Adjuster can now take min-delta and max-delta args.

README.md

@@ -67,7 +67,7 @@ target and a C device driver (unless you can acquire a suitable binary).
 
 # Project status
 
-Oct 2024: Oct 2024: Refresh locking can now be handled by device driver.  
+Oct 2024: Refresh locking can now be handled by device driver.  
 Sept 2024: Refresh control is now via a `Lock`. See [Realtime applications](./README.md#9-realtime-applications).
 This is a breaking change for applications which use refresh control.  
 Sept 2024: Dropdown and Listbox widgets support dynamically variable lists of elements.  
@@ -2652,6 +2652,8 @@ Optional keyword only arguments:
  * `callback=dolittle` Callback function runs when the user moves the knob or
  the value is changed programmatically.
  * `args=[]` A list/tuple of arguments for above callback.
+ * `min_delta=0.01` Amount value changes for one click in fine mode.
+ * `max_delta=0.1` Amount value changes for one click in normal mode.
 
 Methods:
  * `greyed_out` Optional Boolean argument `val=None`. If `None` returns the
@@ -2672,12 +2674,12 @@ linked label.
 ### A numeric entry device
 
 The file [widgets/adjuster.py](./gui/widgets/adjuster.py) includes an example
-class which combines an `Adjuster` with one or two `Label` instances. The
-`Adjuster` changes the displayed value in the `Label` to its left. Its use is
-illustrated in [demos/adjuster.py](./gui/demos/adjuster.py). The class can be
+class `FloatAdj` which combines an `Adjuster` with one or two `Label` instances.
+The `Adjuster` changes the displayed value in the `Label` to its left. Its use
+is illustrated in [demos/adjuster.py](./gui/demos/adjuster.py). The class can be
 used as a template for a user class, which may have a different layout on
 screen. It supports arbitrary mapping and number formatting on a per-instance
-basis. See code comments for further details.
+basis.
 
 ###### [Contents](./README.md#0-contents)
 

gui/widgets/adjuster.py

@@ -1,7 +1,7 @@
 # adjuster.py Tiny control knob (rotary potentiometer) widget
 
 # Released under the MIT License (MIT). See LICENSE.
-# Copyright (c) 2021 Peter Hinch
+# Copyright (c) 2021-2024 Peter Hinch
 
 from gui.core.ugui import LinearIO, display
 from gui.widgets.label import Label
@@ -11,17 +11,42 @@ TWOPI = 2 * math.pi
 # Null function
 dolittle = lambda *_: None
 
-# *********** CONTROL KNOB CLASS ***********
+# *********** ADJUSTER CLASS ***********
 
 
 class Adjuster(LinearIO):
-    def __init__(self, writer, row, col, *,
-                 value=0.0, fgcolor=None, bgcolor=None, color=None,
-                 prcolor=None, callback=dolittle, args=[]):
+    def __init__(
+        self,
+        writer,
+        row,
+        col,
+        *,
+        value=0.0,
+        fgcolor=None,
+        bgcolor=None,
+        color=None,
+        prcolor=None,
+        callback=dolittle,
+        args=[],
+        min_delta=0.01,
+        max_delta=0.1,
+    ):
         height = writer.height  # Match a user-linked Label
-        super().__init__(writer, row, col, height, height,
-                         fgcolor, bgcolor, False, value,
-                         True, prcolor)
+        super().__init__(
+            writer,
+            row,
+            col,
+            height,
+            height,
+            fgcolor,
+            bgcolor,
+            False,
+            value,
+            True,
+            prcolor,
+            min_delta,
+            max_delta,
+        )
         super()._set_callbacks(callback, args)
         radius = height / 2
         self.arc = 1.5 * math.pi  # Usable angle of control
@@ -51,6 +76,7 @@ class Adjuster(LinearIO):
         y_end = int(self.yorigin - length * math.cos(angle))
         display.line(int(self.xorigin), int(self.yorigin), x_end, y_end, color)
 
+
 # This class combines an Adjuster with one or two labels. Numerous layout
 # options exist: users may wish to write a version of this example with
 # different visual characteristics.
@@ -59,10 +85,23 @@ class Adjuster(LinearIO):
 # The object's value is that of the Adjuster, in range 0.0-1.0. The scaled
 # value is retrieved with .mapped_value()
 class FloatAdj(Adjuster):
-    def __init__(self, wri, row, col, *,
-                 lbl_width=60, value=0.0, color=None,
-                 fstr="{:4.2f}", map_func=lambda v: v, text="",
-                 callback=dolittle, args=[]):
+    def __init__(
+        self,
+        wri,
+        row,
+        col,
+        *,
+        lbl_width=60,
+        value=0.0,
+        color=None,
+        fstr="{:4.2f}",
+        map_func=lambda v: v,
+        text="",
+        callback=dolittle,
+        args=[],
+        min_delta=0.01,
+        max_delta=0.1,
+    ):
 
         self.map_func = map_func
         self.facb = callback
@@ -70,8 +109,16 @@ class FloatAdj(Adjuster):
         self.fstr = fstr
 
         self.lbl = Label(wri, row, col, lbl_width, bdcolor=color)
-        super().__init__(wri, row, self.lbl.mcol + 2, value=value,
-                         fgcolor=color, callback=self.cb)
+        super().__init__(
+            wri,
+            row,
+            self.lbl.mcol + 2,
+            value=value,
+            fgcolor=color,
+            callback=self.cb,
+            min_delta=min_delta,
+            max_delta=max_delta,
+        )
         if text:
             self.legend = Label(wri, row, self.mcol + 2, text)
             self.mcol = self.legend.mcol  # For relative positioning