Label widget: add justify option.

README.md

@@ -995,6 +995,9 @@ Constructor args:
  8. `bdcolor=False` Color of border. If `False` no border will be drawn. If
  `None` the `fgcolor` will be used, otherwise a color may be passed. If a color
  is available, a border line will be drawn around the control.
+ 9. `justify=Label.LEFT` Options are `Label.RIGHT` and `Label.CENTRE` (note
+ British spelling). Justification can only occur if there is sufficient space
+ in the `Label` i.e. where an integer is supplied for the `text` arg.
 
 The constructor displays the string at the required location.
 

gui/demos/aclock.py

@@ -1,7 +1,7 @@
 # aclock.py micro-gui analog clock demo.
 
 # Released under the MIT License (MIT). See LICENSE.
-# Copyright (c) 2021 Peter Hinch
+# Copyright (c) 2021-2022 Peter Hinch
 
 # Initialise hardware and framebuf before importing modules.
 import hardware_setup  # Create a display instance
@@ -65,6 +65,7 @@ class BaseScreen(Screen):
         labels = {'bdcolor' : RED,
                   'fgcolor' : WHITE,
                   'bgcolor' : DARKGREEN,
+                  'justify' : Label.CENTRE,
                   }
 
         wri = CWriter(ssd, font, GREEN, BLACK)  # verbose = True

gui/widgets/label.py

@@ -8,8 +8,12 @@ from gui.core.colors import *
 
 # text: str display string int save width
 class Label(Widget):
-    def __init__(self, writer, row, col, text, invert=False, fgcolor=None, bgcolor=BLACK, bdcolor=False):
+    LEFT = 0
+    CENTRE = 1
+    RIGHT = 2
+    def __init__(self, writer, row, col, text, invert=False, fgcolor=None, bgcolor=BLACK, bdcolor=False, justify=0):
         self.writer = writer
+        self.justify = justify
         # Determine width of object
         if isinstance(text, int):
             width = text
@@ -19,11 +23,14 @@ class Label(Widget):
         height = writer.height
         self.invert = invert
         super().__init__(writer, row, col, height, width, fgcolor, bgcolor, bdcolor)
+        self.tcol = col
         if text is not None:
             self.value(text, invert)
 
     def value(self, text=None, invert=False, fgcolor=None, bgcolor=None, bdcolor=None):
-        if self.writer.stringlen(text) > self.width:  # Clip
+        sl = self.writer.stringlen(text)
+        self.tcol = self.col  # Default is left justify
+        if sl > self.width:  # Clip
             font = self.writer.font
             pos = 0
             n = 0
@@ -33,6 +40,11 @@ class Label(Widget):
                     break
                 n += 1
             text = text[: n]
+        elif self.justify == 1:
+            self.tcol = self.col + (self.width - sl) // 2
+        elif self.justify == 2:
+            self.tcol = self.col + self.width - sl
+            
         txt = super().value(text)  # Sets .draw ensuring refresh
         # Redraw even if no text supplied: colors may have changed.
         self.invert = invert
@@ -46,4 +58,4 @@ class Label(Widget):
     def show(self):
         if super().show():  # Draw or erase border
             if isinstance(txt := super().value(), str):
-                display.print_left(self.writer, self.col, self.row, txt, self.fgcolor, self.bgcolor, self.invert)
+                display.print_left(self.writer, self.tcol, self.row, txt, self.fgcolor, self.bgcolor, self.invert)