Feature: add text display and partial refresh of LCD

README.md

@@ -12,10 +12,11 @@ This is a 3.5" USB-C display that shows as a serial port once connected.
 It cannot be seen by the operating system as a monitor but picture can be displayed on it.
 
 A Windows-only software is [available here](https://translate.google.com/translate?sl=auto&u=https://gitee.com/emperg/usblcd/raw/master/dev0/realse.ini) to manage this display.
-This software allows creating themes to display your computer sensors on the display, but does not offer a simple way to display custom pictures.
+This software allows creating themes to display your computer sensors on the screen, but does not offer a simple way to display custom pictures or text.
 
 This Python script has been created to do some simple operations on this display like :
 - **Display custom picture**
+- **Display text**
 - Clear the screen (blank)
 - Turn the screen on/off
 - Display soft reset

main.py

@@ -1,78 +1,184 @@
+#!/usr/bin/env python3
+# A simple Python manager for "Turing Smart Screen" 3.5" IPS USB-C display
+# https://github.com/mathoudebine/turing-smart-screen-python
+
+import os
+import signal
 import struct
+from datetime import datetime
 from time import sleep
 
 import serial  # Install pyserial : pip install pyserial
-from PIL import Image  # Install PIL or Pillow
+from PIL import Image, ImageDraw, ImageFont  # Install PIL or Pillow
 
 # Set your COM port e.g. COM3 for Windows, /dev/ttyACM0 for Linux...
-COM_PORT = "/dev/ttyACM1"
+COM_PORT = "/dev/ttyACM0"
 # COM_PORT = "COM5"
 
-def SendReg(ser, reg, x, y, ex, ey):
+DISPLAY_WIDTH = 320
+DISPLAY_HEIGHT = 480
+
+
+class Command:
+    RESET = 101
+    CLEAR = 102
+    SCREEN_OFF = 108
+    SCREEN_ON = 109
+    SET_BRIGHTNESS = 110
+    DISPLAY_BITMAP = 197
+
+
+def SendReg(ser, cmd, x, y, ex, ey):
     byteBuffer = bytearray(6)
     byteBuffer[0] = (x >> 2)
     byteBuffer[1] = (((x & 3) << 6) + (y >> 4))
     byteBuffer[2] = (((y & 15) << 4) + (ex >> 6))
     byteBuffer[3] = (((ex & 63) << 2) + (ey >> 8))
     byteBuffer[4] = (ey & 255)
-    byteBuffer[5] = reg
+    byteBuffer[5] = cmd
     ser.write(bytes(byteBuffer))
 
 
 def Reset(ser):
-    SendReg(ser, 101, 0, 0, 0, 0)
+    SendReg(ser, Command.RESET, 0, 0, 0, 0)
 
 
 def Clear(ser):
-    SendReg(ser, 102, 0, 0, 0, 0)
+    SendReg(ser, Command.CLEAR, 0, 0, 0, 0)
 
 
 def ScreenOff(ser):
-    SendReg(ser, 108, 0, 0, 0, 0)
+    SendReg(ser, Command.SCREEN_OFF, 0, 0, 0, 0)
 
 
 def ScreenOn(ser):
-    SendReg(ser, 109, 0, 0, 0, 0)
+    SendReg(ser, Command.SCREEN_ON, 0, 0, 0, 0)
 
 
 def SetBrightness(ser, level):
-    # Level : 0 (bright) - 255 (darkest)
-    SendReg(ser, 110, level, 0, 0, 0)
+    # Level : 0 (brightest) - 255 (darkest)
+    SendReg(ser, Command.SET_BRIGHTNESS, level, 0, 0, 0)
 
 
-def PrintImage(ser, image):
-    im = Image.open(image)
-    image_height = im.size[1]
-    image_width = im.size[0]
+def DisplayPILImage(ser, image, x, y):
+    image_height = image.size[1]
+    image_width = image.size[0]
 
-    SendReg(ser, 197, 0, 0, image_width - 1, image_height - 1)
+    SendReg(ser, Command.DISPLAY_BITMAP, x, y, x + image_width - 1, y + image_height - 1)
 
-    pix = im.load()
+    pix = image.load()
+    line = bytes()
     for h in range(image_height):
-        line = bytes()
         for w in range(image_width):
-            if w < image_width:
-                R = pix[w, h][0] >> 3
-                G = pix[w, h][1] >> 2
-                B = pix[w, h][2] >> 3
+            R = pix[w, h][0] >> 3
+            G = pix[w, h][1] >> 2
+            B = pix[w, h][2] >> 3
 
