Move to SDK EInkDisplay and enable anti-aliased 2-bit text (#5)

* First pass at moving to SDK EInkDisplay library

* Add 2-bit grayscale text and anti-aliased rendering of text

* Render status bar for empty chapters

* Refresh screen every 15 pages to avoid ghosting

* Simplify boot and sleep screens

* Give FileSelectionScreen task more stack memory

* Move text around slightly on Boot and Sleep screens

* Re-use existing buffer and write to whole screen for 'partial update'

lib/EpdFont/EpdFontData.h

@@ -31,4 +31,5 @@ typedef struct {
   uint8_t advanceY;                     ///< Newline distance (y axis)
   int ascender;                         ///< Maximal height of a glyph above the base line
   int descender;                        ///< Maximal height of a glyph below the base line
+  bool is2Bit;
 } EpdFontData;

lib/EpdFont/builtinFonts/babyblue.h

@@ -2,6 +2,7 @@
  * generated by fontconvert.py
  * name: babyblue
  * size: 8
+ * mode: 1-bit
  */
 #pragma once
 #include "EpdFontData.h"
@@ -500,5 +501,5 @@ static const EpdUnicodeInterval babyblueIntervals[] = {
 };
 
 static const EpdFontData babyblue = {
-    babyblueBitmaps, babyblueGlyphs, babyblueIntervals, 5, 17, 13, -4,
+    babyblueBitmaps, babyblueGlyphs, babyblueIntervals, 5, 17, 13, -4, false,
 };

lib/EpdFont/builtinFonts/ubuntu_10.h

@@ -2,6 +2,7 @@
  * generated by fontconvert.py
  * name: ubuntu_10
  * size: 10
+ * mode: 1-bit
  */
 #pragma once
 #include "EpdFontData.h"
@@ -762,5 +763,5 @@ static const EpdUnicodeInterval ubuntu_10Intervals[] = {
 };
 
 static const EpdFontData ubuntu_10 = {
-    ubuntu_10Bitmaps, ubuntu_10Glyphs, ubuntu_10Intervals, 31, 24, 20, -4,
+    ubuntu_10Bitmaps, ubuntu_10Glyphs, ubuntu_10Intervals, 31, 24, 20, -4, false,
 };

lib/EpdFont/builtinFonts/ubuntu_bold_10.h

@@ -2,6 +2,7 @@
  * generated by fontconvert.py
  * name: ubuntu_bold_10
  * size: 10
+ * mode: 1-bit
  */
 #pragma once
 #include "EpdFontData.h"
@@ -806,5 +807,5 @@ static const EpdUnicodeInterval ubuntu_bold_10Intervals[] = {
 };
 
 static const EpdFontData ubuntu_bold_10 = {
-    ubuntu_bold_10Bitmaps, ubuntu_bold_10Glyphs, ubuntu_bold_10Intervals, 31, 24, 20, -4,
+    ubuntu_bold_10Bitmaps, ubuntu_bold_10Glyphs, ubuntu_bold_10Intervals, 31, 24, 20, -4, false,
 };

lib/EpdFont/scripts/fontconvert.py

@@ -13,12 +13,14 @@ parser = argparse.ArgumentParser(description="Generate a header file from a font
 parser.add_argument("name", action="store", help="name of the font.")
 parser.add_argument("size", type=int, help="font size to use.")
 parser.add_argument("fontstack", action="store", nargs='+', help="list of font files, ordered by descending priority.")
+parser.add_argument("--2bit", dest="is2Bit", action="store_true", help="generate 2-bit greyscale bitmap instead of 1-bit black and white.")
 parser.add_argument("--additional-intervals", dest="additional_intervals", action="append", help="Additional code point intervals to export as min,max. This argument can be repeated.")
 args = parser.parse_args()
 
 GlyphProps = namedtuple("GlyphProps", ["width", "height", "advance_x", "left", "top", "data_length", "data_offset", "code_point"])
 
 font_stack = [freetype.Face(f) for f in args.fontstack]
+is2Bit = args.is2Bit
 size = args.size
 font_name = args.name
 
@@ -173,26 +175,73 @@ for i_start, i_end in intervals:
                 pixels4g.append(px)
                 px = 0
 
