Move serialization functions to dedicated module

Author: hchargois

library/lcd/lcd_comm_rev_a.py

@@ -21,9 +21,9 @@
 from typing import Optional
 
 from serial.tools.list_ports import comports
-import numpy as np
 
 from library.lcd.lcd_comm import *
+from library.lcd.serialize import image_to_RGB565, chunked
 from library.log import logger
 
 
@@ -173,32 +173,6 @@ def SetOrientation(self, orientation: Orientation = Orientation.PORTRAIT):
         byteBuffer[10] = (height & 255)
         self.serial_write(bytes(byteBuffer))
 
-    @staticmethod
-    def imageToRGB565LE(image: Image.Image):
-        if image.mode not in ["RGB", "RGBA"]:
-            # we need the first 3 channels to be R, G and B
-            image = image.convert("RGB")
-
-        rgb = np.asarray(image)
-
-        # flatten the first 2 dimensions (width and height) into a single stream
-        # of RGB pixels
-        rgb = rgb.reshape((image.size[1] * image.size[0], -1))
-
-        # extract R, G, B channels and promote them to 16 bits
-        r = rgb[:, 0].astype(np.uint16)
-        g = rgb[:, 1].astype(np.uint16)
-        b = rgb[:, 2].astype(np.uint16)
-
-        # construct RGB565
-        r = (r >> 3)
-        g = (g >> 2)
-        b = (b >> 3)
-        rgb565 = (r << 11) | (g << 5) | b
-
-        # serialize to little-endian
-        return rgb565.astype('<u2').tobytes()
-
     def DisplayPILImage(
             self,
             image: Image.Image,
@@ -232,20 +206,12 @@ def DisplayPILImage(
         (x0, y0) = (x, y)
         (x1, y1) = (x + image_width - 1, y + image_height - 1)
 
-        rgb565le = self.imageToRGB565LE(image)
+        rgb565le = image_to_RGB565(image, "little")
 
         self.SendCommand(Command.DISPLAY_BITMAP, x0, y0, x1, y1)
 
         # Lock queue mutex then queue all the requests for the image data
         with self.update_queue_mutex:
-
             # Send image data by multiple of "display width" bytes
-            start = 0
-            end = width * 8
-            while end <= len(rgb565le):
-                self.SendLine(rgb565le[start:end])
-                start, end = end, end + width * 8
-
-            # Write last line if needed
-            if start != len(rgb565le):
-                self.SendLine(rgb565le[start:])
+            for chunk in chunked(rgb565le, width * 8):
+                self.SendLine(chunk)

library/lcd/lcd_comm_rev_b.py

@@ -17,12 +17,10 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-import struct
-
 from serial.tools.list_ports import comports
-import numpy as np
 
 from library.lcd.lcd_comm import *
+from library.lcd.serialize import image_to_RGB565, chunked
 from library.log import logger
 
 
@@ -195,38 +193,12 @@ def SetOrientation(self, orientation: Orientation = Orientation.PORTRAIT):
         else:
             self.SendCommand(Command.SET_ORIENTATION, payload=[OrientationValueRevB.ORIENTATION_LANDSCAPE])
 
-    @staticmethod
-    def imageToRGB565BE(image: Image.Image):
-        if image.mode not in ["RGB", "RGBA"]:
-            # we need the first 3 channels to be R, G and B
-            image = image.convert("RGB")
-
-        rgb = np.asarray(image)
-
-        # flatten the first 2 dimensions (width and height) into a single stream
-        # of RGB pixels
-        rgb = rgb.reshape((image.size[1] * image.size[0], -1))
-
-        # extract R, G, B channels and promote them to 16 bits
-        r = rgb[:, 0].astype(np.uint16)
-        g = rgb[:, 1].astype(np.uint16)
-        b = rgb[:, 2].astype(np.uint16)
-
-        # construct RGB565
-        r = (r >> 3)
-        g = (g >> 2)
-        b = (b >> 3)
-        rgb565 = (r << 11) | (g << 5) | b
-
-        # serialize to big-endian
-        return rgb565.astype('>u2').tobytes()
-
     def serialize_image(self, image: Image.Image, height: int, width: int) -> bytes:
         if image.width != width or image.height != height:
             image = image.crop((0, 0, width, height))
         if self.orientation == Orientation.REVERSE_PORTRAIT or self.orientation == Orientation.REVERSE_LANDSCAPE:
             image = image.rotate(180)
-        return self.imageToRGB565BE(image)
+        return image_to_RGB565(image, "big")
 
     def DisplayPILImage(
             self,
@@ -271,12 +243,5 @@ def DisplayPILImage(
         # Lock queue mutex then queue all the requests for the image data
         with self.update_queue_mutex:
             # Send image data by multiple of "display width" bytes
-            start = 0
-            end = self.get_width() * 8
-            while end <= len(rgb565be):
-                self.SendLine(rgb565be[start:end])
-                start, end = end, end + self.get_width() * 8
-
-            # Write last line if needed
-            if start != len(rgb565be):
-                self.SendLine(rgb565be[start:])
+            for chunk in chunked(rgb565be, self.get_width() * 8):
+                self.SendLine(chunk)

library/lcd/serialize.py

@@ -0,0 +1,39 @@
+from typing import Iterator, Literal
+
+import numpy as np
+from PIL import Image
+
+
+def chunked(data: bytes, chunk_size: int) -> Iterator[bytes]:
+    for i in range(0, len(data), chunk_size):
+        yield data[i : i + chunk_size]
+
+
+def image_to_RGB565(image: Image.Image, endianness: Literal["big", "little"]) -> bytes:
+    if image.mode not in ["RGB", "RGBA"]:
+        # we need the first 3 channels to be R, G and B
+        image = image.convert("RGB")
+
+    rgb = np.asarray(image)
+
+    # flatten the first 2 dimensions (width and height) into a single stream
+    # of RGB pixels
+    rgb = rgb.reshape((image.size[1] * image.size[0], -1))
+
+    # extract R, G, B channels and promote them to 16 bits
+    r = rgb[:, 0].astype(np.uint16)
+    g = rgb[:, 1].astype(np.uint16)
+    b = rgb[:, 2].astype(np.uint16)
+
+    # construct RGB565
+    r = r >> 3
+    g = g >> 2
+    b = b >> 3
+    rgb565 = (r << 11) | (g << 5) | b
+
+    # serialize to the correct endianness
+    if endianness == "big":
+        typ = ">u2"
+    else:
+        typ = "<u2"
+    return rgb565.astype(typ).tobytes()