DM: add bitmap example

examples/epd_bitmap.py

@@ -0,0 +1,94 @@
+import digitalio
+import busio
+import board
+from adafruit_epd.epd import Adafruit_EPD
+from adafruit_epd.il0373 import Adafruit_IL0373
+
+# create the spi device and pins we will need
+spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
+ecs = digitalio.DigitalInOut(board.D10)
+dc = digitalio.DigitalInOut(board.D9)
+srcs = digitalio.DigitalInOut(board.D8)
+rst = digitalio.DigitalInOut(board.D7)
+busy = digitalio.DigitalInOut(board.D6)
+
+# give them all to our driver
+display = Adafruit_IL0373(152, 152, rst, dc, busy, srcs, ecs, spi)
+
+FILENAME = "blinka.bmp"
+
+# clear the buffer
+display.clear_buffer()
+
+def read_le(s):
+    # as of this writting, int.from_bytes does not have LE support, DIY!
+    result = 0
+    shift = 0
+    for byte in bytearray(s):
+        result += byte << shift
+        shift += 8
+    return result
+
+class BMPError(Exception):
+    pass
+
+
+try:
+    with open("/" + FILENAME, "rb") as f:
+        print("File opened")
+        if f.read(2) != b'BM':  # check signature
+            raise BMPError("Not BitMap file")
+
+        bmpFileSize = read_le(f.read(4))
+        f.read(4)  # Read & ignore creator bytes
+
+        bmpImageoffset = read_le(f.read(4))  # Start of image data
+        headerSize = read_le(f.read(4))
+        bmpWidth = read_le(f.read(4))
+        bmpHeight = read_le(f.read(4))
+        flip = True
+
+        print("Size: %d\nImage offset: %d\nHeader size: %d" %
+              (bmpFileSize, bmpImageoffset, headerSize))
+        print("Width: %d\nHeight: %d" % (bmpWidth, bmpHeight))
+
+        if read_le(f.read(2)) != 1:
+            raise BMPError("Not singleplane")
+        bmpDepth = read_le(f.read(2))  # bits per pixel
+        print("Bit depth: %d" % (bmpDepth))
+        if bmpDepth != 24:
+            raise BMPError("Not 24-bit")
+        if read_le(f.read(2)) != 0:
+            raise BMPError("Compressed file")
+
+        print("Image OK! Drawing...")
+
+        rowSize = (bmpWidth * 3 + 3) & ~3  # 32-bit line boundary
+
+        for row in range(bmpHeight):  # For each scanline...
+            if flip:  # Bitmap is stored bottom-to-top order (normal BMP)
+                pos = bmpImageoffset + (bmpHeight - 1 - row) * rowSize
+            else:  # Bitmap is stored top-to-bottom
+                pos = bmpImageoffset + row * rowSize
+
+            # print ("seek to %d" % pos)
+            f.seek(pos)
+            for col in range(bmpWidth):
+                b, g, r = bytearray(f.read(3))  # BMP files store RGB in BGR
+                if r < 0x80 and g < 0x80 and b < 0x80:
+                    display.draw_pixel(row, col, Adafruit_EPD.BLACK)
+                elif r >= 0x80 and g >= 0x80 and b >= 0x80:
+                    display.draw_pixel(row, col, Adafruit_EPD.WHITE)
+                elif r >= 0x80:
+                    display.draw_pixel(row, col, Adafruit_EPD.RED)
+
+except OSError as e:
+    if e.args[0] == 28:
+        raise OSError("OS Error 28 0.25")
+    else:
+        raise OSError("OS Error 0.5")
+except BMPError as e:
+    print("Failed to parse BMP: " + e.args[0])
+
+
+display.display()