Advanced dithering example

examples/7color/advanced/dither.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+print("""dither.py
+
+Advanced dithering example using Hitherdither by Henrik Blidh:
+https://github.com/hbldh/hitherdither
+
+You should read the code, read the README ^ and edit accordingly.
+
+Many of these dithering processes are slow, you might want to pre-prepare an image!
+
+You will need to install hitherdither from GitHub:
+
+sudo python3 -m pip install git+https://www.github.com/hbldh/hitherdither
+
+
+usage: ./dither.py <image_file> <saturation>
+
+- Image file should be RGB and can be a jpg, PNG or otherwise.
+
+- Saturation should be from 0.0 to 1.0 and changes the palette that's used to dither the image.
+  a higher saturation will generally result in a more saturated end image due to how colours are mixed.
+
+""")
+
+import sys
+
+from PIL import Image
+from inky.inky_uc8159 import Inky
+import hitherdither
+
+inky = Inky()
+saturation = 0.5           # Saturation of palette
+thresholds = [64, 64, 64]  # Threshold for snapping colours, I guess?
+
+if len(sys.argv) == 1:
+    print("""
+Usage: {file} image-file
+""".format(file=sys.argv[0]))
+    sys.exit(1)
+
+if len(sys.argv) > 2:
+    saturation = float(sys.argv[2])
+
+palette = hitherdither.palette.Palette(inky._palette_blend(saturation, dtype='uint24'))
+
+image = Image.open(sys.argv[1]).convert("RGB")
+# VERY slow (1m 40s on a Pi 4) - see https://github.com/hbldh/hitherdither for a list of methods
+#image_dithered = hitherdither.diffusion.error_diffusion_dithering(image, palette, method="stucki", order=2)
+
+# Usably quick, your vanilla dithering
+#image_dithered = hitherdither.ordered.bayer.bayer_dithering(image, palette, thresholds, order=8)
+
+# Usuably quick, half-tone comic-book feel, use order=4 for small dots and order=8 dot bigguns
+image_dithered = hitherdither.ordered.cluster.cluster_dot_dithering(image, palette, thresholds, order=8)
+
+# VERY slow
+#image_dithered = hitherdither.ordered.yliluoma.yliluomas_1_ordered_dithering(image, palette, order=8)
+
+inky.set_image(image_dithered.convert("P"))
+inky.show()

library/inky/inky_uc8159.py

@@ -162,14 +162,20 @@ def __init__(self, resolution=(600, 448), colour='multi', cs_pin=CS0_PIN, dc_pin
 
         self._luts = None
 
-    def _palette_blend(self, saturation):
+    def _palette_blend(self, saturation, dtype='uint8'):
         saturation = float(saturation)
         palette = []
         for i in range(7):
             rs, gs, bs = [c * saturation for c in SATURATED_PALETTE[i]]
             rd, gd, bd = [c * (1.0 - saturation) for c in DESATURATED_PALETTE[i]]
-            palette += [int(rs + rd), int(gs + gd), int(bs + bd)]
-        palette += [255, 255, 255]
+            if dtype == 'uint8':
+                palette += [int(rs + rd), int(gs + gd), int(bs + bd)]
+            if dtype == 'uint24':
+                palette += [(int(rs + rd) << 16) | (int(gs + gd) << 8) | int(bs + bd)]
+        if dtype == 'uint8':
+            palette += [255, 255, 255]
+        if dtype == 'uint24':
+            palette += [0xffffff]
         return palette
 
     def setup(self):