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imageconverter/img2array.py

@@ -3,6 +3,9 @@ import math
 import argparse
 import os.path
 
+#for a 2-bit dithered grayscale image use: 
+# convert testimage.png -dither FloydSteinberg -define dither:diffusion-amount=85% -remap 4gray.png -compress RLE -define png:color-type=6 output.png
+
 
 def swapBits(number, nbits):
     if nbits==2:

src/main.cpp

@@ -1,6 +1,22 @@
 // Library, connections and info from: https://www.waveshare.com/wiki/E-Paper_ESP32_Driver_Board#Resource
 // Display: https://www.waveshare.com/product/4.2inch-e-paper.htm
 
+
+//Convert to 1 bit grayscale:
+//maybe dither before
+// convert image to array:
+// python3 img2array.py -i image.png
+
+//Convert to 2 bit grayscale dithered:
+// first convert image to dithered 2 bit image: 
+// convert testimage.png -dither FloydSteinberg -define dither:diffusion-amount=85% -remap 4gray.png -compress RLE -define png:color-type=6 output.png
+
+// then image to array: 
+// python3 img2array.py --bitdepth 2 --lsbfirst --colorlsbfirst testimage.png
+
+// then copy generated ...png.txt content to ImageData.cpp
+
+
 /* Includes ------------------------------------------------------------------*/
 #include "DEV_Config.h"
 #include "EPD.h"
@@ -38,7 +54,7 @@ void setup()
     printf("show image for array\r\n");
     Paint_SelectImage(BWImage);
     Paint_Clear(WHITE);
-    Paint_DrawBitMap(gImage_4in2);  //to convert image use: python3 img2array.py -i image.png
+    Paint_DrawBitMap(gImage_4in2);
     EPD_4IN2_Display(BWImage);
     
     free(BWImage);