From fa403b904c8596d8d1731d7f8bfafa6c0145e3dd Mon Sep 17 00:00:00 2001 From: Genny Date: Wed, 10 Mar 2021 02:44:45 -0600 Subject: Implement, roughly, extensions, animation, and looping --- src/block/extension/mod.rs | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 src/block/extension/mod.rs (limited to 'src/block/extension/mod.rs') diff --git a/src/block/extension/mod.rs b/src/block/extension/mod.rs new file mode 100644 index 0000000..4d65c09 --- /dev/null +++ b/src/block/extension/mod.rs @@ -0,0 +1,36 @@ +mod graphiccontrol; + +pub use graphiccontrol::{DisposalMethod, GraphicControl}; + +pub enum Extension { + GraphicControl(GraphicControl), + Looping(u16) +} + +impl From<&Extension> for Box<[u8]> { + fn from(ext: &Extension) -> Self { + let mut vec = vec![]; + vec.push(0x21); // Push the extension introducer + + match ext { + Extension::GraphicControl(gc) => { + vec.push(0xF9); // Graphic control label + vec.push(0x04); // Block size for this extension is always 4 + vec.push(gc.packed); + vec.extend_from_slice(&gc.delay_time.to_le_bytes()); + vec.push(gc.transparency_index); + }, + Extension::Looping(count) => { + vec.push(0xFF); // Application extension label + vec.push(0x0B); // 11 bytes in this block + vec.extend_from_slice(b"NETSCAPE2.0"); // App. ident. and "auth code" + vec.push(0x03); // Sub-block length + vec.push(0x01); // Identifies netscape looping extension + vec.extend_from_slice(&count.to_le_bytes()); + } + } + + vec.push(0x00); // Zero-length data block indicates end of extension + vec.into_boxed_slice() + } +} \ No newline at end of file -- cgit 1.4.1-3-g733a5