add experimental gif builder api

3 files changed, 133 insertions, 0 deletions

diff --git a/gifed/Cargo.toml b/gifed/Cargo.toml
index 542526f..528f670 100644
--- a/gifed/Cargo.toml
+++ b/gifed/Cargo.toml
@@ -9,6 +9,7 @@ repository = "https://github.com/genuinebyte/gifed"
 
 [dependencies]
 bitvec = "1.0.1"
+colorsquash = { git = "https://github.com/gennyble/colorsquash", version = "0.1.0", optional = true }
 weezl = "0.1.5"
 
 [features]
diff --git a/gifed/src/gif_builder.rs b/gifed/src/gif_builder.rs
new file mode 100644
index 0000000..e701f6e
--- /dev/null
+++ b/gifed/src/gif_builder.rs
@@ -0,0 +1,131 @@
+use std::convert::TryFrom;
+
+#[cfg(feature = "colorsquash")]
+use colorsquash::{Squasher, SquasherBuilder};
+
+use crate::{
+	block::{packed::ScreenPacked, Palette, ScreenDescriptor, Version},
+	writer::ImageBuilder,
+	Color, Gif,
+};
+
+pub struct GifBuilder {
+	width: u16,
+	height: u16,
+	framerate: Option<u16>,
+	frames: Vec<Frame>,
+}
+
+impl GifBuilder {
+	pub fn set_resolution(&mut self, width: u16, height: u16) {
+		self.width = width;
+		self.height = height;
+	}
+	pub fn set_framerate(&mut self, framerate: u16) {
+		self.framerate = Some(framerate)
+	}
+	pub fn add_frame(&mut self, frame: Frame) {
+		self.frames.push(frame)
+	}
+	pub fn build(self) -> Gif {
+		let Self {
+			width,
+			height,
+			framerate,
+			frames,
+		} = self;
+
+		let descriptor = ScreenDescriptor::new(width, height);
+		let mut gif = Gif {
+			version: Version::Gif89a,
+			descriptor,
+			palette: None,
+			blocks: vec![],
+		};
+
+		let images = frames.into_iter().map(|frame| {
+			let Frame {
+				interval,
+				image,
+				palette,
+			} = frame;
+
+			let palette = palette.unwrap();
+			let delay = interval
+				.map(|interval| interval * 10)
+				.or(framerate.map(|fr| 100 / fr))
+				.unwrap_or(10);
+			let image_bytes = image
+				.into_iter()
+				.flat_map(|row| {
+					row.into_iter().map(|c| {
+						palette
+							.from_color(c)
+							.expect("palette should be able to convert any color")
+					})
+				})
+				.collect::<Vec<_>>();
+			let ib = ImageBuilder::new(width, height)
+				.delay(delay)
+				.build(image_bytes)
+				.expect("image building should succeed");
+			ib.image.compress(None).expect("compression should succeed")
+		});
+
+		for compressed_image in images {
+			gif.push(compressed_image);
+		}
+
+		gif
+	}
+}
+
+impl Default for GifBuilder {
+	fn default() -> Self {
+		Self {
+			width: 256,
+			height: 256,
+			framerate: Some(15),
+			frames: vec![],
+		}
+	}
+}
+
+pub struct Frame {
+	image: Vec<Vec<Color>>, //row-major
+	interval: Option<u16>,
+	///in hundredths of a second
+	palette: Option<Palette>,
+}
+
+impl From<Vec<Vec<Color>>> for Frame {
+	fn from(image: Vec<Vec<Color>>) -> Self {
+		Self {
+			image,
+			interval: None,
+			palette: None,
+		}
+	}
+}
+
+impl Frame {
+	#[cfg(feature = "colorsquash")]
+	pub fn optimize_palette(&mut self) {
+		let image_bytes = self
+			.image
+			.iter()
+			.flat_map(|row| row.iter().flat_map(|color| [color.r, color.g, color.b]))
+			.collect::<Vec<_>>();
+		let squasher = SquasherBuilder::default()
+			.max_colors(255u8)
+			.build(image_bytes.as_slice());
+		let pal = Palette::try_from(squasher.palette_bytes().as_slice()).unwrap();
+		self.set_palette(pal)
+	}
+	pub fn set_palette(&mut self, palette: Palette) {
+		self.palette = Some(palette)
+	}
+	pub fn set_interval(&mut self, interval_hundredths: u16) {
+		self.interval = Some(interval_hundredths);
+	}
+}
diff --git a/gifed/src/lib.rs b/gifed/src/lib.rs
index 438ab79..cc1e69f 100644
--- a/gifed/src/lib.rs
+++ b/gifed/src/lib.rs
@@ -3,6 +3,7 @@ mod gif;
 mod lzw;
 
 pub mod block;
+pub mod gif_builder;
 pub mod reader;
 pub mod writer;