swf: Fill styles are byte aligned

A bitmap fill style ends in a matrix, but the overall type should
still be byte aligned. This could cause certain shapes with bitmap
line styles to be incorrectly parsed. Fixes #1192.

swf/src/read.rs

@@ -848,6 +848,7 @@ impl<R: Read> Reader<R> {
         let num_bits = self.read_ubits(5)? as usize;
         m.tx = self.read_sbits_twips(num_bits)?;
         m.ty = self.read_sbits_twips(num_bits)?;
+        self.byte_align();
         Ok(m)
     }
 

swf/src/write.rs

@@ -497,6 +497,7 @@ impl<W: Write> Writer<W> {
         self.write_ubits(5, num_bits.into())?;
         self.write_sbits_twips(num_bits, m.tx)?;
         self.write_sbits_twips(num_bits, m.ty)?;
+        self.flush_bits()?;
         Ok(())
     }