= 0b1000_0000;
+		} else {
+			self.packed &= 0b0111_1111;
+		}
+	}
+
+	pub fn color_table_size(&mut self, size: u8) {
+		// GCT size is calulated by raising two to this number plus one,
+		// so we have to work backwards.
+		let size = (size as f32).log2().ceil() - 1f32;
+		self.packed |= size as u8;
+	}
+
+	//TODO: Setter for sort flag in packed field
+	//TODO: Setter for color resolution in packed field
+}
+
+impl From<&LogicalScreenDescriptor> for Box<[u8]> {
+	fn from(lsd: &LogicalScreenDescriptor) -> Self {
+		let mut vec = vec![];
+		vec.extend_from_slice(&lsd.width.to_le_bytes());
+		vec.extend_from_slice(&lsd.height.to_le_bytes());
+		vec.push(lsd.packed);
+		vec.push(lsd.background_color_index);
+		vec.push(lsd.pixel_aspect_ratio);
+
+		vec.into_boxed_slice()
+	}
+}
\ No newline at end of file
-- 
cgit 1.4.1-3-g733a5