optional dithering

readme.md

@@ -48,6 +48,7 @@ Data should be sent form-encoded.
 |--------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------|----------|
 | `image`      | Image file to display. Any image type supported by the Python PIL library should work.                                                                                                                                                | N/A     | Yes      |
 | `mode`       | Display mode, corresponding to the `display_XXX` method on the `epd` object.<br>`FAST` - uses `display_Fast` for a complete screen refresh.<br>`PARTIAL` - uses `display_Partial` for incremental updates (which may cause ghosting). | `FAST`  | No       |
+| `dither`     | Whether to enable ditering when converting image to mono chromatic. `true` or `1` to enable.                                                                                                                                          | `true`  | No       |
 | `resize`     | `FIT` Resize keeping aspect ratio, without cropping<br>`CROP` Resize keeping aspect ratio, with cropping<br>`STRETCH` fill display, ignoring aspect ratio<br>`NONE` Display without any scaling, pixels drawn 1:1.                    | `FIT`   | No       |
 | `rotate`     | Number of degrees to rotate counter-clockwise, supports increments of 90 degrees.                                                                                                                                                     | 0       | No       |
 | `background` | Background colour to use if the image doesn't fill the display. Either `WHITE` or `BLACK`.                                                                                                                                            | `WHITE` | No       |

src/img_utils.py

@@ -1,10 +1,10 @@
 from typing import Tuple
 from PIL import Image
 
-from models import Resolution, Rotation, Resize, BackgroundColour, Mode
+from models import Resolution, Rotation, Resize, BackgroundColour
 
 
-def resize_img(img: Image, mode: Mode, rotation: Rotation, resize: Resize, background: BackgroundColour,
+def resize_img(img: Image, dither: bool, rotation: Rotation, resize: Resize, background: BackgroundColour,
                display_res: Resolution) -> Image:
     # Rotate
     out_img = img.rotate(angle=rotation, expand=True)
@@ -21,6 +21,9 @@ def resize_img(img: Image, mode: Mode, rotation: Rotation, resize: Resize, backg
 
     scaled_image = out_img.resize(scaled_resolution)
 
+    dither_setting = Image.Dither.FLOYDSTEINBERG if dither else Image.Dither.NONE
+    scaled_image = scaled_image.convert('1', dither=dither_setting)
+
     # Add scaled image to full size canvas
     bg_colour = 255 if background == BackgroundColour.WHITE else 0
     x = int((display_res.width - scaled_image.width) / 2)

src/server.py

@@ -64,7 +64,9 @@ def show_image() -> tuple[Response, int]:
     except ValueError:
         return jsonify(message=f'"mode" invalid, must be one of {", ".join([x for x in Mode])}'), 422
 
-    image_to_display = resize_img(image, mode, rotate, resize, background, DISPLAY_RESOLUTION)
+    dither = request.form.get('dither', 'true') in ['true', '1']
+
+    image_to_display = resize_img(image, dither, rotate, resize, background, DISPLAY_RESOLUTION)
 
     try:
         update_image = image_changed(Image.open(IMG_PATH), image_to_display)