g13gui: Add LPBM image conversion and tests

This is the first step to actually rendering to the G13's display by way of the
g13d daemon. The bitmap format is kinda weird: it's actually 860 bytes of
useable pixel data, but padded out to 960. Each byte corresponds with one
vertical column of 8-pixels, going from top to bottom.

The tests for this effectively check to make sure the length is correct, and
also dumps it out to a running g13d (if there is one). This should probably be
automated a bit more by checking the bytes directly, but given that this is a
visual task anyway, I'm being a bit lazy.

g13gui/g13gui/bitwidgets/__init__.py

@@ -1,3 +1,4 @@
-from g13gui.bitwidgets.display import Fonts
-from g13gui.bitwidgets.display import FontManager
+from g13gui.bitwidgets.fonts import Fonts
+from g13gui.bitwidgets.fonts import FontManager
 from g13gui.bitwidgets.display import Display
+from g13gui.bitwidgets.display import DisplayMetrics

g13gui/g13gui/bitwidgets/display.py

@@ -1,12 +1,51 @@
+import struct
+import PIL.ImageDraw
+import PIL.PyAccess
+import sys
+from io import BytesIO
 from PIL import Image
-from PIL.ImageDraw import ImageDraw
 from g13gui.observer import Subject
 from g13gui.observer import ChangeType
 
 
 class DisplayMetrics(object):
     WIDTH_PIXELS = 160
-    HEIGHT_PIXELS = 48
+    HEIGHT_PIXELS = 43
+
+
+LPBM_LENGTH = 960
+
+
+def ImageToLPBM(image):
+    i = PIL.PyAccess.new(image, readonly=True)
+    bio = BytesIO()
+
+    maxBytes = (DisplayMetrics.WIDTH_PIXELS * DisplayMetrics.HEIGHT_PIXELS // 8)
+    row = 0
+    col = 0
+
+    for byteNum in range(0, maxBytes):
+        b = int()
+
+        if row == 40:
+            maxSubrow = 3
+        else:
+            maxSubrow = 8
+
+        for subrow in range(0, maxSubrow):
+            b |= i[col, row + subrow] << subrow
+
+        bio.write(struct.pack('<B', b))
+
+        col += 1
+        if (col % 160) == 0:
+            col = 0
+            row += 8
+
+    # padding? lpbm files are always 960 bytes, the last bytes are filled with garbage.
+    bio.write(bytes(LPBM_LENGTH - maxBytes))
+
+    return bio.getvalue()
 
 
 class Display(Subject):
@@ -17,7 +56,7 @@ class Display(Subject):
                                        DisplayMetrics.HEIGHT_PIXELS))
 
     def getContext(self):
-        return ImageDraw.Draw(self._bitmap)
+        return PIL.ImageDraw.Draw(self._bitmap)
 
     def commit(self):
         # convert to LPBM

g13gui/g13gui/bitwidgets/display_tests.py

@@ -1,20 +1,29 @@
+import unittest
+
+import PIL.Image
+
+from g13gui.bitwidgets.display import LPBM_LENGTH
+from g13gui.bitwidgets.display import ImageToLPBM
 from g13gui.bitwidgets import Fonts
 from g13gui.bitwidgets import FontManager
 from g13gui.bitwidgets import Display
+from g13gui.bitwidgets import DisplayMetrics
 
 
-d = Display()
-ctx = d.getContext()
-ctx.text((0, 0), "Hello world!",
-         font=FontManager.getFont(Fonts.TINY),
-         fill=(1))
-ctx.text((0, 6), "Hello world!",
-         font=FontManager.getFont(Fonts.MEDIUM),
-         fill=(1))
-ctx.text((0, 11), "Hello world!",
-         font=FontManager.getFont(Fonts.LARGE),
-         fill=(1))
-ctx.text((0, 19), "Hello world!",
-         font=FontManager.getFont(Fonts.HUGE),
-         fill=(1))
-d.debug()
+class DisplayTests(unittest.TestCase):
+    def setUp(self):
+        self.d = Display()
+
+    def testConversion(self):
+        ctx = self.d.getContext()
+        ctx.text((0, 0), "Hello world!",
+                 font=FontManager.getFont(Fonts.HUGE), fill=1)
+        result = ImageToLPBM(self.d._bitmap)
+
+        self.assertEqual(len(result), LPBM_LENGTH)
+
+        with open('/run/g13d/in', 'wb') as fp:
+            fp.write(result)
+
+if __name__ == '__main__':
+    unittest.main()

g13gui/g13gui/bitwidgets/fonts.py

@@ -26,9 +26,10 @@ X11_FONT_PATH = pathlib.Path('/usr/share/fonts/X11/misc')
 
 class Fonts(enum.Enum):
     TINY = X11_FONT_PATH / '4x6.pcf.gz'
-    MEDIUM = X11_FONT_PATH / '5x7.pcf.gz'
-    LARGE = X11_FONT_PATH / '8x13.pcf.gz'
-    HUGE = X11_FONT_PATH / '9x18.pcf.gz'
+    SMALL = X11_FONT_PATH / '5x7.pcf.gz'
+    MEDIUM = X11_FONT_PATH / '8x13.pcf.gz'
+    LARGE = X11_FONT_PATH / '9x18.pcf.gz'
+    HUGE = X11_FONT_PATH / '10x20.pcf.gz'
 
 
 class PcfFontConverter(PcfFontFile):

g13gui/g13gui/bitwidgets/fonts_tests.py

@@ -0,0 +1,33 @@
+#!/usr/bin/python
+
+import unittest
+
+from g13gui.bitwidgets import Fonts
+from g13gui.bitwidgets import FontManager
+from g13gui.bitwidgets import Display
+
+
+class FontsTests(unittest.TestCase):
+    def testFontDrawing(self):
+        d = Display()
+        ctx = d.getContext()
+        ctx.text((0, 0), "Hello world!",
+                 font=FontManager.getFont(Fonts.TINY),
+                 fill=(1))
+        ctx.text((0, 6), "Hello world!",
+                 font=FontManager.getFont(Fonts.SMALL),
+                 fill=(1))
+        ctx.text((0, 11), "Hello world!",
+                 font=FontManager.getFont(Fonts.MEDIUM),
+                 fill=(1))
+        ctx.text((0, 19), "Hello world!",
+                 font=FontManager.getFont(Fonts.LARGE),
+                 fill=(1))
+        ctx.text((0, 31), "Hello world!",
+                 font=FontManager.getFont(Fonts.HUGE),
+                 fill=(1))
+        d.debug()
+
+
+if __name__ == '__main__':
+    unittest.main()