Cosmic Unicorn: Add P4 and P8 support.

libraries/cosmic_unicorn/cosmic_unicorn.cpp

@@ -565,6 +565,25 @@ namespace pimoroni {
           }
         }
       }
+      else if(graphics->pen_type == PicoGraphics::PEN_P8 || graphics->pen_type == PicoGraphics::PEN_P4) {
+        int offset = 0;
+        graphics->frame_convert(PicoGraphics::PEN_RGB565, [this, offset](void *data, size_t length) mutable {
+          uint16_t *p = (uint16_t *)data;
+          for(auto i = 0u; i < length / 2; i++) {
+            int x = offset % 32;
+            int y = offset / 32;
+
+            uint16_t col = __builtin_bswap16(*p);
+            uint8_t r = (col & 0b1111100000000000) >> 8;
+            uint8_t g = (col & 0b0000011111100000) >> 3;
+            uint8_t b = (col & 0b0000000000011111) << 3;
+
+            set_pixel(x, y, r, g, b);
+            offset++;
+            p++;
+          }
+        });
+      }
     }
   }