3.0.0: Fix code & test

Author: Chi-EEE

__test__/index.spec.ts

@@ -64,7 +64,12 @@ test('Decoding Individual Frames', (t) => {
   for (let gif_test_case of gif_test_cases_2) {
     let gif = Decoder.decodePath(gif_test_case.file)
     for (let i = 0; i < gif.frames.length; i++) {
-      t.is(gif.decodeFrame(i).length, gif_test_case.expected)
+      t.is(gif.decodeFrame(i, {
+        implementDisposalPrevious: true,
+        storeCache: true,
+        disableDisposalMethods: false,
+        rawDecode: false,
+      }).length, gif_test_case.expected)
     }
   }
 })

src/lib.rs

@@ -115,10 +115,10 @@ impl Gif {
       None => None,
     };
 
-    let previous_disposal_method = self
-      .frames
-      .get(maybe_previous_frame_index.unwrap())
-      .map_or(0, |frame| frame.gcd.disposal_method);
+    let previous_disposal_method = match maybe_previous_frame_index {
+      Some(previous_frame_index) => self.frames[previous_frame_index].gcd.disposal_method,
+      None => 0,
+    };
 
     Ok(self.decode_frame_internal(
       frame_index as usize,