Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/gif/examples/check.rs

@@ -0,0 +1,41 @@
+use std::{env, fs, process};
+
+fn main() {
+    let file = env::args().nth(1)
+        .unwrap_or_else(|| explain_usage());
+    let file = fs::File::open(&file)
+        .expect("failed to open input file");
+    let mut reader = {
+        let mut options = gif::DecodeOptions::new();
+        options.allow_unknown_blocks(true);
+        options.read_info(file).unwrap()
+    };
+
+    loop {
+        let frame = match reader.read_next_frame() {
+            Ok(Some(frame)) => frame,
+            Ok(None) => break,
+            Err(error) => {
+                println!("Error: {:?}", error);
+                break;
+            }
+        };
+
+        println!(
+            " Frame:\n  \
+                 delay: {:?}\n  \
+                 canvas: {}x{}+{}+{}\n  \
+                 dispose: {:?}\n  \
+                 needs_input: {:?}",
+            frame.delay,
+            frame.width, frame.height, frame.left, frame.top,
+            frame.dispose,
+            frame.needs_user_input
+        );
+    }
+}
+
+fn explain_usage() -> ! {
+    println!("Print information on the frames of a gif.\n\nUsage: check <file>");
+    process::exit(1)
+}

vendor/gif/examples/explode.rs

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+//! Exports each GIF frame as a separate image.
+
+use std::env;
+use std::fs::File;
+use std::path::PathBuf;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let input_path = PathBuf::from(
+        env::args_os()
+            .nth(1)
+            .ok_or("Specify a GIF path as the first argument")?,
+    );
+
+    let input = File::open(&input_path)?;
+    let mut options = gif::DecodeOptions::new();
+    options.set_color_output(gif::ColorOutput::Indexed);
+    let mut decoder = options.read_info(input)?;
+    let screen_width = decoder.width();
+    let screen_height = decoder.height();
+    let global_pal = decoder.global_palette().unwrap_or_default().to_vec();
+
+    let output_file_stem = input_path.file_stem().unwrap().to_str().unwrap();
+    let mut frame_number = 1;
+    while let Some(frame) = decoder.read_next_frame()? {
+        let output_path = format!("{}.{:03}.gif", output_file_stem, frame_number);
+        let mut output = File::create(&output_path)?;
+        let mut encoder = gif::Encoder::new(&mut output, screen_width, screen_height, &global_pal)?;
+        encoder.write_frame(&frame)?;
+        frame_number += 1;
+
+        use gif::DisposalMethod::*;
+        let disposal = match frame.dispose {
+            Any => "any",
+            Keep => "keep",
+            Background => "background",
+            Previous => "previous",
+        };
+        eprintln!(
+            "Written {} ({}x{}@{}x{} delay={} {})",
+            output_path, frame.width, frame.height, frame.top, frame.left, frame.delay, disposal
+        );
+    }
+    Ok(())
+}