Added image function and font-based numbers example

Author: makermelissa

adafruit_is31fl3731.py

@@ -27,7 +27,7 @@
 CircuitPython driver for the IS31FL3731 charlieplex IC.
 
 
-* Author(s): Tony DiCola
+* Author(s): Tony DiCola, Melissa LeBlanc-Williams
 
 Implementation Notes
 --------------------
@@ -336,6 +336,28 @@ def pixel(self, x, y, color=None, blink=None, frame=None):
         return None
     #pylint: enable-msg=too-many-arguments
 
+    def image(self, img, blink=None, frame=None):
+        """Set buffer to value of Python Imaging Library image.  The image should
+        be in 8-bit mode (L) and a size equal to the display size.
+
+        :param img: Python Imaging Library image
+        :param blink: True to blink
+        :param frame: the frame to set the image
+        """
+        if img.mode != 'L':
+            raise ValueError('Image must be in mode L.')
+        imwidth, imheight = img.size
+        if imwidth != self.width or imheight != self.height:
+            raise ValueError('Image must be same dimensions as display ({0}x{1}).' \
+                .format(self.width, self.height))
+        # Grab all the pixels from the image, faster than getpixel.
+        pixels = img.load()
+
+        # Iterate through the pixels
+        for x in range(self.width):       # yes this double loop is slow,
+            for y in range(self.height):  #  but these displays are small!
+                self.pixel(x, y, pixels[(x, y)], blink=blink, frame=frame)
+
 
 class CharlieWing(Matrix):
     """Supports the Charlieplexed feather wing

examples/is31fl3731_pillow_numbers.py

@@ -0,0 +1,34 @@
+"""
+Example to utilize the Python Imaging Library (Pillow) and draw bitmapped text
+to 8 frames and then run autoplay on those frames.
+
+Author(s): Melissa LeBlanc-Williams for Adafruit Industries
+"""
+
+import board
+from PIL import Image, ImageDraw, ImageFont
+import adafruit_is31fl3731
+
+i2c = board.I2C()
+
+# uncomment line if you are using Adafruit 16x9 Charlieplexed PWM LED Matrix
+#display = adafruit_is31fl3731.Matrix(i2c)
+# uncomment line if you are using Adafruit 16x9 Charlieplexed PWM LED Matrix
+display = adafruit_is31fl3731.CharlieBonnet(i2c)
+
+display.fill(0)
+
+# 256 Color Grayscale Mode
+image = Image.new('L', (display.width, display.height))
+draw = ImageDraw.Draw(image)
+
+# Load a font in 2 different sizes.
+font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', 10)
+
+# Load the text in each frame
+for x in range(8):
+    draw.rectangle((0, 0, display.width, display.height), outline=0, fill=0)
+    draw.text((x + 1, -2), str(x + 1), font=font, fill=32)
+    display.image(image, frame=x)
+
+display.autoplay(delay=500)