From 9b4ed6eb620a4363f09999729a8bfafd97662251 Mon Sep 17 00:00:00 2001
From: Luke D Jones <luke@ljones.dev>
Date: Tue, 6 Apr 2021 22:03:06 +1200
Subject: [PATCH] anime: discard frames if specified

---
 rog-anime/src/anime_gif.rs | 47 ++++++++++++++++++++++++++++----------
 rog-anime/src/lib.rs       |  6 +++--
 2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/rog-anime/src/anime_gif.rs b/rog-anime/src/anime_gif.rs
index 5bc209b8..79c38b22 100644
--- a/rog-anime/src/anime_gif.rs
+++ b/rog-anime/src/anime_gif.rs
@@ -1,8 +1,8 @@
+use glam::Vec2;
 use serde_derive::{Deserialize, Serialize};
 use std::{fs::File, path::Path, time::Duration};
-use glam::Vec2;
 
-use crate::{AniMeDataBuffer, AniMeDiagonal, AniMeImage, error::AnimeError, Pixel};
+use crate::{error::AnimeError, AniMeDataBuffer, AniMeDiagonal, AniMeImage, Pixel};
 
 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct AniMeFrame {
@@ -27,7 +27,6 @@ pub struct AniMeGif(Vec<AniMeFrame>);
 
 impl AniMeGif {
     pub fn create_diagonal_gif(file_name: &Path, brightness: f32) -> Result<Self, AnimeError> {
-        let mut frames = Vec::new();
         let mut matrix = AniMeDiagonal::new();
 
         let mut decoder = gif::DecodeOptions::new();
@@ -37,8 +36,12 @@ impl AniMeGif {
         let file = File::open(file_name)?;
         let mut decoder = decoder.read_info(file)?;
 
+        let mut frames = Vec::with_capacity(decoder.buffer_size());
         while let Some(frame) = decoder.read_next_frame()? {
             let wait = frame.delay * 10;
+            if matches!(frame.dispose, gif::DisposalMethod::Background) {
+                frames = Vec::new();
+            }
             for (y, row) in frame.buffer.chunks(frame.width as usize * 4).enumerate() {
                 for (x, px) in row.chunks(4).enumerate() {
                     if px[3] != 255 {
@@ -68,25 +71,45 @@ impl AniMeGif {
         let file = File::open(file_name)?;
         let mut decoder = decoder.read_info(file)?;
 
+        let height = decoder.height();
         let width = decoder.width();
-        let pixels: Vec<Pixel> = vec![Pixel::default(); (decoder.width() as u32 * decoder.height() as u32) as usize];
-        let mut image = AniMeImage::new(Vec2::new(1.0, 1.0), 0.0, Vec2::new(0.0, 0.0),
-        brightness, pixels, decoder.width() as u32);
+        let pixels: Vec<Pixel> =
+            vec![Pixel::default(); (decoder.width() as u32 * decoder.height() as u32) as usize];
+        let mut image = AniMeImage::new(
+            Vec2::new(1.0, 1.0),
+            0.0,
+            Vec2::new(0.0, 0.0),
+            brightness,
+            pixels,
+            decoder.width() as u32,
+        );
 
         while let Some(frame) = decoder.read_next_frame()? {
             let wait = frame.delay * 10;
+            if matches!(frame.dispose, gif::DisposalMethod::Background) {
+                let pixels: Vec<Pixel> =
+                    vec![Pixel::default(); (width as u32 * height as u32) as usize];
+                image = AniMeImage::new(
+                    Vec2::new(1.0, 1.0),
+                    0.0,
+                    Vec2::new(0.0, 0.0),
+                    brightness,
+                    pixels,
+                    width as u32,
+                );
+            }
             for (y, row) in frame.buffer.chunks(frame.width as usize * 4).enumerate() {
                 for (x, px) in row.chunks(4).enumerate() {
                     if px[3] != 255 {
                         // should be t but not in some gifs? What, ASUS, what?
                         continue;
                     }
-                    let pos = (x + frame.left as usize) + ((y + frame.top as usize) * width as usize);
-                    image.get_mut()[pos] =
-                        Pixel {
-                            color: ((px[0] as u32 + px[1] as u32 + px[2] as u32) / 3),
-                            alpha: 1.0,
-                        };
+                    let pos =
+                        (x + frame.left as usize) + ((y + frame.top as usize) * width as usize);
+                    image.get_mut()[pos] = Pixel {
+                        color: ((px[0] as u32 + px[1] as u32 + px[2] as u32) / 3),
+                        alpha: 1.0,
+                    };
                 }
             }
             image.update();
diff --git a/rog-anime/src/lib.rs b/rog-anime/src/lib.rs
index cd62bad6..b25abe33 100644
--- a/rog-anime/src/lib.rs
+++ b/rog-anime/src/lib.rs
@@ -55,11 +55,13 @@ impl AniMeSequence {
         Ok(Self::Image(Box::new(data)))
     }
 
-    pub fn png_gif(file: &Path,
+    pub fn png_gif(
+        file: &Path,
         // scale: Vec2,
         // angle: f32,
         // translation: Vec2,
-        brightness: f32,) -> Result<Self, AnimeError> {
+        brightness: f32,
+    ) -> Result<Self, AnimeError> {
         let frames = AniMeGif::create_png_gif(file, brightness)?;
         Ok(Self::Animation(frames))
     }