More trait impls for screen writers

src/writers/graphics_320x200x256.rs

@@ -33,8 +33,8 @@ const SIZE: usize = WIDTH * HEIGHT;
 ///     mode.draw_character(118 + offset * 8, 27, character, 255);
 /// }
 /// ```
-#[derive(Default)]
-pub struct Graphics320x200x256 {}
+#[derive(Debug, Clone, Copy, Default)]
+pub struct Graphics320x200x256;
 
 impl Screen for Graphics320x200x256 {
     #[inline]

src/writers/graphics_640x480x16.rs

@@ -36,7 +36,7 @@ const WIDTH_IN_BYTES: usize = WIDTH / 8;
 ///     mode.draw_character(270 + offset * 8, 72, character, Color16::White)
 /// }
 /// ```
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Default)]
 pub struct Graphics640x480x16;
 
 impl Screen for Graphics640x480x16 {

src/writers/text_40x25.rs

@@ -26,7 +26,7 @@ const HEIGHT: usize = 25;
 /// text_mode.clear_screen();
 /// text_mode.write_character(0, 0, screen_character);
 /// ```
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Default)]
 pub struct Text40x25;
 
 impl Screen for Text40x25 {

src/writers/text_40x50.rs

@@ -26,7 +26,7 @@ const HEIGHT: usize = 50;
 /// text_mode.clear_screen();
 /// text_mode.write_character(0, 0, screen_character);
 /// ```
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Default)]
 pub struct Text40x50;
 
 impl Screen for Text40x50 {

src/writers/text_80x25.rs

@@ -26,7 +26,7 @@ const HEIGHT: usize = 25;
 /// text_mode.clear_screen();
 /// text_mode.write_character(0, 0, screen_character);
 /// ```
-#[derive(Default)]
+#[derive(Debug, Clone, Copy, Default)]
 pub struct Text80x25;
 
 impl Screen for Text80x25 {