#22 Fix bytearray errors

src/picam/picam.py

@@ -17,14 +17,14 @@ class PiCam:
         """
         self.preview_resolution = resolution
 
-    def capture(self) -> bytes:
+    def capture(self) -> bytearray:
         """Capture an image
 
         :returns: Image data as a byte buffer
         """
         raise NotImplementedError
 
-    def capture_preview(self) -> bytes:
+    def capture_preview(self) -> bytearray:
         """Capture a preview image for the viewfinder
 
         :returns: Image data as a byte buffer

src/picam/picam1.py

@@ -36,13 +36,17 @@ class PiCam1(PiCam):
 
     def capture(self, preview: bool = False) -> bytearray:
         # Bytes to hold output buffer
-        out = bytearray()
-        bytes_stream = BytesIO()
+        if preview:
+            # Multiply by 3 for individual R, G, B values
+            out = bytearray((self.preview_resolution[0] * self.preview_resolution[1]) * 3)
+        else:
+            out = bytearray((self.capture_resolution[0] * self.capture_resolution[1]) * 3)
 
         if not preview:
             # If preview we'll already have the right resolution
             self.set_camera_resolution(self.capture_resolution)
 
+        bytes_stream = BytesIO()
         self.camera.capture(bytes_stream, format='rgb', use_video_port=preview)
 
         bytes_stream.seek(0)
@@ -55,5 +59,5 @@ class PiCam1(PiCam):
 
         return out
 
-    def capture_preview(self) -> bytes:
+    def capture_preview(self) -> bytearray:
         return self.capture(preview=True)