1 files changed, 45 insertions, 0 deletions
diff --git a/src/block/imagedescriptor.rs b/src/block/imagedescriptor.rs
new file mode 100644
index 0000000..c911baa
--- /dev/null
+++ b/src/block/imagedescriptor.rs
@@ -0,0 +1,45 @@
+pub struct ImageDescriptor {
+	// Image Seperator 0x2C is the first byte //
+	pub left: u16,
+	pub top: u16,
+	pub width: u16,
+	pub height: u16,
+	pub packed: u8
+}
+
+impl ImageDescriptor {
+	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 interlace flag in packed field
+}
+
+impl From<&ImageDescriptor> for Box<[u8]> {
+	fn from(desc: &ImageDescriptor) -> Self {
+		let mut vec = vec![];
+
+		vec.push(0x2C); // Image Seperator
+		vec.extend_from_slice(&desc.left.to_le_bytes());
+		vec.extend_from_slice(&desc.top.to_le_bytes());
+		vec.extend_from_slice(&desc.width.to_le_bytes());
+		vec.extend_from_slice(&desc.height.to_le_bytes());
+		vec.push(desc.packed);
+
+		vec.into_boxed_slice()
+	}
+}
+
+//TODO: Impl to allow changing the packed field easier
\ No newline at end of file