Create EoL_HandlingAnd4LineSupport.py

Author: rainierez

Adafruit_CharLCDPlate/EoL_HandlingAnd4LineSupport.py

@@ -0,0 +1,106 @@
+#----------------------------------------------------------------
+# Author: Chris Crumpacker                               
+# Date: May 2013
+#
+# Heavily modified version of the "message" function from Adafruit's 
+# CharLCD code as written for the RaspberryPi LCD Plate. This handles 
+# the end of row/line So that it is actually is cut off and does not 
+# overflow into the buffer on the 16x2 displays and worse onto 
+# line 3 on the 20x4 displays
+# 
+# All orginal functionality is retained with the addition of handling the
+# \n's Cariage returns for all 4 lines on the 20x4
+#
+# When calling the message function you can add a "mode" variable to the end
+# to describe how to handle strings over the length of the display.
+#
+# MODE:
+# 0 or empty = Normal handling as it was from Adafruit
+# 1 = Truncates the string right at the display's limit
+# 2 = Truncates the string 3 short of the limit and adds an elipse
+#
+# Future plans will be to both handle proper cariage returns and to 
+# cut at the spaces as to not leave partial words.
+#
+# Orginal was written by Adafruit Industries.  
+# Under MIT license.
+#
+# "This is essentially a complete rewrite, but the calling syntax
+# and constants are based on code from lrvick and LiquidCrystal.
+# lrvic - https://github.com/lrvick/raspi-hd44780/blob/master/hd44780.py
+# LiquidCrystal - https://github.com/arduino/Arduino/blob/master/libraries/LiquidCrystal/LiquidCrystal.cpp"
+#----------------------------------------------------------------
+
+from Adafruit_CharLCDPlate import Adafruit_CharLCDPlate
+
+lcd = Adafruit_CharLCDPlate()
+
+class CrumpLCD_EoL_Handling(Adafruit_CharLCDPlate):
+    
+    def __init__(self, cols=20, rows=4):    # Defaulted to 20x4 displays
+        self.numrows = rows
+        self.numcols = cols                 # Added a var for the column count to act as the line length limit (say that 10x fast)
+    
+    
+    def message(self, text, limitMode = 0):
+        """ Send string to LCD. Newline wraps to next line"""
+        lines = str(text).split('\n')       # Split at newline(s)
+        for i, line in enumerate(lines):    # For each substring...
+            if i == 1:                      # If newline(s),
+                lcd.write(0xC0)             # set DDRAM address to 2nd line
+            elif i == 2:
+                lcd.write(0x94)
+            elif i >= 3:
+                lcd.write(0xD4)
+            """Now depending on the limit mode set by the function call this will handle """
+            lineLength = len(line)
+            limit = self.numcols
+            if limitMode == 0: 
+                lcd.write(line, True)     
+            elif lineLength >= limit and limitMode == 1:
+                '''With the limit mode set to 1 the line is truncated 
+                at the number of columns available on the display'''
+                limitedLine = line[0:self.numcols]
+                lcd.write(limitedLine, True)  
+            elif lineLength >= limit and limitMode == 2:
+                '''With the limit mode set to 2 the line is truncated 
+                at the number of columns minus 3 to add in an elipse'''
+                limitedLine = line[0:self.numcols-3]+'...'
+                lcd.write(limitedLine, True)
+            elif lineLength >= limit and limitMode == 3:
+                '''Future todo, add in proper line after line cariage return'''
+                print lines
+            else:
+                lcd.write(line, True)
+                
+#!/usr/bin/python
+
+if __name__ == '__main__':
+    from time import sleep
+
+    numcolumns = 20
+    numrows = 4
+    
+    eol = CrumpLCD_EoL_Handling(numcolumns, numrows)
+    
+    lcd.backlight(lcd.ON)
+    lcd.begin(numcolumns, numrows)
+    
+    eol.message("CrumpLCD\nEnd of Line Handling\nWith Forced\nCarriage Returns")
+    sleep(2)
+    
+    lcd.clear()
+    eol.message("Short String")
+    sleep(2)
+    
+    lcd.clear()
+    eol.message("Longer string then can't fit in one line",0)
+    sleep(2)
+    
+    lcd.clear()
+    eol.message("Longer string then can't fit in one line",1)
+    sleep(2)
+    
+    lcd.clear()
+    eol.message("Longer string then can't fit in one line",2)
+    sleep(2)