-                rgb = (R << 11) | (G << 5) | B
-                line += struct.pack('H', rgb)
+            rgb = (R << 11) | (G << 5) | B
+            line += struct.pack('H', rgb)
+
+            # Send image data by multiple of DISPLAY_WIDTH bytes
+            if len(line) >= DISPLAY_WIDTH*4:
+                ser.write(line)
+                line = bytes()
+
+    # Write last line if needed
+    if len(line) > 0:
         ser.write(line)
 
     sleep(0.01)  # Wait 10 ms after picture display
 
 
+def DisplayBitmap(ser, bitmap_path, x=0, y=0):
+    image = Image.open(bitmap_path)
+    DisplayPILImage(ser, image, x, y)
+
+
+def DisplayText(ser, text, x=0, y=0,
+                font="roboto/Roboto-Regular.ttf",
+                font_size=20,
+                font_color=(0, 0, 0),
+                background_color=(255, 255, 255),
+                background_image=None):
+    # Convert text to bitmap using PIL and display it
+    # Provide the background image path to display text with transparent background
+
+    if background_image is None:
+        # A text bitmap is created with max width/height by default : text with solid background
+        text_image = Image.new('RGB', (DISPLAY_WIDTH, DISPLAY_HEIGHT), background_color)
+    else:
+        # The text bitmap is created from provided background image : text with transparent background
+        text_image = Image.open(background_image)
+
+    # Draw text with specified color & font
+    font = ImageFont.truetype("./res/fonts/" + font, font_size)
+    d = ImageDraw.Draw(text_image)
+    d.text((x, y), text, font=font, fill=font_color)
+
+    # Crop text bitmap to keep only the text
+    text_width, text_height = d.textsize(text, font=font)
+    text_image = text_image.crop(box=(x, y, min(x + text_width, DISPLAY_WIDTH), min(y + text_height, DISPLAY_HEIGHT)))
+
+    DisplayPILImage(ser, text_image, x, y)
+
+
+stop = False
+
 if __name__ == "__main__":
-    ser = serial.Serial(COM_PORT, 115200, timeout=1, rtscts=1)
+
+    def sighandler(signum, frame):
+        global stop
+        stop = True
+
+    # Set the signal handlers, to send a complete frame to the LCD before exit
+    signal.signal(signal.SIGINT, sighandler)
+    signal.signal(signal.SIGTERM, sighandler)
+    is_posix = os.name == 'posix'
+    if is_posix:
+        signal.signal(signal.SIGQUIT, sighandler)
+
+    # Do not change COM port settings unless you know what you are doing
+    lcd_comm = serial.Serial(COM_PORT, 115200, timeout=1, rtscts=1)
 
     # Clear screen (blank)
-    Clear(ser)
+    Clear(lcd_comm)
 
     # Set brightness to max value
-    SetBrightness(ser, 0)
+    SetBrightness(lcd_comm, 0)
 
     # Display sample picture
-    PrintImage(ser, "res/example.png")
-
-    ser.close()
+    DisplayBitmap(lcd_comm, "res/example.png")
+
+    # Display sample text
+    DisplayText(lcd_comm, "Basic text", 50, 100)
+
+    # Display custom text with solid background
+    DisplayText(lcd_comm, "Custom italic text", 5, 150,
+                font="roboto/Roboto-Italic.ttf",
+                font_size=30,
+                font_color=(0, 0, 255),
+                background_color=(255, 255, 0))
+
+    # Display custom text with transparent background
+    DisplayText(lcd_comm, "Transparent bold text", 5, 300,
+                font="roboto/Roboto-Bold.ttf",
+                font_size=30,
+                font_color=(255, 255, 255),
+                background_image="res/example.png")
+
+    # Display text that overflows
+    DisplayText(lcd_comm, "Text overflow!", 5, 430,
+                font="roboto/Roboto-Bold.ttf",
+                font_size=60,
+                font_color=(255, 255, 255),
+                background_image="res/example.png")
+
+    # Display the current time as fast as possible
+    while not stop:
+        DisplayText(lcd_comm, str(datetime.now().time()), 160, 2,
+                    font="roboto/Roboto-Bold.ttf",
+                    font_size=20,
+                    font_color=(255, 0, 0),
+                    background_image="res/example.png")
+
+    lcd_comm.close()