-        # Downsample to 1-bit bitmap - treat any non-zero as black
-        pixelsbw = []
-        px = 0
-        pitch = (bitmap.width // 2) + (bitmap.width % 2)
-        for y in range(bitmap.rows):
-            for x in range(bitmap.width):
-                px = px << 1
-                bm = pixels4g[y * pitch + (x // 2)]
-                px += 1 if ((x & 1) == 0 and bm & 0xF > 0) or ((x & 1) == 1 and bm & 0xF0 > 0) else 0
+        if is2Bit:
+            # 0 = white, 15 black, 8+ dark grey, 7- light grey
+            # Downsample to 2-bit bitmap
+            pixels2b = []
+            px = 0
+            pitch = (bitmap.width // 2) + (bitmap.width % 2)
+            for y in range(bitmap.rows):
+                for x in range(bitmap.width):
+                    px = px << 2
+                    bm = pixels4g[y * pitch + (x // 2)]
+                    bm = (bm >> ((x % 2) * 4)) & 0xF
 
-                if (y * bitmap.width + x) % 8 == 7:
-                    pixelsbw.append(px)
-                    px = 0
-        if (bitmap.width * bitmap.rows) % 8 != 0:
-            px = px << (8 - (bitmap.width * bitmap.rows) % 8)
-            pixelsbw.append(px)
+                    if bm == 15:
+                        px += 3
+                    elif bm >= 8:
+                        px += 2
+                    elif bm > 0:
+                        px += 1
 
+                    if (y * bitmap.width + x) % 4 == 3:
+                        pixels2b.append(px)
+                        px = 0
+            if (bitmap.width * bitmap.rows) % 4 != 0:
+                px = px << (4 - (bitmap.width * bitmap.rows) % 4) * 2
+                pixels2b.append(px)
+
+            # for y in range(bitmap.rows):
+            #     line = ''
+            #     for x in range(bitmap.width):
+            #         pixelPosition = y * bitmap.width + x
+            #         byte = pixels2b[pixelPosition // 4]
+            #         bit_index = (3 - (pixelPosition % 4)) * 2
+            #         line += '#' if ((byte >> bit_index) & 3) > 0 else '.'
+            #     print(line)
+            # print('')
+        else:
+            # Downsample to 1-bit bitmap - treat any non-zero as black
+            pixelsbw = []
+            px = 0
+            pitch = (bitmap.width // 2) + (bitmap.width % 2)
+            for y in range(bitmap.rows):
+                for x in range(bitmap.width):
+                    px = px << 1
+                    bm = pixels4g[y * pitch + (x // 2)]
+                    px += 1 if ((x & 1) == 0 and bm & 0xF > 0) or ((x & 1) == 1 and bm & 0xF0 > 0) else 0
+
+                    if (y * bitmap.width + x) % 8 == 7:
+                        pixelsbw.append(px)
+                        px = 0
+            if (bitmap.width * bitmap.rows) % 8 != 0:
+                px = px << (8 - (bitmap.width * bitmap.rows) % 8)
+                pixelsbw.append(px)
+
+            # for y in range(bitmap.rows):
+            #     line = ''
+            #     for x in range(bitmap.width):
+            #         pixelPosition = y * bitmap.width + x
+            #         byte = pixelsbw[pixelPosition // 8]
+            #         bit_index = 7 - (pixelPosition % 8)
+            #         line += '#' if (byte >> bit_index) & 1 else '.'
+            #     print(line)
+            # print('')
+
+        pixels = pixels2b if is2Bit else pixelsbw
 
         # Build output data
-        packed = bytes(pixelsbw)
+        packed = bytes(pixels)
         glyph = GlyphProps(
             width = bitmap.width,
             height = bitmap.rows,
@@ -216,7 +265,7 @@ for index, glyph in enumerate(all_glyphs):
     glyph_data.extend([b for b in packed])
     glyph_props.append(props)
 
-print(f"/**\n * generated by fontconvert.py\n * name: {font_name}\n * size: {size}\n */")
+print(f"/**\n * generated by fontconvert.py\n * name: {font_name}\n * size: {size}\n * mode: {'2-bit' if is2Bit else '1-bit'}\n */")
 print("#pragma once")
 print("#include \"EpdFontData.h\"\n")
 print(f"static const uint8_t {font_name}Bitmaps[{len(glyph_data)}] = {{")
@@ -244,4 +293,5 @@ print(f"    {len(intervals)},")
 print(f"    {norm_ceil(face.size.height)},")
 print(f"    {norm_ceil(face.size.ascender)},")
 print(f"    {norm_floor(face.size.descender)},")
+print(f"    {'true' if is2Bit else 'false'},")
 print("};")