Prepare for user saving of anime sequences

rog-anime/src/error.rs

@@ -1,5 +1,6 @@
 use std::error::Error;
 use std::fmt;
+use gif::DecodingError;
 use png_pong::decode::Error as PngError;
 
 #[derive(Debug)]
@@ -7,6 +8,7 @@ pub enum AnimeError {
     NoFrames,
     Io(std::io::Error),
     Png(PngError),
+    Gif(DecodingError),
     Format
 }
 
@@ -17,6 +19,7 @@ impl fmt::Display for AnimeError {
             AnimeError::NoFrames => write!(f, "No frames in PNG"),
             AnimeError::Io(e) => write!(f, "Could not open: {}", e),
             AnimeError::Png(e) => write!(f, "PNG error: {}", e),
+            AnimeError::Gif(e) => write!(f, "GIF error: {}", e),
             AnimeError::Format => write!(f, "PNG file is not 8bit greyscale"),
         }
     }
@@ -34,4 +37,10 @@ impl From<PngError> for AnimeError {
     fn from(err: PngError) -> Self {
         AnimeError::Png(err)
     }
+}
+
+impl From<DecodingError> for AnimeError {
+    fn from(err: DecodingError) -> Self {
+        AnimeError::Gif(err)
+    }
 }